养殖中国对虾肌肉提取物的研究──不同提取方法对养殖中国对虾肌肉提取物中含氮化合物的影响

研究不同提取方法对中国对虾肌肉提取物中含氮化合物组成和含量的影响。以ＴＣＡ、ＰＣＡ、ＳＳＡ和ＡＬ法沉淀蛋白质后得到对虾肌肉提取物中总氮量分别为８３３、８７８、８４０和７０１ｍｇ·Ｎ／１００ｇ。前三种方法处理的提取物中游离氨基酸总量相近，而结合氨基酸含量相差甚大。ＴＣＡ法和ＡＬ法对肌肉提取物中大分子化合物沉淀效果较好。提取对虾肌肉中的核着酸以ＴＣＡ、ＳＳＡ法较好。氧化三甲胺和甜菜碱含量分别为８０～１００ｍｇ／１００９和３００～３２０ｍｇ／１００ｇ之间，ＴＣＡ、ＰＣＡ、ＳＳＡ三法比较接近，而ＡＬ法明显偏低。提取物中含氮化合物的分布为：游离和结合氨基酸氮占７１～７８％，核苷酸类氮占９～１１％，甜菜碱氮占３～５％，氧化三甲胺占１～２％。

STUDIES ON THE MUSCLE EXTRACT OF CULTURED PRAWNS --EFFECTS OF DIFFERENT EXTRACTION METHODS ON THE NITROGEN COMPOUNDS IN THE MUSCLE EXTRACT OF CULTURED PRAWNS (PENAEUS CHINENSIS)

Effects of different extraction methods on non--protein compounds in cultured prawn muscle extracts are studied. The total nitrogen in the samples prepared with the TCA, PCA, SSA and AL methods are 833, 878, 841 and 701 mgN/100g respectively. The results show that the amounts of free amino acids in the extracts prepared with the TCA, PCA and SSA methods are similar, but those of combined amino acids are quite different. Most proteinous nitrogen compounds are precipitated by the TCA and AL methods. The TCA and SSA methods are better for the extraction of nucleotides. The contents of trimethylamine oxide and betaine are between 80-- 100mg/100g and 300-- 320mg/100g. The. TCA, PCA, and SSA methods produced a very similar result, but the AL method gave a very low content of trimethylamine and betaine. The distribution of nitrogen compounds are as follows: free and combined amino acids 71--78%, nucleotides 9-- 11 %, betaine 3-5 %, and trimethylamine oxide 1--3 %.