Roberta Claro da Silva

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.

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.

Chemical Interesterification of Blends of Palm Stearin, Coconut Oil, and Canola Oil: Physicochemical Properties

trans-Free interesterified fat was produced for possible usage as a margarine. Palm stearin, coconut oil, and canola oil were used as substrates for chemical interesterification. The main aim of the present study was to evaluate the physicochemical properties of blends of palm stearin, coconut oil, and canola oil submitted to chemical interesterification using sodium methoxide as the catalyst. The original and interesterified blends were examined for fatty acid composition, softening and melting points, solid fat content, and consistency. Chemical interesterification reduced softening and melting points, consistency, and solid fat content. The interesterified fats showed desirable physicochemical properties for possible use as a margarine. Therefore, our result suggested that the interesterified fat without trans-fatty acids could be used as an alternative to partially hydrogenated fat.

Propriedades físicas de lipídios estruturados obtidos a partir de banha e óleo de soja

Human milk fat is essential for the development of term infants. The fatty acid composition and distribution in the triacylglycerols chains must be object of studies in infant formulas. The objective of this paper was to obtain structured lipids that have similar characteristics to the human milk fat. Binary mixtures of lard and soybean oil in different ratios (80:20, 60:40, 50:50, 40:60, 20:80) were submitted to chemical interesterification. The fatty acid composition, acid value, iodine value, solid fat content, consistency and melting point were analyzed in the mixtures before and after the interesterification. The solid fat content and consistency of lard decreased by the addition of soybean oil. Chemical interesterification modified the behavior the binary mixtures of lard with soybean oil, in all ratios, possibly as a function of the increase of di and trisatured triacylglycerols produced by the randomic effect. The interactions between lard and soybean oil presented a monotectic effect before and after the chemical interesterification. The modified mixtures with 20 and 40% of soybean oil presented similar fatty acid composition to human milk fat.

Effects of emulsifier addition on the crystallization and melting behavior of palm olein and coconut oil.

Two commercial emulsifiers (EM1 and EM2), containing predominantly monoacylglycerols (MAGs), were added in proportiond of 1.0 and 3.0% (w/w) to coconut oil and palm olein. EM1 consisted of approximately 90% MAGs, whereas EM2 consisted of approximately 50% MAGs. The crystallization behavior of these systems was evaluated by differential scanning calorimetry (DSC) and microscopy under polarized light. On the basis of DSC results, it was clear that the addition of EM2 accelerated the crystallization of coconut oil and delayed the crystallization of palm olein. In both oils EM2 addition led to the formation of smaller spherulites, and these effects improved the possibilities for using these fats as ingredients. In coconut oil the spherulites were maintained even at higher temperatures (20 °C). The addition of EM1 to coconut oil changed the crystallization pattern. In palm olein, the addition of 3.0% (w/w) of this emulsifier altered the pattern of crystallization of this fat.

Fatty acid composition in preterm and term breast milk.

The aim of this study was to determine and compare the fatty acid (FA) composition of colostrum and mature milk produced by nursing mothers of preterm and at-term newborns, in Florianópolis, SC, Brazil. Low contents of Eicosapentaenoic acid (EPA) (0.02%/colostrum and 0.01%/mature milk for preterm and term milk) and Docosahexaenoic acid (DHA) (colostrum group: 0.10%/preterm and 0.09%/term; mature milk: 0.05%/preterm and 0.03%/term) were determined. The comparison among the groups showed that the elaidic acid content was significantly higher (1.67%) in mature term milk. The content of rumenic acid (conjugated linoleic acid) was significantly higher in at-term colostrum compared with preterm colostrum. When considering the maturity of the milk, there was a significant increase in the percentage of this FA in the preterm group. The results show that, overall, the greatest differences observed were between the colostrums and mature milks for both groups and not between preterm and at-term mothers.

Comportamento de cristalização de lipídios estruturados por interesterificação química de banha e óleo de soja

The aim of this study was to evaluate the crystallization behavior of binary mixtures of lard and soybean oil in different ratios and their respective structured lipids obtained by chemical interesterification. Crystallization kinetics and polarized light microscopy were used to analyze the mixtures before and after interesterification. The addition of soybean oil changed the lard crystallization, by the effect of the dilution. Crystal diameter increased, while the number of crystals decreased, as a function of temperature. Interesterification resulted in the formation of fewer crystals, with larger diameter in comparison with the original mixtures.

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.

Physical properties of structured lipids from lard and soybean oil produced by enzymatic interesterification

O objetivo deste trabalho foi avaliar as propriedades fisicas das misturas entre banha e oleo de soja modificadas pela interesterificacao enzimatica catalisada por duas diferentes lipases comerciais, a AY30TM proveniente do microorganismo Candida cylindracea e a M10TM proveniente do microorganismo Mucor circinelloides. A banha apresentou ponto de amolecimento de 31,8 °C antes da interesterificacao e este valor foi reduzido a 29,1 e 28,8 °C apos a interesterificacao com as lipases AY30TM e M10TM, respectivamente. A consistencia da banha diminuiu apos a interesterificacao enzimatica com ambas as lipases, e a reducao foi maior quando o catalisador utilizado foi a lipase M10TM. Este resultado se deve a especificidade das posicoes sn-1,3 da lipase M10TM. A banha apresentou menor conteudo de gordura solida apos a interesterificacao, e essa reducao foi mais efetiva quando a reacao foi catalisada pela lipase M10TM. A banha nao interesterificada apresentou conteudo de gordura solida de 31,3% a 10 °C, que foi reduzido a 23,8 e 19,9% apos a interesterificacao com as lipases AY30 e M10, respectivamente. A banha e suas misturas binarias com o oleo de soja foram afetadas pela interesterificacao enzimatica e pela diluicao com o oleo de soja.

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.