Desenvolvimento de cream cheese simbiótico: caracterização e perfil lipídico com ênfase em ácido linoléico conjugado

Abstract

Dairy products form the major part of functional foods available on market place. Fresh cheeses are propitious to addition of probiotics due to their suitable pH, acidity and moisture. The objective of this study was evaluate the potential of cream cheese as a vehicle of probiotics, the physical-chemical, microbiological and sensory characteristics and the lipid profile of this product when additioned of prebiotic and probiotics. Treatments of cream cheeses were produced with addition of different levels of probiotics (Bifidobacterium animalis and Lactobacillus acidophilus) and prebiotic (inulin) in amounts according to Central Composite Design, totalizing 12 treatments, with 4 fatorials, 4 axial, 3 repetitions on central point and 1 control. The characteristics were evaluated in all treatments during storage for 45 days at 8°C. No significant changes were observed on physical-chemical characteristics of fat, protein and ash in comparison with control, while moisture was altered by prebiotic addition. The surface response was done to verify the influence of different levels of inulin and probiotic on pH and tritable acidity during storage; only linear and quadratic terms of probiotic level were significant (p<0,05). The pH and tritable acidity affect the viability of cultures; starter culture (S. termophilus) exhibited high viability during storage. Bifidobacterium animalis showed counts above 106 UFC g-1 during all period, assuring the probiotic potential in all treatments. The counts of Lactobacillus acidophilus reduced along storage, probably by competition with starter culture. Assessment of sensory attributes (global appearance, color, aroma, texture, acidity and taste) was evaluated using test with hedonic scale of 7 levels and ordering test. No significant difference was found by Tukey s test (p>0,05) on assessment using hedonic scale, neither on the ordering test. The linear, quadratic and interaction terms of multiple linear regression were not significant (p>0,05) for any sensory attribute; only the intercept of each equation was significant (p<0,01). Lipid profile was not significantly changed by the different levels of probiotic, with amounts of saturated fatty acids, monounsaturated, polyunsaturated and trans fatty acids similar to that of the milk used on cheese manufacture and control. The different levels of probiotic no altered the concentration of conjugated linoleic acid (CLA) in comparison with control, probably due to the low addition of probiotic, the reduced viability of Lactobacillus acidophilus during storage and the short shelf-life of cream cheese, with small time to produce CLA. In conclusion, cream cheese with addition of prebiotic and probiotic on levels of this study showed functional potential; nevertheless, the amount of probiotic used does not increase the concentration of CLA compared to the traditional product.