Study On Browning Characteristics And Microbial Growth Forecast Model Of Vacuum-packaging Lotus Root

Vacuum-packaging lotus roots are new products of processing in recent years, whichare susceptibly browned and infected microbial. Study the browning and the changes ofcorruption microbes in order to provide theory and application foundations for lotus-root ofthe quality control.The most suitable wave length is410nm, pH value is7.0, the temperature is35℃,concentration of substrate0.09mol/L of PPO enzyme activity when to use catechol assubstratethe.Orthogonal experiments indicated that the factor browning inhibitioncomboination is that the concentration of the Vc is0.20%,the concentration of the sodiumsulfite is0.10%, the concentration of the citric acid is0.20%,the concentration of theEDTA is0.25%.During the storage, the degree of browning increased, moisturecontent,solute protein content and PPO activity rose firstly and then decreased.Seven strains of bacteria in the vacuum-packaging lotus root were isolated withdifferent selective media such as pseudomonas isolation agar、violet red bile agar、manrogosa and sharpe agar、mannitol salt agar. Seven strains DNA of bacteria was extractedusing kit.The product directly16S rDNAof PCR amplificaed. Product would be comparedwith BLAST database of program the sequence after two-way sequences. Theexperimental results show that seven strains of bacteria were two strains of Lactobacillusplantarum, Enterobacteriacea—Klebsiella oxytoca and Rahnella、 Pseudomonas—Pseudomonas fulva and Pseudomonas putid,one strains of Staphylococcus aureus. Throughthe microflora change of vacuum-packaging lotus roots at4℃,we discover thelactobacillus plantarum was the dominating bacteria for spoilage with the faster growth.The quantity change of lactobacillus plantarum were monitored succession at0℃、4℃、10℃、15℃a nd20℃.Growth models of lactobacillus plantarum at differenttemperatures using SAS9.1software were developed.The Gompertz type model indicatedthat the dynamic change of number of lactobacillus plantarum during differenttemperatures with R-square more than0.99. And growth model of different temperature slactobacillus plantarum was getted. On that basis, the modle of relationship between temperature and maximum specific growth rate, lag phase were built respectively usingBelehradek model with R-square more than0.98. The correlation regression suggested thatit could describe the influence of temperature on maximum specific growth rate and lagphase when deviation degree and accuracy with an average of1.0125and1.1006. And thenthe prediction model of the shelf-life of Lotus root in the region of0℃to20℃weredeveloped, the real and predicted shelf life of chilling pork was compared at7℃, and thebasic errors was1.8%,which demonstrated the model developed could be effectivelypredicted the microbial quality and remaining shelf life of Lotus root stored from0℃to20℃.Research provides a foundation to maintain quality for vacuum-packaging lotus roots,which have certain theoretical and applied meaning...