| 摘要: |
| 目的 探究草莓的液氮速冻工艺特性。方法 利用自行研制的液氮喷雾式速冻装置，温度设置在?40~?70 ℃之间，以5 ℃为间距进行草莓液氮速冻实验，并检测、分析不同冻结温度条件下的草莓冻结速率、失水率、色差、Vc含量和花青素含量等指标。结果 随着冻结温度的降低，草莓冻结时间缩短，冻结速率由9.75 cm/h提高到20.00 cm/h，但当冻结温度低于?55 ℃时，继续降低冻结温度，其冻结速率增幅减小。随着冻结温度的降低，液氮速冻后草莓的失水率、Vc含量、花青素含量和总酚含量呈现增大趋势，但增幅逐渐变小。结论 液氮速冻草莓采用?55 ℃冻结温度进行速冻时，既可保证草莓快速冻结，又可最大程度地保留草莓的营养品质。 |
| 关键词: 草莓 喷雾式 液氮速冻 品质 |
| DOI：10.19554/j.cnki.1001-3563.2018.23.011 |
| 分类号:TS255.3 |
| 基金项目:上海市联盟计划（LM201826）；普莱克斯项目（3A308014） |
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| Quick-frozen Characteristics and Nutritional Quality of Strawberries in LN2-spraying Freezer |
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WANG Xi-fang1, LI Bao-guo1, ZHU Hang2
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1.University of Shanghai for Science and Technology, Shanghai 200093, China;2.Shanghai Praxair for Industrial Gas Co., LTd., Shanghai 201204, China
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| Abstract: |
| The work aims to explore the characteristics of strawberries' liquid nitrogen (LN2) quick freezing process. The LN2 quick-frozen strawberries experiment was conducted at the temperatures ranging from ?40 ℃ to ?70 ℃ with 5 ℃ interval by means of a self-made LN2-spraying quick freezing device. The indexes of strawberries including freezing rate, water loss rate, chromatic aberration, contents of vitamin C and anthocyanin, etc. under different freezing temperatures were tested and analyzed. The freezing time was shortened and the freezing rate was increased from 9.75 cm/h to 20.00 cm/h with the reduction of freezing temperature. When the freezing temperature was lower than ?55 ℃, the increase of freezing rate decreased as the temperature continued to reduce. Water loss rate, Vc, anthocyanin and total phenolics of LN2 quick-frozen strawberries showed an increasing tendency with the reduction of freezing temperature, but the rate of increase was gradually decreased. The LN2 quick-frozen process of strawberries at ?55 ℃ can ensure the rapid freezing and maximally retain nutritional quality of the strawberries. |
| Key words: strawberry spraying LN2 quick-frozen quality |
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