[关键词]
[摘要]
为寻求杨梅最适宜的冷冻模式,并为改善其冻品品质特性提供技术理论支撑。本研究采用液氮喷雾速冻(-20 ℃、-40 ℃、-60 ℃、-80 ℃、-100 ℃),以浸渍冷冻(immersion freezing,IF)和冰柜冷冻(refrigerator freezing,RF)作对比,分析不同冷冻方式下杨梅的冷冻时间、穿过最大冰晶生成带时间、汁液流失率、总酚、花色苷、总糖、硬度、维生素C、氧化自由基吸收能力、多酚氧化酶等变化,并进行评价。结果表明:液氮速冻方式显著优于其他冷冻方式,其中-100 ℃环温的液氮速冻,穿过最大冰晶生成带时间仅为IF的6.44%、RF的1.34%;冻结后杨梅的营养物质(总糖、维生素C、总酚和花色苷含量分别为29.22 mg/g、27.98 mg/g、1.52 mg/g、0.89 mg/g)能够保持新鲜组的80%以上,较IF和RF处理组的汁液流失率分别降低58.91%、63.39%;硬度分别提高15.15%、34.75%;综上,对杨梅进行冷冻处理时,在-20 ℃~-100 ℃的温度范围内,采用液氮速冻﹣100 ℃的冷冻方式对维持其品质效果最好。
[Key word]
[Abstract]
In order to find an optimal freezing method and provide technical and theoretical support for improving frozen quality characteristics of Bayberry, liquid nitrogen spraying quick-freezing (NF-20,-40,-60,-80,-100 ℃) was adopted with immersion freezing (IF) and refrigerator freezing (RF) as comparison. The frozen time, maximum ice crystal zone time (ti), thawing loss rate, total phenol, anthocyanin, total sugar, hardness, vitamin C, oxygen radical absorbance capacity, polyphenol oxidase changes of frozen bayberries were investigated. The results showed that the ti of NF-100 ℃ treatment was only 6.44% of that of IF, and was 1.34% of that of RF. The significant advantages of NF-100 ℃ were also shown on the quality proprieties, the nutrients(total sugar, vitamin C, total phenol and anthocyanin content were 29.22 mg/g, 27.98 mg/g, 1.52 mg/g and 0.89 mg/g, respectively) could be kept more than 80% of the fresh bayberry; compared with immersion freezing and refrigerator freezing, the thawing loss rate was lowered by 58.91% and 63.39% respectively; the hardness was enhanced by 15.15% and 34.75% respectively. In conclusion, Liquid nitrogen sparying quick-freezing is an optimal way to freeze bayberry, and -100 ℃ of NF is the appropriate frozen temperature to maintain the quality of bayberry in the temperature range of -20 ℃~-100 ℃.
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[基金项目]
广东省重点领域研发计划项目(2020B020225003);广东省现代农业产业技术体系创新团队建设专项资金(2019KJ117);广东省农业科学院院长基金(201806B);广东省农业科学院果蔬加工研究团队项目(201604TD)