Study On Preservation Of Postharvest Green Asparagus And Green-Maitaining Mechanism Of Cholesterol Treatment

Postharvest green asparagus (Asparagus officinalis L.) was treated with antiseptic, film coating antistaling agents, plant growth regulator, cholesterol and L-arginine. The physical, chemical and physiology changes of green asparagus during storage were measured and the effect of preservation of green asparagus was studied. Preliminary study of cholesterol on chlorophyll protection was conducted to explore the mechanism of green-maintaining.Green asparagus was treated by dipping or nutrient solution absorption method, stored at4℃until commodity rate was below85%and then several indexes were measured. The results showed that dipping treatment of0.2%HMC,0.5%ascorbic acid,0.5%soy lecithin,50mg/kg gibberellins and compound preservative (0.1%HMC+25mg/kg gibberellins+0.2%soy lecithin), or absorption treatment of0.1%WSC,0.2%CaCl2,0.2%soy lecithin,25mg/kg gibberellins and compound preservative(0.1%WSC+25mg/kg gibberellins+0.2% soy lecithin) could effectively control water loss, lignifications, decay, chlorosis, improve quality of green asparagus and keep fresh.Green asparagus was treated by cholesterol,L-arginine and compound preservative and stored at4℃. Compared with treatment of HMC (dipping treatment) and WSC (nutrient absorption treatment), the result showed that both dipping treatment of0.5g/L cholesterol or0.1mmol/L L-arginine, and absorption treatment of0.2g/L cholesterol or0.05mmol/L L-arginine could effectively decrease decay rate and the weightlessness rate of green asparagus, reduce PAL enzyme activity lignin accumulation to maintain high quality. Treatment of cholesterol maintained low MDA content, reduced the degradation of soluble protein and significantly suppress the degradation of chlorophyll. Chlorophyll content of green asparagus dipping treated with0.5g/L cholesterol was0.0228mg/g after being stored for30days. Chlorophyll content of green asparagus absorption treated with0.2g/L cholesterol was0.0209mg/g after30days, significantly higher than other treatment. Green asparagus treated with L-arginine showed higher total antioxidant capacity and total phenol content than other treatment. Compound preservative (0.2%HMC+0.5%cholesterol+0.1mmol/L L-arginine) and compound nutrient (0.1%WSC+0.2%cholesterol+0.05mmol/L L-arginine) could better control the physiological and biochemical indexes and maintain high quality of green asparagus during storage. Cholesterol and L-arginine could be applied in postharvest fruits and vegetables preservation study as new preservatives.Adding Vc and H2O2in chlorophyll extract to study the protective effect of cholesterol aqueous solution on it, and the results showed that there was no significant effect of cholesterol aqueous solution on the tolerance of chlorophyll extract towards oxidants and reducing agent, but cholesterol aqueous solution had a significant effect on prolonging the vitro degradation of chlorophyll in natural conditions. After being dipped in0.5g/L cholesterol aqueous solution, the stability of chlorophyll protein complex from green asparagus was above the control group; As for the fatty acid composition of thylakoid membranes, the content of palmitic and tridecanoic acid increased, while the content of linoleate andy-linolenic acid declined. And during the storage, a new fatty acid, dodecenoic acid generated. Compared with the control group, the variation of fatty acid from the treatment group was not significant, and there was no dodecenoic acid being detected.