Impact of whey protein - Beet pectin conjugation on the physicochemical stability of 尾-carotene emulsions
- 作者：Duoxia Xu ; Xiaoya Wang ; Junping Jiang ; Fang Yuan ; Yanxiang Gao ; gyxcau@126.com
- 关键词：尾-Carotene emulsion ; Whey protein ; Beet pectin ; Conjugation ; Physicochemical stability
- 刊名：Food Hydrocolloids
- 出版年：2012
- 期刊代码：37_0268005x
- 类别：ch
- 出版时间：August, 2012
- 卷：28
- 期：2
- 页码：258-266
- 文件大小：694 K
摘要
The aim of the present study was to investigate the impact of whey protein isolate (WPI)-beet pectin conjugation on the physical and chemical properties of oil-in-water emulsions incorporating 尾-carotene within the oil droplets. Covalent coupling of WPI to beet pectin was achieved by dry heating of WPI-beet pectin mixtures of different weight ratios at 80, 90, 100聽掳C and 79%relative humidity for incubation times ranging from 1 to 9聽h. It was confirmed by SDS-polyacrylamide gel electrophoresis that WPI covalently linked to beet pectin. The physical and chemical stability of 尾-carotene emulsions was characterized by droplet size and distribution, transmission profiles using novel centrifugal sedimentation technique, microstructure and 尾-carotene degradation during the storage. Compared with those stabilized by WPI alone and unheated WPI-beet pectin mixtures, 尾-carotene emulsions stabilized by WPI-beet pectin conjugates had much smaller droplet sizes, more homogenous droplet size distribution, less change in centrifugal transmission profiles and obviously improved freeze-thaw stability, indicating a very substantial improvement in the physical stability. Rheological analysis exhibited that emulsions stabilized by WPI-beet pectin conjugates changed from a shear thinning to more like Newtonian liquid compared those with WPI alone and unheated WPI-beet pectin mixtures. Degradation of 尾-carotene in emulsion during storage was more obviously retarded by WPI-beet pectin conjugate than WPI and unheated WPI-beet pectin mixture, probably due to a thicker and denser interfacial layer in emulsion droplets. These results implied that protein-polysaccharide conjugates were able to improve the physical stability of 尾-carotene emulsion and inhibit the deterioration of 尾-carotene in oil-in-water emulsions.