Semester of Graduation

Fall 2022

Degree

Master of Science (MS)

Department

School of Nutrition and Food Sciences

Document Type

Thesis

Abstract

Frozen yogurts contain yogurt culture bacteria which might impart health benefits to its consumers. Global frozen yogurt market sales are expected to grow 4.8% by 2028 which represents an important opportunity for the industry, consumers, and researchers. Polyphenols are metabolites found in plants which have antioxidant and anti-inflammatory properties and might prevent chronical diseases such as cancer, diabetes, and cardiovascular diseases. The objective of this study was to elucidate the effect of the polyphenol hesperidin on the physico-chemical, microbiological, and sensory characteristics of frozen yogurts. Hesperidin was incorporated in frozen yogurt at three concentrations (500, 250 and 125 mg/90g of product). Yogurt with no hesperidin was used as control. Viscosity and overrun of the frozen yogurt were analyzed as randomized block design at day 0. Hardness, pH, color, enumeration of Lactobacillus bulgaricus, and Streptococcus thermophilus counts were determined as randomized block design over days (0, 30, and 60). A factorial arrangement with three factors (hesperidin concentration, day, and minutes/hours) in a randomized block design over days (0, 30, and 60) was done for melting rate at minutes 60 and 90, bile tolerance of Streptococcus thermophilus, bile tolerance of Lactobacillus bulgaricus (0, 4, and 8 hours), acid tolerance of Streptococcus thermophilus (0, 1 and 2 hours), and acid tolerance of Lactobacillus bulgaricus (0, 15, and 30 minutes) were performed at days 7 and 60. A hedonic scale of 9 points was used to measure sensory attributes. Sensory data were analyzed as a completely randomized design. Data were analyzed at α = 0.05 using PROC GLM and ANOVA with Tukey adjustment. McNemar’s test was used to analyze purchase intent. Hesperidin did not influence pH, overrun, and microbial characteristics. Polyphenol addition decreased melting rate and increased hardness and bile tolerance of L. bulgaricus, L*, and b*. Sensory characteristics were not influenced by the lowest concentration of hesperidin being statistically the same compared to the control. Moreover, consumers were interested in purchasing frozen yogurt with hesperidin added after a health claim. This study serves as an important tool to develop a healthier frozen yogurt in an increasingly demanding market.

Date

10-27-2022

Committee Chair

Aryana, Kayanush

DOI

10.31390/gradschool_theses.5669

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