Synergistic Effects Of GSNO And β-CD On Storage Quality Of Peach Fruits And Three Common Diseases

The peach fruit is favored by the public for its rich nutritional value and fresh,sweet and juicy taste.However,the pulp of peach fruit is soft and the skin is thin.It is easy to cause mechanical damage during picking and transportation.In addition,the mature period is high temperature and humidity in summer.Many pathogenic bacteria can infect peach fruits through wounds,causing a large number of peach fruits to rot and deteriorate.However,storage under low temperature conditions is prone to problems such as chilling injury,which greatly shortens the shelf life of peach fruits.Therefore,it is urgent to find a safe and effective treatment method to maintain the storage quality of peach fruits.Nitrosoglutathione（GSNO）is the existing form of cellular NO,and as the main physiological NO donor,participates in protein S-nitrosylation and plays an important role in plant stress resistance.β-cyclodextrin（β-CD）has the functions of improving the stability of food and medicine,increasing solubility and enhancing bioavailability.However,there are few reports on the synergistic effects of GSNO andβ-CD on physiological,biochemical and storage diseases.In this paper,"Xintaihong"peach fruit was used as the test material,and treated with 0.5%β-CD as the control.And different concentrations(0.5,1.0,1.5 mmol·L^-1 GSNO+0.5%β-CD)were used to treat postharvest peach fruits.The synergistic effects of GSNO andβ-CD on peach fruits postharvest quality,nitric oxide（NO）metabolic pathways,hydrogen sulfide（H₂S）metabolic pathways,phenylpropane metabolism and three common pathogens of postharvest peach fruits were discussed,and the optimal concentration of combined treatment was found,which provided theoretical and experimental basis for storage and preservation of nitroglutathione in peach fruits.（1）The results showed that 1.0 mmol·L^-1GSNO+0.5%β-CD treatment effectively inhibited the increase of soluble solid content（SSC）and increased the color difference value in peach fruit,and thus reduced the browning degree of peach fruits.1.0 mmol·L^-1GSNO+0.5%β-CD treatment effectively reduced the respiration rate of peach fruits,effectively delayed the decrease of peach fruits hardness,inhibited the increase in the weight loss rate and relative conductivity of peach fruits,and maintained the nutrition of peach fruits.The postharvest quality of peach fruits were better maintained.（2）The results showed that 1.0 mmol·L^-1GSNO+0.5%β-CD treatment increased the endogenous NO content in peach fruits,increased nitric oxide synthase（NOS）activity and L-arginine content,thereby promoted the accumulation of NO content,but the nitrate reductase（NR）activity and nitrite content in the peach fruits did not increase significantly.The experimental results showed that 1.0 mmol·L^-1 GSNO+0.5%β-CD regulate the increase of NO content in peach fruits through NOS pathway.（3）The results showed that 1.0 mmol·L^-1 GSNO+0.5%β-CD treatment effectively increased the activities of L-cysteine desulfurylase,O-acetylserine sulfur lyase（OAS-TL）and serine acetyltransferase（SAT）in peach fruits,thus promoted the cleavage of L-cysteine in peach fruits.Combination treatment increased the content of endogenous H₂S in peach fruits and maintained the postharvest quality of peach fruits.（4）The results showed that 1.0 mmol·L^-1 GSNO+0.5%β-CD treatment increased the activity of phenylalanine ammonia lyase（PAL）,4-coumaric acid-Co A ligase（4CL）and cinnamic acid-4-hydroxylase（C4H）in peach fruits,which increased the content of total phenols,flavonoids and lignin in peach fruits.1.0 mmol·L^-1 GSNO+0.5%β-CD treatment enhanced the antioxidant capacity and antibacterial activity of peach fruits and better prolonged the storage time of peach fruits.（5）The results showed that 1.0 mmol·L^-1 GSNO+0.5%β-CD treatment inhibited the growth of Monilinia fructicola and Botrytis cinerea in vitro,but combination treatment had not obvious antibacterial effect on Rhizopus stolonifer.Compared with the control,the results showed that 1.0 mmol·L^-1 GSNO+0.5%β-CD treatment significantly enhanced the antibacterial activity against Monilinia fructicola and Botrytis cinerea,and better maintained the storage quality of peach fruits.