Date of Graduation

12-2015

Document Type

Thesis

Degree Name

Master of Science in Food Science (MS)

Degree Level

Graduate

Department

Food Science

Advisor

Navam S. Hettiarachchy

Committee Member

Pengyin Chen

Second Committee Member

Suresh K. Thallapuranam

Third Committee Member

Han-Seok Seo

Keywords

Biological sciences; High protein beverage; Non-GMO soybean; Soy protein hydrolysate

Abstract

Protein beverages made with non-genetically modified (non-GM) ingredients have been in demand due to the increasing consumers’ interest in healthy eating habit. Beverages formulated with non-GM soy protein are rare in the United States market since 93% soybeans planted in U.S (2013) are labeled as GM. This study aimed to develop protein hydrolysate beverages using one cultivar among the four Arkansas grown non-GM soybean cultivars including Osage, R95-1705, R08-4004 and R05-4969. R08-4004 was selected since it had the highest amounts of the three branched amino acids including Phenylalanine (51.4 mg/g), Leucine (74.9 mg/g), and Isoleucine (49.7 mg/g) with lowest amount of anti-nutrients including stachyose (42.0 mg/g) and trypsin inhibitor (23.0 TUI/mg). Soy protein isolate (SPI) was prepared using the aqueous extraction (pH = 9), and hydrolyzed at optimal condition of Alcalase concentration 1.0 AU (3.2 µL/g), 50 ºC, and 120 min incubation. The result was protein hydrolysate with low S0 value (35.4), low turbidity (0.9), high soluble protein content (46.7%), and highest Angiotensin-I Converting Enzyme (ACE-I) inhibition activity (66.6%).

Protein beverages containing 20 g SPH per 500 mL serving size were developed with Chai tea, tangerine, and mixed berries flavors. The sensory evaluation showed that the tangerine flavor had highest likeness followed by mixed berries, and Chai tea flavor. It also indicated that the usage of citric acid alone in tangerine flavor and the combination with bitter blocker and masking agent in mix berries flavor effectively minimized the bitter taste of SPH and increased the consumer acceptability. Shelf-life stability testing was at refrigerated storage (5 °C) over a 42 days period. Pasteurization (90-95 °C, 5 min) effectively prevented microbial growth. Turbidity increased significantly only in Chai tea drink, but not in tangerine and mixed berries flavored ones. Soluble protein content of three beverages decreased significantly caused by the precipitation of SPH over the storage period. Total color difference values changed during 42 days of storage due to the degradation of natural colors in the three beverages. Overall, the tangerine and mix berries flavored beverages received high consumer acceptance and have potential for commercial application.

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