菜用大豆食用品质关键组分及其积累动态研究

Key Components of Eating Quality and Their Dynamic Accumulation in Vegetable Soybean Varieties [Glycine max(L.) Merr.]

选用30个菜用大豆品种(系),测定其食用品质与籽粒的化学组分,分析二者的相关性;再选其中3个可溶性糖含量不同的品种(系)测定食用品质组分,并采用主成分分析方法探讨每个组分的作用,研究其积累动态。结果表明,蔗糖、果糖+葡萄糖、蜜三糖、水苏糖、蛋白质、游离氨基酸和脂肪对菜用大豆食用品质的总贡献率为67.8%;其中蔗糖含量与菜用大豆食用品质呈极显著正相关(0.864**),蛋白质含量与菜用大豆食用品质评分呈显著负相关(–0.439*)。鲜食期不同菜用大豆品种籽粒中蜜三糖和水苏糖的平均含量仅有成熟期的7.4%和12.4%,对菜用大豆食用品质影响有限。菜用大豆的鲜食期一般在开花后42 d,可维持一周左右。此期蔗糖含量最高,蛋白质含量比成熟期低3%左右,氨基酸含量明显高于成熟期,而蜜三糖、水苏糖含量最低,果糖+葡萄糖居中,食用品质最佳;鲜食期过后,籽粒中蔗糖和单糖含量降低,脂肪与蛋白质积累增加,蜜三糖和水苏糖含量显著增高,导致食用品质下降。

The eating quality and seed chemical compositions of 30 vegetable soybean cultivars （lines）, as well as their correla-tions were analyzed. At the same time, main quality compositions and their roles for eating quality were investigated by path analysis, while the dynamic accumulation of each component was also studied with three cultivars differing in soluble sugar content. Results showed that the cumulative contribution of sucrose, fructose ＋ glucose, raffinose, stachyose, protein, free amino acid and oil for eating quality was 67.8%. A significant positive correlation was found between eating quality score and sucrose content （0.864＊＊）, while a significant negative correlation between eating quality score and protein content （–0.439＊）. The average content of raffinose and stachyose at fresh harvest stage was only 7.4% and 12.4% of that at mature stage respectively, which had much less negative impact on eating quality of vegetable soybean than field grain soybean. The optimum harvest time for fresh pods was at 42 days after flowering and could last for one week with highest sucrose content and lowest raffinose and stachyose contents. Besides, the average content of amino acids was higher and fructose ＋ glucose contents were medium, and protein content was 3% less than that at mature stage. Postponing the harvest time deteriorated eating quality due to decreased content in sucrose and monosaccharide, increased content in fat and protein contents, as well as a dramatic increase in raffinose and stachyse.