采前水杨酸处理对树莓果实贮藏效果及抗氧化能力的影响

探讨采前水杨酸处理对树莓果实贮藏效果以及抗氧化能力的影响。树莓果实于采前用1mmol/L 水杨酸喷施1 次、2 次和3 次后，采摘并贮藏于1℃条件下，分别隔10、23d 统计好果率，同时测定清除自由基的能力并研究总酚、总黄酮和花青素含量的变化规律。结果表明水杨酸喷施2～3 次均能显著提高树莓采后贮藏期间的好果率，其中喷施2 次的效果最好。采前水杨酸处理可提高采摘时树莓果实花青素、总酚和总黄酮的含量，以及总抗氧化能力、羟自由基和DPPH 自由基清除能力，而显著降低过氧化氢含量，以喷施2 次效果最为明显。同时，水杨酸处理可提高树莓果实采后贮藏期间的过氧化氢、总黄酮含量和清除DPPH 自由基的能力，降低花青素和总酚含量、以及总抗氧化能力和清除羟自由基能力。采前水杨酸处理主要通过诱导次生代谢物质产生和增强清除DPPH 自由基能力来显著提高树莓果实采后贮藏效果。

Effect of Pre-harvest Salicylic Acid Spray Treatment on Fruit Quality and Antioxidant Capacity of Raspberry during Post-harvest Storage

Raspberry fruits were sprayed with 1 mmol/L salicylic acid 1, 2 or 3 times every 3 days before harvest, harvested and stored at 1 ℃. Their sound fruit rate, contents of bioactive components, and antioxidant capacity were determined after storage for 10 or 23 days. The results showed that 2-time and 3-time pre-harvest salicylic acid spray treatments both increased significantly sound fruit rate and 2-time salicylic acid spray treated raspberry fruits revealed higher sound fruit rate than 3-time salicylic acid spray treated ones. Each pre-harvest salicylic acid spray treatment improved the contents of anthocyanins, total phenolics, total flavonoids and total antioxidant capacity, hydroxyl and DPPH radicals scavenging capacity, whereas obviously decreased the content of H2O2 of freshly harvested raspberry fruits. The most obvious changes in these parameters were observed in 2-time pre-harvest salicylic acid spray treated raspberry fruits. In addition, pre-harvest salicylic acid spray treated raspberry fruits exhibited an increase in the contents of H2O2 and total flavonoids and DPPH radical scavenging capacity and a decrease in the contents of anthocyanins, total phenolics and total antioxidant capacity and hydroxyl radical scavenging ability during postharvest storage. Pre-harvest salicylic acid spray treatment induced the generation of secondary metabolites and the enhancement. of DPPH radical scavenging capacity of raspberry fruits so that their post-harvest storage quality was improved.