机械损伤对富士苹果酶促褐变的影响

Effects of Mechanical Damage on Enzymatic Browning in Fuji Apples

研究了富士苹果机械损伤后在5℃和18℃贮藏条件下对生理变化及酶活性的影响。结果表明,机械损伤后的果实相对电导率急剧增大、L*值迅速下降、多酚含量逐渐降低、丙二醛(MDA)含量逐渐上升,果肉快速发生褐变。机械损伤提高了多酚氧化酶(PPO)、过氧化物酶(POD)和过氧化氢酶(CAT)的活性,抑制了超氧化物歧化酶(SOD)的活性。随着贮藏时间的延长,除了PPO外,其它指标都呈现了上升、下降的反复过程,说明组织自身的保护酶系统对伤胁迫具有生理防御作用,而且在低温贮藏时酶活性较强而能有效地延缓果实的衰老。

The effects of mechanical damage on physiological changes and the enzymatic activity of Fuji apples during storage at 5 ℃ and 18℃ were investigated. The results showed that the relative electrical conductivity increases rapidly, L＊ value decreases rapidly, the content of polyphenol decreased gradually, the content of malondialdehyde（MDA）increases gradually and flesh becomes brown rapidly in Fuji apples after mechanical damage. The activities of polyphenol oxidase（PPO） and peroxidase（POD） and catalase （CAT） all increase while the activity of superoxide dismutase （SOD） is restricted after mechanical damage. The parameters show the increasing and reducing cycles except PPO after extension of storage. It also showed that the protective enzyme system of injured tissue defends stress and the better activity of enzyme delays aging of fruit during low temperature storage.