丙二酸处理对豇豆采后贮藏品质的影响

以新鲜豇豆为试材,研究100、200、300、400 mg·L^-1 丙二酸处理的豇豆在(8±2) ℃贮藏期间锈斑指数及生理生化指标的变化。结果表明,贮藏12 d后,丙二酸处理的豇豆锈斑指数均显著低于对照,200、300 mg·L^-1 丙二酸处理效果最好;丙二酸处理的失重率始终低于对照,300 mg·L^-1 丙二酸处理显著低于对照;贮藏9 d时,丙二酸处理的豆荚、豆粒可溶性蛋白含量始终高于对照,贮藏12 d时,300 mg·L^-1丙二酸处理的豆荚可溶性蛋白含量最高,高于对照68.49%,豆粒可溶性蛋白含量高于对照6.42%;贮藏期间豇豆的叶绿素、维生素C含量呈下降趋势,300 mg·L^-1丙二酸处理组始终高于对照;豇豆豆荚、豆粒的可溶性糖含量在贮藏期间迅速下降,200、300 mg·L^-1丙二酸处理豆荚可溶性糖含量始终高于对照;豇豆的纤维素含量呈上升趋势,300 mg·L^-1丙二酸处理豇豆纤维素含量均显著低于对照组;豇豆多酚氧化酶(PPO)活性总体呈上升趋势,但在贮藏期间,丙二酸处理的PPO活性始终低于对照;所有处理的过氧化物酶活性均在第6天达到峰值然后下降,300、400 mg·L^-1丙二酸处理在贮藏期间过氧化物酶(POD)活性变化一直比较平稳。不同浓度丙二酸处理通过抑制豇豆锈斑指数增加,延缓失重率、纤维素含量、PPO活性的升高和叶绿素、可溶性糖、可溶性蛋白含量的降低,保持较高水平的POD活性清除自由基,来维持豇豆采后品质,从而提高豇豆采后保鲜效果;综合比较4个丙二酸浓度处理,以300 mg·L^-1 丙二酸处理豇豆保鲜效果最好。

Effect of malonic acid treatment on postharvest storage quality of cowpea

The physiological and biochemical indexes of cowpea treated with malonic acid concentration of 100, 200, 300 and 400 mg·L^-1 were studied during storage at (8±2) ℃ with fresh cowpea as experimental material. The results showed that after 12 days of storage, the rust spot index of cowpea treated with malonic acid was significantly lower than that of the control, the effect of cowpea treated with 200, 300 mg·L^-1 malonic acid were the best; the weight loss rate of cowpea treated with malonic acid was always lower than that of the control and 300 mg·L^-1 malonic acid treatment was significantly lower than that of the control; on the 9th day of storage, the soluble protein content of pods and beans treated with malonic acid was always higher than that of the control. On the 12th day of storage, the soluble protein content of pods treated with 300 mg·L^-1 malonic acid was the highest, 68.49% higher than that of the control and the soluble protein content was 6.42% higher than that of the control; the contents of chlorophyll and vitamin C of cowpea decreased during storage, in 300 mg·L^-1 malonic acid treatment group were always higher than those in the control group. Soluble sugar content of cowpea pods and beans decreased rapidly during storage, the soluble sugar content of pods treated with 200 and 300 mg·L^-1 malonic acid was always higher than that of the control. The cellulose content in cowpea showed an increasing trend, and the cellulose content in cowpea treated with 300 mg· L^-1 malonic acid was significantly lower than that in the control group. The activity of polyphenol oxidase (PPO) in cowpea increased, but the PPO activity in malonic acid treatment was always lower than that in the control during storage. The peroxidase (POD) activity of all treatments reached the peak on the 6th day and then decreased. The changes of POD activity were stable in 300 and 400 mg·L^-1 malonic acid treatment during storage. Different concentrations of malonic acid could inhibit the increase of cowpea rust index, delay the increase of weight loss rate, cellulose content, PPO activity and the decrease of chlorophyll, soluble sugar and soluble protein contents, and maintain a high level of POD activity to eliminate free radicals, so as to maintain the quality of cowpea after harvest, further improve the postharvest fresh-keeping effect of cowpea. The results showed that 300 mg·L^-1 malonic acid had the best effect on the preservation of cowpea.