Effects Of Three Fruit Bags On Fruit Quality Of ’Shannongsu’ Pear

Pear is the second largest fruit of deciduous fruit trees in China and one of the most important fruits in the world.It has a unique taste and flavor,high nutritional value,and is favored by consumers.’Shannongsu’pear has few stone cells,good flavor and excellent comprehensive quality,which has become the first choice for the renewal of pear varieties.Bagging is one of the main technical measures to improve fruit quality.Therefore,in this experiment,’Shannongsu’pear was used as the research material,and plastic film bag,single-layer paper bag and three-layer paper bag were selected to determine the physical and chemical indexes such as bag microenvironment,fruit weight,fruit shape index,fruit point density,fruit hardness,sugar acid composition,total phenol,stone cell and aroma substance content.The effects of different types of fruit bags on the appearance and internal quality of’Shannongsu’pear fruit were investigated.The main results are as follows:1.The light transmittance of plastic film bag was the highest,which was 90.70%.The light transmittance of the three-layer paper bag was the lowest,which was 0.The light transmittance of the single-layer paper bag is between the two,which is 47.01%.The change of temperature and humidity difference between inside and outside of different fruit bags showed dynamic changes.The temperature difference between inside and outside of the three-layer paper bag was greater than that of single-layer paper bag and plastic film bag,while the humidity difference between inside and outside of the plastic film bag was greater than that of single-layer paper bag and three-layer paper bag.2.The peel of pear fruit treated with plastic film bag was rough,the fruit dots were large and sparsely arranged,and the appearance quality was the worst.The fruit treated with paper bag became lighter in color,the peel became smooth,and the surface finish was improved.The fruit treated with three layers of paper bag was yellow and white,the surface was smooth,the fruit dots were small and arranged closely,and the appearance quality was the best.The fruit shape index of pear fruit treated with three-layer paper bag was 23.4%and 18.4%higher than that of plastic film bag and single-layer paper bag respectively,and the fruit point density increased by 72.8%and 24.8%,respectively.3.The peel of pears treated with laminated paper bags was the thinnest,and the fruit hardness was significantly（P<0.05,the same below）higher than that of plastic film bags and single-layer paper bags,which were 36.5%and 5.8%higher than them,respectively.The stone cell content was significantly lower than the other two kinds of fruit bag treatments,which were 14.3%and 8.4%lower,respectively.4.The fruit sugar-acid ratio of the three-layer paper bag treatment was the lowest,the total aroma content was significantly lower than that of the plastic film bag and the single-layer paper bag treatment,and the fruit flavor decreased.The total sugar and total acid contents of the fruits treated with single-layer paper bags were the highest,which were 111.48mg·kg^-1 and 2.38 mg·kg^-1,respectively.The sugar-acid ratio was high,and the total aroma content was the highest,reaching 527.19μg·kg^-1.The fruit treated with plastic film bag had the highest sweetness value,the lowest total acid content,only 2.14 mg·kg^-1,the highest sugar-acid ratio,the highest total phenol content and free radical scavenging rate,and the best nutritional quality related indicators.5.Through the principal component analysis of the related indexes of fruit quality of’Shannongsu’pear under different treatments,it can be seen that the main influencing factors of fruit comprehensive quality under different treatments were fruit hardness,fruit point density,stone cells,aldehydes,total aroma and sugar-acid ratio.The comprehensive evaluation results of three kinds of fruit bags were three-layer paper bag>single-layer paper bag>plastic film bag.Based on the above research results,although the sugar acid ratio and total aroma content of’Shannongsu’pear with three-layer paper bags decreased,the appearance quality was the best,the fruit hardness was the highest,the stone cell content was the least,and the comprehensive quality was the best.Therefore,three-layer paper bags are recommended in the production of’Shannongsu’pear.