中华草龟蛋营养成分及消化特性研究

Study on nutrition and digestion properties of Mauremys reevesii eggs

对中华草龟蛋的一般营养成分、矿质元素、脂肪酸、氨基酸组成及体外模拟消化过程中抗氧化特性等进行测定分析。结果表明,中华草龟的受精蛋、无精蛋中水分含量分别为(77.82±0.54)%、(79.33±0.94)%,无显著差异。干基的受精蛋中灰分、总糖、粗脂肪及葡萄糖含量分别为(7.22±0.05)%、(12.60±0.02)%、(32.63±1.36)%、(0.114±0.006)%,显著高于无精蛋中对应成分含量(6.19±0.13)%、(11.09±0.05)%、(30.68±1.24)%、(0.036±0.005)%;二者粗蛋白含量均较高,分别为(52.68±0.38)%、(52.79±0.27)%,且无显著差异;在测定的8种矿物质元素中,磷含量最高(12900~14300 mg/kg),还含有少量硒元素(约为0.4835~0.4315 mg/kg),仅钠和钾元素含量受精蛋显著高于无精蛋。无精蛋的总脂肪酸含量为(279.43±0.94)mg/g显著高于受精蛋(213.41±3.74)mg/g,且人体必需脂肪酸含量也存在显著差异,但饱和脂肪酸和不饱和脂肪酸含量占脂肪酸总量的比例无显著差别。中华草龟的受精蛋、无精蛋中的氨基酸总量(521.94~529.99 mg/g)及人体必需氨基酸比例(40.34%~40.58%)均无显著差别。体外模拟消化过程中,中华草龟的受精蛋与无精蛋的ABTS阳离子自由基清除能力、铁离子还原能力及可溶性蛋白均显著增强,且在肠消化阶段的ABTS阳离子自由基清除能力约提高4倍、铁离子还原能力约提高3倍,但二者间无显著区别;Tricine SDS-PAGE电泳图显示消化过程中,受精蛋与无精蛋在肠消化液中的蛋白分子质量集中于3.3 kDa以下,小分子肽的增多与抗氧化特性的变化趋势相符。这为中华草龟蛋的食用和开发利用提供科学依据。

Taking the Mauremys reevesii eggs as the research object,the general nutrients,mineral elements,fatty acids,amino acids,and antioxidant properties of the eggs in vitro were determined and analyzed.Results showed that the water content of fertilized and non-fertilized eggs was(77.82±0.54)%and(79.33±0.94)%,respectively,without significant difference.The contents of ash,total sugar,crude fat,and glucose in dry weight of fertilized eggs were(7.22±0.05)%,(12.60±0.02)%,(32.63±1.36)%,and(0.114±0.006)%,respectively.They were significantly higher than those of unrefined eggs(6.19±0.13)%,(11.09±0.05)%,(30.68±1.24)%,(0.036±0.005)%,respectively.The contents of crude protein in fertilized and non-fertilized eggs were higher with(52.68±0.38)%and(52.79±0.27)%and there was no significant difference.Among the eight mineral elements measured,the phosphorus content was the highest(12900-14300 mg/kg)in Mauremys reevesii eggs,as well as a small amount of selenium(0.4835-0.4315 mg/kg).The contents of sodium and potassium in fertilized eggs were significantly higher than those in non-fertilized eggs.The total fatty acid of unfertilized eggs(279.43±0.94)mg/g was significantly higher than that of fertilized eggs(213.41±3.74)mg/g.The essential fatty acid of humans was also significantly different,however,there was no significant difference between the proportions of saturated fatty acid and unsaturated fatty acid in the total fatty acid.There was no significant difference in total amino acid(521.94-529.99 mg/g)and essential amino acid ratio(40.34%-40.58%)between fertilized and non-fertilized eggs of Mauremys reevesii.During the simulated digestion in vitro,the ABTS cationic radical scavenging ability,ferric ion-reducing antioxidant power,and protein digestibility increased significantly.The ABTS cationic radical scavenging ability and ferric ion reducing antioxidant power increased by 4 times and 3 times in the intestinal digestion,but there was no significant difference between fertilized and non-fertilized eggs of Mauremys reevesii.The Tricine SDS-PAGE showed that the protein molecular weight of fertilized and unfertilized eggs in intestinal digestive juices was less than 3.3 kDa with the progress of digestion.The increase of small molecular peptides was consistent with the trend of antioxidant properties.It provides a scientific basis for the consumption,development,and utilization of Mauremys reevesii eggs.