外源乙烯和1-MCP预处理对鲜切马铃薯褐变的影响
Effects of exogenous ethylene and 1- MCP pre- treatment on enzymatic browning of fresh- cut potato tubers
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摘要: 为评价乙烯对鲜切马铃薯褐变的影响,分别采用外源乙烯、1-MCP和乙烯+1-MCP处理鲜切马铃薯,观察色差值（L*,a*和b*）、褐变度、酚类物质含量以及相关酶活性的变化。结果表明,外源乙烯提高了马铃薯的呼吸强度,增加了褐变度,提高多酚氧化酶（PPO）,过氧化物酶（POD）的活性,而1-MCP则起到了抑制作用;外源乙烯和1-MCP均能抑制马铃薯苯丙氨酸解氨酶（PAL）的活性,与对照（118.13 U）相比,经外源乙烯和1-MCP处理的马铃薯PAL活性分别为102.71 U和82.08 U,降低了13.1%和30.5%;外源乙烯预处理促进了鲜切马铃薯的褐变,1-MCP的施用可以抑制或减缓乙烯的负面作用。Abstract: Potatoes were treated by exogenous ethylene,1- MCP,and ethylene + 1- MCP,respectively.The changes of color parameters( L*,a*,b*),browning degree and activities of related enzymes in fresh- cut potato were used to evaluate the influence of each treatment on browning reaction.The results showed that exogenous ethylene treatment increased the respiration,browning degree and the activities of PPO and POD,while those above parameters showed a decreased trend by 1- MCP treatment.Both exogenous ethylene and 1- MCP treatment could decrease the activity of PAL. Compared with the PAL activity of control( 118.13 U),the PAL activity of potatoes treated by exogenous ethylene and 1- MCP were 102.71 U and 82.08 U,reduced 13.1% and 30.5% respectively.In conclusions,pretreatment of exogenous ethylene induced the browning of fresh- cut potato. However,the application of 1- MCP could inhibit or retard this negative effect of ethylene.
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