基于正交偏最小二乘判别分析探究^(60)Co-γ辐照 对羊肚菌采后低温贮藏品质的影响

Effect of ^(60)Co-γ Irradiation on the Postharvest Quality of Morchella angusticeps during Cold Storage Investigated Using Orthogonal Partial Least Square Discriminant Analysis

目的:探究^(60)Co-γ辐照处理对采后低温贮藏期间羊肚菌保鲜效果的影响。方法:以黑脉羊肚菌为试材,分别用实际吸收剂量1.64、2.18、2.43 kGy和2.93 kGy进行辐照处理,测定低温贮藏期间其感官品质和理化指标的变化。采用正交偏最小二乘判别分析(orthogonal partial least squares-discriminant analysis,OPLS-DA)建立基于羊肚菌理化品质指标的辐照处理判别模型,并采用变异权重参数值(variable importance in the projection,VIP)筛选差异显著指标。结果:经不同辐照剂量处理后,羊肚菌在4℃贮藏条件下其感官品质和理化特性呈现不同的变化规律。贮藏5 d后,与对照组相比,1.64 kGy和2.18 kGy辐照处理能提高过氧化氢酶活力、总酚含量和类黄酮含量,降低丙二醛含量、多酚氧化酶活力和过氧化物酶活力,有效延缓褐变和软化现象,其中1.64 kGy剂量处理保鲜效果最好(P<0.05),而2.43 kGy和2.93 kGy辐照处理样品则在贮藏末期品质劣变加剧。通过构建辐照处理判别模型,有效区分样品因辐照处理所造成的差异,并筛选出过氧化氢酶和过氧化物酶活力为相应的差异显著指标。结论:1.64 kGy和2.18 kGy辐照处理可明显延缓羊肚菌采后品质的劣变,且1.64 kGy处理组和对照组差异最大;OPLS-DA法能有效区分不同处理的样品组。

Objective:To investigate the effect of ^(60)Co-γirradiation on the quality of harvested Morchella angusticeps during cool storage.Methods:M.angusticeps was irradiated with different absorbed doses of ^(60)Co-γ(1.64,2.18,2.43 and 2.93 kGy),and the sensory quality and physiological and biochemical indexes of the control and irradiated samples during cold storage were evaluated.Orthogonal partial least square discriminant analysis(OPLS-DA)was used to establish a discriminant model for irradiation treatment based on the physiological and biochemical indexes of M.angusticeps,and the significantly differential indexes between the control and irradiation groups were identified using variable importance in the projection(VIP).Results:The patterns of changes in the sensory quality and physiological and biochemical characteristics of M.angusticeps irradiated with different doses of ^(60)Co-γwere different during storage at 4℃.After five days of storage,the activity of catalase and the contents of total phenols and flavonoids in the 1.64 and 2.18 kGy irradiation groups were increased,malondialdehyde content and the activities of polyphenol oxidase and peroxidase were reduced,and browning and softening were retarded as compared to the control group.The dose of 1.64 kGy provided better preservation of the quality of M.angusticeps(P<0.05).On the contrary,the doses of 2.43 and 2.93 kGy increased the quality deterioration of M. angusticeps at the end of storage. The developed discriminant model could distinguish the differences between the control and irradiation treatments effectively. The activities of catalase and peroxidase were identified as significantly differential indexes. Conclusion: ^(60)Co-γ irradiation at doses of 1.64 and 2.18 kGy can delay the quality deterioration significantly and prolong the shelf life of M. angusticeps, the dose of 1.64 kGy being more effective. The OPLS-DA model could effectively distinguish between the different treated sample groups.