Ana Carolina Rodrigues Florence

Effect of different prebiotics on the fermentation kinetics, probiotic survival and fatty acids profiles in nonfat symbiotic fermented milk.

The simultaneous effects of different binary co-cultures of Lactobacillus acidophilus, Lactobacillus bulgaricus, Lactobacillus rhamnosus and Bifidobacterium lactis with Streptococcus thermophilus and of different prebiotics on the production of fermented milk were investigated in this paper. In particular, we determined and compared the kinetics of acidification of milk either as such or supplemented with 4% (w/w) maltodextrin, oligofructose and polydextrose, as well as the probiotic survival, chemical composition (pH, lactose, lactic acid and protein contents), fatty acids profile and conjugate linoleic acid (CLA) content of fermented milk after storage at 4 degrees C for 24 h. Fermented milk quality was strongly influenced both by the co-culture composition and the selected prebiotic. Depending on the co-culture, prebiotic addition to milk influenced to different extent kinetic acidification parameters. All probiotic counts were stimulated by oligofructose and polydextrose, and among these B. lactis always exhibited the highest counts in all supplemented milk samples. Polydextrose addition led to the highest post-acidification. Although the contents of the main fatty acids were only barely influenced, the highest amounts of conjugated linoleic acid (38% higher than in the control) were found in milk fermented by S. thermophilus-L. acidophilus co-culture and supplemented with maltodextrin.

Use of lactulose as prebiotic and its influence on the growth, acidification profile and viable counts of different probiotics in fermented skim milk.

Lactulose can be considered as a prebiotic, which is able to stimulate healthy intestinal microflora. In the present work, the use of this ingredient in fermented milk improved quality of skim milk fermented by Lactobacillus acidophilus, Lactobacillus rhamnosus, Lactobacillus bulgaricus and Bifidobacterium lactis in co-culture with Streptococcus thermophilus. Compared to control fermentations without lactulose, the addition of such a prebiotic in skim milk increased the counts of all probiotics, with particular concern to B. lactis (bifidogenic effect), the acidification rate and the lactic acid acidity, and concurrently reduced the time to complete fermentation (t(pH4.5)) and the pH at the end of cold storage for 1 to 35 days.

Fatty acid profile, trans-octadecenoic, α-linolenic and conjugated linoleic acid contents differing in certified organic and conventional probiotic fermented milks

Development of dairy organic probiotic fermented products is of great interest as they associate ecological practices and benefits of probiotic bacteria. As organic management practices of cow milk production allow modification of the fatty acid composition of milk (as compared to conventional milk), we studied the influence of the type of milk on some characteristics of fermented milks, such as acidification kinetics, bacterial counts and fatty acid content. Conventional and organic probiotic fermented milks were produced using Bifidobacterium animalis subsp. lactis HN019 in co-culture with Streptococcus thermophilus TA040 and Lactobacillus delbrueckii subsp. bulgaricus LB340. The use of organic milk led to a higher acidification rate and cultivability of Lactobacillus bulgaricus. Fatty acids profile of organic fermented milks showed higher amounts of trans-octadecenoic acid (C18:1, 1.6 times) and polyunsaturated fatty acids, including cis-9 trans-11, C18:2 conjugated linoleic (CLA-1.4 times), and α-linolenic acids (ALA-1.6 times), as compared to conventional fermented milks. These higher levels were the result of both initial percentage in the milk and increase during acidification, with no further modification during storage. Finally, use of bifidobacteria slightly increased CLA relative content in the conventional fermented milks, after 7 days of storage at 4°C, whereas no difference was seen in organic fermented milks.

Contribuição ao estudo das características físico-químicas e da fração lipídica do leite orgânico

Produtos orgânicos consistem em uma alternativa para uma alimentacao saudavel. Considera-se leite orgânico aquele produzido em sistema no qual e vedado o uso de agrotoxico sintetico ou outros insumos artificiais toxicos e organismos geneticamente modificados, visando a oferta de produtos saudaveis e de elevado valor nutricional. Existem poucos dados disponiveis sobre leite orgânico na literatura, mas ha indicacoes de que este apresenta maior teor nutritivo quando comparado ao leite produzido em sistema convencional. O objetivo deste trabalho foi caracterizar a composicao fisico-quimica, o perfil de acidos graxos e acido linoleico conjugado (CLA) em leites pasteurizados integrais oriundos de agricultura orgânica brasileira. Os leites orgânicos foram analisados durante o periodo de doze meses e os resultados comparados com aqueles obtidos de leites pasteurizados integrais provenientes de sistemas convencionais. A sazonalidade e o manejo dos animais afetaram a composicao quimica dos leites estudados no periodo de doze meses. Os teores de proteina foram maiores em leite orgânico, porem tendencia inversa foi observada nos niveis de gordura. Os principais acidos graxos do leite nao apresentaram diferencas significativas durante as estacoes do ano e entres os leites. Entretanto, foi verificado maior teor de CLA em leites orgânicos (2,8 vezes maior que em leite convencional), provavelmente devido a dieta dos animais.

Survival of Bifidobacterium Lactis hn019 and Release of Biogenic Compounds in Unfermented and Fermented milk is affected By Chilled Storage at 4°C

Development of dairy products containing bifido bacteria is one of the main focuses in the food industry, considering the health benefits attributed to its survival through gut intestinal tract and the liberation of biogenic compounds. In order to evaluate the effect of process conditions on survival of Bifidobacterium animalis subsp. Lactis HN019 and release of biogenic compounds during cold storage two technological processes were employed: (i) addition of Probiotic (unfermented bifido milk; UFBM) and (ii) fermentation (fermented bifido milk; FBM). B. Lactis HN019 counts were stable only in fermented milks during seven weeks of cold storage. Moreover, dairy matrices associated with cold storage appeared to protect bifidobacteria during exposition to gastric conditions, assuring the correct Probiotic counts at gut entrance. The distribution of fatty acids was affected by the different Probiotic products. In contrast, fermentation process increased the relative contents of some bioactive fatty acids, such as elaidic acid (+11%) and conjugated linoleic acids (+20%). It was also noted an increase in polyunsaturated fatty acids in the FBM and a higher relative content of monounsaturated fatty acids in the UFBM, as compared to control milk. In addition, fermentation process by bifido bacteria enhanced the long chain fatty acids fraction in bifido milks as compared to control and unfermented bifido milks. Control milk and unfermented bifido milk showed the same peptides even after seven days of storage in contrast with fermented milks that had increase bioactive peptides. It is possible to suggest that opioid peptides are formed during fermentation process, increasing the source of bioactive peptides. Finally, the cold conservation process modified peptides and could improve antibacterial activity.