摘要
文中分析了绍兴白方腐乳白点的组成,并对有白点和无白点腐乳坯中的含氮物质进行了对比研究,同时利用傅里叶红外光谱对汤汁中蛋白质的二级结构进行了分析。结果表明:绍兴白方腐乳白点中的92.49%的物质为游离氨基酸,主要为酪氨酸,占86.27%,同时还含有少量蛋白质,该蛋白质经TCA-丙酮沉淀、Tricine-SDSPAGE分析和质谱鉴定,为大豆球蛋白Glycinin亚基碱性端肽链B1b,其分子质量为25.4 k Da。傅里叶红外光谱分析表明,有白点腐乳汤汁中蛋白质的二级结构中α-螺旋比无白点腐乳汤汁中蛋白质的高13.70%,而β-折叠比无白点腐乳汤汁中蛋白质的低20.04%,说明有白点腐乳汤汁中蛋白质的疏水性要高于无白点腐乳汤汁中的蛋白质。显著性水平检验结果表明,有白点腐乳和无白点腐乳坯中的三氯乙酸-氮溶指数、蛋白质水解度和游离酪氨酸含量差异显著,说明绍兴白方腐乳白点的产生跟腐乳坯中大豆蛋白质的过度水解产生过量酪氨酸有关。
This paper focused on the composition of white particles in Shaoxing White tofu, and nitrogen content in sufu with white particles and without white particles. The secondary structure of the protein in the liquid part of sofu was analysis using Fourier transform infrared spectroscopy （ FTIR）. This provided a theoretical reference to control the formation of white particles in Shaoxing white sufu. The results showed that： Free amino acids was 92.49% and mainly composed of tyrosine, 86.27% , and a small amount of protein. The protein in white particles was precipitated with TCA-acetone, analyzed with N-tris （hydroxymethyl） glycine-sodium dodecyl sulfate-polyacrylamide gel electrophoresis （Tricine-SDS-PAGE） and matrix-assisted laser desorption ionisation-time of flight/time of flight mass spectrometry （MALDI-TOF/TOF MS） , and identified as basic polypeptide Blb of soy Glyeinin G1 with the molecular weight of 25.4kDa. The secondary structure of proteins in the liquid part of sufu was investigated by fourier transform infrared spectrometer （FTIR）. The results showed that α-helix of proteins in sufu soup with white particles was 13.70% higher than that without white particles, while β-folding was 20.04 % lower, indicating that the proteins has higher hydrophobicity. Significant level test results showed that there were significant differences in TCA-NSI, DH and the content of free tyrosine between sufu pehtze with white particles and without white particles. This showed that the white particles had a relationship with the content of tyrosine from excessive hydrolysis of soy protein in sufu pehtze.
出处
《食品与发酵工业》
CAS
CSCD
北大核心
2016年第7期153-157,共5页
Food and Fermentation Industries
基金
973项目(2012CB720802)
973项目(2013CB733602)
绍兴市科技计划项目(2015018003)
国家自然科学基金重点项目(31130043)
江苏高校优势学科建设工程资助项目
高等学校学科创新引智计划(111计划)资助项目(111-2-06)
关键词
绍兴腐乳
白点
蛋白质
含氮物质
二级结构
Shaoxing sufu
white particles
protein
nitrogen containing materials
secondary structure
