Study On Properities Of Polyphenoloxidase And Control Of Browning In Lily(Lilium Davidd Duchantrin Elues)Bulbs

By researching in the properties of PPO from lily,the browning degree during storage and PPO activities from lily,this article have stating these and also selected some anti-browning medicaments.Partial properties of PPO from lily(Lilium davidd Duchantrin Elues)were researched in this article.The results showed that PPO activities declined gradually as the temperature rising from 10 to 60℃.Its activities were higher at 10℃and 35℃,respectively.PPO activities had a absorbed peak at pH4.5 and pH 6.0 from pH3.0 to 7.5 respectively;however PPO activities of pH6.0 was lower than that of pH4.5.PPO activities increased with the increasing of concentration of catechol.When the concentration of substrate reached 14mM, PPO activities didn't increase anymore.There were a liner-relation between additional amount of crude enzyme and PPO activities,and the relational coefficient was 0.986.PPO activities were effectively inhibited by sodium sulfite anhydrous,L-cysteine,sodium pyrosulfite and ascorbic acid,respectively.Sodium sulfite anhydrous was the most effective inhibitor among the seven tested inhibitors,and L-cysteine was also effective one.By researching of the browning degree during storage and PPO activities from lily,the results showed that different layers of lily scales have different PPO activities.The details as follows:the PPO activities of the core part is the highest,it's the 5.45 times higher than outer layers;and 2.78 times than inner layers,and outer layers is the lowest.Storage under low temperature can delay the browning speed and decline speed of PPO activities of lily bulb. The browning speed of whole bulb is iower than slice of lily.Under low temperature,the whole bulb with vacuum storage can prevent the browning effectively.The experiments of anti-browning reagent showed:treatment with 0.5%Ascorbic acid, 0.5%D-iso-ascobate,0.75%Sodium Pyrophosphates,and 1%Calcium Chloride can prevent the browning.0.5%Ascorbic acid or same consistenty's Sodium gave effective for the browning of the lily bulb,and there isn't any obviously difference.The experiments of anti-browning composed agent of combining showed:the treatment with 0.75%Sodium D-iso-ascobate,0.2%Citric acid and 1.25%Calcium Chloride gave effective for the browning of lily bulb.The best composed agent of combining(0.75%Sodium D-iso-ascobate,0.2%Citric acid and 1.25%Calcium Chloride)with the best reagent of single agent have obviously effects on anti-browning.As its safe,low cost and convenient,the formula can be extending in production.