二氧化氯缓释剂的制备及对龙眼保鲜效果综合评价

Preparation and evaluation of slow-releasing chlorine dioxide preservative on longan

龙眼采后易由褐变引起品质劣变,该研究研制出一种自动释放二氧化氯(ClO_(2))的新型缓释剂,并通过主成分分析(principal components analysis,PCA)和数学模型评价了其对龙眼综合保鲜效果。结果表明,经单因素和正交试验优化,最佳ClO_(2)缓释剂组成为m(亚氯酸钠)∶m(酒石酸)∶m(硅胶)∶m(硅藻土)=3∶1∶0.5∶0.5。该缓释剂在5~25℃条件下,ClO_(2)释放周期均达到240 h以上,稳定性良好。对比不同使用量(0.3、0.6、1.2 g)缓释剂发现,与对照组相比,使用1.2 g缓释剂的龙眼的色泽指标L*值在第9天显著提高了10.7%(P<0.05),而a*、b*、着色指数(color contribution index,CCI)分别下降了19.6%、17.2%、12.2%,抑制褐变效果最好;同时,硬度和可溶性固形物也分别显著降低了19.3%、11.6%(P<0.05)。PCA表明,2个主成分能代表所有品质指标(6个)71.795%的信息,通过所建立的数学模型评价保鲜效果排序为1.2 g缓释剂>0.6 g缓释剂>0.3 g缓释剂>对照组。此外,9 d贮藏期间只有1.2 g缓释剂处理的龙眼综合得分一直低于临界值(0),再次验证了其保鲜效果最佳。

Longan is easy to deteriorate after harvest by browning.In this study,a new automatic slow-releasing chlorine dioxide(ClO_(2))preservative was optimized.Subsequently,the comprehensive fresh-keeping effects on longan were evaluated by principal components analysis(PCA)and mathematical models.Results showed that after a single factor and orthogonal experimental optimization,the best slow-releasing ClO_(2)preservative was as follows:sodium chlorite∶tartaric acid∶silica∶diatomite=3∶1∶0.5∶0.5.The release time of ClO_(2)reached more than 240 h at 5-25℃,showing outstanding stability.Then,0.3,0.6,and 1.2 g slow-releasing ClO_(2)preservatives were compared.It was found that the color index lightness(L*)value was significantly increased by 10.7%(P<0.05),while a*,b*,and color contribution index(CCI)decreased by 19.6%,17.2%,and 12.2%respectively,showing the best browning inhibition effect.Meanwhile,the hardness and soluble solids(TSS)were significantly decreased by 19.3%and 11.6%(P<0.05).PCA demonstrated that the two principal components could represent 71.795%of the information of all six quality indicators,and the preservation effect was ranked by the established mathematical models:1.2 g>0.6 g>0.3 g>CK.In addition,the comprehensive score of longan treated with 1.2 g slow-releasing ClO_(2)preservative remained below the critical value(zero)during 9 days of storage,which verified the best browning inhabitation and preservation effect again.