Beijing Laboratory for Food Quality and Safety, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China.
Department of Food Science, Nutrition and Health Promotion, Mississippi State University, Starkville, MS, USA.
J Sci Food Agric. 2021 Aug 30;101(11):4799-4807. doi: 10.1002/jsfa.11126. Epub 2021 Feb 20.
Channel catfish farming is very important aquaculture industry in the southern states of the USA. However, huge amounts of by-products are generated from catfish fillet-processing. The by-products (mostly heads and bone frames) are excellent sources of proteins. Currently, catfish by-product has little value, and is regarded as a 'waste', which if not utilized properly could cause serious environmental pollution. Therefore, to find a way to utilize those by-products is critical for the economy of aquaculture.
Protein isolates were extracted from the mixture of catfish by-products (heads and frames) under different alkaline conditions (pH 7.5-11) and made into protein gels. Secondary structures of extracted protein isolates were studied. Microbial transglutaminase (MTGase, 0-4 U g proteins) was incorporated to improve gel structure. Gelling, physicochemical, textural and thermal properties of protein gels treated with/without MTGase were investigated. Protein pattern changes of MTGase-treated protein gels were studied and the microstructure of the protein gels was analyzed.
Alpha-helicity of protein isolates made at pH 11 was 21.5% lower than that extracted at pH 8.5. Storage modulus (G') of protein gel decreased with increasing extraction pH (pH > 9) of the corresponding protein isolate. MTGase treatment exhibited significant effects on denaturation temperature and enthalpy of protein gels. Excessive MTGase (>2 U g ) could weaken the gel structure.
Protein isolates can be extracted from catfish by-products and made into protein gels, which are a value-added product. © 2021 Society of Chemical Industry.
鲶鱼养殖是美国南部各州非常重要的水产养殖产业。然而，从鲶鱼片加工中会产生大量的副产物。这些副产物（主要是鱼头和鱼骨架）是蛋白质的极好来源。目前，鲶鱼副产物的价值很低，被视为“废物”，如果处理不当，可能会造成严重的环境污染。因此，找到利用这些副产物的方法对水产养殖业的经济发展至关重要。
在不同的碱性条件（pH 7.5-11）下，从鲶鱼副产物（鱼头和鱼骨架）混合物中提取蛋白质分离物，并制成蛋白质凝胶。研究了提取的蛋白质分离物的二级结构。加入微生物转谷氨酰胺酶（MTGase，0-4 U g 蛋白质）以改善凝胶结构。研究了用/不用 MTGase 处理的蛋白质凝胶的胶凝、物理化学、质构和热性质。研究了 MTGase 处理的蛋白质凝胶的蛋白质图谱变化，并分析了蛋白质凝胶的微观结构。
在 pH 11 下制备的蛋白质分离物的α-螺旋度比在 pH 8.5 下提取的低 21.5%。随着相应蛋白质分离物提取 pH（pH>9）的增加，蛋白质凝胶的储能模量（G'）降低。MTGase 处理对蛋白质凝胶的变性温度和焓有显著影响。过量的 MTGase（>2 U g）会削弱凝胶结构。
可以从鲶鱼副产物中提取蛋白质分离物并制成蛋白质凝胶，这是一种增值产品。© 2021 化学工业协会。
