Screening Of Special Fruit-growing Bags For New Apple Variety 'Ruixue'

‘Ruixue' is a new apple variety selected from the cross between Fuji and Pink Lady.It has excellent quality,late maturity,high yield,storage stability,strong cold resistance,etc.,and has wide adaptability and great promotion value.The bagged ‘Ruixue' fruit has a smooth,yellow-white appearance and an excellent appearance.However,in recent years,it has been found that there will be irregular browning on the surface of the bagging,which will affect the appearance of the fruit.The brown fruit surface of the bagged fruit without the bagging does not brown,but the appearance is not good.In order to solve this problem,eight different types of fruit-growing bags were designed in this study.The browning of the fruit after bagging and the dynamic changes of the micro-environment in the fruit-growing bag were analyzed.The content of mineral elements,antioxidants and heat-resistant substances of different nutrient bags and different varieties were discussed.The relationship between the browning of ‘Ruixue' apple fruit and the quality index of the fruit bag?the micro-environment of the bag were discussed in order to selected special fruit-growing bag suitable for ‘Ruixue' apple.The main findings obtained are as follows:1.The moisturizing and breathability of the fruit bag has a significant effect on the browning of the fruit surface.The higher the gas permeability of the fruit bag,the worse the moisture retention and the higher the browning rate of the fruit surface.8 kinds of fruit bag breathability from low to high order is double-layer double wax fruit bag G,H,double-layer single wax fruit bag E,F,yellow single-layer bag D,yellow striped single-layer bag C,pear Bag B,A;fruit browning rate from high to low is H(59.38%),G(52.94%),F(40.23%),E(35.82%),D(31.25%),C(18.92%),A(6.67%),B(6.45%),no bagged fruit(0%).Comprehensive screening,the single-layer bag of pear bag B has the best effect,and the double-layer single-wax fruit bag E has the best effect.2.The temperature and humidity changes in different fruit bag have different effects on fruit browning.The temperature in the different fruit-growing bags is from double to double waxed fruit bag G,H,double-layer single wax fruit bag E,F,yellow single-layer bag D,yellow striped single-layer bag C,pear bag B,A,the maximum temperature and the lowest temperature between the fruit bag are about 2 °C;the humidity in the different fruit bags is from G to H,E,F,D,C,B,A,the highest humidity and the lowest humidity.The average difference is about 7 percentage points.The humidity difference between different fruit bags was significant,and the temperature difference was not significant.The order of browning rate of fruit surface is H,G,F,E,D,C,A,B.This indicates that browning of the fruit surface may be caused by high temperature and high humidity co-stress.3.The amount of browning of the fruit that is born in the upper part of the tree is smaller than that of the lower part.The order of browning fruit from small to large is the upper part of the tree(32.16%),the middle part(42.27%),and the lower part(45.97%).4.Bagging may cause a decrease in the Ca content of the peel,an increase in the K and Mg contents,and a decrease in the Ca/K and Ca/Mg ratios.The order of Ca peel content from low to high is double-layer double wax fruit bag G,H,double-layer single wax fruit bag E,F,yellow single-layer bag D,yellow striped single-layer bag C,pear bag B,A,no bagging,the difference is significant.The highest and lowest levels differ by 0.31 mg.g-1.K and Mg content from high to low are G,H > E,F> D>C> B,A> no bagging,the difference is significant.The highest and lowest contents differ by 2.51 mg.g-1 and 0.18 mg.g-1,respectively.The ratios of Ca / K and Ca / Mg from low to high are G,H,E,F,D,C,B,A,and no bagging,and the difference is significant.Compared with the mineral elements of Ruixue,Fuji,Pink Lady and Golden Crown,the content of Ca was the lowest and the content of Mg and K was the highest.Significant difference.The ratio of Ca / K and Ca / Mg is the lowest.Significant difference.5.Different fruit-growing bags had little effect on the polyphenol content of bagged apple peel,and had a great influence on the flavonoid content of the peel,and the higher the flavonoid content of the bagged apple peel,the lower the browning rate of the fruit surface.The order of polyphenols in apple peel is from double to double waxed fruit bag G,H,double layer single wax fruit bag E,F,yellow single layer bag D,yellow striped single layer bag C,pear bag B,A,no bagging.The highest and lowest content of polyphenols in apple pericarp of different fruit-growing bags differed by 1.0 mg.g-1,and the difference was not significant.The content of polyphenols in the uncased peel was up to 17.5 mg.g-1;the order of flavonoids in the peel was from G to H,E,F,D,C,B and A.The difference between the highest and lowest peel flavonoids was 6.18 mg.g-1,and the difference was significant.The unflavored peel flavonoid content was up to 12.12 mg.g-1.Among different varieties,the content of polyphenols in the peel(15.87 mg.g-1)was slightly lower than that in the golden crown(17.23 mg.g-1),pink lady(18.18 mg.g-1)and Fuji(18.59 mg.g-1),the difference was not significant.The flavonoid content of the peel was 5.12 mg.g-1 lower than that of the golden crown(5.74 mg.g-1),and the difference between the pink lady(13.13 mg.g-1)and Fuji(14.75 mg.g-1)was significant.6.Different fruit bag reduced the content of soluble protein,superoxide dismutase(SOD)and catalase(POD)in apple peel.The more soluble protein,SOD and POD content in fruit peel,the lower the browning rate of fruit surface.The soluble protein,SOD and POD of the peel are from double to double waxed fruit bag G,H,double layer single wax fruit bag E,F,yellow single layer bag D,yellow striped single layer bag C,pear Bags B,A,no bagging.The highest and lowest content of soluble protein,SOD and POD in fruit peels of different fruit-growing bags were 1.08 mg.g-1,729.49 U/gFW and 58.7 U/gFW,respectively.The difference was significant.Among different varieties,the SOD content of fruit peel was lower than that of Jinguan,Fuji and Pink,and the difference was significant.The content of POD and soluble protein is similar to other varieties.In the bagging cultivation,only the fruit surface browning occurred in Ruixue,and no other varieties occurred.