菠萝是我国南方裁培面积大、产量多的大宗水果之一。但由于成熟后不耐贮运,除作鲜果供应外,主要用于制罐头、密饯果脯和果汁等食品工业。在交通不便的边远地区,或资金不足的小单位、个体户,当菠萝滞销时,将其加工成菠萝干也是一条出路。但是如果加工不好,菠萝干会变成褐色或黑褐色,严重影响产品质量,商品价值大大降低。菠萝在制干或贮运过程中,这种变褐或黑色的现象称“褐变”。其原因是:在氧化酶的作用下,使菠萝中的单宁类物质氧化聚合而呈现褐色或黑色,称酶褐 Pineapple is one of the large-scale fruit production in southern China. However, due to the maturity of the impotence storage, in addition to fresh fruit supply, mainly for canning, candied fruit preserved fruits and juice and other food industries. In remote areas with limited transportation, or under-funded small units or self-employed households, processing pineapple into pineapple is also a way out when the pineapple is slow to sell. However, if the processing is not good, the pineapple dry will turn brown or dark brown, seriously affecting the quality of the product, greatly reducing the value of the commodity. Pineapple in the dry or storage process, the brown or black phenomenon called “Browning.” The reason is: under the action of oxidase, the pineapple tannin oxidized and polymerized to brown or black, said enzyme brown