41-8 |
Enhanced conjugated linoleic acid (CLA) content of yogurt products through incorporation of probiotic bacteria |
S. XU1, T. D. Boylston2, and B. A. Glatz2. (1) Food Science and Human Nutrition, Iowa State University, 2622 Food Science Building, Ames, IA 50011, (2) Dept. of Food Science & Human Nutrition, Iowa State Univ., 2547 Food Sciences Bldg., Ames, IA 50011-1061 Conjugated linoleic acid (CLA) and probiotic bacteria, frequently found in dairy products, have been shown to have numerous health benefits. The development of yogurt products with enhanced CLA content using probiotic bacteria will further improve the nutritional value of yogurt. Our hypothesis is that we can increase the content of CLA in a modified yogurt product using probiotic bacteria and unique processing techniques without adversely affecting the flavor and texture of the yogurt. The objective of this research was to develop CLA-enriched yogurt products with probiotic bacteria. Four probiotic bacteria, Propionibacterium freudenreichii ssp. Shermanii 56, Pr. freudenreichii ssp. Shermanii 51, Pr. freudenreichii ssp. freudenreichii 23, and Lactobacillus rhamnosus, were used to produce yogurt with and without the conventional yogurt cultures (S. thermophilus and L. bulgaricus). The yogurts were prepared from skim milk with hydrolyzed soy oil (1%) and 1% fat milk. The yogurt was analyzed for CLA content, acidity and viable cells at 1, 7, and 14 days. Flavor and texture of the yogurts were evaluated using instrumental and sensory methods. All probiotic bacteria increased the content of CLA in the skim milk with hydrolyzed soy oil (1%). Pr. freudenreichii ssp. Shermanii 51 increased CLA content of yogurt products 2.6-fold compared to the control. Probiotic bacteria were more effective in producing CLA in skim milk with hydrolyzed soy oil (1%) than in 1% fat milk. No significant sensory differences were found between the yogurt prepared with probiotic bacteria and the control yogurt. The yogurt produced with mixed Pr. freudenreichii ssp. Shermanii 51 and yogurt culture showed the optimal flavor and texture. CLA-enriched foods are needed to evaluate the nutritional benefits of CLA in humans. This research demonstrated the ability of probiotic bacteria to form CLA through the biohydrogenation of free linoleic acid in yogurt products.
Session 41, Dairy Foods: Dairy microbiology
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