Academic literature on the topic 'Biopreservation compounds'

Microbial spoilage causes food losses in the food industry and as such, the use of synthetic chemical preservatives is still required. The current study proposes the use of agro-waste, i.e., grape pomace extracts (GPE), as production medium for biopreservation compounds. Production kinetics, subsequent to optimization using response surface methodology (RSM) for biopreservation compounds production was studied for three yeasts using GPE broth as a fermentation medium. The results showed that the highest volumetric zone of inhibition (VZI) was 1.24 L contaminated solidified media (CSM) per mL biopreservation compounds used (BCU) when Candida pyralidae Y1117 was inoculated in a pH 3-diluted GPE broth (150 g L−1) incubated at 25 °C for 24 h. Similar conditions were applied for Pichia kluyveri Y1125 and P. kluyveri Y1164, albeit under slightly elongated fermentation periods (up to 28 h), prior to the attainment of a maximum VZI of only 0.72 and 0.76 L CSM mL−1 ACU, respectively. The potential biopreservation compounds produced were identified to be isoamyl acetate, isoamyl alcohol, 2-phenyl ethylacetate and 2-phenyl ethanol.

Presently, biopreservation through protective bacterial cultures and their antimicrobial products or using antibacterial compounds derived from plants are proposed as feasible strategies to maintain the long shelf-life of products. Another emerging category of food biopreservatives are bacteriophages or their antibacterial enzymes called “phage lysins” or “enzybiotics”, which can be used directly as antibacterial agents due to their ability to act on the membranes of bacteria and destroy them. Bacteriophages are an alternative to antimicrobials in the fight against bacteria, mainly because they have a practically unique host range that gives them great specificity. In addition to their potential ability to specifically control strains of pathogenic bacteria, their use does not generate a negative environmental impact as in the case of antibiotics. Both phages and their enzymes can favor a reduction in antibiotic use, which is desirable given the alarming increase in resistance to antibiotics used not only in human medicine but also in veterinary medicine, agriculture, and in general all processes of manufacturing, preservation, and distribution of food. We present here an overview of the scientific background of phages and enzybiotics in the food industry, as well as food applications of these biopreservatives.

There is a growing consumer demand for natural foods, and it is of great interest to develop and produce natural and effective substances for food preservation, replacing synthetic preservatives. The growth of bacteria can occur in food due to environmental conditions during handling and storage, even if good manufacturing practices have been observed. This can cause losses for the industry, also becoming a risk of contamination to the consumer, being necessary to develop new techniques for controlling these sources of contamination. Lactic acid bacteria are known for their benefits to the organisms of those who consume them and for the ability to produce, under appropriate conditions, natural antimicrobial compounds, which can be used as biopreservatives in food and contribute to the increase of shelf life. Bacteriocins are proteins or peptides produced in ribosomes that have the capacity to act against certain pathogens, preventing their multiplication in products during the periods of storage and distribution. The aim of this review is to present the main bacteriocin-producing microorganisms, the forms of production, as well as the techniques by which these bioproducts have been applied in the biopreservation of food products and the results obtained. Biopreservation using bacteriocins has been studied and established as a new and important method, however it is necessary to search for production processes of these bacteriocins on a larger scale and with cost reduction, so that their potential can be increasingly explored by science and industry. Studies related to mechanisms of action and applications in food are also necessary in order to support the decisions of regulatory agencies.

Lactic acid bacteria produce a variety of small molecular weight compounds, which have antimicrobial properties. Such substances are: organic acids, alcohols, carbon dioxide, diacetyl, hydrogen peroxide and bacteriocins. Many of these compounds have a wide inhibitory spectrum but the bacteriocins are able to inhibit species, namely, related with the bacteriocin-producing strain. In the last years bacteriocins have gained a lot of concern because some of them are able to inhibit the growth of pathogenic bacteria, like Listeria monocytogenes. The term "biopreservation" refers to the extension of storage life, as well as to the enhancement of the food safety, using the bacteriocin-producing lactic acid strains or their metabolic antibacterial products. In this review will be reported bacteriocins, which are produced by the lactic acid bacteria and will be discussed the potential application of the bacteriocinogenic strains or their bacteriocins on the foods, as protective cultures or as protective compounds, respectively.

Fermentation of various foodstuffs by lactic acid bacteria (LAB) is one of the oldest forms of biopreservation practised by mankind. In recent years, significant advances have been made in elucidating the genetic and physiological basis of key LAB traits involved in these industrially significant processes. One important attribute of many LAB is their ability to produce antimicrobial compounds called bacteriocins. Interest in these compounds has grown substantially due to their potential usefulness as natural substitutes for chemical food preservatives in the production of foods with enhanced shelflife and/or safety. There is growing consumer awareness of the link between diet and health. Recent scientific evidence supports the role of probiotic LAB in mediating many positive health effects. In addition, some LAB are currently being assessed for their ability to act as live delivery vectors in the development of new oral vaccines.

Background: One of the main objectives of the food industry is the shelf life extension of food products, taking into account the safety requirements and the preference of consumers attracted by a simple and clear label. Following this direction, many researchers look to find out antimicrobials from natural sources. Methods: Tomato, carrot, and melon by-products were used as substrates for lactic acid fermentation using seven strains belonging to the Lactobacillus genus, L. plantarum, L. casei, L. paracasei, and L. rhamnosus. The obtained fermented by-products were then extracted and the antimicrobial activity toward fourteen pathogenic strains of Listeria monocytogenes, Salmonella spp., Escherichia coli, Staphylococcus Aureus, and Bacillus cereus was tested through agar well diffusion assay. Results: All the extracts obtained after fermentation had highlighted antimicrobial activity against each pathogen tested. In particular, a more effective activity was observed against Salmonella spp., L. monocytogenes, S. aureus, and B. cereus, while a lower activity was observed against E. coli. Conclusion: Lactic acid fermentation of vegetable by-products can be a good strategy to obtain antimicrobials useful in food biopreservation.

A Lactobacillus sake strain LKE5 and four strains of Carnobacterium piscicola were evaluated as biopreservation cultures to control the growth of Listeria monocytogenes on vacuum-packed, cold-smoked salmon stored at 5°C. All five strains were antilisterial as live cultures in an agar diffusion assay. Cell-free supernatants of two strains of C. piscicola and L. sake LKE5 were also antilisterial because of the production of bacteriocins. The presence of high cell numbers of strains of C. piscicola had no influence on the sensory quality of cold-smoked salmon stored at 5°C, but L. sake LKE5 caused strong sulfurous offflavors and was rejected as a culture for biopreservation of cold-smoked salmon. A bacteriocin-producing strain of C. piscicola (A9b) initially caused a 7-day lag phase of L. monocytogenes, followed by a reduction in numbers of L. monocytogenes from 103 CFU/ml to below 10 CFU/ml after 32 days of incubation, coinciding with the detection of antilisterial compounds. The presence of a nonbacteriocin-producing strain of C. piscicola (A10a) prevented the growth of L. monocytogenes during the 32-day incubation. The growth of L. monocytogenes was strongly repressed on cold-smoked salmon in the presence of C. piscicola A9b and A10a, respectively. The initial cell numbers of L. monocytogenes that were found on Oxford plates incubated at 25°C reached low maximum cell counts of 104 and 2 × 103 after 14 and 20 days of storage in mixed culture with C. piscicola A9b and A10a.

Thesis (MTech (Chemical Engineering))--Cape Peninsula University of Technology, 2016.
Microbial spoilage has been reported in various food products and this has led to increased food, fruit and beverage losses, thereby threatening economic growth, food safety and security. Furthermore, statistics have shown that more than 30% of agricultural produce in developing countries, mostly in Africa, is lost owing to microbial spoilage. Beverages, food and fruits are predominant contributors to the South African export market. In recent years, contamination of these products resulting in spoilage has been a problem, although partial spoilage control has been achieved using chemical preservatives such as dimethyl dicarbonate, sodium benzoate, potassium sorbate, and sulphur dioxide (SO2). However, prolonged exposure to these chemical preservatives can cause human health problems such as skin and/or eyesight damage, muscle and stomach pain, cardiovascular disease and the impairment of brain function. To mitigate such health concerns, biologically benign alternatives are deemed suitable, providing the rationale for this study.

Thesis (PhD (Chemical Engineering))--Cape Peninsula University of Technology, 2019
The agro-processing industry is currently facing losses due to microbial spoilage of agricultural produce and associated value-added products such as beverages. Decay and undesired fermentation of fruit and beverages by fungal, yeast and bacterial spoilage organisms are among the major contributors of product losses in the food industry. When looking at the different level of food spoilage, it is common to find different spoilage organisms occurring in the same food item; which usually requires food producers to utilise a mixture of synthetic preservatives for spoilage organism control. Some of the synthetic chemical compounds with growth inhibition properties that have been used in food preservation are sulphur dioxide, benzoic, lactic, sorbic and acetic acid. These compounds act against a variety of spoilage microorganisms. In post-harvest control of fungi, triazoles, hydroanilide fenhexamid, dicarboximides and succinate dehydrogenase are also being used. Some spoilage organisms have been found to be resistant to the use of synthetic chemical preservatives which usually favour the use of higher dosage of preservatives in food. The use of synthetic chemicals as preservative and as postharvest control agents has been found to present serious health risks such as cardiovascular diseases, muscles and stomach pains, eyesight and skin damages and impairment of brain functions. The problem posed by the current use of synthetic chemicals in food put pressure on food producers and exporters to seek alternatives that will allow for the eradication of the use of synthetic chemicals as preservative in beverages and as postharvest control agents on fruits. Yeasts have been found to have the ability to grow at a faster rate on cheap media and to colonise dried surfaces rapidly. It has also been found that yeasts produce extracellular compounds of proteinaceous and volatile organic nature with growth inhibition properties against spoilage organisms. The current findings lack some engineering concept that could assist in the design of a production system for high scale production of biopreservation compounds from yeasts. The availability of a cost effective production media, the growth and production kinetics data using a cheaply available nutrient sources as well as the biological thermodynamic data are some of the gaps in biopreservation bioprospecting. Although several yeasts have already been studied to have great inhibition properties against fruit fungal pathogens, it was still unclear what was the minimum inoculum dose to be able to have a fungistatic and fungicidal effect on the growth of fruit spoilage organisms. The concept of combination of biopreservatives and the interaction effect of their biopreservation activity against consortia of spoilage organisms has also been lacking. As an attempt to seek alternatives to the use of synthetic chemicals as preservatives or postharvest control agents, Candida pyralidae Y1117, Pichia kluyveri Y1125 and Pichia kluyveri Y1164 strains were assessed for antimicrobial activity against spoilage yeasts (Dekkera bruxellensis, Dekkera anomala, Zygosaccharomyces bailii) and spoilage fungi (Botrytis cinerea, Colletotrichum acutatum and Rhizopus stolonifer). As alternative to refined media, a cost effective approach was explored whereby the use of agro-waste, i.e. grape pomace extracts (GPE), as production medium for biopreservation compounds, was studied. Production kinetics using modified existing models, subsequent to optimization using response surface methodology (RSM) for biopreservation compounds production was studied for the three biocontrol yeasts using GPE broth as the fermentation medium. The evaluation of the interaction study between mixtures of crude biopreservatives against consortia of common spoilage organisms present in beverages was also conducted by producing the crude biopreservation compounds separately from yeasts and then formulating growth inhibition combinations (GICs); GIC 1 (Candida pyralidae Y1117 and Pichia kluyveri Y1125); GIC 2 (C. pyralidae Y1117 and P. kluyveri Y1164), GIC 3 (P. kluyveri Y1125 and Pichia kluyveri Y1164); GIC 4 (C. pyralidae, P. kluyveri Y1125 and P. kluyveri Y1164). The spoilage organism consortia combinations, i.e. SC1, D. anomala and D. bruxellensis; SC2 (D. anomala and Z. bailii); SC3 (D. bruxellensis and Z. bailii) and SC4 (D. anomala, D. bruxellensis and Z. bailii) were also prepared. This study also investigated the effect of varying inoculum dose (ID) of Candida pyralidae strain Y1117, Pichia kluyveri Y1125 and Pichia kluyveri Y1164 on the biocontrol of Botrytis cinerea by contaminating the headspace of the growth medium with a fungal plug subsequent to biotreatment with different initial inoculum dose of the respective biocontrol yeasts. Finally, grape pomace extracts was used as fermentation medium to study the biological thermodynamics of biopreservation compound production from the three biocontrol yeasts. The results obtained demonstrated some interesting results. The antagonistic properties of C. pyralidae and P. kluyveri were observed on cheap solidified medium (grape pomace extracts) as well as on fruits (grapes and apples). These yeasts produced extracellular volatile organic compounds (VOCs) that could be responsible for yeast and fungal growth inhibition. Twenty-five VOCs in the category of alcohols, organic acids and esters were identified by GC-MS. The results of the kinetic study showed that the highest volumetric zone of inhibition (VZI) was 1.24 L contaminated solidified media (CSM) per mL biopreservation compounds used (BCU) when Candida pyralidae Y1117 was inoculated in a pH 3-diluted GPE broth (150 g L−1) incubated at 25 °C for 24 h. Similar conditions were applied for Pichia kluyveri Y1125 and P. kluyveri Y1164, albeit under slightly elongated fermentation periods (up to 28 h), prior to the attainment of a maximum VZI of only 0.72 and 0.76 L CSM mL−1 ACU, respectively. The potential biopreservation compounds produced were identified to be isoamyl acetate, isoamyl alcohol, 2-phenyl ethylacetate and 2-phenyl ethanol. The growth inhibition interaction study showed a variation in growth inhibition proficiency depending on the spoilage organisms or the consortia of spoilage organisms being deactivated. It was then suggested that, a food environment contaminated with a consortium of spoilage organisms can be controlled by employing either the crude biopreservation compounds from individual yeast or those of the following yeast combinations, GIC1-4, which showed a better growth inhibition proficiency against SC1-3. The fungistatic and fungicidal effects on the fungal pathogen were dose dependent. The fungistatic characteristics against Botrytis cinerea were displayed after 7 days when 102-105 cells mL-1 of Candida pyralidae Y1117, Pichia kluyveri Y1125 and Pichia kluyveri Y1164 were independently used in-vitro and in-vivo. However, 106-108 cells mL-1 inoculum doses displayed fungicidal characteristics. Additionally, the fungicidal property of yeasts studied was also confirmed on table grape (in vivo studies) using closed jar method. The biological thermodynamic study showed that, dried biomass molecular weight of 28.9 g/C-mol, 29.163 g/C-mol, and 27.176 g/C-mol were obtained for Candida pyralidae strain Y1117, Pichia kluyveri Y1125 and Pichia kluyveri Y1164 respectively. The results obtained successfully established useful biological thermodynamic data applicable to the design of adequate biopreservatives production system from yeasts using cheaply available nutrients source.

La contamination fongique des produits laitiers est à l’origine de pertes économiques conséquentes et de gaspillage alimentaire. Dans un contexte de demande pour plus de « naturalité », les cultures de bioprotection et leurs métabolites représentent une alternative d’intérêt aux conservateurs chimiques pour lutter contre ces contaminants.Les objectifs de cette thèse étaient i) de sélectionner des micro-organismes présentant une activité antifongique, pour élaborer des cultures de bioprotection applicables dans des produits laitiers, et ii) d’étudier les composés potentiellement supports de l’activité antifongique observée. Dans un premier temps, l’activité antifongique de 32 souches de bactéries lactiques et propioniques a été étudiée en modèles « fromage » et « yaourt ». L’étude de combinaisons de souches et de leur innocuité a conduit à sélectionner 2 combinaisons binaires de lactobacilles (A1 et A3). Leur efficacité et applicabilité a été évaluée à l’échelle pilote en fabrication de crème fraîche et de fromage.Les challenges tests et tests d’usages ont montré que selon le produit laitier, A1 et A3 ont une activité antifongique similaire ou supérieure que les cultures bioprotectrices commerciales. Selon l’inoculum ajouté, ces cultures n’impactent pas les caractéristiques technologiques et organoleptiques des produits laitiers. Des méthodes chromatographiques des composés antifongiques suivies d’analyses statistiques ont permis de mettre en évidence des « cocktails » de 2 à 17 composés, selon la matrice et la culture considérée, qui sont probablement supports de l’activité antifongique.Ces travaux contribuent à une meilleure compréhension des mécanismes d’action de l’activité antifongique et devraient conduire au développement de cultures antifongique pour remplacer les conservateurs dans les produits laitiers
Fungal contamination of dairy products is responsible for economic losses and food waste. In a context of “preservative-free” product demand, bioprotective cultures and their metabolites represe,t an alternative of interest of chemical preservatives to control these spoilers.The objective of this study was i) to select microorganisms exhibiting an antifungal activity, in order to elaborate bioprotectivecultures applicable in dairy products, and ii) to study the compounds potentially supporting the observed activity. Firstly, the antifungal activity of 32 strains of lactic acid and propionic bacteria screened in cheese model and yogurt. Strain combinaison study and safety assessment led to the selection of 2 binary lactobacilli combinations (A1 and A3). Their efficiency and applicability were then evaluated in pilot-scale productions of sour cream and cheese.Challenge and shelf life tests showed that depending on the dairy product, A1 and A3 have a similar or higher antifungal activity than the commercial bioprotective cultures. In addition, depending of inoculum, A1 and A3 did not impact the technological and organoleptic characteristics. Chromatographic methods and statistical analyses allowed identifying cocktails of 2 to 17 compounds, according to the considered dairy product and culture that probably support the antifungal activity.The obtained results contribute to a better understanding of the antifungal activity action mechanisms and should lead to the development of antifungal cultures to replace preservatives in dairy products

博士
國立中興大學
食品暨應用生物科技學系所
103
Recently, drugs and chemical preservatives are generally used in food products resulting in many serious problems in food safety. In addition, antibiotics overuse lead to evolution of Multiple drugs-resistant strains such as Methicillin-resistant Staphylococcus Aureus (MRSA) and Vancomycin-resistant strains. Futhermore, molds are able to proliferate in food to produce mycotoxin such as alpha-toxin. Many studies have demonstrated that mycotoxin can induce cell mutation leading to induction of hepatic tumor. At present, many studies focused on natural products to replace chemical preservatives against bacteria and molds. The three Bacillus lipopeptides, surfactins, iturins and fengycins, have broad anti-pathogens activities including bacteria and molds. Today, our study successfully purified non-toxic biopreservative from GRAS Bacillus. In addition, our study added the non-toxic biopreservative in food and cosmetics to develop a natural biopreservative and skin-care products. In this study, candidate strain isolated from chicken intestines was cocultured with Asp. niger by using spot on the lawn method, and the candidate bacteria strain with anti-molds activity were analyzed and isolated. Furthermore, the candidate bacterial strain and its antimicrobial gene were identified by PCR method. Next, we extracted the antimicrobial lipopeptides by aicd precipitation , then analyzed the lipopeptide structure by using LC-ESI-Mass/Mass. After that, the antimicrobial spectrum of the CFS products produced from bacillus amyloliquefaciens JN68 were determined by various indicators. The preservative activities of food and cosmetics containing CFS crude extracts were futher analyzed in this study. Our results showed that CFS extracts successfully inhibit growh of various bacteria and molds including MRSA、Vancomycin-resistant E.coli, EIEC, alpha-toxin producing molds、Helicobacter pylori、pathogen、food spoilage bacteria、clinical skin dermatophyte. On the other hand, the gene and structure analysis data showed that the activity compounds from CFS crude extracts are classified into three lipopeptides families，surfactin，iturin and fengycin. Importantly, food and skin-care products with this CFS extracts have obvious biopreservative activities. Therefore, our results indicated that CFS extracts produced from Bacillus amyloliquefaciens JN68 have great potential to replace chemical preservative to act as biopreservative.