Effects Of Sodium Chloride Solution On Browning Of Fresh-cut Pear Fruit

As a characteristic of pear fruit,different varieties have different browning characteristics.In the process of postharvest storage and processing of pear,the original complete regional structure of cell membrane is often destroyed due to chilling injury or mechanical cutting,resulting in direct contact between enzyme and substrate,browning phenomenon,which seriously affects its commercial value.The browning characteristics of different pear varieties are different due to their own characteristics.As an emerging food,fresh cut fruits and vegetables are popular with consumers because of their high edible,fresh,hygienic,convenient,healthy and environmental protection.Fresh cut pear fruit,as a kind of fresh cut fruits and vegetables,is more prone to browning because it contains more polyphenols,which seriously affects its shelf life.There have been many studies on the methods to inhibit the browning of fresh cut fruits and vegetables,For example,physical methods such as coating treatment,chemical methods such as antioxidant treatment,and biological methods such as transgenic technology,but most inhibition methods can not be popularized because of their high cost,complex operation and low safety,As an antioxidant,sodium chloride solution has the characteristics of safety,convenience,edible and low cost in inhibiting the browning of fruits and vegetables.Therefore,this study took the pear fruits of’Qiuyue’,’Xinli No.7’,’yuluxiang’and’xincixiang’as test materials to explore the differences of their browning characteristics and the relationship between them and vitamin C content,and studied the inhibitory effect and mechanism of sodium chloride solution on the browning of fresh cut’Qiuyue’and fresh cut’xincixiang’fruit blocks.The results are as follows:1.When the flesh of four varieties of pears,namelyQiuyue‘,Xinli No.7‘Yuluxiang‘andXincixiang‘,is placed in normal temperature air,the browning rate and browning degree within one hour are as follows:"Xincixiang","Xinli No.7","Yuluxiang"and"Qiuyue".2.There is a negative correlation between vitamin C content and browning degree,that is,varieties with high vitamin C content are not easy to browning,and varieties with low vitamin C content are easy to browning.3.After screening the concentration of sodium chloride solution treatment,it was found that after soaking fresh cut’xincixiang’fruit blocks with sodium chloride solutions of 0.05mol/L,0.1 mol/L and 0.15 mol/L for 5 minutes,the three concentrations could inhibit the browning of’xincixiang’fruit blocks compared with the control.Among them,the treatment concentration of sodium chloride solution which can control the browning phenomenon most is 0.1 mol/L.compared with the control,the browning degree is significantly less when stored for 12 days,And delayed the decay time.4.The browning related enzyme activities and total phenol content were measured.It was found that compared with the control,sodium chloride solution treatment could reduce the total phenol content,PPO activity and the probability of enzymatic browning,so as to inhibit the browning of fresh cut pear fruit.5.Sodium chloride solution treatment can slow down the degree of pulp browning by alleviating the decline of vitamin C,and reduce the increase of soluble solid content,so as to alleviate the occurrence of browning from the aspect of inhibiting fruit senescence.6.Compared with the control,sodium chloride treatment can maintain the stability of cell membrane structure,delay the increase of H₂O₂ and MDA and improve the activity of antioxidant enzymes.In conclusion,the browning degree of pear fruit is negatively correlated with its own vitamin C content,especially in’xincixiang’and other fruits with very low vitamin C content.The treatment with 0.1 mol/L sodium chloride solution can inhibit the browning of fresh cut Pear by alleviating the degradation of vitamin C,delaying the rise of soluble solid content,reducing the activity of PPO and other browning related enzymes,reducing the content of total phenol,improving the antioxidant capacity of fruit and maintaining the stability of cell membrane of fruit.