Yao Hongli, Liu Shuangping, Chang Rui, Liu Tiantian, Zhou Zhilei, Mao Jian
State Key Laboratory of Food Science and Resources, National Engineering Research Center of Cereal Fermentation and Food Biomanufacturing, School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China; Department of Biology and Food Engineering, Bozhou University, Bozhou, Anhui 236800, China.
State Key Laboratory of Food Science and Resources, National Engineering Research Center of Cereal Fermentation and Food Biomanufacturing, School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China; Guangdong Engineering Research Center of High-Value Utilization and Equipment Development of Marine Biological Resources, Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou, Guangdong 511458, China; Jiangnan University (Shaoxing) Industrial Technology Research Institute, Shaoxing, Zhejiang 31200, China; National Engineering Research Center of Huangjiu, Zhejiang Guyuelongshan Shaoxing Wine CO., LTD, Shaoxing 646000, Zhejiang, China.
Food Res Int. 2025 Jan;200:115470. doi: 10.1016/j.foodres.2024.115470. Epub 2024 Nov 29.
To explore the mechanism of Virgibacillus proteases on hydrolysis of shrimp myofibrillar protein (SMP) and formation of volatile compounds, the fermented broth of Virgibacillus halodenitrificans was purified and the protease was identified as peptidase S8. The enzyme had optimum activity at pH 7.0-8.5 and 40-50 °C, and showed good stability at pH 6.5-8.5 and 20-50 °C. The enzyme showed certain salt and metal ion tolerance. Inhibitor results indicated that the enzyme might belong to the serine protease family. V. halodenitrificans proteases (BP) had a stronger ability to degrade SMP compared to Bacillus subtilis proteases (BS). After 60 min of hydrolysis, the hydrolysis index and surface hydrophobicity value of the BP sample were 36.7 % and 177.5 higher than those of the BS sample, respectively. Various spectral measurement results showed that the structural conformation of the BP-treated SMP was significantly changed, with a smaller particle size (510.4 nm) and a lower zeta potential (-27.7 mV). Molecular docking results showed that the enzyme had the highest degradation capacity for myofibrillar heavy chains, followed by actin, and the lowest for myofibrillar light chains, with the interaction forces being hydrogen bonding and hydrophobic interactions. In addition, BP-treated SMP had higher levels of peptides, small molecular weight peptides (<1 kDa), and umami amino acids compared to the BS sample. Solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) results showed that BP hydrolysates contained more volatile compounds and key volatile compounds than BS hydrolysates. Pyrazines and alcohols were the main volatile flavor compounds in BS and BP hydrolysates, respectively.
为探究嗜盐脱氮弧菌蛋白酶对虾肌原纤维蛋白（SMP）水解及挥发性化合物形成的作用机制，对嗜盐脱氮弧菌发酵液进行了纯化，并鉴定该蛋白酶为肽酶S8。该酶在pH 7.0 - 8.5和40 - 50℃时具有最佳活性，在pH 6.5 - 8.5和20 - 50℃时表现出良好的稳定性。该酶对盐和金属离子具有一定耐受性。抑制剂实验结果表明该酶可能属于丝氨酸蛋白酶家族。与枯草芽孢杆菌蛋白酶（BS）相比，嗜盐脱氮弧菌蛋白酶（BP）降解SMP的能力更强。水解60分钟后，BP样品的水解度和表面疏水性值分别比BS样品高36.7%和177.5。各种光谱测量结果表明，经BP处理的SMP的结构构象发生了显著变化，粒径更小（510.4 nm），ζ电位更低（-27.7 mV）。分子对接结果表明，该酶对肌原纤维重链的降解能力最高，其次是肌动蛋白，对肌原纤维轻链的降解能力最低，相互作用力为氢键和疏水相互作用。此外，与BS样品相比，经BP处理的SMP含有更高水平的肽、小分子肽（<1 kDa）和鲜味氨基酸。固相微萃取-气相色谱-质谱联用（SPME-GC-MS）结果表明，BP水解产物比BS水解产物含有更多的挥发性化合物和关键挥发性化合物。吡嗪类和醇类分别是BS和BP水解产物中的主要挥发性风味化合物。
