低温贮藏期间萝卜不同部位可溶性糖变化规律研究

Change of Soluble Sugar in Skin and Flesh Tissues of Radish Taproot with Low Temperature Storage

糖的种类和质量分数是影响水果萝卜品质的重要指标。以水果萝卜珍品‘潍县萝卜’为试材,通过3 a的重复试验,系统研究了低温冷库贮藏10个月内,萝卜皮和萝卜肉中可溶性糖和含水量的变化规律。结果表明,萝卜肉和皮中的总糖、果糖、葡萄糖、蔗糖质量分数和甜度值总体上呈现先升高后降低的趋势。萝卜肉中的果糖、葡萄糖和蔗糖质量分数在贮藏1月时达到峰值,分别比刚收获时平均增加80.04%、69.52%和119.87%;萝卜皮中的蔗糖质量分数也在贮藏1月时达到峰值,但果糖和葡萄糖质量分数却在贮藏2月时达到峰值,分别比刚收获时平均增加101.73%、102.64%和98.80%。萝卜肉的总糖和甜度值在贮藏6个月内可以保持较高水平,特别是在贮藏1~2个月时,比刚收获时均显著提高40%以上;萝卜皮的总糖和甜度值分别在贮藏6个月和8个月内维持较高水平,在贮藏2个月时达到峰值。萝卜皮和肉的含水量在贮藏9个月内失水不明显。以上结果表明,潍县萝卜在温度为-0.5~1℃、湿度为90%~95%的冷库中贮藏,适宜的贮藏期为6个月,最佳的食用期为贮藏后1~2个月。

Taste quality is closely associated with the type and content of soluble sugars in fruit radish.In this study,the mature taproots of Weixian radish were stored at ambient temperature(-0.5-1℃)and with a relative humidity of 90%-95%for 10 months and analyzed monthly for change in sucrose,glucose,fructose,total sugar and water.This storage experiment was repeated for three years.Sucrose,glucose,fructose,total sugar mass fraction and sweetness in the flesh and skin of taproots showed basically consistent trends,it increased at earlier stage and decreased at the later stage.After storage for 1 month post harvest(MPH),the mass fraction of fructose,glucose and sucrose in the flesh reached a peak and increased by 80.04%,69.52%and 119.87%,respectively.In radish skin,the sucrose mass fraction reached a peak at 1 MPH while the fructose and glucose mass fraction reached the peak at 2 MPH,and increased 101.73%,102.64%and 98.80%,respectively.Total sugar mass fraction and sweetness in flesh of radishes were in higher level during storage of 6 months,and they all increased more than 40%at 1-2 MPH compared with 0 MPH.Total sugar mass fraction and sweetness in skin of radishes were in higher level during storage of 6 and 8 months,respectively,and both of the months mreached a peak at 2 MPH.Water content in the flesh and skin of taproots didn‘t change significantly during the storage time from 0 to 9 MPH.The results indicated that the suitable storage time for Weixian radish was 6 MPH,the optimum edible period was 1-2 MPH under the storage conditon of-0.5-1℃,and 90%-95%RH.