Academic literature on the topic 'Bifidobacterium lactis (Bb-12)'

The influence of the honey addition on the fermentative activity of Bifidobacterium lactis Bb-12 and Bifidobacterium longum Bb-46 in soymilk was determined. Additionally, the inhibitory potential of honey-sweetened fermented soymilk against Listeria monocytogenes strain was examined. Two monofloral honey types were added to soymilk before the fermentation: dark-coloured chestnut honey and light-coloured acacia honey. On the basis of our previous studies on cow and goat milks, the basic hypothesis of this study was that the addition of honey could influence the growth of Bifidobacterium lactis and Bifidobacterium longum during the fermentation of soymilk. The addition of honey also influenced the decrease of raffinose and stachyose contents during fermentation. Furthermore, a higher inhibitory potential was assumed against Listeria monocytogenes caused by the honey addition. The obtained results show that both types of honey influenced the fermentative activity and numbers of Bifidobacterium lactis Bb-12 and Bifidobacterium longum Bb-46 viable cells in soymilk. Chestnut honey strongly influenced the acidity increase during the soymilk fermentation. A disc assay showed that the development of the inhibition zones of the growth depended on the type and concentration of honey, as well as on the type of milk. The chestnut honey had generally a higher inhibitory effect than acacia honey.  

Correction of the microbiota profile using prebiotics and probiotic strains of bifidobacteria and lactobacilli is important not only for the nutritional support during pregnancy, but also for the long-term health support of the mother and child. In this study, we performed systematic computer analysis of all available fundamental and clinical studies assessing interactions between probiotic bifidobacteria and various vitamins (B vitamins, vitamins A, C, E, D, etc.). We found that vitamins produce substantial amounts of vitamins (primarily folates and other B vitamins). Using the example of genome and proteome analysis of the probiotic strain BB-12 of Bifidobacterium lactis, we assessed molecular mechanisms underlying interactions of this strain with vitamins and trace elements. Key words: probiotics, microbiota, BB-12 strain of B. lactis, pregnancy, docosahexaenoic acid, vitamin D, folic acid, synergy of vitamins and bifidobacterial

ABSTRACT Several strains belonging to the genus Bifidobacterium were tested to determine their abilities to produce succinic acid. Bifidobacterium longum strain BB536 and Bifidobacterium animalis subsp. lactis strain Bb 12 were kinetically analyzed in detail using in vitro fermentations to obtain more insight into the metabolism and production of succinic acid by bifidobacteria. Changes in end product formation in strains of Bifidobacterium could be related to the specific rate of sugar consumption. When the specific sugar consumption rate increased, relatively more lactic acid and less acetic acid, formic acid, and ethanol were produced, and vice versa. All Bifidobacterium strains tested produced small amounts of succinic acid; the concentrations were not more than a few millimolar. Succinic acid production was found to be associated with growth and stopped when the energy source was depleted. The production of succinic acid contributed to regeneration of a small part of the NAD+, in addition to the regeneration through the production of lactic acid and ethanol.

In this study, the physical, chemical, rheological, and microbiological characteristics and the sensory properties of nonfat probiotic yoghurt produced at two different concentrations of apricot fibre (1% and 2%, w/v) and three different types of probiotic culture (Lactobacillus (L.) acidophilus LA-5, Bifidobacterium animalis subsp. lactis BB-12 (Bifidobacterium BB-12), and their mixtures) were investigated. As the fibre content increased, the rheological, structural, and sensory properties of probiotic yoghurt were negatively affected, while counts of L. delbrueckii subsp. bulgaricus, L. acidophilus LA-5, and Bifidobacterium BB-12 increased. When all the results were evaluated, the best results were obtained by using L. acidophilus LA-5 as probiotic culture and adding 1% (w/v) apricot fibre.

The effect of yoghurt and soya yoghurt containing Bifidobacterium lactis Bb-12 or B. longum Bb-46 on Ehrlich ascites tumour cell proliferation was investigated in vitro and in vivo. Tumour cells were incubated with B. lactis Bb-12 or B. longum Bb-46 cultivated in de Mann Rogosa Sharpe (MRS) broth medium, or with their centrifuged supernatant fractions or sediments, for 2 h at 37°C. Treatment resulted in the inhibition of tumour cell proliferation by 85·42 (sd 0·78) and 85·10 (sd 1·28) % by intact micro-organisms, 77·61 (sd 0·29) and 71·43 (sd 1·75) % by their supernatant fractions, but only 4·00 (sd 0·19) and 9·09 (sd 1·24) % by the two sedimented bacteria, respectively. The incubation of tumour cells with yoghurt and soya yoghurt containing Bb-12 for 2 h resulted in 83·01 (sd 0·11) and 88·23 (sd 0·06) % inhibition, respectively, while it was 83·82 (sd 0·24) and 86·36 (sd 0·06) %, respectively for the same products containing Bb-46. Corresponding values for plain yoghurt and soya milk (without bifidobacteria) were 32·81 (sd 0·14) and 5·55 (sd 0·12) %, respectively. The differences between yoghurt or soya yoghurt containing Bb-12 or Bb-46 and plain yoghurt, soya milk or control treatments were statistically significant (n 3; P>0·05). Female Swiss albino mice were injected intraperitoneally with the same tumour cells. The lifespan of mice fed diets supplemented with yoghurt or soya yoghurt containing Bb-12 or Bb-46 was prolonged by 16, 23, 34 and 39%, respectively compared with that of the positive control group (n 6; P>0·05). The lifespan of groups fed plain yoghurt or soya milk was prolonged by 15 and 8%, respectively. Prolongation of lifespan was positively correlated with faeces bifidobacterial count in the groups fed yoghurt or soya yoghurt containing bifidobacteria (r 0·917; P>0·05).

The aim of this study was to assess the possibility of using collagen protein hydrolysate in the production of milk fermented by Bifidobacterium animalis ssp. lactis Bb-12 and Lactobacillusrhamnosus. Physicochemical and organoleptic properties were studied and microbiological analysis of fermented milk was performed on days 1 and 21 of storage. Milk with the addition of 3% collagen protein hydrolysate was pasteurized (85 °C/30 min), divided into two groups, cooled to 37 °C and inoculated: the first group with Bifidobacteriumanimalis ssp. lactis Bb-12, second with Lactobacillus rhamnosus. Incubation was carried out at 37 °C/10 h. After 21 days of refrigerated storage, the pH value decreased in all analyzed milk samples. Collagen protein hydrolysate was a good milk additive to increase gel hardness and reduce syneresis. Moreover, its addition did not change the taste and odour of milk fermented with the use of Bifidobacterium Bb-12 and Lactobacillus rhamnosus. Collagen protein hydrolysate favourably stimulated the survival of Bifidobacterium Bb-12 during 21 days of storage. After 21 days of cold storage in milk with collagen, the number of Lactobacillus rhamnosus cells was reduced by 0.11 log cfu g−1.

Giardia duodenalis, formerly known as Giardia lamblia, is an important zoonotic protozoan parasite. It mainly infects the intestines of humans, dogs, cats and domestic animals, causing diarrhea, abdominal pain, indigestion and weight loss. At present, all the clinical drugs for the treatment of Giardia have problems such as side effects and drug resistance to varying degrees, and the development of new drugs for the treatment of Giardia is still a hot issue. There is growing interest in using probiotics as an anti-intestinal parasite strategy. The present study aimed to assess the effect of supernatants of Bifidobacterium Animalis Subsp. lactis BB-12 on giardia the growth of giardia trophozoites. In this study, the Bifidobacterium animalis subsp. lactis BB-12 were cultured in BBL liquid medium, and the effects of the supernatants on the growth and adhesion of trophozoites of Giardia were observed. The results showed that the growth of Giardia flagellate was significantly inhibited by the supernatant. The influence of the supernatant on the morphology of the trophozoites was observed by microscope, and it was found that the surface of the trophozoites was uneven, the shape was atrophied, the surface cell membrane was broken to some extent, and the contents were spilt. In summary, the results of this study suggest that the fresh-cultured supernatants of the probiotic Bifidobacterium Animalis subsp. lactis BB-12 have anti-Giardia effects.

This study was conducted to investigate the suitability of fresh-cut apple slices as carriers of the probiotic strain Bifidobacterium animalis subsp. lactis BB-12 (B. lactis BB-12). Furthermore, the effect of this strain against the colonization of apple by Escherichia coli O157:H7 was also evaluated. Apple wedges were suspended in an edible solution containing B. lactis BB-12 (greater than 8 log10 cfu mL–1) and/or E. coli O157:H7. Microbiological quality and physicochemical properties (pH, moisture content, soluble solids, titratable acidity, color, and texture) of probiotic samples were evaluated on days 1, 5, 9, and 14 of refrigerated storage. Sensory evaluation was performed on days 1 and 7. The probiotic concentration was above the recommended level of 10⁶ cfu/g during the test period. Co-inoculation with probiotic bacteria neither affected E. coli O157:H7 population dynamics, nor influenced the physicochemical and organoleptic properties of fresh-cut apple wedges. Minimally processed apples seem to be suitable vehicles for probiotic bacteria including B. lactis BB-12. Such probiotic products can be a desirable probiotic food choice for consumers, particularly those who are allergic or intolerant to dairy products. However, further studies are required to address the antagonistic effects of probiotic species on food-borne pathogens.

Abstract Bifidobacteria are one of the most important probiotics in dairy products. They have positive effects on human health. Nutritional benefits of bifidobacteria are genetically determined and can be promoted with addition of prebiotics. The aim of the present study was to examine the properties of Bifidobacterium lactis in dairy products. Pasteurised milk, freeze-dried starter culture Bb-12 (Bifidobacterium lactis, Chr. Hansen, Denmark), syrup of lactulose (Duphalac®, the Netherlands), and inulin (“Raftiline®HP”, ORAFI, Belgium) were used in the experiments. The optimal concentrations of lactulose (2%) and inulin (4%) were established in preliminary studies, based on quality indices and nutritional value of fermented dairy products (Beitane, 2008). Amino acids, carbohydrates, such as lactose, lactulose and inulin, as well as cholesterol were determined during the study using appropriate analytical procedures. The enzymatic activity of bifidobacteria determines nutritional value of the fermented dairy products. Addition of 2% lactulose resulted in significant increase of some amino acid concentrations, such as leucine, phenylalanine, lysine and arginine concentrations (P < 0.05), compared with those in other treatments. The presence of prebiotics caused a decrease of cholesterol level by 35% and lactose content by 31% in fermented milk samples. The enzymatic activity of bifidobacteria should be promoted with addition of lactulose and inulin to increase nutritional value of functional dairy products.

Three novel dehydrated wheat/rice cereal functional products with an addition of well documented probiotic Bifidobacterium animalis ssp. lactis BB-12® (BB-12®) were developed in Podravka factory for the infants older than 4 months: instant rice cereal, instant rice cereal with fruits and instant wheat cereal with vanilla. Notably, the number of viable BB-12® cells in each of the novel products was higher than the required minimal number of probiotic cells per gram of product (106 CFU/g) during the storage period of 106 weeks. Therefore, BB-12® strain recovery and genome stability were evaluated by strain-specific polimerase chain reaction and amplified fragment length polymorphism fingerprinting analysis. Further aim was to evaluate the influence of these three different cereal food matrices on specific probiotic properties of BB-12® strain in vitro. Applied food matrices positively influenced the survival in the simulated conditions of the gastrointestinal tract and antagonistic activity against undesirable microorganisms, while no influence on auto- and coaggregation ability of B. animalis ssp. lactis BB-12® was observed. Adhesion to extracellular matrix proteins and intestinal epithelial Caco-2 cells together with antibacterial activity emphasized competitive pathogen exclusion from Caco-2 cells by probiotic strain BB-12®.

Este trabalho teve como objetivo o desenvolvimento e a avaliação das propriedades funcionais, físico-químicas, reológicas, sensoriais de preferência pareada (do cheesecake e de sua cor) e microbiológica (contagens de coliformes fecais/totais e da bifidobactéria) do cheesecake manufaturado com farinha de trigo (ou amido de milho ceroso modificado), queijo fresco, sacarose, eritritol (como substituinte parcial de sacarose), ovos in natura, manteiga [ou frutoligossacarídeos (FOS) - prebiótico - como substituinte da manteiga], curcumina e Bifidobacterium animalis subespécie lactis BB-12 (probiótico). A análise estatística dos dados considerou a existência quatro grupos experimentais, sendo: [2 cheesecakes lights (em açúcar e gordura) potencialmente funcional e simbiótico: T1= farinha de trigo e FOS; T2 = AMCM e FOS] e [2 cheesecake light (em açúcar) potencialmente funcional e probiótico: T3 = farinha de trigo e manteiga; T4 = AMCM e manteiga]. Foi estabelecido um tratamento T0 como padrão da Tese, adaptado da formulação da QuarkTorte por Henning Fleissig (Alemanha). As variáveis de resposta foram do tipo quantitativa, considerando unidades formadoras de colônias (UFC) de bactérias láteas, unidade formadora de colônias (UFC) de coliformes totais e fecais, pH, atividade da água, dureza, adesividade, elasticidade, coesividade, gomosidade e mastigabilidade. Estas variáveis de respostas compuseram um modelo de Análise de Variância com medidas repetidas, pois as unidades experimentais foram observadas após 1, 8, 15, 22 e 28 dias. Medidas (como médias, medianas e desvio padrão), gráficos e ANOVA, foram geradas pelo pacote estatístico STATA® - versão 9.0. Os resultados da ANOVA não mostraram resultados estatisticamente significativos que indicassem existir diferenças entre os grupos experimentais [p-value: 0,7981; 0,4204; 0,9974; 0,6825; 0,6401; 0,4800; 0,6469; 0,4258; 0,4615] e nem entre os valores ao longo do tempo, dentro de cada grupo experimental [p-value: 0,1725; 0,0000; 0,4076; 0,8957; 0,8787; 0,0001; 0,6214; 0,8845; 0,6820] [p-value correspondentes respectivamente a: log de UFC de bactérias láteas; pH; atividade de água (aw); mastigabilidade; gomosidade; coesividade; elasticidade; adesividade; dureza]. Não houve proteção do probiótico pelo prebiótico, ao nível de FOS utilizado neste estudo. Foram efetuadas análises sensoriais de preferência pareada para o cheesecake (em três tratamentos: T0, T1 e T2) e para sua cor (em três amostras com curcumina a: 0%, 0,0076% e 0,0152%). O resultado para o cheesecake revelou que: a amostra mais preferida foi a T0; os tratamentos T1 e T2 não diferem entre si quanto à preferência; T0 não difere da T2; T0 difere da T1. O resultado para a cor do cheesecake revelou que: a amostra mais preferida foi a com curcumina a 0,0076%; e que as três amostras são iguais quanto à preferência da cor. O presente estudo dá sua contribuição para ampliar a oferta de alimentos láteos promotores da saúde humana com características: light, potencialmente funcional e simbiótico.
The aim of this work was the development and the evaluation of the functionals, physical-chemistry, rheological and sensorial analysis for the pairwise ranking test (cheesecake and its color), and microbiological properties of the cheesecake manufactured with wheat flour (or modified waxy corn starch - AMCM), fresh cheese, sucrose, erythritol (as sucrose partial substitute), eggs in nature, butter [or frutooligosaccharide (FOS) - prebiotic - as butter fat replacer], curcumin and Bifidobacterium animalis subspecies lactis Bb-12 (probiotic). The statistical analysis of the data was considered the existence four experimental groups: [2 cheesecakes lights (in sucrose and fat) potentially functional and symbiote: T1= wheat flour and FOS; T2 = AMCM and FOS] and [2 cheesecake light (in sucrose) potentially functional and probiotic: T3 = wheat flour and butter; T4 = AMCM and butter]. It was established a treatment T0 as the standard Thesis, adapted the wording of QuarkTorte by Henning Fleissig (Germany). The response variables were type of quantitative, whereas colony forming units (CFU) of lactic bacteria, forming unit colonies (CFU) of total and faecal coliforms, pH, water activity, hardness, adhesiveness, elasticity, cohesiveness, gumminess, chewiness. These variables of responses comprised a model of Analysis of Variance with repeated measures, because the experimental units were observed after 1, 8, 15, 22 and 28 days. Measures (such as average, median and standard deviation), graphics and ANOVA, were generated by statistical package STATA® - version 9.0. The results of the ANOVA showed no statistically significant results that indicate differences between the experimental groups [p-value: 0,7981; 0,4204; 0,9974; 0,6825; 0,6401; 0,4800; 0,6469; 0,4258; 0,4615] and not between the values over time, within each experimental group [p-value: 0,1725; 0,0000; 0,4076; 0,8957; 0,8787; 0,0001; 0,6214; 0,8845; 0,6820] [p-value corresponding respectively to: log of UFC of lactic bacteria; pH; water activity (aw); chewiness, gumminess, cohesiveness, elasticity, adhesiveness and hardness]. There was no protection of probiotic by prebiotic, at the level of FOS used in this study. Were made sensorial analysis of paired preference for the cheesecake (In three treatments: T0, T1 and T2) and to its color (in three samples with curcumin: 0%, 0.0076% and 0.0152%). The result for the color of the cheesecake revealed that: the sample most preferred was with curcumin to 0.0076%; and that the three samples are equal as the color preference. The present study gives its contribution to extend the offer of lactic food human health promoters with characteristics: light, potentially functional and symbiote.

Orientador: Carlos Raimundo Ferreira Grosso
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
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Resumo: Esse trabalho visou a encapsulação de Lactobacillus acidophilus e Bifidobacterium lactis e a avaliação "in vitro" da tolerância desses microrganismos livres e encapsulados quando inoculados em soluções biliares e de pHs ácidos, ou seja, em condições semelhantes às encontradas no intestino e no estômago humano, respectivamente. Além disso, foi determinada a estabilidade de B. lactis livres e encapsulados, incorporados em iogurte que foi mantido sob refrigeração, durante 28 dias. Para tanto, foram utilizados como agentes encapsulantes os polímeros entéricos aceto fitalato de celulose e alginato e os métodos de microencapsulação por spray drying e de imobilização por extrusão, respectivamente. Lactobacillus acidophilus e Bifidobacterium lactis foram extremamente resistentes às soluções biliares, tanto livres, quanto encapsulados. Apresentaram boa resistência quando inoculados em soluções de pH 2. Entretanto, nas soluções de pH 1, as populações das células livres e imobilizadas em alginato foram dizimadas, enquanto as células microencapsuladas em aceto fitalato de celulose apresentaram uma maior resistência. B. lactis não apresentaram uma boa viabilidade em iogurte, em nenhuma das condições testadas. Foi possível encapsular Lactobacillus acidophilus e Bifidobacterium lactis pelos métodos de extrusão e por spray drying mantendo um número elevado de células viáveis. A imobilização em alginato de sódio não foi eficaz na proteção às células de Lactobacillus acidophilus e Bifidobacterium lactis e a microencapsulação em aceto fitalato de celulose foi efetiva na proteção dos mesmos inoculados em soluções ácidas, embora não tenha sido eficiente quando B. lactis microencapsulado foi inoculado em iogurte.
Abstract: This study aimed at encapsulating Lactobacillus acidophilus and Bifidobacterium lactis and at carrying out an "in vitro" studyof the tolerance of these microorganisms, both free and encapsulated, when inoculated into bile solutions and acid pH solutions, that is, into conditions similar to those encountered in the human intestine and stomach respectively. In addition, the stability of free and encapsulated B. lactis was determined, when inoculated into yoghurt and stored under refrigeration for 28 days. The encapsulating agents used for this purpose were the enteric polymers cellulose acetate phthalate and alginate, and the methods of microencapsulation were spray drying and immobilisation by extrusion, respectively. Lactobacillus acidophilus and Bifidobacterium lactis were extremely resistant to bile solutions, both in the free forms and encapsulated. They also presented good resistance when inoculated into solutions at pH 2.0. However at pH 1.0, both the free cells and those encapsulated in alginate were destroyed, whilst those encapsulated in cellulose acetate phthalate showed greater resistance. B. lactis showed poor viability in yoghurt, under ali conditions tested. It was possible to encapsulate Lactobacillus acidophilus and Bifidobacterium lactis by both the methods of extrusion and by spray drying, retaining an elevated number of viable cells. Immobilisation in sodium alginate was not efficient in protecting cells of Lactobacillus acidophilus and Bifidobacterium lactis, and microencapsulation was efficient in protecting these same organisms when inoculated into acid solutions, although it was not efficient when microencapsulated B. lactis was incorporated into yoghurt.
Doutorado
Doutor em Tecnologia de Alimentos

The hypocholesterolemic effect of peptides present in crude casein hydrolysate using trypsin from Bifidobacterium animalis subsp. lactis (Bb-12) culture grown in casein solution or in MRS broth were compared with the control (unhydrolysed crude casein). These samples have shown to reduce cholesterol level in vitro to varying degree between 24-87%. The unhydrolysed crude casein (control) has shown not to have a reducing effect on cholesterol level. The reduction level of cholesterol was found to be dependant on the degree of hydrolysis. Fractions obtained after size exclusion from crude casein hydrolysate formed by trypsin after 48h hydrolysis have shown to reduce cholesterol level to degree vary between 2.7% to 50%. Bb-12 or trypsin crude casein hydrolysates were also found to possess angiotensin-converting enzyme (ACE) inhibitory activity in vitro to a varying degree between 29% and 38%, respectively. Unhydrolysed crude casein showed no real effect on ACE inhibitory activity. Trypsin hydrolysate has slightly more effect on ACE activity than Bb-l2. A relationship was also found between ACE-inhibitory activity and degree of hydrolysis. Fractions of crude casein hydrolysate after 48h hydrolysis with trypsin by size exclusion have shown to have ACE-inhibitory activity varying between 37% and 50%. Several identified ACE-inhibitory peptides from active fractions were found to have Phe, Trp, Tyr, Arg, Lys or Pro at their ultimate C-terminal position, making them a possible candidate for ACE-inhibitory activity. Further analysis on the profiles of casein and whey protein fractions, obtained by fast protein liquid chromatography (FPLC), of skimmed milk and four different commercial types of probiotic health drinks, and casein profile of added Bb-12 culture were investigated to study the possible effect of probiotics on milk proteins. Differences in protein-profile were found between the control and the four commercial probiotic health drinks as well as with added Bb-12 culture. Whey proteins were more resistance to hydrolysis than caseins.

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Agrárias, Programa de Pós-Graduação em Ciência dos Alimentos, Florianópolis, 2009
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Em uma primeira etapa foi avaliado o efeito da adição da bactéria probiótica Bifidobacterium Bb-12 e de ácido lático nas propriedades microbiológicas, físico-químicas, reológicas, microestruturais e de cor de queijo Minas Frescal nos dias 1 e 28 de armazenamento (5 ± 1 °C). Queijos sem ácido lático (Q1 e Q2) e com ácido lático (Q3 e Q4) foram fabricados, sendo a bifidobactéria adicionada nos queijos Q2 e Q3. Durante o armazenamento, queijos com bifidobactéria puderam ser classificados como probióticos, pois apresentaram contagem de células viáveis acima de 6 log UFC/g. A adição da bifidobactéria nos queijos Q2 e Q3 não influenciou (p > 0,05) no rendimento, no teor protéico e lipídico. Além disso, no dia 28, os queijos sem ácido lático apresentaram menor (p < 0,05) umidade em comparação aos adicionados de ácido lático, influenciando no comportamento reológico e microestrutural, tornando-os mais elásticos, firmes e compactos, no entanto, todos os queijos avaliados demonstraram comportamento viscoelástico com maior contribuição da componente viscosa. Os valores de L* e b* diminuíram (p < 0,05) durante o armazenamento em todos os queijos, sendo que apenas os adicionados de bifidobactéria mantiveram os valores de a* e ?E, ao longo dos 28 dias. Em uma segunda etapa foi realizada a avaliação sensorial dos queijos Minas Frescal contendo a bifidobactéria e diferenciados quanto à adição de ácido lático, através de testes de comparação pareada-preferência, perfil de consumidores, aceitabilidade global e intenção de compra. A adição de ácido lático não interferiu (p > 0,05) na preferência dos queijos, no entanto, os consumidores que avaliaram este produto apresentaram como perfil o gênero feminino, com idade entre 18 e 27 anos e que já possuem o hábito de consumir alimentos que ajudam a melhorar o funcionamento do intestino. Além disso, pôde-se observar que a maioria dos consumidores classificou os queijos como de boa aceitabilidade, sendo que comprariam este tipo de alimento funcional.

Microorganisms have been known to play a major role in human health since early times. The ingestion of microorganisms as probiotics to restore and/or maintain health is a widely accepted and common practice. The challenge in industry is to ensure viability of probiotics until their ingestion to their site of action, the colon, for health benefits to be realised. Microencapsulation is one of the techniques used to protect probiotic bacteria and ensure viability. A method that does not involve the use of extreme temperatures and/or solvents which would otherwise adversely affect viable cells was developed and patented. The method is solventless and is based on complexation of Food and Drug Administration-approved polymers, poly (vinylpyrrolidone) and poly (vinylacetate-co-crotonic acid) in supercritical carbon dioxide. The use of this method of encapsulation was found to be suitable in target release in earlier studies. Microparticles produced were found to have pH-dependent swellability, protecting bioactives, in this case probiotic bifidobacteria, in acid (simulated gastric acid) and only releasing them in an alkaline environment (simulated intestinal fluid). Further studies were, however, needed to investigate the suitability of the microparticles for food and pharmaceutical applications. The current study therefore aimed to characterize these microparticles in terms of size range, distribution of bacteria within the microparticles, and particle size distribution. The average size of the Bifidobacterium lactis Bb12-encapsulating microparticles was found to be within the acceptable size in food applications. High encapsulation efficiency was obtained, with live bacteria distributed evenly within the microparticles, demonstrating the potential of the microparticles to deliver high numbers of probiotic cultures as required for this type of microorganisms to deliver purpoted benefits to the consumer. Probiotic products are normally kept under refrigerated storage, yet the viability of bacterial cells still decreases. An additional benefit of encapsulation within microparticles would be protection of the encapsulated probiotics from the detrimental factors to which the probiotic products are exposed during storage. In order to investigate this for the microparticles in this study, the shelf life of encapsulated B. lactis Bb 12 powder stored in glass vials was investigated. High temperatures were used for accelerated shelf life studies. Encapsulated B. lactis Bb 12 maintained the viable levels above the therapeutic minimum for the duration of the study (12 weeks), which was 7 weeks more than was the case with unencapsulated probiotic. Thus the microparticles provided protection to the probiotic cultures at temperatures much higher than those normally used for storage of probiotic products. These results further indicate the possibility for storage of the B. lactis Bb12 encapsulated in the tested microparticles, at ambient temperatures for at least two months, without drastic loss of culture viability. Research has recently focused on the development of probiotic foods other than dairy and dairy-based foods. This has been necessitated by increasing vegetarian lifestyle and concerns of allergenicity. A maize-based traditional fermented beverage, mageu, was investigated for use as a vehicle for probiotic delivery. Although no significant difference was noted between survival of encapsulated and unencapsulated probiotic was noted, pH decrease in mageu with encapsulated B. lactis Bb 12 was less than with unencapsulated cells. This suggested that encapsulation would ensure that metabolites produced by encapsulated probiotics, if any, would not negatively affect a product in which they are incorporated. Further studies may be needed for investigation of the effect of the encapsulating microparticles in traditional fermented non-dairy products, using more acid-sensitive probiotic strains as the test strain used in the current study is well-known for its inherent resistance to acidity. This study filled gaps in knowledge in terms of the characteristics of microparticles produced using supercritical technology. The main highlights of the research findings were that the microparticles were suitable for food applications, improved probiotic viability under nonrefrigerated temperatures, and delayed browning of the probiotic powder and minimized drop in pH of the fermented product containing the probiotic encapsulated within. The results showed that microparticles encapsulating B. lactis Bb 12 are appropriate to consumers in areas where refrigeration is absent. Furthermore, the study showed that mageu is a suitable alternative vehicle to dairy-based products, for delivery of probiotic B. lactis Bb 12. This possibility extends accessibility of probiotic products to consumers who do not take dairy products for various reasons. There is also a potential increase of probiotic products on the market. Copyright
Dissertation (MSc)--University of Pretoria, 2012.
Microbiology and Plant Pathology
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