44F-37 |
Use of cultured dairy solids on shelf-life extension of low-fat yogurt |
H. C. ALEXANDERSON-LEE, M. M. Marciniec, and A. Scotty. Division of Food & Nutrition, California State Univ., Long Beach, 1250 Bellflower Blvd., Long Beach, CA 90840-0501 Fruit-flavored, low-fat yogurt generally has a four to six week shelf-life when refrigerated properly. Physical changes may take place over time other than microbial spoilage that affect flavor and shelf-life of yogurt. Few studies describe variance in sensory properties of yogurt during shelf-life. This research was conducted to investigate the stability effects of “Cultured Dairy Solids” (CDS), Which affects flavor and yeast and mold growth in dairy products. Titratable acidity, pH, yeast and mold plating, and descriptive sensory analysis were conducted for a commercial, fruit-on the bottom (FOB) style yogurt. Experimental yogurts were manufactured with no CDS, and with the addition of 0.01% CDS to the yogurt base. The yogurts were studied for nine weeks; sensory analysis took place during weeks 5-9. Eight trained panelists developed nine descriptors for appearance, texture and flavor, to evaluate differences from the fresh reference yogurt. Eight descriptors were related to the yogurt base or the fruit-on-the bottom. Additionally, overall quality was rated after the yogurt was completely mixed. Chemical and microbiological tests showed constant quality throughout the study period. Analysis of variance indicated that there were no significant differences between the experimental yogurts for all sensory attributes tested. Significant differences (p<0.05) were found between the reference and both experimental yogurts for sweetness, consistency, and fruit freshness. No significant differences were detected in all sensory attributes over study period. Our results suggested that fruit freshness decreased and yogurt base thickened and was perceived to become sweeter over time. However, the overall quality of experimental yogurts compared well with the fresh reference for up to nine weeks and beyond.
Session 44F, Product Development
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