Effect Of Acidic Electrolyzed Water Ice On Polyphenol Oxidase

Acidic electrolyzed water(AEW)technology has been widely concerned due to its advantage of easy operation,environmental and economical protection as well as safe.Acidic electrolyzed water technology was divided into three major types based on their state: AEW,AEW ice and AEW spray.Nowadays,AEW technology has been widely used in the food industry,medical,health management and other industry.With the continuous study of AEW technology,more and more attention was on the effect of AEW technology on delaying the browning of fruits,vegetables and aquatic products.Previous papers shown AEW technology had advantages in protecting the color of fruits and aquatic products.However,the current researchers focused on the food preservation of AEW technology on fruits,vegetables and aquatic products via measuring physical,microbiological and chemical changes,little attention has been paid to investigating the effects of AEW technology on the PPO activity,which is an essential enzyme related with browning in fresh fruit,vegetable and aquatic products.In the present study,the contents of AEW was analysed and the preliminary mechanism of AEW technology on delaying the browning of food was investigated.Thus,this study may provide theoretical bases for AEW technology used in food preservation in the future.The main content of this study were summarized as follows: 1.AEW is produced from anodic electrolysis of salt solution in an electrolytic cell,its component has not been clearly determined.In this paper,the compounds related to chlorine and active oxygen of AEW was measured with five-step iodometric method and dimethyl sulfoxide(DMSO)capture method.AEW was achieved with different concentration of sodium chloride solution and its decay kinetics was monitored.Results shown AEW gained with higher concentration of electrolyte,the higher content of available chlorine(ACC),chlorine and hypochlorite ions in AEW were detected.With the duration of storage,ACC and chlorine displayed a progressive decrease but the hypochlorite ions and hydroxyl radicals shown an unstable state.Moreover,Analysis the components of AEW could provide the foundation for studing of the mechanism of AEW technology on delaying the browning in food.2.Browning frequently occurs at fruits,vegetables and aquatic products during storage,it drastically reduces the consumer’s acceptability and considerable financial loss.The objective of this paper was to investigate the effects of acidic electrolyzed water(AEW)technology on polyphenoloxidase(PPO),which is an essential enzyme for browning.AEW ice exhibited a good ability in delaying browning in shrimp.Kinetic study revealed that AEW exhibited the mixed type inhibition of PPO with Ki value of 1.96 mM.Moreover,both Circular dichroism spectrum and Fourier transform infrared spectroscopy analyses revealed that α-helix in PPO decreased whereas random coil increased which indicates that PPO conformation was destroyed.Thus,this paper may provide a deeper understanding of the application of AEW technology for preventing browning in food industry.3.Recently,acidic electrolyzed water(AEW)has been applied in preservation as a novel technology.It is reported that AEW has strong ability in delaying melanosis in Litopenaeus vannamei and extending its shelf-life.In this paper,polyphenoloxidase(PPO),which is an essential enzyme for melanosis,from Litopenaeus vannamei was extracted and purified.The effects and kinetic study of AEW on purified PPO were then investigated.Based on SDS-PAGE,PPO from Litopenaeus vannamei was well purified.Kinetic study revealed that AEW exhibited inhibitory effects on PPO with dose-effect relationship.Moreover,AEW showed the mixed inhibition of PPO with Ki value of 0.18 mmol/L.In conclusion,this paper provided theoretical basis for further exploring the mechanism of AEW on food preservation.