Academic literature on the topic 'Fermented food products'

The bacterial population in several Philippine fermented food preparations was assessed by PCR-denaturing gradient gel electrophoresis (PCR-DGGE) of the 16S rRNA gene (16S rDNA). Genomic DNA was isolated directly from alamang (fermented shrimp paste), burong isda (fermented fish and rice), burong hipon (fermented shrimp and rice), burong mustasa (fermented mustard leaves), tuba (sugar cane wine), suka (vinegar) and sinamak (spiced vinegar) using one of two protocols, namely – MoBio DNA Extraction Kit procedure and a cetyltrimethylammonium bromide-based method. Samples recalcitrant to both methods underwent enrichment in three culture broths prior to DNA isolation. Isolated DNA was amplified using nested primer pairs targeting the bacterial 16S rDNA. PCR products were subjected to DGGE to elucidate the bacterial diversity in each fermented food. 16S rDNA sequence analyses revealed that lactic acid bacteria (LAB) and acetic acid bacteria (AAB) were dominant in the food samples. The LAB identified were Lactobacillus fermentum, Lactobacillus plantarum, Lactobacillus panis, Lactobacillus pontis and Weissella cibaria. Identified AAB were Acetobacter pomorum, Acetobacter ghanensis, Acetobacter orientalis, and Acetobacter pasteurianus. Among these, L. fermentum, L. plantarum and W. cibaria are established probiotic bacteria, while L. panis and L. pontis are potential probiotic bacteria. This finding would increase the appeal and significance of local fermented foods to consumers. Furthermore, the majority of the identified bacteria in the study have not been reported before in culture-dependent studies of similar food preparations. As such, some of the bacterial 16S rDNA obtained were cloned to have an initial partial bacterial 16S rDNA library for Philippine fermented foods.

Fermenting foods can make poorly digested, reactive foods into health giving foods. The process of fermentation destroys many of the harmful microorganisms and chemicals in foods and adds beneficial bacteria. These bacteria produce new enzymes to assist in the digestion. Foods that benefit from fermentation are soy products, dairy products, grains, and some vegetables. The beneficial effect of fermented food which contains probiotic organism consumption includes: improving intestinal tract health, enhancing the immune system, synthesizing and enhancing the bioavailability of nutrients, reducing symptoms of lactose intolerance, decreasing the prevalence of allergy in susceptible individuals, and reducing risk of certain cancers. This article provides an overview of the different starter cultures and health benefits of fermented food products, which can be derived by the consumers through their regular intake.Keywords: Fermentation; Fermented food; Starter cultures; Probiotics; Nutritional benefits.© 2014 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved.doi: http://dx.doi.org/10.3329/jsr.v6i2.16530 J. Sci. Res. 6 (2), 373-386 (2014)

One of the main strategies for preventing chronic diseases is a balanced diet from early childhood, with the inclusion of functional ingredients: dietary fiber, vitamins and vitamin-like compounds, minerals, polyunsaturated fatty acids, prebiotics and probiotics. A combined enrichment of fermented dairy products with prebiotics and probiotics contributes to the summation of their positive effective influence. Adding prebiotics and probiotics to the diet leads to the change in the intestinal microbiota composition towards a more balanced structure, thereby increasing the intestinal barrier function and the formation of optimal immune interactions. The most commonly used in human nutrition is a combination of bifidobacteria or lactobacilli with fructo-oligosaccharides in synbiotic products. It is important that the microorganisms are safe, stable in storage and able to survive in the gastrointestinal tract. The use of probiotic fermented dairy products has a positive impact on child health: it has anti-infectious and immunomodulatory effects, helps to normalize the gastrointestinal motility. These statements are confirmed by controlled studies in which children aged 8 to 18 months, recovering from acute respiratory disease, for which antibiotic therapy was prescribed, included in the diet drinking yoghurts enriched with Bifidobacterium lactis BB12 and inulin for 3 months. The inclusion of yoghurts in the children’s diet helped to normalize the intestinal microbiota composition after antibiotic therapy, as well as to strengthen the immune system by stimulating the synthesis of protective factors – secretory immunoglobulin A and lysozyme. Key words: fermented dairy products, child nutrition, probiotics, prebiotics, synbiotics, inulin, microbiota, functional foods, immune system, Bifidobacterium lactis BB12

Purpose – The purpose of this paper is to outline the present status of various fermented foods and beverages across the globe and reviews on the microbiology and therapeutic effects of fermented foods. Design/methodology/approach – Fermented foods play an important socio-economic role in developing countries as well as making a major contribution to the nutrition requirements of natural populations. These foods have attracted attention all over the world as foods that might promote longevity. The approach is based on observations of online research with respect to fermented foods and their origins, analysis of research papers in journals and systematic research on the microbiology and health benefits of fermented products. Findings – In general, traditional fermented foods produced with indigenous practices throughout the world are made under primitive conditions, which result in low yield and poor quality. But since, these foods are not only traditional but also functional foods. They are experiencing a burst of popularity as health foods worldwide. The raw materials traditionally used for fermentation are as diverse as: fruits, cereals, vegetables, milk, meat, and fish. It is possible to obtain a large variety of different food products by selecting different raw materials, starter cultures, and fermentation conditions. Originality/value – The paper offers a holistic view that would guide a reader to identify various fermented products and enlighten them about their therapeutic properties.

Several fermented foods and beverages for human nutritionthat incorporate lactic acid bacteria and others beneficial microorganisms are produced throughout the world. Lactic acid bacteria (LAB) are widely distributed in nature and occur as natural microflora in many fermented foods (fermented milk, cereal fermented food, fermented fruit products, fermented roots products like cassava and others). This study gave characteristics, nutritional, Health and functional properties of probiotics microorganisms involved in cassava fermentation forGariand Attiéké production. During cassava fermentation for Gariand Attiéké production many microorganisms with probiotic properties were involved and gave benefic properties. Lactic acid bacteria and yeast involved in food fermentation or production particular in cassava products may possess probiotic properties.Probiotics may have potential roles, as natural barriers to pathogens associated with intestinal disease with functional role.Probiotic microorganisms role and importance in cassava fermentation for Gari andAttiéképroduction for healthy nutrition for consumers were developed in this work.

Efforts to attain sustainable nutritional diets in sub-Saharan Africa (SSA) are still below par. The continent is envisaged to face more impending food crises. This review presents an overview of common edible insects in Africa, their nutritional composition, health benefits and utilization in connection with fermentation to enrich the inherent composition of insect-based products and offer foods related to existing and generally preferred culinary practice. Attempts to explore fermentation treatments involving insects showed fermentation affected secondary metabolites to induce antimicrobial, nutritional and therapeutic properties. Available value-added fermented edible insect products like paste, powder, sauces, and insect containing fermented foods have been developed with potential for more. Novel fermented edible insect-based products could effectively fit in the continent’s food mix and therefore mitigate ongoing food insecurity, as well as to balance nutrition with health risk concerns limiting edible insects’ product acceptability in SSA.

Mahua (Madhuca longifolia) belongs to family sapotaceae, is known for its sweet flowers which possess a lot of ethnic values among the tribal people for the development of various fermented and non-fermented food products. The non-fermented products include halwa, meethi puri, barfi whereas fermented products include mahua daaru or mahuli. Because of its numerous phytochemical attributes traditionally it is also used as a medicine for many diseases including headache, diarrhoea, skin and eye diseases. The present review highlights and explore the composition (dry and fresh flowers), utilization, medicinal and nutritive important along with its future prospective to improve the livelihood of the tribal people with the increase chances of the employment.

This study was conducted to investigate the rate of proteolysis and peptide profiles of different Finnish fermented milk products. The highest rate of proteolysis was observed in Biokefir, while the greatest change in the rate of proteolysis was observed in Gefilus®. Differences in starters and manufacturing processes reflected on the peptide profiles of the products. Most of the identified peptides originated from either the N- or C-terminal region of β-casein or from the N-terminal region of αs1-casein.

1-4% of pulse fractions including pea protein and fiber, chickpea and lentil flour as well as soy flour and protein concentrate were selected and characterized. As preliminary results the functional properties of pulse ingredients are varied upon their protein content and pH of the food carrier. Orange juice, apple juice, yogurt and two probiotic fermented milk were selected for supplementation. 1% and 2% pulse fractions gave comparable results in terms of turbidity, cloud and visual stability, color and sensory attributes for both orange and apple juices beverages. All supplements improved the acidification rate of yogurt and probiotic cultures, but the highest effects were obtained with probiotic supplementation with lentil and soy flour. As for the main study, skim milk (9.5 % w/v solid content) was supplemented with 1-3% (w/v) lentil flour, pea flour or skim milk powder and they were inoculated with yogurt starter cultures or probiotic (L. rhamnosus). Acid production during the fermentation, the pH, syneresis, color, rheological properties (dynamic oscillation temperature sweep test at 4-50 ˚C), and sensory properties (only for yogurt) were studied after production and 28 days of refrigerated storage.1-3% lentil and pea flour enhanced acid production during yogurt fermentation, but the microbial population (CFU) of both S. thermophilus and L. bulgaricus were in the same range in all lentil and pea flour and skim milk supplemented yogurts, after production. Pea flour supplementation enhanced survival of L. bulgaricus after storage. The pH decreased from 4.5 to 4.1 in lentil flour and from 4.5 to 3.75 in pea flour supplemented yogurts, after 28 days. Syneresis in 1-2% lentil and pea flour supplemented yogurts was higher than other samples. In lentil supplemented yogurts, "a" and "L" values did not significantly differ in all samples and remained constant after 28 days whereas, "b" value increased as a result of supplementation. Pea flour supplementation did not alter redness or greenness of yogurts, but the yellowness was significantly higher than other yogurts. Yogurt with 3% lentil and pea flour had higher storage (G΄) and loss (G˝) moduli in comparison with samples supplemented with 1-3% skim milk and the control yogurt. 1-2% lentil and pea flour supplemented yogurt showed comparable sensory properties in comparison with 1-2% skim milk supplemented and control samples.1-3% lentil and pea flour enhanced acid production during probiotic fermentation, and the CFU's of L. rhamnosus were comparable with non-supplemented control sample after production. After 28 days, the CFU`s of 2% and 3% lentil supplemented probiotic were as high as 1% skim milk supplemented sample and the CFU`s of 3% pea flour supplemented probiotic was the highest followed by 3-2% skim milk and 1-2% pea flour supplemented samples. The pH decreased from 4.50 to 3.90 for lentil flour supplemented probiotics and from 4.50 to 4.04 for pea flour supplemented probiotics, over 28 days. Syneresis in 1-3% lentil and pea flour supplemented probiotic was significantly lower than other samples. All lentil flour supplemented samples had significantly lower "L" values and higher "b" and "a" values in comparison with skim milk supplemented samples. Pea flour supplementation slightly changed the color which was not as light as skim milk supplemented samples and they showed more yellowness in final product after production and storage. Probiotic fermented milk with 1-3% lentil and pea flour showed higher G΄ and G˝ in comparison with other samples.
Des légumineuses tels que des protéines et fibres de pois, farine de pois chiche, de lentille et de soja ont été sélectionnées et caractérisés. Des résultats préliminaires ont montré que des propriétés fonctionnelles ont variés en fonction de la teneur en protéines et du pH des légumineuses employées. Du jus d'orange et de pomme, du yogourt et deux laits fermentés à l'aide de probiotiques ont été supplémentés avec les différentes légumineuses à des taux de 1 à 4%. Les supplémentations à 1 et 2% ont donné des résultats comparables en termes de turbidité, de stabilité, de couleur et d'attributs sensoriels pour les jus d'orange et de pomme. L'addition de légumineuse a permis d'avoir une acidification plus rapide dans les yaourts et les cultures probiotiques, mais le effet le plus important a été obtenu avec farine de lentilles et le soja dans les cultures probiotiques. Comme précédemment, des laits écrémés (9,5% p/v) ont été supplémentés avec 1-3% (p/v) de farine de lentilles, de pois ou de poudre de lait écrémé. Ils ont été inoculés avec des cultures de yogourt, des probiotiques (L.rhamnosus). La production d'acide lors de la fermentation, le pH, la synérèse, la couleur, les propriétés rhéologiques (essai dynamique balayer oscillation de température à 40-50˚C), et les propriétés sensorielles (uniquement pour les yogourts) ont été étudiés après la production et durant 28 jours d'entreposage frigorifique. 1-3% de farine de lentilles ou de pois ont amélioré la production d'acide pendant la fermentation du yogourt, mais les UFC ont les même compte pour les laits suppléments que pour les témoins (lait écrémé). Il est a noter que L. bulgaricus avaient un meilleur taux de survie au jour 28 avec une supplémentation en farine de pois. La diminution du pH dans les yogourts est de 4,5 à 4,1 avec la farine de lentille et de 4,5 à 3,75 avec farine de pois, après 28 jours. La synérèse pour les yogourts supplémentés à 1 et 2% avec de la farine de lentille ou de pois était supérieure d'autres échantillons. Lorsque le taux de supplémentation augmente en farine de lentille ou de pois, il n'y a pas de différence significative pour les valeurs de a alors que la valeur b a augmenté en fonction de la supplémentation.Les yogourts faits de 1 a 3 % farine de lentilles et de pois 1 3% avaient un module élastique (G') et un module visqueux (G˝) plus élevés que les échantillons supplémentés en lait écrémé et que les témoins. Les Yogourts avec 1 à 2% de farine de lentilles et de pois possèdent des propriétés sensorielles comparable a celles des yogourts faits avec 1 a 2% de lait écrémé et celles des témoins. 1-3% de farine de lentilles ou de pois dans des laits avec probiotiques ont amélioré la production d'acide pendant la fermentation, et les UFC de L rhamnosus étaient comparable a ceux des témoins (lait écrémé) après production. Après 28 jours, les UFC pour les échantillons supplémentés avec 2 et 3% de farine de lentille étaient aussi élevées que ceux supplémentés avec 1% de lait écrème et les UFC pour les échantillons supplémentés avec 3% de farine de pois étaient plus élevées que ceux de tous les autres échantillons. Durant les 28 jours de production le pH diminue dans les laits probiotiques contenant de la farine de lentille de 4,50 à 3,90 et pour ceux contenant de la farine de pois de 4,50 à 4,04. La synérèse dans laits probiotiques avec 1 à 3% de farine de lentilles ou de pois a été significativement plus faible que les autres échantillons. Tous les échantillons contenant de farine de lentilles avaient significativement une valeur de L plus bas et des valeurs de b et a plus élevés en comparaison aux échantillons supplémentés en lait écrémé. L'addition de farine de pois a entraîné une modification de couleur b.Les laits probiotiques supplémentés avec 1 a 3 % de farine de lentilles et de pois ont des valeurs de G' et G˝ supérieures aux autres échantillons.

Bakgrund: Med industrialiseringen har de traditionella yoghurtkulturerna med en mångfald av samverkande mjölksyrabakterier fått ge plats åt de mer standardiserade. En gårdskultur framställs genom att obehandlad mjölk spontanfermenteras av gårdens egen bakterieflora och får därigenom en unik karaktär. Bakteriekulturen kan sedan ympas vidare för tillverkning av yoghurt.Syfte: Syftet med studien är framställning och vidareympning samt sensorisk och mikrobiologisk karaktärisering av termofil gårdskultur från obehandlad mjölk. Vidareympningen avser framställning av yoghurt fermenterad av gårdens egen bakterieflora.Metod: Gårdskulturen framställdes och ympades till yoghurt. Yoghurten undersöktes genom mikrobiologisk karaktärisering, antibiotikaresistens och sensorisk profilering samt jämfördes med industriell kultur och en traditionell heirloomkultur.Resultat: Resultatet visade att gårdskulturen skiljde sig både mikrobiologisk och sensoriskt. Gårdskulturen innehöll stammar av enterokocker vilka inte visade på resistens mot analyserade antibiotika.Slutsats: Det är möjligt att framställa en gårdskultur av godtagbar mikrobiologisk och sensorisk kvalitet. Gårdskulturen ger en differentierad mikrobiologisk och sensorisk karaktär i jämförelse med en industriell kultur och en traditionell heirloomkultur Metoden kan vara riskfylld och kulturen bör analyseras med avseende på patogen tillväxt. En unik gårdsyoghurt kan vara en metod för gårdsmejerister att i sitt varumärke bygga på terroir och platsens unicitet.
Background: With industrialization, the traditional yoghurt cultures with a multitude of lactic acid bacteria had to make way for the more standardized. An artisanal farm culture is produced by raw milk spontaneously fermented by the farm's own bacterial flora and thus develops a unique character. The bacterial culture can then be inoculated for the production of yoghurt.Purpose: The pupose of the study is to produce and inoculate as well as sensory and microbiological characterization of a thermophilic artisanal farm culture from raw milk. The inoculation relates to the production of yoghurt fermented by the farm's own bacterial flora.Method: The artisanal farm culture was produced and inoculated into yoghurt which was assessed by microbiological characterization, antibiotic resistance, sensory profiling and then compared with industrial culture and a traditional heirloom culture.Result: The result showed that the artisanal farm culture differed both microbiologically and with regard to sensory paramters. The farm culture contained strains of enterococci which did not show resistance to analyzed antibiotics.Conclusion: It is possible to produce an artisanal farm culture of good microbiological and sensory quality. The artisanal farm culture provides a differentiated microbiological and sensory character in comparison to an industrial culture and a traditional heirloom culture The method may be risky and the culture should be analyzed for pathogens. A unique farm yoghurt can be a method for artisan farm dairies to build their brand based on terroir.

Akamu is a lactic acid bacteria fermented cereal-based food that complements infant diets in most African countries. Uncontrolled fermentation increases the variability in quality and safety of akamu. This study was aimed at the controlled fermentation of akamu with selected lactic acid bacteria (LAB), investigation of the probiotic potential of the LAB and the effect of variation in production method on the product quality and sensory properties. PCR-DGGE analysis of traditional akamu samples revealed LAB community dominated by Lactobacillus fermentum, L. plantarum, L. delbrueckii subsp. bulgaricus and L. helveticus. Isolated yeasts were Candida tropicalis, C. albicans, Clavispora lusitaniae and Saccharomyces paradoxus. The isolated Lactobacillus plantarum strains (NGL5 and NGL7) fermented irradiated ground maize slurries and produced significant levels of lactic acid (>73 mmol L-1) and low pH ≤3.63 displaying inhibitory activity against Salmonella enterica serovar Enteritidis NCTC 5188, Escherichia coli 1077 (NCTC 11560), Bacillus cereus NCIMB 11925, Staphylococcus aureus NCTC 3750 and Listeria monocytogenes NCTC 7973 in MRS agar and E. coli 1077 in maize slurry fermentation. Viability of both strains of L. plantarum at pH 2 after 3 h was reduced from ≥8.26±0.05 to ≤4.94±0.49 Log10 CFU mL-1 while incubation in 0.3% bile allowed growth to 5.73±0.13 and 7.93±0.12 Log10 CFU mL-1 after 6 h for NGL5 and NGL7 respectively. Auto-aggregation of the L. plantarum strains at 37oC (≥25 after 5 h) correlated with adhesion to hydrocarbons (<15, 26, 33 and 64% for Hexane, Hexadecane, Ethyl acetate and Chloroform respectively). The strains failed to exhibit gelatinase or haemolytic activity but adhered to porcine mucin (OD403 nm ≥0.63 with viability ≥6.52 Log10 CFU mL-1) and Caco-2 cells (≥5.13 Log10 CFU mL-1). The ash, mineral (Ca, K, Mg, Na, S and Zn), IDF, SDFP and TDF content of the L. plantarum fermented ground maize slurries were significantly (p≤0.05) higher than that of the traditional akamu but the peak and final viscosities (139.5 and 68.5 cP respectively) were significantly (p≤0.05) the least. The aroma, appearance, colour, flavour and texture of the resultant porridges were liked moderately by 75% of the assessors. This study demonstrated that fermentation with the L. plantarum strains would contribute towards product safety and the L. plantarum strains possessed some probiotic potential that could be beneficial to the consumers particularly in those developing countries were the main staple foods are fermented cereals.

L'objectif de ce travail était de sélectionner de manière rationnelle une bactérie probiotique par la mise en place d'un crible ainsi que d'étudier et de comprendre l'impact du potentiel d'oxydoréduction (Eh) et du bullage de gaz sur la survie de Bifidobacterium bifidum dans un produit laitier fermenté. Nous avons tout d'abord développé des techniques de sélection des bactéries sur des critères de viabilité / vitalité (analyse par cytométrie en flux) ainsi que sur des critères de fonctionnalité (pouvoir antioxydant). Nous avons pu sélectionner des souches d'intérêt industriel ainsi qu'une souche d'étude académique, Bifidobacterium bifidum.Nous avons ensuite étudié l'effet de la modification du Eh par bullage de gaz sur la survie de B. bifidum dans un produit laitier fermenté. Les laits fermentés conditionnés sous atmosphère anaérobie (Azote) et/ou réductrice (Azote-Hydrogène) permettent une meilleure survie de la souche au cours du stockage (28 jours - 4 °C) par rapport au Contrôle. Puis, nous avons analysé l'effet d'une croissance sous différents Eh sur la viabilité en milieu modèle et la fonctionnalité de B. bifidum. Une croissance en condition anaérobie et/ou réductrice permet d'améliorer à la fois la résistance aux stress (stress oxydant d'ordre physiologique, stress aux sels biliaires et stress côlon), le pouvoir réducteur (sels de tétrazolium), le pouvoir antioxydant (test KRL et test des comètes) et l'adhérence par rapport au Contrôle. Une modulation des propriétés biochimiques membranaires sous Azote et sous Azote-Hydrogène pourraient expliquer ces phénomènes. L'augmentation des composés thiols exofaciaux et l'augmentation des acides gras insaturés à longues chaines est observée pour des cellules produites sous conditions Azote et Azote-Hydrogène. Ainsi ces conditions de croissance présentent une amélioration majeure de l'effet probiotique de B. bifidum, à la fois d'un point de vue de sa résistance aux stress que d'un point de vue de sa fonctionnalité

Thesis (MScFoodSc)--Stellenbosch University, 2001.
ENGLISH ABSTRACT: The preservation of various fresh fish products is achieved by either smoking, salting, canning, freezing or fermenting a highly perishable raw product. Since many of these facilities are not readily available, the use of fermentation as a means of preserving the product has been extensively practiced. However, the fermentation of fish is a time consuming practise and only by accelerating the process would it be possible to ensure the production of a more cost effective and readily available safe end-product. The quality of the fermented fish product is partially determined by the fermentation conditions and the metabolic activity of the microbes present. The rapid identification of the microbes present during the fermentation would enable the selection of possible starters to ensure an accelerated production of high quality fermented fish products. This study was thus undertaken to develop identification fingerprints for bacteria isolated from fermented fish products. A 1300 bp fragment of the 16S rRNA genes of each of the bacteria previously isolated was successfully amplified using the PCR technique. The isolates included strains of the genera Bacillus, Staphylococcus, Sphingomonas, Kocuria, Brevibacillus, Cryseomonas, Vibrio, Stenotrophomonas and Agrobacterium. The data obtained can, therefore, be used in the identification of these microbes isolated from other similar fermented fish products. The fingerprints could also be used to assist in determining the dominant microbial populations responsible for the characteristic qualitative changes occurring in the fish product during fermentation. The microbial composition of a fermenting fish product partially determines the quality of the end-product, therefore, the use of selected bacterial starters could result in the accelerated production of a microbial safe fermented fish product. A further objective of this study was to accelerate the production of a fermented fish product by inoculating macerated trout with either selected lactic acid bacteria (LAB) or with selected bacteria with high proteolytic activity over a 30 day fermentation period. The LAB included a combination of Lactobacillus plantarum, Lactococcus diacetylactis and Pediococcus cerevisiae strains, whereas the bacteria with high proteolytic activity included strains of Kocuria varians, Bacillus subtilis, two strains of B. amyloliquefaciens and a combination of these bacterial species. The quality of the fermented product was determined using changes in product pH, titratable acidity (%TA) and free amino nitrogen (FAN) formation as efficiency parameters. The data obtained during the fermentation of the macerated trout showed that the selected starters did not have a significant effect on the pH decrease in the product over a 30 day fermentation period. The LAB strains did not have a significant effect on the %TA of the fermenting fish product, yet the presence of these bacteria appeared to limit the FAN production in the product. The bacteria with high proteolytic activity resulted in slightly enhanced %TA values and a higher FAN content in the fermented product. It was also determined that the LAB and Kocuria varians, in contrast to the Bacillus spp. inoculums, did not survive the fermentation conditions well, possibly due to the low pH environment. The presence of the starter bacteria in the fermenting fish mixture at the end of the fermentation was also successfully determined with the use of the PCR-RFLP technique. The fermented fish product, obtained at the end of the fermentation period, had a good aroma and compared favourably to similar commercially available fermented fish products. The use of different microbial starters could in future enable the production of a diverse range of high quality products, which could be produced and marketed locally.
AFRIKAANSE OPSOMMING: Die preservering van ‘n verskeidenheid vars vis produkte word bereik deur die hoogs bederfbare produk te rook, te sout, te blik, te vries of te fermenteer. Aangesien baie van hierdie fasiliteite nie geredelik beskikbaar is nie, is die gebruik van fermentasie as ‘n preserverings metode al ekstensief beoefen. Die fermentasie van vis is egter 'n tydsame proses en slegs deur die versnelling van die proses sal dit moontlik wees om die produksie van ‘n meer koste effektiewe en geredelike beskikbare veilige eindproduk te verseker. Die kwaliteit van die gefermenteerde vis produk word gedeeltelik bepaal deur die fermentasie kondisies en die metaboliese aktiwiteit van die mikrobes teenwoordig. Die vinnige identifikasie van die mikrobes teenwoordig gedurende die fermentasie sal die seleksie van moontlike suursels om die versnelde produksie van hoë kwaliteit gefermenteerde vis produkte moontlik maak. Hierdie studie is dus onderneem om identifikasie vingerafdrukke vir bakteriee wat gei'soleer is van gefermenteerde vis produkte moontlik te maak. ‘n 1300 bp fragment van die 16S rRNA gene van elkeen van die bakteriee wat voorheen gei'soleer is, is suksesvol geamplifiseer deur die PCR tegniek. Die isolate sluit in stamme van die genera Bacillus, Staphylococcus, Sphingomonas, Kocuria, Brevibacillus, Cryseomonas, Vibrio, Stenotrophomonas en Agrobacterium. Die data kan dus gebruik word in die identifikasie van hierdie mikrobes as dit gei'soleer word van ander gefermenteerde vis produkte. Die vingerafdrukke kan ook gebruik word om die dominante mikrobiese populasies wat verantwoordelik is vir die kenmerklike kwalitatiewe veranderinge wat plaasvind in die vis produk gedurende die fermentasie, te identifiseer. Die mikrobiese samestelling van ‘n fermenterende vis produk bepaal gedeeltelik die kwaliteit van die eindproduk, daarom kan die gebruik van geselekteerde bakteriese suursels die versnelde produksie van ‘n mikrobies veilige gefermenteerde vis produk teweeg bring. ‘n Verdere doel van hierdie studie was om die produksie van ‘n gefermenteerde vis produk te versnel deur fyngemaakte forel met of geselekteerde melksuurbakteriee of met geselekteerde bakteriee met hoë proteolitiese aktiwiteit te inokuleer oor ‘n 30 dag fermentasie periode. Die melksuurbakteriee het ingesluit ‘n kombinasie van Lactobacillus plantarum, Lactococcus diacetylactis en Pediococcus cerevisiae, terwyl die bakterieë met hoë proteolitiese aktiwiteit stamme van Kocuria varians, Bacillus subtilis, twee stamme van Bacillus amyloliquefaciens en ‘n kombinasie van hierdie bakteriese stamme ingesluit het. Die kwaliteit van die gefermenteerde produk is bepaal deur die veranderinge in die pH, titreerbare suur (%TS) en vrye amino stikstof (VAS) vorming van die produk as effektiwiteits parameters te gebruik. Die data wat verkry is gedurende die fermentasie van die fyngemaakte forel het gedui daarop dat die geselekteerde suursels nie ‘n merkwaardige effek op die afname in pH in die produk oor ‘n 30 dag fermentasie periode het nie. Die melksuurbakteriee het nie ‘n merkwaardige effek op die %TS van die gefermenteerde vis produk gehad nie, terwyl dit geblyk het dat die teenwoordigheid van hierdie bakterieë die produksie van VAS in die produk belemmer het. Die bakteriee met hoe proteolitiese aktiwiteit het ‘n effense verhoogde %TS en ‘n hoër VAS inhoud in die gefermenteerde produk veroorsaak. Dit is ook bepaal dat die melksuurbakteriee en Kocuria varians, in teenstelling met die Bacillus spp. inokulums, nie die fermentasie kondisies goed oorleef het nie, moontlik as gevolg van die lae pH omgewing. Die teenwoordigheid van die suursel bakteriee in die fermenterende vis mengsel aan die einde van die fermentasie is ook suksesvol bepaal met die PKR-RFLP tegniek. Die gefermenteerde vis produk, verkry aan die einde van die fermentasie periode, het ‘n goeie aroma gehad en het goed vergelyk met soortgelyke kommersieel beskikbare gefermenteerde vis produkte. Die gebruik van verskillende mikrobiese suursels kan in die toekoms die produksie van ‘n diverse reeks hoë kwaliteit produkte wat plaaslik geproduseer en bemark kan word moontlik maak.

Ogi is a fermented food made from maize, sorghum or millet which serves as complementary food for infants and breakfast for adults in Nigeria, West Africa. This study characterized the microbial diversity of maize and sorghum grains and ogi produced by their natural fermentation in an attempt to understand the roles of the key microbial species and the impact of the population dynamics and selected species on changes in nutritional composition and aroma notes of ogi during fermentation. A combined approach of culture dependent and culture independent methods of analysis was applied to investigate the microbial community of grains and ogi from two different sources. Microbial diversity and viable populations varied with the source of the grain. Bacterial and fungal genera identified with the partial 16S rRNA and 26S rRNA sequence analysis respectively in maize and sorghum were Bacillus, Enterobacter, Micrococcus, Kytococcus, Pantoea, Staphylococcus, Amycolatopsis, Methanoculleus, Aspergillus, Penicillium, Eupenicillium, Acremonium, Schizosaccharomyces, Meyerozyma, Hyphopichia, and Pichia in maize grains; Enterococcus, Enterobacter, Pantoea, Bifidobacterium, Aspergillus, Cladosporum, and Penicillium in maize ogi; Enterococcus, Enterobacter, Pantoea, Aeribacillus, Cyanobacterium, Acinetobacter, Fusarium and Trametes in sorghum grains; and Pediococcus, Lactobacillus, Enterococcus, Bacillus, Cladosporum and Penicillium in sorghum ogi. Similar species were observed in both sources of maize while those of sorghum differed slightly. Predominant microbes included species of Enterobacteriaceae and moulds. Acetic acid bacteria were not identified as part of the diverse community. Following the predominance of moulds during the natural fermentation, preliminary screening was performed by PCR using specific biosynthetic gene primers to test whether they are the mycotoxin producing species. None of the genes tested were detected by PCR thus they may not be the toxin producing species. Starch, non-starch polysaccharide (NSP), phytate and phenolic compounds were determined in the grains and respective ogi to ascertain the levels of these nutritionally important components in the naturally fermented ogi and the impact of the varying microbial populations on the fate of these compounds during fermentation. In the grains, the average starch and NSP contents in each case were 80.35 g/100g and 9.40g/100g in maize and 93.12 g/100g and 8.14 g/100g in sorghum. Out of the total in grain the average percentage recovery of starch and NSP respectively in the ogi showed 63% and 42% in maize and 58% and 27% in sorghum. Maize showed good starch and fibre (NSP) retention than sorghum after fermentation. To further understand the types and levels of polymers in NSP hydrolysis in ogi fermentation, HPLC analysis of the hydrolysed extract was performed. Glucose was entirely present in maize and sorghum ogi which represents the beta-D-glucans while arabinose and xylose (in maize only), mostly lost with the pomace, signify the arabinoxylans. Overall variations in the microbial populations of sorghum seemed causal to the difference in starch and NSP recoveries. Phytate was assessed based on release of total phosphorus in the samples by enzymatic and chemical methods. Recovery of phytate in the naturally fermented ogi ranged from 18-25% in maize and 40-48% in sorghum suggesting greater phytase activity and more nutrient bioavailability in maize ogi than in the sorghum. Greater activity in maize reflects the presence of phytate hydrolysing species such as Aspergillus in the grain. Total phenolic content (TPC) was assessed by Folin-Ciocalteu colorimetric method after direct extraction of samples by saponification. TPC in the original grains ranged from 410–437 mg GAE/100g in maize and 221–247 mg GAE/100g in sorghum. Due to the nutritional significance, the amount of phenolics that are either freely soluble or are covalently bound to the food matrix were assessed. Soluble phenolics in ogi ranged from 16-38% in maize and 32-49% in sorghum based on the total soluble fraction in the original grain. In all cases loss of soluble phenolics with the waste waters accounted for 12-25% and 31-39% with the pomace. Only the LAB population seemed to correlate with the release of phenolics in the natural fermentation. Given the higher value of soluble phenolics, naturally fermented sorghum ogi appeared to have higher antioxidant potential than the maize ogi. Furthermore an attempt was made to ascertain whether the use of selected microbes would improve the antioxidant properties and aroma of ogi while minimizing the incidence of pathogens due to chance inoculation. Thus the impact of selected LAB (Pediococcus pentosaceus) and fungi (T. hirsuta and A. zeae previously shown to have phytase activity) on changes in phytate, phenolics and aroma of ogi was assessed following a parallel experiment to the previous study but using autoclaved grains. Five fermentation treatments of the pure and co-cultures were investigated. Cell populations in all culture fermentations varied and reached the average maximum of log 6-9 cfu/ml. Changes in the distribution of bound and soluble phenolics were observed showing esterase activity. Leaching of phenolics was evident in all cases but was higher in the sorghum fermentations. Higher levels of soluble phenolics were recovered in pure culture fermented ogi using T. hirsuta or P. pentosaceus than in the natural fermentation having 76% and 45% of the original soluble fraction in maize and sorghum respectively. This suggests greater antioxidant potentials than the naturally fermented ogi. Pure culture fermentations using T. hirsuta and co-culture of P. pentosaceus with A. zeae reduced phytate by 97% and 96% in maize and sorghum ogi respectively showing greater phytase activity and more nutrient bioavailabilty in the ogi than in the natural fermentation. The aroma profile of ogi was analysed by solid-phase microextraction and gas chromatography-mass spectrophotometry (SPME GC-MS). Ethyl acetate, butyl acetate and ethyl hexanoate were observed as the key active aroma components in ogi. The ester, methyl thiobutanoate was found to be unique to the naturally fermented ogi suggesting that it may have been generated by species other than the selected starter organisms. Overall in both natural and starter culture fermentations, maize ogi showed high relative abundance of volatile components suggesting good substrate compatibility and utilization during fermentation. Thus compounds with high threshold values may be significant in the aroma notes of maize ogi. P. pentosaceus and T. hirsuta in pure and in co-culture fermentations produced ogi with aroma notes mostly related to the naturally fermented product. In conclusion the diversity and levels of the initial microflora and the structural composition of grain could be major factors contributing to the nutritional compositional changes in ogi fermentation.

Les folates sont des vitamines indispensables à tous les âges, particulièrement pendant la grossesse et l’enfance, étant donné leur fonction dans la division cellulaire. Le régime alimentaire en Afrique est essentiellement basé sur les céréales, consommées toujours après transformation. La fermentation est l’un des moyens de transformation des céréales pouvant augmenter les folates dans les aliments. L’objectif de ce travail était d’utiliser la fermentation pour augmenter les ingérés en folates des populations africaines via la consommation d’aliments céréaliers fermentés. Sept aliments céréaliers fermentés couramment consommés en Afrique de l’Ouest ont été investigués. La plupart des aliments avaient des teneurs en folates (1,8–31,3 µg/100g matière fraîche) inférieures à celles des céréales de départ (13,8-73,4 µg/100g matière fraîche). Des pertes en folates ont lieu au cours de certaines étapes de procédés dont le décorticage, le séchage, le trempage, le broyage et la filtration. Toutefois, la fermentation a permis une augmentation de la teneur en folates dans certains aliments. La bioaccessibilité des folates, évaluée à l'aide d'un modèle de digestion statique in vitro, variait de 23% à 81%. Elle était influencée par la matrice alimentaire et la stabilité des folates au cours de la digestion. Il a été calculé qu’au maximum 8% des besoins journaliers en folates des jeunes enfants consommant l’un des aliments étudiés pourraient être couverts. Des essais d’inoculation de bouillies fermentés à base de mil avec des souches de bactéries lactiques sélectionnées pour leurs propriétés nutritionnelles (synthèse de folates, hydrolyse de l’amidon) permettaient d’augmenter significativement les teneurs en folates (jusqu’à 8,7 µg/100 g matière fraîche) par rapport à leur équivalent préparées de manière traditionnelle (2,5-5,4 µg/100 g matière fraîche). L’inoculation par un pied-de-cuve provenant d’une fermentation spontanée permettait aussi une augmentation significative des teneurs folates (jusqu’à 7,4 µg/100 g matière fraîche). La caractérisation de la diversité bactérienne de 7 aliments céréaliers fermentés du Burkina Faso, d’Ethiopie et de la Finlande montrait que les bactéries lactiques du genre Lactobacillus, Enterococcus, Weissella, Pediococcus, Lactococcus et Streptococcus étaient les principaux acteurs de la fermentation de ces aliments. Toutefois, une présence non négligeable d’autres microorganismes potentiellement pathogènes des genres Bacillus, Pseudomonas, Staphylococcus, Erwinia, Klebsiella, Escherichia et Acinetobacter a été identifiée. Cette contamination était liée à certaines étapes du procédé de transformation des céréales dont le stockage et broyage dans les moulins publics. Ces microorganismes pathogènes étaient réduits par fermentation et finalement éliminés après l'étape de cuisson
Folates represent an essential vitamin in the human diet at all ages, particularly during pregnancy and infancy, as it is required for the production of new cells. In many African countries, the main staple foods are based on cereals, which are always consumed after processing. Fermentation is one of the processing, which could increase folate contents in foods. The objective of this work was to increase folates intake of African people through the consumption of cereal-based fermented foods using fermentation. Seven types of cereal-based fermented foods (CBFF), commonly consumed in West Africa, were investigated in this study. Total folate content of cereal-based fermented ranged between 1.8 and 31.3 µg/100g fresh weight, and was almost always lower than in the raw material (13.8-73.4 µg/100g fresh weight). Folate losses occurred during some processing steps like debranning, soaking and drying steps. However, fermentation was able to increase the folate content in some CBFF. Folate bioaccessibility was assessed using a static in vitro digestion model, and ranged from 23% to 81%. The bioaccessible folate content was influenced by total folate content, the structure of food matrices that modulated folate release, and folate stability during digestion process. Calculations of the contributions of CBFF to the reference nutrient intake for folate showed that folate intakes from these foods would cover a maximum of 8% of the folate requirements for young children. Porridges prepared with starter cultures of lactic acid bacteria selected for the nutritional properties (folate synthesis, starch hydrolysis) had significantly higher folate contents (up to 8.7 µg/100 g fresh matter) than the porridge prepared using the traditional process (2.5-5.4 µg/100 g fresh matter). Back slopping using an inoculum from a spontaneous fermentation also enabled an interesting increase in folate contents (up to 7.4 µg/100 g fresh matter). The bacterial diversity of seven cereal-based fermented foods from Burkina Faso, Ethiopia and Finland were assessed using 16S rRNA amplicon sequencing. Lactic acid bacteria genus, including Lactobacillus, Enterococcus, Weissella, Pediococcus, Lactococcus and Streptococcus were the main bacteria present in cereal-based fermented foods. Several potentially pathogenic bacteria, namely, Bacillus, Pseudomonas, Staphylococcus, Erwinia, Escherichia, Klebsiella and Acinetobacter were also found in some intermediary products resulting from storage and wet milling. These microorganisms were reduced by fermentation and finally removed after the cooking step

Thesis (PhD Food Sc)--Stellenbosch University, 2012.
ENGLISH ABSTRACT: The fermentation of milk has been known for millennia and leads to nutritious and prolonged shelf-life dairy products. In Southern Africa, traditional fermented dairy products have the same value as local staple foods and are consumed as a part of or as a whole meal. However, the retail price and the technology make many commercialised fermented dairy products unaffordable to the majority of the population. There is thus a need for a healthy nutritious low-cost easily prepared fermented dairy product. A product that could be the answer to the above need, is Kefir. The principle advantage is that the Kefir beverage is made from reusable Kefir grains, which unfortunately are not easily available and grow slowly. Kefir grains can only be obtained from pre-existing grains, which presents a problem in the marketing of the grains. A mass culturing technique was developed to produce large masses of grains but preparation of Kefir using these grains results in a product (MG Kefir) lacking in the sensory attributes of Traditional Kefir. Thus, the overall objective of this research was to determine the impact of environmental factors on the metabolic profiles of Kefir produced using different Kefir grains and this was then followed by the subsequent enrichment of Kefir prepared with mass cultured grains so as to obtain a Kefir beverage that has improved organoleptic qualities. To determine the impact of environmental factors Traditional and MG Kefir were prepared under controlled and uncontrolled conditions. Traditional Kefir was found to give the best beverage and was thus considered as the control. Under controlled conditions the optimum incubation temperature for the production of Kefir was 22ºC as over-acidification was observed at 25ºC. The metabolic profiles of both Traditional and MG Kefir showed that both contained acetaldehyde, ethanol, acetone, diacetyl and acetic acid. In addition, the metabolic profiles revealed that an inadequate ratio of diacetyl to acetaldehyde as well as the lack of ethyl acetate was responsible for the flavour defect in MG Kefir. In order to overcome this defect, citrate and ascorbate (0.015 % w.v-1) were added during Kefir fermentation to enhance the diacetyl and ethyl acetate production. This addition showed a positive impact on diacetyl but not on ethyl acetate production. Improvement of the overall flavour of Kefir was observed as the ratios of diacetyl to acetaldehyde were higher (0.21 – 0.5) in the samples with added citrate and ascorbate than in the samples without (0.12 – 0.17). The production of ethyl acetate in MG Kefir was enhanced by combining the effects of longer incubation (24 h + 18 h at 22ºC), addition of ethanol and acetic acid at 0.79% (m.v-1) and the addition of either Lactococcus lactis ssp. diacetylactis biovar diacetylactis 318 or Candida kefyr 1283. The best yields were obtained in samples containing C. kefyr 1283 and only added ethanol (9.22 mg.L-1), indicating that ethanol is an important factor in ethyl acetate production by Kefir starter strains and suggesting that the absence of ethyl acetate is an indication that the grains do not contain a yeast capable of producing sufficient ethyl acetate. During this investigation, the impact of ethyl acetate on the organoleptic quality of Kefir during storage at refrigerated and room temperatures were also studied. The results indicated that refrigerated Kefir contained up to 40 mg.L-1 of ethyl acetate and was not found defective and thus ethyl acetate was considered a positive contributor to Kefir flavour. This is of particular interest as ethyl acetate is a potent flavour compound at concentrations below 5 mg.L-1. Improvements of MG Kefir’s flavour were successful and will be of value for commercial Kefir production where the main aim is to optimise the flavour of Kefir. However, stabilising the grain microbial consortium was found to be important as it is responsible, over time, for both stable and acceptable Kefir. Acceptability of Traditional, MG and other Kefirs (Candi-Kefir and Lacto-Kefir) prepared with microbially stabilised MG was evaluated by 85 consumers. Results indicated that pH (r = 0.978; p < 0.05) was a significant driver of liking for flavour, especially for female consumers (r = 0.982; p < 0.05). In addition, three clusters, each characterised by different liking attributes were identified. Cluster I generally disliked all the products whereas slight acidic Kefir such as Candi-Kefir (7.63) and Lacto-Kefir (7.09) were preferred by Cluster III. Cluster II showed preference to Kefir with moderate acidity and high ethanol content. In that regard, Traditional Kefir obtained the best score (7.50) and MG Kefir the lowest score (4.87). The sensory study is of value as it led to the identification of the drivers of consumers liking by the different types of consumers. In the course of this project, near infrared reflectance spectroscopy was developed as a rapid method to estimate lactic and acetic acids, which are the organic acids responsible for acidity in Kefir, as well as pH and titratable acidity (TA). The results showed that the calibration models for lactic acid (RPD = 2.57 – 3.16), pH (RPD = 2.90) and TA (RPD = 2.60) were good for screening purposes (2 < RPD < 3); indicating that these models would show if the concentrations of lactic acid, the pH or the TA varied from the normal range. This study has demonstrated that the flavour of MG Kefir, prepared with enriched grains, was successfully improved and has provided some understanding on the preference liking of Kefir, an unknown fermented dairy product to South African consumers.
AFRIKAANSE OPSOMMING: Die fermentering van melk is al vir millennia bekend en lei tot voedsame suiwelprodukte met 'n verlengde raklewe. In Suidelike Afrika het tradisioneel gefermenteerde suiwelprodukte dieselfde waarde as plaaslike stapelvoedsels en word dit as 'n maaltyd of as deel van 'n maaltyd geëet. Die kleinhandelsprys en tegnologie van kommersieel gefermenteerde suiwelprodukte maak hierdie produkte egter onbekostigbaar vir die grootste deel van die populasie. Daar is dus 'n behoefte aan 'n gesonde, voedsame, goedkoop, maklik-om-te-berei gefermenteerde suiwelproduk. 'n Moontlike produk om aan die bogenoemde te voldoen is Kefir. Die hoof voordeel is dat die Kefir drankie van herbruikbare Kefirkorrels gemaak word, maar ongelukkig is hierdie korrels nie vrylik beskikbaar nie, en vermeerder dit stadig. Kefirkorrels kan net van reeds bestaande korrels verkry word wat problematies is vir die bemarking van hierdie korrels. 'n Massakwekingstegniek is ontwikkel vir die produksie van groot hoeveelhede korrels maar die voorbereiding van Kefir met hierdie korrels lei tot 'n produk (MG Kefir) wat sensories minder aanvaarbaar is as tradisionele Kefir. Die hoofdoel van hierdie navorsing was dus om die invloed van omgewingsfaktore op die metaboliese profiele van Kefir, berei deur gebruik te maak van verskillende Kefirkorrels, te bepaal. Dit is gevolg deur die verryking van Kefir berei van massagekweekte korrels om 'n Kefir drankie met verbeterde organoleptiese kwaliteite te verkry. Tradisionele en MG Kefir is voorberei onder gekontroleerde en ongekontroleerde toestande om die impak van omgewingsfaktore te bepaal. Die beste drankie is van tradisionele Kefir verkry en is dus beskou as die kontrole. Die optimum temperatuur vir die produksie van Kefir onder gekonroleerde toestande is 22ºC aangesien oor-versuring by 25ºC waargeneem is. Die metaboliese profiele van beide tradisionele en MG Kefir het gewys dat beide produkte asetaldehied, etanol, asetoon, diasetiel en asynsuur bevat. Die metaboliese profiele het verder gewys dat 'n onvoldoende diasetiel tot asetaldehied verhouding sowel as 'n tekort aan etielasetaat verantwoordelik was vir 'n geur defek in MG Kefir. Om hierdie defek te oorkom is sitraat en askorbaat (0.015% m.v-1) tydens Kefir fermentasie bygevoeg om diasetiel en etielasetaat produksie te verhoog. Hierdie byvoeging het 'n positiewe effek gehad op diasetiel produksie, maar nie op die produksie etielasetaat nie. 'n Verbetering in die algehele geur van Kefir is waargeneem aangesien die diasetiel tot asetaldehied verhoudings hoër (0.21 – 0.5) was in die monsters met bygevoegde sitraat en askorbaat as in die monsters daarsonder (0.12 – 0.17). Die produksie van etielasetaat in MG Kefir is verhoog deur die effekte van 'n verlengde inkubasie tydperk (24 h + 18 h by 22ºC), die byvoeging van etanol en asynsuur teen 0.79% (m.v-1) en die byvoeging van óf Lactococcus lactis ssp. diacetylactis biovar diacetylactis 318 óf Candida kefyr 1283 te kombineer. Die beste opbrengs is verkry in monsters wat C. kefyr 1283 en slegs etanol (9.22 mg.L-1) bevat het. Dit dui daarop dat etanol 'n belangrike faktor is vir etielasetaat produksie in Kefir beginstamme en wys moontlik op die afwesigheid van etielasetaat wat daarop dui dat die korrels nie 'n gis bevat wat bevoeg is om genoegsame hoeveelhede etielasetaat te produseer nie. Tydens hierdie ondersoek is die impak van etielasetaat op die organoleptiese kwaliteit van Kefir gedurende opberging by verkoelde- en kamertemperatuur ook bestudeer. Die resultate het gewys dat verkoelde Kefir tot 40 mg.L-1 etielasetaat bevat het sonder dat dit defektief was. Etielasetaat is dus beskou as 'n positiewe bydraer in terme van Kefir geur. Dit is van besondere belang aangesien etielasetaat 'n sterk geurkomponent teen konsentrasies laer as 5 mg.L-1 is. Verbeteringe in MG Kefir se geur was suksesvol en sal van waarde wees vir kommersiële Kefir produksie waar die hoofdoel die optimisering van Kefir geur is. Stabilisering van die korrels se mikrobiologiese konsortium is ook belangrik aangesien daar gevind is dat dit oor tyd verantwoordelik is vir stabiele en aanvaarbare Kefir. Die aanvaarbaarheid van tradisioneel, MG en ander Kefirs (Candi-Kefir en Lacto-Kefir), voorberei van mikrobiologies gestabiliseerde MG, is deur 85 verbruikers geëvalueer. Die resultate het aangedui dat pH (r = 0.978; p < 0.05) 'n belangrike faktor is in die bepaling van verbruikers se voorkeur van geur is, veral by vroulike verbruikers (r = 0.978; p < 0.05). Drie groepe, elk gekenmerk deur verskillende voorkeur en aanvaarbaarheid eienskappe, is verder geïdentifiseer. Groep I het oor die algemeen van geen van die produkte gehou nie en Groep III het die effense suur Kefirs soos Candi-Kefir (7.63) en Lacto-Kefir (7.09) verkies. Groep II het die Kefir met 'n matige suurheid en hoë etanolinhoud verkies. Tradisionele Kefir het die hoogste telling (7.50) en MG Kefir die laagste telling (4.78) behaal. Die sensoriese studie is van waarde aangesien dit gelei het tot die identifisering van die drywers van verbruikersvoorkeure deur die verskillende tipes verbruikers. Tydens hierdie projek is 'n naby-infrarooi reflektansie spektroskopiese metode ontwikkel vir die vinnige skatting van melk- en asynsuur, die organise sure wat verantwoordelik is vir die suurheid van Kefir, asook die pH en titreerbare suurheid (TS). Die resultate het getoon dat die kalibrasiemodelle vir melksuur (RPD = 2.57 – 3.16), pH (RPD = 2.90) en TS (RPD = 2.60) voldoende was vir siftingsdoeleindes (2 < RPD < 3). Dit dui daarop dat hierdie modelle sal aandui wanneer die konsentrasie van melksuur, pH of TS afwissel van die normale reeks. Hierdie studie het gewys dat die geur van MG Kefir, berei van verrykte korrels, suksesvol verbeter is en het ook gelei tot insigte in die voorkeur van aanvaarbaarheid van Kefir, 'n onbekende gefermenteerde suiwelproduk vir Suid-Afrikaanse verbruikers.

Face aux pathologies de malnutrition en croissance exponentielle en particulier dans les pays du Sud, le développement d’aliments fonctionnels à base de céréales fermentées représente une alternative aux produits laitiers déjà commercialisés. L’incorporation, la stabilité de composés bioactifs liposolubles tels que les caroténoïdes et les phytostérols, ainsi que leur devenir lors de la digestion gastro-duodénale doivent être étudiés afin de démontrer le potentiel nutritionnel de ce nouvel aliment. En effet, il est connu que les phytostérols diminuent la biodisponibilité des caroténoïdes. Le principal objectif de ces travaux a été de concevoir un aliment fonctionnel probiotique à base de maïs fermenté enrichi en caroténoïdes et phytostérols, et d’étudier la stabilité, la bioaccessibilité et l’absorption intestinale de ces composés liposolubles. La formulation et la standardisation du procédé, incluant la sélection de starters de fermentation afin d’obtenir un aliment probiotique, ont été mis au point. Au cours de la fabrication, la stabilité des composés liposolubles a montré un taux de rétention de 73 %. L’effet des phytostérols dispersibles sur la bioaccessibilité de la β-cryptoxanthine, du β carotène et du lycopène de l’aliment fonctionnel a été évalué à l’aide d’un modèle de digestion in vitro simulant les conditions gastriques et duodénales. L’absorption intestinale des composés a également été mesurée en couplant le modèle de digestion in vitro aux cellules de type Caco-2 (TC7). L’étude a démontré que grâce à leur véhicule, les phytostérols dispersibles apportent un potentiel hypocholesterolémiant au produit, sans affecter la bioaccessibilité des carotènes. In fine, cet aliment fonctionnel a été optimisé d’un point de vue organoleptique et nutritionnel par l’utilisation de protéines sériques
Because of the exponential growth of malnutrition pathologies particularly in South countries, the development of functional foods based on fermented cereals represents an alternative to dairy products already marketed. The incorporation, the stability of lipophilic bioactive compounds such as carotenoids and phytosterols, as well as their behavior during the gastro-duodenal digestion have to be studied, in order to demonstrate the nutritional potential of this new product. Indeed, it is known that phytosterols decrease the carotenoid bioavailability. The main objective of this work was to design a probiotic functional food based on maize and enriched with carotenoids and phytosterols, and study the stability, the bioaccessibility and the intestinal absorption of these fat-soluble compounds. The formulation and the standardization of the manufacturing process, including the selection of starters for fermentation in order to obtain a probiotic product, were developed. During the production, the stability of fat-soluble compounds showed a retention level of 73%. The effect on dispersible phytosterols on the β-cryptoxanthine, β-carotene and lycopene bioaccessibilities was evaluated thanks to an in vitro digestion model mimicking the gastric and duodenal conditions. The intestinal absorption of these compounds was also estimate by crossing the in vitro digestion model with a Caco-2 cells model (TC7). The study demonstrated that thanks to their vehicles, dispersible phytosterols provide a potential cholesterol-lowering effect to this food, without affecting the carotene bioaccessibility. In fine, this functional food was optimized in terms of sensory and nutritional levels, by using whey protein isolates

Mycotoxins, the secondary fungal metabolites are important contaminants of food and feed. Among the other contaminants, aflatoxin B1 (AFB1) and OTA are frequently detected in the animal feed product. In the present study, the mixed dairy cow feed products were collected from the supermarkets in Qatar and analyzed for the presence of AFB1 and OTA. Yeast strains were isolated and tested for their biological control activities against aflatoxigenic and ochratoxin fungi. We demonstrated that local 15 yeasts isolates have important antifungal potential activities through the synthesis of volatile organic compounds (VOC) that are able to act against the mycotoxigenic fungi and their synthesis of the mycotoxins. Two Yeast strains (4&2) isolated from fermented food, have shown a great antifungal inhibition growth in-vitro as well as spores inhibition and mycotoxins synthesis.

For meat and meat products, secondary processes are those that relate to the downstream of the primary chilling of carcasses. Secondary processes include maturation chilling, deboning, portioning, mincing and other operations such as thermal processing (cooking) that create fresh meat, meat preparations and ready-to-eat meat products. This review systematically identified and summarised information relating to antimicrobial resistance (AMR) during the manufacture of secondary processed meatand meat products (SPMMP). Systematic searching of eight literature databases was undertaken and the resultantpapers were appraised for relevance to AMR and SPMMP. Consideration was made that the appraisal scores, undertaken by different reviewers, were consistent. Appraisal reduced the 11,000 initially identified documents to 74, which indicated that literature relating to AMR and SPMMP was not plentiful. A wide range of laboratory methods and breakpoint values (i.e. the concentration of antimicrobial used to assess sensitivity, tolerance or resistance) were used for the isolation of AMR bacteria.The identified papers provided evidence that AMR bacteria could be routinely isolated from SPMMP. There was no evidence that either confirmed or refuted that genetic materials capable of increasing AMR in non-AMR bacteria were present unprotected (i.e. outside of a cell or a capsid) in SPMMP. Statistical analyses were not straightforward because different authors used different laboratory methodologies.However, analyses using antibiotic organised into broadly-related groups indicated that Enterobacteriaceaeresistant to third generation cephalosporins might be an area of upcoming concern in SPMMP. The effective treatment of patients infected with Enterobacteriaceaeresistant to cephalosporins are a known clinical issue. No AMR associations with geography were observed and most of the publications identified tended to be from Europe and the far east.AMR Listeria monocytogenes and lactic acid bacteria could be tolerant to cleaning and disinfection in secondary processing environments. The basis of the tolerance could be genetic (e.g. efflux pumps) or environmental (e.g. biofilm growth). Persistent, plant resident, AMR L. monocytogenes were shown by one study to be the source of final product contamination. 4 AMR genes can be present in bacterial cultures used for the manufacture of fermented SPMMP. Furthermore, there was broad evidence that AMR loci could be transferred during meat fermentation, with refrigeration temperatures curtailing transfer rates. Given the potential for AMR transfer, it may be prudent to advise food business operators (FBOs) to use fermentation starter cultures that are AMR-free or not contained within easily mobilisable genetic elements. Thermal processing was seen to be the only secondary processing stage that served as a critical control point for numbers of AMR bacteria. There were significant linkages between some AMR genes in Salmonella. Quaternary ammonium compound (QAC) resistance genes were associated with copper, tetracycline and sulphonamide resistance by virtue of co-location on the same plasmid. No evidence was found that either supported or refuted that there was any association between AMR genes and genes that encoded an altered stress response or enhanced the survival of AMR bacteria exposed to harmful environmental conditions.