Date of Award

2011

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Family and Consumer Sciences

First Advisor

Ibrahim, Salam A. Dr.

Abstract

Quality and consumer acceptability are essential parameters in dairy products The objectives of the present study were to examine the microbiological (viability of L. bulgaricus, S. thermophilus, and bifidobacteria), chemical (pH, titratable acidity, and total solids), and physical(syneresis) qualities of yogurt enriched with rice extract as a stabilizer during 28 days of storage at 4°C. Additionally, viscosity measurements and consumer acceptability were determined for yogurt enriched with rice extract. Results showed that the viability of L. bulgaricus was maintained with the addition of rice extract. Population of Streptococcus thermophilus and bifidobacteria decreased significantly (p<0.05) in the control sample but the addition of rice extract at 15% concentration supported the viability of bifidobacteria in yogurt over storage. The addition of rice extract did not alter the pH or titratable acidity of yogurt. Viscosity, total solids and syneresis values slightly changed with the addition of rice extract. Yogurt prepared with rice extract ranked higher in terms of texture and appearance by the panelists. Our results indicated that the addition of rice extract could improve the quality characteristics and consumer acceptability of plain yogurt. Hence, rice extract has a promising potential to be used as an alternative stabilizer in dairy products.

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