苜蓿冰结构蛋白对冷冻湿面筋品质及结构的影响  

Effect of Alfalfa Ice Structuring Proteins on Quality and Structure of Frozen Wet Gluten

作　　者：曲敏[1] 吴征 杜婷婷 朱秀清[1] 陈凤莲[1] 李凌俐 卢曼曼[1] QU Min;WU Zheng;DU Tingting;ZHU Xiuqing;CHEN Fenglian;LI Lingli;LU Manman(College of Food Engineering,Harbin University of Commerce,Harbin 150076,China)

机构地区：[1]哈尔滨商业大学食品工程学院,黑龙江哈尔滨150076

出　　处：《食品科学》2020年第18期42-50,共9页Food Science

基　　金：黑龙江省科技重大专项(2019ZX08B02);哈尔滨商业大学科学基金项目(18XN073);黑龙江省教育厅科研项目(2018-KYYWF-0669)。

摘　　要：采用冰球结合磷酸盐缓冲液法提取苜蓿冰结构蛋白(alfalfa ice-structuring proteins,AISPs),并对其氨基酸组成及其分离纯化后不同组分性质和结构进行鉴定。将AISPs与面筋蛋白干粉混合进行冷冻处理,旨在研究AISPs对冷冻湿面筋品质及结构的影响。结果显示:AISPs含17种氨基酸,亲水性氨基酸与疏水性氨基酸的比例约为7∶4;分离得到分子质量为34 kDa和52 kDa的2个蛋白组分,其热滞值最高均为0.41℃;Schiff染色显示,前者为糖蛋白,后者为非糖蛋白;其二级结构的比例分别为α-螺旋∶β-折叠∶β-转角∶无规卷曲=13.19∶60.21∶12.21∶19.16和α-螺旋∶β-折叠∶β-转角∶无规卷曲=16.87∶39.41∶26.69∶17.03。AISPs对-40℃处理样品的保护效果比-18℃更为显著。随着冻藏时间的延长和冻融周期的增加,湿面筋蛋白持水性下降,可冻结水含量上升,ω-麦醇溶蛋白部分降解,HMW-GS全部降解,冻藏样品的LMW-GS的B亚基和C亚基较稳定,D亚基有所增加;冻融样品则呈现B、C、D亚基均不同程度的增加,且以B亚基和C亚基的增加为主。加入AISPs后,在一定程度上缓解了蛋白组分降解。扫描电子显微镜结果显示,冷冻处理造成湿面筋蛋白网络质地粗糙、孔洞增大,而AISPs的添加使面筋网络得以清晰连续。In this paper,ice-structuring proteins(AISPs)from alfalfa were extracted using ice spheres combined with phosphate buffer,and their amino acid composition and the properties and structures of the purified AISP fractions were identified.In order to study the effect of AISPs on the quality and structure of frozen wet gluten,AISPs was mixed with dry gluten powder in water for freezing treatment.The results showed that AISPs contained 17 amino acids with a ratio of hydrophilic amino acids to hydrophobic amino acids of 7:4.Two protein components with molecular masses of 34 and 52 kDa were obtained from the fractionation of AISPs,and their thermal hysteresis values were both 0.41℃.Schiff staining showed that the former was glycoprotein and the latter was non-glycoprotein,and the proportions of secondary structure in them wereα-helix:β-sheet:β-turn:random coil=13.19:60.21:12.21:19.16,and 16.87:39.41:26.69:17.03,respectively.The protective effect of AISPs on frozen wet gluten samples at−40℃was more significant than at−18℃.With the increase in freezing time and the number of freezing-thawing cycles,the water-holding capacity of wet gluten protein decreased while the content of freezable water increased,andω-gliadin was partially degraded.High-molecular-weight glutenin subunit(HMW-GS)was completely degraded.The B and C subunits of low-molecular-weight glutenin subunit(LMW-GS)in frozen samples were stable,while the D subunit increased.The frozen-thawed samples showed an increase in subunits B,C and D,especially for subunits B and C.After adding AISPs,the degradation of gluten protein components was alleviated to some extent.Scanning electronic microscopy(SEM)results showed that freezing treatment resulted in rough texture and enlarged pores in the wet gluten network,while the addition of AISPs made the gluten network clearer and more continuous.

关 键 词：苜蓿冰结构蛋白 冷冻湿面筋 可冻结水含量 蛋白分子质量 微观结构 

分 类 号：TS213[轻工技术与工程—粮食、油脂及植物蛋白工程]