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ARS Home » Southeast Area » New Orleans, Louisiana » Southern Regional Research Center » Food Processing and Sensory Quality Research » Research » Publications at this Location » Publication #310911
Title: Physical properties of a frozen yogurt fortified with a nano-emulsion containing purple rice bran oil

Author
item ALFARO, LUIS - Louisiana State University
item HAYES, DANIEL - Louisiana State University
item BOENEKE, CHARLES - Louisiana State University
item XU, ZHIMIN - Louisiana State University
item BANKSTON, DAVID - Louisiana State University
item Bechtel, Peter
item SATHIVEL, SUBRAMANIAM - Louisiana State University

Submitted to: LWT - Food Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/30/2015
Publication Date: 2/7/2015
Citation: Alfaro, L., Hayes, D., Boeneke, C., Xu, Z., Bankston, D., Bechtel, P.J., Sathivel, S. 2015. Physical properties of a frozen yogurt fortified with a nano-emulsion containing purple rice bran oil. LWT - Food Science and Technology. 62:1184-119.

Interpretive Summary: The U.S. frozen dessert business, including retail and food service markets, is the largest in the world. Purple rice bran oil is an excellent source of natural antioxidants. Adding nano-emulsion of purple rice bran-oil to products, including frozen yogurts, will improve the nutritional profile of the products by substantially increasing the natural antioxidant content. The objectives of this study were to produce a nano-emulsion containing purple rice bran oil, and to determine the effect of addition of a nano-emulsion containing the purple rice bran oil on the characteristics of frozen yogurt. A nano-emulsion with a droplet size range of 150-300 nm was produced by sonication followed by ultra-shear homogenization. The nano-emulsion was mixed with the frozen yogurt ingredients to produce a frozen yogurt containing nano purple rice bran oil. Plain-frozen-yogurt and frozen yogurt with sodium caseinate were used as controls. Triplicate experiments were conducted. All of the frozen yogurts had similar texture, melting rate, overrun, and similar lactic acid bacteria counts. After storage for 6 weeks the frozen yogurt retained 7 (µg/g oil) alpha-tocopherol, 17(µg/g oil) gamma-tocotrienol, and 858 (µg/g oil) gamma-oryzanol. This study demonstrated that frozen yogurt could be fortified with a nano-emulsion containing purple rice bran oil to create a product with unique marketing potential.

Technical Abstract: The objectives of this study were to develop and evaluate a frozen yogurt (FY) fortified with a nano-emulsion containing purple rice bran oil (NPRBO). A nano-emulsion with a droplet size range of 150-300 nm was produced by sonication followed by ultra-shear homogenization. The nano-emulsion was mixed with the frozen yogurt (FY) ingredients to produce a FY-containing-nano PRBO (FYNRO). Plain-frozen-yogurt (PFY) and frozen-yogurt-with-sodium caseinate (FYSC) were used as controls. The yogurts were analyzed for lactic acid bacteria (LAB), thiobarbituric-acid-reactive-substances (TBARS), peroxide value (PV), rheological properties, texture, melting percent, overrun, microstructure, and alpha-tocopherol, gamma-tocotrienol, and gamma-oryzanol content. Triplicate experiments were conducted and data was analyzed at a = 0.05. All of the frozen yogurts had similar texture, melting rate, and overrun. LAB counts were similar for all FY. PV’s (mmol/kg of FY) were 0.48, 0.27 and 0.17 for FYNRO, FYSC, and PFY, respectively, while TBARS (µmoles malonaldehyde /kg of FY) values were 3.88, 3.38, and 3.39 for FYNRO, FYSC, and PFY, respectively. FYNRO had 6.98 (µg/g oil) alpha-tocopherol, 16.80 (µg/g oil) gamma-tocotrienol, and 858.05 (µg/g oil) gamma-oryzanol at the end of storage. This study demonstrated that frozen yogurt could be fortified with a nano-emulsion containing purple rice bran oil (NPRBO).