Development of probiotic soy food with fruit pulp

Author(s)

Natalia Silva Matias

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Conjunto das Químicas (IQ e FCF) (CQ/DBDCQ)
• Defense date: 2011-10-21

Examining board members

Susana Marta Isay Saad; Helena Maria André Bolini Cardello; Sueli Rodrigues

• Advisor: Susana Marta Isay Saad

Abstract

Favorable changes in the composition of the intestinal microbiota can be observed with the regular consumption of functional foods containing probiotics. Probiotics are live microorganisms which when administered in adequate amounts confer a health benefit on the host. They are traditionally incorporated into fermented milks and other fermented milk products. Currently, the idea of reducing milk components as vehicles for probiotic agents has been promoted due to the high proportion of people who have lactose intolerance, and the search for vegetarian alternatives. In this context, soy appears as an ideal replacement for consumption, promoting health through intrinsic nutritional characteristics. This work aimed to develop a product similar to petit-suisse cheese, but soy based, with fruit pulp, and with probiotic micro-organisms, as well as evaluating the acceptability of the product from the point of view of its sensory and physico-chemical characteristics, microbiological and instrumental texture profile during storage at 4 ± 1 °C for up to 28 days. Three formulations were produced (in triplicates): F1 - formulation of probiotic petit-suisse cheese prepared with quark cheese, as control (milk product) F2 - formulation with soy \"cheese\" and milk cream (mixed product with soy and milk), F3 - formulation with soy \"cheese\" and soy cream (soy product). The three formulations were produced with the probiotic ABT-4 culture, consisting of the probiotic microorganisms Bifidobacterium animalis subsp. lactis Bb-12, Lactobacillus acidophilus La-5 and the starter culture Streptococcus thermophilus. The products were stored at 4 ± 1 °C and subjected to sensory evaluation (acceptability test, using an hedonic scale), after 7, 14, and 21 days, by 50 consumers in each period. Additionally, the products were monitored weekly during storage for up to 28 days regarding the viability of the probiotics and starter culture and their pH profile and the instrumental texture (double compression of samples test, using a TA-XT2 texture analyzer). Also, samples were monitored for the presence of contaminants, and, the chemical composition of the products was determined from samples kept frozen. The viability of the La-5 was satisfactory until the 28th day of storage for F1 and F2, with populations ranging from 8.29 to 7.56 log cfu/g and from 8.17 to 6.49 log cfu/g respectively. However, for F3, the population of La-5 proved to be satisfactory until the 21st day (8.18 to 6.84 log cfu/g), not reaching the minimum recommended in the last week. On the other hand, Bb-12 viability remained above 8 log cfu/g throughout the 28 days of storage for F1, F2, and F3. The starter culture populations were always between 9.73 and 8.86 log cfu/g. The pH remained stable for all formulations, but was significantly lower (p<0.05) for F2, compared to F1 and F3. As for the texture parameters hardness and gumminess, F1 showed antagonistic behavior in relation to F2 and F3. All texture parameters evaluated differed significantly for F1, F2, and F3 (p<0.05). There was no significant difference (p>0.05) in the sensory scores obtained for the same formulation, when different storage periods were compared. However, when the 3 formulations were compared, higher average scores (p<0.05) were obtained on day 21 for F3 (6.4) than for F2 (4.6). The soy-based foods, F2 and F3, proved to be good vehicles for probiotic microorganisms, with appropriate populations to characterize them as probiotics, and F3 showed a trend towards a better performance in sensory evaluation on days 14 and 21 days of storage. (AU)

• FAPESP's process: 09/05006-1 - Development of probiotic soy food with fruit pulp
• Grantee: Natalia Silva Matias
• Support Opportunities: Scholarships in Brazil - Master