常温贮藏期间潍县萝卜肉质根糠心指数与营养成分的变化规律及其相关性研究

Study on the variation of nutrient components and hollowness index and their relationship in Weixian radish taproot during room temperature storage

为了探讨萝卜糠心与营养成分之间的关系,以潍县萝卜为试材,研究了常温(15℃)贮藏0、10、20、30、40d时潍县萝卜肉质根糠心指数及皮和肉中相对含水量、维生素C、可溶性蛋白、游离氨基酸、可溶性糖及淀粉含量的变化,并分析了萝卜糠心指数与营养指标的相关性。结果表明,随着贮藏时间的延长,潍县萝卜肉质根糠心指数显著增加,至贮藏40d时糠心指数达48.09%;潍县萝卜肉质根皮和肉中的相对含水量及维生素C、可溶性蛋白、可溶性糖和淀粉含量总体呈显著下降的趋势;而潍县萝卜肉质根皮中游离氨基酸的含量总体呈上升的趋势,肉中则正好相反。相关分析表明,潍县萝卜肉中的相对含水量、维生素C含量及皮中的可溶性糖含量均与糠心指数呈显著负相关,说明相对含水量、维生素C和可溶性糖含量的下降可能是导致萝卜糠心的重要因素之一;且除维生素C和游离氨基酸外,其他指标皮和肉之间均存在显著的相关关系,说明其他指标在皮和肉中的变化趋势一致。此外,在贮藏20d内,萝卜肉质根中营养物质的变化幅度较小,且糠心指数仅为31.91%,因此为了保证萝卜的食用品质,其常温贮藏的时间以不超过20d为宜。

To explore the relationship between hollowness and nutrient components,the hollowness index wascalculatedand the contents of relative water,vitamin C,soluble protein,free amino acid,soluble sugar and starch were measured in different tissues of Weixian radish taproot during storage at room temperature(15℃)for 40d.The results showed that hollowness index increased rapidly during the entire storage period,and reached upto 48.09% at 40d.The contents of relative water,vitamin C,soluble protein,soluble sugar and starch in taproot skin and flesh basically showed decreasing trends.Free amino acid content increased in taproot skinwhiledecreased in flesh during the storage.Correlation analysis showed that the hollowness index was negatively correlated with the contents of relative water,vitamin C in taproot flesh and soluble sugar content in taproot skin,indicating that the decrease of the contents of relative water,vitamin C and soluble sugar probably resulted in the hollowness of radish taproot.Furthermore,a significantly positive correlation was observed between measured indexes except vitamin C and free amino acid contents in radish taproot skin and flesh,showing that the change trend of the nutrient components in skin was similar to that in flesh.In addition,nutrient component contents changed little from 0 to 20d,and the hollowness index was 31.91% at 20d.Therefore,the storage time at room temperature should not exceed 20din order to ensure the edible quality of radish taproot.