Effect of Pre-cooling Treatment and Low Temperature Storage on Storage Quality of Broccoli

In order to explore the effect of pre-cooling treatment combined with low-temperature storage (0 ± 1) ℃ on the storage quality of broccoli, the “Su Qing” No. 6 broccoli test material was used to periodically sensory evaluation and determined the respiration, color, chlorophyll content, chlorophyllase activity, V_C content, total glucosinolate content, isothiocyanate content, peroxidase activity, catalase activity, ascorbic acid peroxide activity, and malondialdehyde content. The results showed that pre-cooling treatment and low-temperature storage of broccoli could effectively delay its yellowing, maintain lower respiratory and higher vitamin C, chlorophyll, free phenol, glucosinolate and isothiocyanate content. The isothiocyanate content of broccoli by pre-cooling treatment and low-temperature storage reached 241.41 mg/100 g·FW on the 31st day; the treatment group effectively maintained high APX, CAT activity and DPPH free radical scavenging ability, effectively inhibited POD and chlorophyllase activity. Correlation analysis showed that the chlorophyll content of broccoli was extremely negatively correlated with chlorophyllase activity (P<0.01), and significantly negatively correlated with POD activity (P<0.05); The content of glucosinolates, isothiocyanates showed a significant ( P<0.05) negative correlation with MDA content . The results of principal component analysis showed that chlorophyll content, CAT activity, total glucosinolate content, chlorophyllase activity, respiratory intensity and malondialdehyde content can be used as key indicators for evaluating the quality characteristics of broccoli. This study can provide a theoretical basis for the preservation research of broccoli.