The mechanism of cholesterol-effect on the quality of green asparagus (Asparagus officinalis L.) spears during low temperature storage

The effectiveness of cholesterol in maintaining the quality of postharvest asparagus was demonstrated in our previous work. In this study, the effect of cholesterol on chlorophyll degradation in green asparagus were determined by analysing chlorophyll content, redox ability of chlorophyll, chlorophyll degradation, chlorophyll-protein binding capacity and fatty acid composition in thylakoid membrane. Results showed that chlorophyll contents were significantly (p ≪ 0.01) reserved by cholesterol treatments. Cholesterol significantly (p ≪ 0.05) reduced chlorophyll degradation in a near neutral aqueous solution and acidic solution, respectively, but failed to inhibit chlorophyll degradation in strong reducing acidic solution (ascorbic acid) and oxidizing solution (hydrogen peroxide). Chlorophyll-protein binding capacity was better maintained under cholesterol treatment compared with the untreated samples, indicating higher content of chlorophyll-protein complexes. In addition, the content of linolenic acid and linoleic acid in thylakoid membrane could be better retained after cholesterol treatment. Hence, the stability of thylakoid membrane and chlorophyll were effectively sustained under cholesterol treatment, providing a new opportunity to preserve the quality of green vegetables.