The Effect Of Space Electric Field Combined With Low Temperature Storage On Fresh-keeping Of Bayberry

Bayberry is favored by consumers because of its sweet and sour taste and rich nutrition.It is rich in various nutrients such as organic acids,sugars,anthocyanins,vitamins and minerals.However,due to its soft texture and rich water content,bayberry is prone to physical damage and other reasons.In addition,the high temperature and high humidity of the bayberry harvest,the plum rain continues,which is conducive to the growth and reproduction of pathogenic bacteria.Therefore,the effective preservation of bayberry has always been a major obstacle to its development.At present,the mainstream preservation method is low-temperature storage,but the preservation effect can not meet the needs of people;Many scientist tried to find new preservation methods but still have drawbacks.Therefore,it is extremely urgent to study a green,safe and no negative impact on the preservation of bayberry.This paper takes Zhoushan“Wandao bayberry”as the experimental material.Use space electric field combined with low temperature storage to preserve it.Through the study,the effects of organic acid content,soluble sugar content and main pathogenic bacteria on the fresh-keeping effect of bayberry were analyzed,and the shelf life prediction model was used to analyze its storage period.It is hoped to provide a new basis for the development and utilization of bayberry preservation technology.1.The changes of four organic acids in citrus,malic acid,tartaric acid and succinic acid in bayberry under space electric field were investigated and determined by HPLC.The results showed that the citric acid content was the most abundant(42.19 mg/mL)in the early stage of storage,and malic acid(8.22 mg/mL)and succinic acid(4.92 mg/mL)were also present,with the lowest tartaric acid content(0.54 mg/mL);At the end of storage,tartaric acid(<0.25 mg/mL)and succinic acid(<1.25 mg/mL)were not detected,and malic acid was still present in small amounts(0.91 mg/mL).The organic acid other than citric acid is substantially decomposed.The decomposition of organic acids in bayberry was delayed under the space electric field.2.The variation of soluble sugar content in bayberry under space electric field was investigated.It was determined by 3,5-dinitrosalicylic acid method.The results showed that the soluble sugar content of bayberry increased first and then decreased during the whole storage process.The soluble sugar content of the experimental group and the control group were 9.35%and 9.58%,respectively,and the organic acid conversion increased to 10.19%and 9.82%on the 12th day.Respiratory effects in the middle and late stages consumed a large amount of sugar,which was only 5.15%and 4.39%at the 60th day.The soluble sugar content of the experimental group was significantly higher than that of the control group during storage(P<0.05).It is indicated that the space electric field is beneficial to slow the consumption of soluble sugar in the fruit of bayberry and improve the storage quality.3.The effects of space electric field on the main pathogenic bacteria in bayberry were studied.The effects of arbutus rot,chitinase and?-1,3-glucanase,PAL,POD and PPO activity and total number of molds and yeasts.The results showed that the experimental group bayberry rot index reached 79.9%on the 60th day,while the control group was 95.8%,which was significantly higher than the experimental group.Chitinase activity decreased from 6.38U/mg to 2.88 U/mg and 1.67 U/mg,respectively,and?-1,3-glucanase activity decreased to9.54 U/mg and 7.43 U/mg,respectively,PAL,POD and PPO activity are reduced.4.The relationship between decay index,shelf life and temperature during storage of bayberry was explored.By determining the decay index of bayberry under different temperatures(271,273,275,277,279 K),the kinetic model of the change index of bayberry decay index was established by combining the Arrhenius formula with the Gompertz equation,and the activation energy Ea=11.07×10~3 J/(mol K),rate constant k=-Exp(-1332/T+5.194)was obtained.The model was verified at storage temperature 272 K and 274K,and the relative error(RE)of the prediction was 4.03%.After verification,the accuracy of the kinetic equation is confirmed,and the rot of the bayberry in the environment of271~279 K can be predicted well.