摘要
生物解离形成的乳状液是限制生物解离技术普及的重要瓶颈,本研究以大豆生物解离过程中形成的乳状液为研究对象,利用动态光散射技术、激光扫描共聚焦显微镜分别表征不同酶解时间(1、2、3 h)下乳状液粒径分布和乳状液内油脂与蛋白的空间分布,利用拉曼光谱从发色基团、二硫键及油脂-蛋白疏水相互作用角度重点解析乳状液中蛋白质荧光强度减弱机理。结果表明:生物解离使乳状液蛋白被酶解成小分子肽,从油滴表面脱落,导致油滴聚集合并。随着酶解时间延长,乳状液粒径变大,油滴数量减少,呈现出不规则形状;同时,激光扫描共聚焦显微镜结果显示随着酶解时间延长荧光强度减弱;拉曼光谱中与相同酶解时间条件下大豆分离蛋白比较,乳状液发色基团的强度明显减弱,且随着酶解时间延长强度减弱,说明乳状液中油脂-蛋白疏水相互作用屏蔽了分子内部的疏水性基团,使发色基团被掩盖,导致乳状液中荧光强度减弱。
Emulsion formation during enzyme-assisted aqueous extraction of soybean oil is an important bottleneck restricting the popularization of enzyme-assisted aqueous extraction.The particle size distribution and spatial distribution of lipids and proteins in emulsions obtained after different times(1,2,3h)of enzymatic hydrolysis of soybeans were characterized by dynamic light scattering and laser scanning confocal microscopy.The mechanism for the attenuation of fluorescence intensity in emulsions was analyzed by Raman spectroscopy based on hydrophobic interaction of chromophores,disulfide bonds and oil-protein interactions.The results showed that enzymatic hydrolysis resulted in the cleavage of proteins in emulsions into small peptides,which fell off from the surface of the oil droplets,leading to the aggregation of the oil droplets.The particle size increased with extended hydrolysis time,and the number of oil droplets decreased correspondingly,becoming irregular in shape.Laser scanning confocal microscopy showed that the fluorescence intensity was attenuated with increasing hydrolysis time.The Raman spectral intensity of chromophores from the emulsion resulting from enzymatic hydrolysis of whole soybean flour was dramatically reduced as compared with that from soybean protein isolate(SPI)at the same hydrolysis time and it decreased with the increase in hydrolysis time.These findings led us to conclude that hydrophobic oil-protein interaction in emulsions shielded the intermolecular hydrophobic groups and masked the chromophores,thus resulting in a reduction of fluorescence intensity.
作者
江连洲
王立敏
隋晓楠
毕爽
丁俭
张亮
高宇
扈莹莹
李杨
JIANG Lianzhou;WANG Limin;SUI Xiaonan;BI Shuang;DING Jian;ZHANG Liang;GAO Yu;HU Yingying;LI Yang(College of Food Science and Technology, Northeast Agricultural University, Harbin 150030, China)
出处
《食品科学》
EI
CAS
CSCD
北大核心
2018年第5期14-19,共6页
Food Science
基金
"十三五"国家重点研发计划重点专项(2016YFD0401402)
国家自然科学基金重点项目(31430067)
关键词
乳状液
空间分布
荧光强度
拉曼光谱
疏水相互作用
emulsion
spatial distribution
fluorescence intensity
Raman spectrum
hydrophobic interaction