Screening Of Litchi Complex Preservatives And Studies Of Its Preservation Effect

The purpose of this study is to screen out safe,environmentally friendly,and efficient complex preservatives and their concentration formula and explore the Preservation Effect.Two batches of litchi fruits from two different cultivars,‘cv.Feizixiao’and ‘cv.Jingganghongnuo’,were used as materials to study the effects of Sportak,Brassinolide,kojic acid,D-Isoascorbic acid and soaking time on the preservation of litchi fruits.Through orthogonal experimental design,the formula of preservative which can effectively alleviate litchi browning and improve the storage effect of litchi fruit was screened out.The appearance quality indexes of litchi pericarp,such as browning index,color value were determined.The changes of total soluble solids(TSS)content,titratable acid(TA)content and Vitamin C(Vc)content in pulp,relative conductivity of pericarp,proline content,p H value and activities of polyphenol oxidase(PPO),peroxidase(POD)and laccase(Lac)were observed.Multivariate statistics,principal effect analysis,variance analysis,significant difference analysis,relevance analysis,means comparison,and other methods were used to compare and analyze the indicators,so as to screen out the best preservative formula for litchi storage.The experimental results are as follows:1.The results of single factor experiment showed that 500 mg/L Sportak treatment had better effect;30 and 50 μmol/L BR treatment had better effect than 70 μmol/L Brassinolide,0.75% and 1.00% kojic acid treatment had better effect than 0.50% kojic acid treatment;0.50% D-Isoascorbic acid treatment had better effect.In the single factor experiment of ‘cv.Feizixiao’,with the extension of soaking time,storage effect was significantly improved,soaking for 8 minutes of test No.17 effect is the best;the results of interaction test showed that there was no interaction between Brassinolide,kojic acid,D-isoascorbic acid,soaking time and sportak.2.In this study,under the condition of Sportak as the basic reagent,the formula ofpreservative for litchi preservation at room temperature(25℃)was selected as 40 μmol/L brassinolide,0.50% kojic acid,Soak for 3 minutes;and low temperature(4℃)was selected as 40 μmol/L brassinolide,1.00% kojic acid,Soak for 1 minute.3.Compared with the control(CK)and the ‘Sportak’ treatment,the formula of preservatives screened at room temperature and low temperature could significantly reduce the browning index and decay rate of litchi fruits;maintain bright pericarp color in the late storage period,maintain higher chroma L*,a*,C* value and anthocyanin content;delay the decrease of Vc content and the increase of pericarp p H,relative conductivity;while the activities of PPO,POD and Lac activities decreased.