纳米壳聚糖涂膜对鲜切茭白品质的影响

Effect of Nano-chitosan Coating on Quality of Fresh-cut Zizania latifolia

研究了纳米壳聚糖涂膜对鲜切茭白品质的影响。鲜切茭白分别在去离子水(对照)、10 g/L壳聚糖或10 g/L壳聚糖+1.5 g/L纳米壳聚糖溶液中浸泡3 min,自然晾干包装后于1±0.5℃下贮藏12 d。贮藏过程中每3 d测定鲜切茭白的白色指数(WI)、硬度、失重率及木质素、还原糖、抗坏血酸含量,PAL、SOD、CAT和POD活力。结果显示,纳米壳聚糖涂膜显著抑制了鲜切茭白WI值的下降和木质素含量的增加,维持了相对高的硬度及还原糖和抗坏血酸含量;贮藏12 d后失重率为1.12%;PAL和POD活性显著低于对照(P<0.05),SOD和CAT活性显著高于对照(P<0.05)。以上结果表明,纳米壳聚糖涂膜能有效延缓鲜切茭白褐变和木质化,提高抗氧化酶类活性,提示纳米壳聚糖涂膜具有商业上控制鲜切茭白品质劣变的潜在价值。

The effect of nano-chitosan coating on the quality of fresh-cut Z. latifolia was investigated. Fresh-cut Z. latifolia slices were dipped into deionised water （the control）, 10 g/Lchitosan or the mixture of 10 g/L chitosan and 1.5 g/L nano-chitosan for 3 min, and then dried, packaged and finally stored for 12 days at 1±0.5℃. Changes in whiteness index （WI）, firmness, weight loss, lignin, reducing sugar and ascorbic acid contents, phenylalanine ammonia-lyase （PAL）, superoxide dismutase （SOD）, catalase （CAT） and peroxidase （POD） activities were evaluated at intervals of two days. The results showed that the nano-chitosan coating significantly inhibited the decline of WI value and the increase of lignin content, maintained relatively high firmness, reducing sugars and ascorbic acid contents of fresh-cut Z. latifolia. After a 12-day storage at 1±0.5℃, the weight loss of the fresh-cut Z. latifolia slices was 1.12%. The treatment also inhibited the activities of PAL and POD but promoted SOD and CAT activities compared with the control. The present findings indicated that the nano-chitosan coating could inhibit browning and lignifacation and improve antioxidant enzymes activities, which suggested that the uano-chitosan coating had potential commercial value in controlling quality deterioration of fresh-cut Z latifolia.