Improvement of the emulsifying and oxidative stability of myofibrillar protein prepared oil-in-water emulsions by addition of zein hydrolysates

摘要

This study investigated the effects of zein hydrolysate (ZH) on the improvement of the emulsifying and oxidative stability of oil-in-water (O/W) emulsions prepared by myofibrillar protein (MP). The emulsifying activity index (EAI) and emulsion stability index (ESI) increased with the increase of ZH concentrations. Emulsions with 5 mg/mL ZH had the highest ESI and zeta-potential, the smallest mean particle size, and the lowest creaming index (p <0.05). Confocal laser scanning microscopy (CLSM) observation proved that emulsions with ZH possessed relatively small oil droplets, especially emulsions with 5 mg/mL ZH, which were coincident with the results of droplet diameters and particle size distributions. The micrographs demonstrating the-adsorption of ZH on the interfacial membrane of oil droplets in emulsions by CLSM also revealed that the interfacial membrane in emulsions with 5 mg/mL ZH were more compact and more massive than that those without ZH. The addition of ZH significantly reduced the peroxide values and thiobarbituric acid-reactive substances values (p <0.05) of emulsions during 10 days of storage. In general, our results revealed that the ZH promoted the adsorption of protein on the O/W interface and improved the emulsifying and oxidative stability of the MP O/W emulsion. (C) 2016 Elsevier Ltd. All rights reserved.