Effects Of UV-B Irradiation On Morphology,Nutritional Quality And Postharvest Storage Quality Of Radish Sprouts

Sprout vegetables refer to vegetable seedlings that are formed through the hydroponic or earth-culture of plant seeds or other nutrient storage organs.Its texture is soft and nutritional value is high,and it is unnecessary to apply chemical substances such as chemical fertilizers,pesticides,and hormones during the production process.Therefore,this new type of green,pollution-free,nutritious and healthy "living sprout vegetable" is becoming more and more popular.Radish sprouts are a kind of green vegetables which can be eaten and used medicinally,It has a crispy taste and rich nutrition,at the same time,radish sprouts also have the function of invigorating the spleen and eliminating food,enhancing the immune function of the body and preventing cancer,and has high nutritional and health value.Therefore,it is a current research hotspot to improve its nutritional quality through certain technical means.In addition,radish sprouts have high moisture content,and the stems and leaves are crisp,and they still maintain a vigorous metabolic activity after harvesting,which makes them extremely prone to loss of water,shrinkage,decay and metamorphism,resulting in short shelf life,not resistant to storage and transportation,and reduction of commodity value and edible value.Therefore,how to prolong the storage period of radish sprouts and increase their storage quality is a problem that the sprouting vegetable industry needs to solve urgently.As a new type of fruit and vegetable processing technology,UV-B irradiation is green,safe and economical.Studies have shown that: UV-B irradiation not only affects the growth and morphology of plants,but also can induce plants to produce a series of physiological metabolism reaction,promote the synthesis of related secondary metabolites,on the other hand,as a means of preservation of fruits and vegetables,UV-B irradiation can improve the quality of fruits and vegetables during storage and extend the shelf life.In this experiment,an improved 791 cans of radish seeds were used as materials and treated with different doses of UV-B radiation to investigate its effects on morphology,nutritional quality,and postharvest storage quality of radish sprouts.The results show that:(1)compared with the control group,with the increase of UV-B irradiation dose,the hypocotyl length of radish seedling was gradually shorter,and the dry and fresh weight of the ground part decreased gradually,the stomatal opening degree of the upper epidermis of the leaf gradually becomes smaller;(2)When irradiated with UV-B for 2 h(irradiation dose of 1.584 k J/m2),The content of total flavonoids and DPPH free radical scavenging rate were significantly increased.At 4 h after UV-B irradiation(irradiation dose of 3.168 k J/m2),the contents of chlorophyll,vitamin C,soluble sugar,soluble protein and total sugar were significantly improved.Indicating that the appropriate dose of UV-B irradiation can effectively improve the nutritional quality of radish sprouts;(3)UV-B irradiation at 3 h(irradiation dose of 2.376 k J/m2)could significantly inhibit the post-harvest weight loss of radish sprouts,delay the decline of chlorophyll content,and increase the activity of peroxidase(POD),to improve its sensory quality.When the UV-B irradiation time was 5 h(irradiation dose of 3.96 k J/m2),the content of anthocyanin,soluble sugar,soluble protein,vitamin C,total flavonoids,DPPH free radical scavenging rate and peroxidase(POD)activity of radish sprouts after harvest were significantly improved.Experiments show that UV-B irradiation is an effective radish sprouts green harmless physical preservation methods.In summary,moderate doses of UV-B radiation can have a positive effect on the morphology,nutritional quality,and post-harvest storage quality of radish sprouts.Among them,UV-B irradiation treatment at 2 or 4 hours could significantly improve the nutritional quality of radish sprouts,while UV-B irradiation treatment at 3 or 5 hours could improve the storage quality during post-harvest storage.This provides theoretical guidance for the production of high-quality radish sprouts in actual production,and also provides a simple,economical,and ecologically sound physical treatment method for the preservation of radish sprouts.