Effect Of Postharvest Na₂SeO₃ On The Quality And Storage Characteristics In Spinach

Selenium?Se?has anti-aging and anti-cancer effects.The researchers showed that a certain concentration of selenium could promote plant growth and development,delay senescence and increase production.Spinach is one of the most popular green leafy vegetables in the market.Because of the strong respiration and transpiration after harvest of the large surface area of edible part.It is vulnerable to oxidize,wilt and yellowing during storage and transportation.In this paper,spinach was used as test material to study the effects of postharvest sodium selenite?Na2Se O3?treatment on its storage quality,antioxidant capacity and energy metabolism.Research indicates:1.The effects of Na₂SeO₃ solution different concentration?0 mg/L,0.5 mg/L,1.0 mg/L,1.5 mg/L,2.0mg/L,2.5 mg/L?and soaking time?5 min,10 min,15 min,20 min,25 min?on spinach quality were studied.The results showed that postharvest Na₂SeO₃ treatment could improve the soluble solids content?SSC?of spinach,and keep low weight loss rate and rot rate.Also effectively inhibit the respiratory intensity,delay the decline of sensory quality,chlorophyll content and vitamin C content in varying degrees.The results showed that the optimum Na₂SeO₃ concentration was 2.0 mg/L and soaking time was 20 minutes.in this situation,the weight loss rate and respiratory intensity of spinach decreased significantly,and the decrease of sensory quality,chlorophyll content and SSC was delayed significantly?P< 0.05?.2.Spinach treated with 2.0 mg/L Na₂SeO₃ can effectively increase the content of total flavonoids,and slow down the decrease of reducing sugar content and increase the content of Se significantly,and increase its total reducing power,ABTS+·clearance rate and metal ion chelating ability during storage.In addition,the Na₂SeO₃ treatment delayed the DPPH· clearance rate and hydroxyl?·OH?clearance rate of spinach and maintained its antioxidant activity;The treatment could maintain the activity of superoxide dismutase?SOD?and peroxidase?POD?,and increase the activity of catalase?CAT?and ascorbate peroxidase?APX?,control the increase of malondialdehyde?MDA?content,reduce H2O2 content,and increase its free radical scavenging ability.Therefore,Na₂SeO₃ treatment can effectively delay the loss of antioxidants in spinach,enhance its ability of scavenging free radicals and delay senility.3.This study was on the energy metabolism level of spinach with a single 2.0 mg/L Na₂SeO₃treatment and 2.0 mg/L Na₂SeO₃+ 1.0% chitosan?CTS?treatment.,the results showed that the contents of AMP,ATP and ADP and the activities of succinate dehydrogenase?SDH?,H+-ATPase and Ca2+-ATPase in spinach increased in different degrees respectively in the early stage.While energy?EC?,the activities ofcytochrome oxidase?CCO?and pyruvate dehydrogenase?PDH?decreased.The contents of AMP,ATP,ADP and the activities of CCO,PDH,SDH,H+-ATPase,Ca2+ATPase and EC in spinach compound treatment with 2.0 mg/L Na₂SeO₃ + 1.0% CTS were significantly higher than those in water control group at the later stage of storage.At this situation,both groups of single 2.0 mg/L Na₂SeO₃ treatment group and2.0 mg/L Na₂SeO₃ + 1.0% CTS compound treatment group could all effectively reduce the EC loss,thus delaying its aging.In summary,2.0 mg/L Na₂SeO₃ treatment with spinach treatment can effectively maintain its quality,slow down the loss of nutrients,maintain high antioxidant activity,reduce the increase of spinach MDA content and improve the ability to scavenge free radicals.The single 2.0 mg/L Na₂SeO₃ treatment group and 2.0 mg/L Na₂SeO₃+1.0% CTS compound treatment could effectively increase the energy of spinach in the late storage period.And 2.0 mg/L Na₂SeO₃+1.0% CTS compound treatment to maintain the energy supply of spinach.In conclusion,post-harvest Na₂SeO₃ treatment can maintain the storage quality of spinach,delay the decline of antioxidant capacity and improve the energy supply of spinach storage.