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| Author(s): |
Clara Simone dos Santos
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Conjunto das Químicas (IQ e FCF) (CQ/DBDCQ) |
| Defense date: | 2016-06-16 |
| Examining board members: |
Susana Marta Isay Saad;
Luiz Antonio Gioielli;
Carmen Silvia Favaro Trindade
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| Advisor: | Susana Marta Isay Saad; Juliana Neves Rodrigues Ract |
| Abstract | |
The purpose of this study was to improve the sensory attributes of a tablespread previously developed by our research group, supplemented with the probiotic strain Bifidobacterium animalis Bb-12, besides inulin, and caseinomacropeptide, as well as to evaluate the product sensory acceptance, its physico-chemical and instrumental texture profile during refrigerated storage, and to verify the viability of the probiotic incorporated into the tablespread and its in vitro survival under conditions simulating the gastrointestinal tract during storage. Six binary blends of milk fat (MF) (x1) and palm olein (PO) (x2) were prepared in different proportions, whith two samples representing the pure components and four corresponding to binary blends, The fatty acid composition, free fatty acids, crystallization, and melting behaviors, and consistency analyses were performed for all MF:PO blends. Additionally, a commercial margarine (CM) was analyzed as a reference standard to the potentially probiotic tablespreads to be developed and its lipid base (CMLB) was analyzed as a reference for the selection of the MF:PO blends most suitable for the tablespreads preparation. Then, two MF:PO blends were selected to produce two tablespreads with Bb-12, inulin, and caseinomacropeptide, which were monitored during storage at 5 °C in time 0 (after processing), and after 1, 7, 14, 21, and 28 days. Microbiology assays, pH test, in vitro gastrointestinal survival, consistency, and sensory acceptance were performed. After 35 days of storage, the in vitro simulated gastrointestinal assay was repeated for subsequent probiotic DNA extraction in the food matrix in order to compare the different methods, including plate count and species-specific qPCR combined with the use of the Propidium Monoazide (PMA). All the MF:PO blends showed high concentration of palmitic and oleic acids, in the range between 30-34% and 10-50%, respectively. The addition of PO into MF resulted in an onset crystallization temperature delay for the MF:PO blends due to a physical interaction resulting from the MF high melting point triacylglycerol dilution. The consistency of the MF:PO blends varied between 385.9 and 12.172 gf/cm2 at 5 °C and 40:60 and 20:80 MF:PO blends presented consistency similar to (CMLB) at 10 °C. Thus, the 40:60 and 20:80 MF:PO blends were selected for the production of tablespreads, for presenting thermal behavior and consistency most suitable for this purpose. Following the tablespreads production, the Bb-12 populations remained stable ranging from 8 to 9 cfu/g throughout 28 days of storage at 5 °C (p>0.05) and their viability was not influenced by pH reduction. There was a decrease of up to 2 log cfu/g of the probiotic populations after 6 h of simulated gastrointestinal in vitro assay during all the studied periods (7, 14, 21, and 28 days) (p<0.05). On the other hand, the storage period did not significantly influence the survival rate of Bb-12 (p>0.05) and after 28 days the tablespreads TS 40:60 and 20:80 showed values of 80 and 75%, respectively. The different methods, count plate and qPCR with PMA, showed positive correlation in almost all steps of the in vitro assay. However, the tablespread TS 40:60 presented higher viable cell counts with the qPCR with PMA, when compared to the conventional plating method. The tablespreads sensory acceptability presented similar scores, ranging from 6.2 to 6.9, with consistency between 213.3 and 2,466.6 gf/cm2 between 5 and 15 °C. Therefore, the results obtained suggest that the TS40:60 tablespread may be considered the best formulation due the good technological parameters and good probiotic viability and survival under in vitro simulated gastrointestinal stress, besides presenting the highest sensory acceptance. (AU) | |
| FAPESP's process: | 14/04784-9 - Improvement of probiotic margarine sensory features and evaluation of the product functional potential |
| Grantee: | Clara Simone dos Santos |
| Support Opportunities: | Scholarships in Brazil - Master |