冷激对琯溪蜜柚室温贮藏效果的影响

Effect of Cold Shock on Quality of Guanxi Honey Pomelo Fruits Stored at Room Temperature

琯溪蜜柚经0℃的冰水混合物分别冷激处理0(CK)、0.5(L0.5h)、1(L1h)、1.5h(L1.5h)和2h(L2h)后室温贮藏166d,分析贮藏期内果实出汁率、可食率、可溶性固形物、总糖、总酸、丙二醛、抗坏血酸、过氧化氢酶活性和质膜相对透性等变化,探讨贮前冷激处理对琯溪蜜柚室温贮藏效果的影响。结果表明,冷激处理组相对电导率均低于CK(0.44),其中以L1h最低(0.35);L1h总糖量保持最高(2.83g/10g),其次是L0.5h(2.37g/10g),分别比CK高31.6%和10.2%;MDA量以L1h最低,其次是L0.5h,分别为CK(5.9mmol/g)的0.81和0.83倍;L1h可食率最高(72.8%),其次是L0.5h(71.7%),分别比CK高5.2%和3.6%;L1h保持较高CAT活性,其次是L0.5h,分别是CK的1.12倍和1.03倍;抗坏血酸量均高于CK,高低顺序为L1.5h>L0.5h>L2h>L1h>CK。短时冷激处理可减缓出汁率的下降速度并保持较高的总酸量,其中L0.5h(76.4%)和L1h(75.6%)出汁率高于CK(75.1%);L1h总酸最高(168.3g/kg),其次是L0.5h(155.5g/kg),分别比CK约高19.2%和10.0%;TSS量则稍高于或接近CK。贮前冷激处理可增强琯溪蜜柚的室温耐贮性,以冷激1h效果最佳。

Guanxi honey pomelo fruits were immersed in ice-water （0 ℃） for 0 （CK）, 0.5 （L0.5h）, 1 （L1h）, 1.5 （L1.5h） and 2 h （L2h）, and then stored at room temperature for 166 days to evaluate the effect of cold shock pre-treatment on product quality during storage. Juice rate, edible rate, total soluble solids （TSS）, total sugar （TS）, total acids （TA）, malondialdehyde （MDA）, ascorbic acid （AA）, catalase activity （CAT） and relative permeability of plasma membrane （RPPM） were analyzed. Results indicated that relative conductivity of the cold shock treatment group was lower than that of cold shock control group （0.44）, and the relative conductivity of the L1h group was the lowest （0.35）. TS content in L1h group was the highest （2.83 g/10 g） and then followed by L0.5h group （2.37 g/10 g）, which was higher than CK group by 31.6% and 10.2%, respectively. MDA content in L1h group was the lowest, which was 0.81-fold of CK and next was in L0.5h group with 0.83-fold of CK. Edible rate in L1h group was the highest （72.8%） and next was in L0.5h group （2.37 g/10 g）, which was higher than 5.2% and 3.6% of CK, respectively. CAT activity in L1h group remained the highest level, which was 1.12-fold of CK group and next was in L0.5h group, which was 1.03-fold of CK. AA content was totally higher than CK, and the order from high to low was L1.5h, L0.5h, L2h, L1h and CK. Short time cold shock could alleviate the reduction of juice rate and maintain a higher TA content. The juice rates were 76.4 % and 75.6% in L0.5h and L1h groups, which were higher than CK group （75.1%）. TA content in L1h group （168.3 g/kg） was the highest level with 19.2% higher than CK group and next was in L0.5h group （155.5 g/kg） with 10.0% higher than CK. TSS content was a little higher than or close to CK group. In a word, cold shock pretreatment can improve the product quality of Guanxi honey pomelo fruits during storage at room temperature and immersion in ice-water for 1 h has the best effect.