Abstract: In order to investigate the effect of oxalic acid on the browning and preservation quality of fresh cut yam,with Chinese yam as test material,fresh cut yam pieces were treated by 0.1%,0.3%,0.5% oxalic acid solution respectively and dipped in water as control.The changes in weight loss rate,titratable acid content,ascorbic acid content,malonaldehyde(MDA) content,relative electrical conductivity,browning degree,lightness(L) value,polyphenol oxidase(PPO) activity and total phenol content were measured.The results showed that,oxalic acid treatment could maintain higher titratable acid and ascorbic acid content at the later stage of storage,sustain the lower weight loss rate and maintain the quality of fresh cut yam. In addition,0.3% oxalic acid treatment could significantly inhibit the increase of MDA content, relative conductivity,PPO activity and total phenol content,and maintain higher L value and lower browning degree.The results indicated that, 0.3% oxalic acid treatment could reduce membrane lipid peroxidation reaction of fresh cut yam,inhibit enzymatic browning,and had a better effect on fresh cut yam storage and preservation.

Key words: Fresh cut yam, Oxalic acid, Storage and preservation, Membrane lipid peroxidation, Enzymatic browning, Polyphenol oxidase, Total phenol

摘要： 为研究草酸对鲜切山药褐变及贮藏品质的影响，以菜山药为试材，采用0.1%、0.3%、0.5%草酸溶液处理鲜切山药，以清水浸泡鲜切山药为对照，测定失重率、可滴定酸含量、抗坏血酸含量、丙二醛（MDA）含量、相对电导率、褐变度、色度值、多酚氧化酶（PPO）活性、总酚含量等指标变化，研究草酸处理对鲜切山药贮藏保鲜效果。结果表明，草酸处理能维持鲜切山药贮藏后期较高可滴定酸和抗坏血酸含量，保持较低失重率，维持其产品质量。0.3%草酸处理能显著抑制鲜切山药MDA含量和相对电导率升高，显著抑制PPO活性和总酚含量增加，并维持较高色度值和较低褐变度。研究认为，0.3%草酸处理能降低鲜切山药膜脂过氧化反应、抑制酶促褐变，对鲜切山药具有较好的贮藏保鲜效果。

关键词: 鲜切山药, 草酸, 贮藏保鲜, 膜脂过氧化, 酶促褐变, 多酚氧化酶, 总酚