青菜机械损伤的检测方法研究

Study on Determination Method for Brassica campestris Mechanical Damage

以"上海五月慢"青菜为试材,分别在常温和2℃低温贮藏5d和15d,按照大量、少量、无损3个等级对青菜进行折伤、刺伤、砸伤3种损伤处理,采用伤口染色、测定电导率、亨特L值色泽测定、伤口糖含量测定等方法,测定3种损伤处理青菜的电导率、伤口微生物总数、伤口糖含量、伤口色泽L值的变化。结果表明:伤口染色法可以快速直观检测出3种机械伤,即使少量损伤也能检出,可用于样品抽查;电导率法可以检出大量砸伤和大量折伤的青菜;损伤引起电导率升高,在常温下,损伤青菜的电导率随贮藏时间的延长而上升,但在2℃低温下则相反;伤口糖含量的测定方法,对3种青菜损伤的检测效果均不理想;伤口微生物检测法可用于检测贮藏后期青菜的大量砸伤和大量折伤;亨特L值色泽测定法检测效果较好,损伤引起伤口L值下降,能检测砸伤和刺伤,青菜在常温和2℃低温贮藏,伤口L值持续下降,而对照L值不变或上升。

Taking Brassica campestris as material,and the samples were stored at ambient and 2℃ low temperature for 5 d or 15 d respectively,the leaves of Brassica campestris were treated with fractured, punctured and compressed injuries at large numbers,few and non-destructive three different levels in this study, and by wound staining method, electrical conductivity rate method,total plate count determination, sugar content determination and Hunter L value,the effect of three injuries level on electrical conductivity rate, total microbial count, sugar content, and Hunter L value variation were determired. The results showed that wound staining method could find three mechanical injuries fast and directly,even few wound. The method could inspect mechanical damage rate of samples. The electrical conductivity rate of wound leaves increased. The large numbers fractured and compressed wounds could he detected by electrical conductivity method. The rate increased during storage at ambient temperature,and reverse result was found at 2℃. Microbial detection method was feasible to investigate large numbers fractured and compressed wounds for leaves at later storage. The detecting sugar content method was not sufficient for inspecting three types of mechanical injuries. Wound decreased Hunter L value of leaves. The punctured and compressed wound samples could be determined by L values. The L value of wound leaves continued decline,while the control had not changed or increased during storage at ambient temperature or 2℃.