海藻酸钠/纳米TiO2复合涂膜对采后番木瓜果实软化及细胞壁降解影响

为探究海藻酸钠/纳米TiO₂(sodium alginate/nano-TiO₂,SA/TiO₂)复合涂膜处理抑制采后番木瓜果实软化的作用机理,以“日升10号”番木瓜为试材,采用SA/TiO₂复合涂膜处理,研究采后番木瓜果实硬度、细胞壁组分含量和细胞壁水解酶活性的变化规律。结果表明,SA/TiO₂复合涂膜处理能有效地抑制采后番木瓜果实中多聚半乳糖醛酸酶(polygalacturonase,PG)、果胶甲酯酶(pectin methylesterase,PME)、纤维素酶(cellulase,Cx)和β-半乳糖苷酶(β-D-galaetosidase,β-Gal)活性,减缓原果胶和纤维素的水解,减少可溶性果胶的增加,从而保持较完整的细胞壁结构,维持果实硬度。因此认为,SA/TiO₂复合涂膜处理可延缓采后番木瓜果实的软化进程,提高果实耐贮性。

Effect of Sodium Alginate/Nano-TiO2Compound Coating on Softening and Cell Wall Degradation of Post-harvest Papaya Fruit

To determine the inhibitory mechanism of sodium alginate/nano-TiO₂composites(SA/TiO₂)coating on softening of postharvest papaya(Carica papaya L.)fruit,‘Risheng No.10’papaya fruit was coated with SA/TiO₂,and the changes of fruit firmness,cell wall component and activities of cell wall degrading enzymes were studied.The results showed that coated with SA/TiO₂could effectively inhibit the activities of polygalacturonase(PG),pectin methylesterase(PME),cellulase(Cx)andβ-D-galaetosidase(β-Gal)in postharvest papaya fruit,decrease the degradation of protopectin and cellulose,and delay the increase of soluble pectin,so as to maintain the integrity of cell wall structures and fruit hardness.From the results,it could be concluded that treatment with SA/TiO₂could delay the softening process and increase the storability of harvested papaya fruits.