预冷时机对四季豆和豇豆品质和生理生化特性的影响

Impact of Precooling Time on Quality and Physio-Biochemical Characteristics of Common Bean(Phaseolus vulgaris L.) and Cowpea(Vigna sinensis) under Controlled Atmosphere Storage Conditions

本实验以四季豆和豇豆为试材,研究预冷时机对其气调贮藏后期和常温货架后期品质和生理生化特性的影响。将采收后的四季豆和豇豆于常温(温度(20.5±4.5)℃、相对湿度72%)下分别放置0、6、12 h,以强制通风方式预冷至中心温度9.0℃左右,于气体组分为体积分数3%O2+1%CO2+96%N2条件(温度(9.0±0.5)℃、相对湿度(80±5)%)下贮藏15 d后于常温(温度(24.5±4.5)℃、相对湿度(65±2)%)下放置2 d模拟货架期,分别在气调贮藏15 d和常温货架期2 d取样,测定其品质和生理特性。结果表明:与常温放置6 h和12 h后预冷相比,即时预冷的四季豆和豇豆在贮藏后期和货架后期均具有较低的质量损失率、呼吸强度、锈斑指数和纤维素含量,以及较高的感官评价得分、还原糖和叶绿素含量。同时,即时预冷可维持较高的超氧化物歧化酶、过氧化氢酶、过氧化物酶和纤维素酶活力,抑制呼吸强度、超氧阴离子产生速率、过氧化氢和丙二醛形成。实验结果表明,即时预冷能提高气调贮藏和常温货架期四季豆和豇豆抗氧化能力,降低氧化胁迫,从而延缓其衰老,保持产品品质。

In order to explore the impact of precooling time on their quality and physio-biochemical characteristics, freshly harvested common bean （Phaseolus vulgaris L.） and cowpea （Vigna sinensis） were placed at room temperature （（20.5 ± 4.5） ℃） with a relative humidity of 72% for 0, 6 and 12 h, respectively, and precooled to 9.0 ℃ before 15 d controlled atmosphere storage （gas composition： 3% O2 ＋ 1% CO2 ＋ 96% N2, temperature： （9.0 ± 0.5） ℃, humidity： （80 ± 5）%） followed by 2 d stimulated shelf life at room temperature （temperature： （24.5 ± 4.5） ℃; humidity： （65 ± 2）%）. Samples were collected for quality and physio-biochemical analysis after controlled atmosphere storage and shelf life. Results showed that compared with those precooled after 6 and 12 h at room temperature, P. vulgaris L. and V. sinensis precooled immediately after harvest possessed higher sensory evaluation score and higher contents of reducing sugar and chlorophyll as well as lower mass loss rate, respiration intensity, spot index and cellulose content after controlled atmosphere storage and shelf life. Meanwhile, immediate precooling maintained high activities of peroxidase （POD）, catalase （CAT）, superoxide dismutase （SOD） and cellulose （CEL）, and low levels of respiration intensity （RI）, superoxide anion （O2-·） production rate, hydrogen peroxide （H2O2） and malondialdehyde （MDA）. Therefore, immediate precooling could delay the senescence of P. vulgaris L. and V. sinensis during controlled atmosphere storage and shelf life and maintain high quality by improving antioxidant status and reducing oxidative stress.