High-Quality Thawing of Frozen Food by Far-Infrared Radiation

通过远红外辐射对冷冻食品进行高质量解冻

• 批准号: 07660155
• 负责人: SAKAI Noboru
• 金额: $ 1.15万
• 依托单位: Tokyo University of Fisheries
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1995
• 资助国家: 日本
• 起止时间: 1995 至 1996
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07660155/
• 关键词: far-infrared heating; thawing; tuna; apparent specific heat model; infinite element method

(1) ExperimentFrozen tuna was used as a sample. The sample was placed in a constant temperature box, in which fans were set inside to control an air flow rate, and was heated by a ceramic heater placed above the box. The temperature distribution was measured by using thermocouples and was recorded on a floppy disk.(2) Mathematical modelAn apparent specific heat model was introduced to predict two dimensional and three dimensional heat transfer in frozen food. A finite element method was applied to solve the fundamental equation and boundary conditions. Thermal properties (apparent specific heat, density, thermal conductivity) were estimated by Hakawa's empirical equations.(3) Experimental and numerical calculation resultsWe performed some numerical calculations to examine the influence of the heater temperature, the ambient temperature of the sample and the sample thickness on thawing rate. Experiments were carried out to check the validity of the mathematical model. Temperature distributions in samples were measured by using thermocouples and they agreed well with the theoretical predictions.During these experiments, deterioration, which was caused by drip loss or discoloration of the red muscles of tuna, was occurred because the surface temperature of the sample increased to unacceptable levels. However, we demonstrated that frozen tuna could be thawed without drip loss and discoloration by keeping the surface temperature below 10ﾟC.This was performed by irradiation of the energy intermittently or by reducing the heater temperature when the surface temperature reached 7ﾟC.

(1)实验以冷冻金枪鱼为样品。将样品放置在恒温箱中，其中风扇设置在恒温箱中以控制空气流速，并通过放置在恒温箱上方的陶瓷加热器加热。通过使用热电偶测量温度分布并记录在软盘上。(2)数学模型采用表观比热容模型预测冷冻食品的二维和三维传热。采用有限元法求解基本方程和边界条件。热性能（表观比热，密度，导热系数）的Hakawa的经验公式估计。(3)实验和数值计算结果我们进行了一些数值计算来研究加热器温度，样品的环境温度和样品厚度对解冻速率的影响。通过实验验证了数学模型的有效性。用热电偶测量了样品的温度分布，结果与理论预测吻合较好，在实验过程中，由于样品表面温度升高到不可接受的水平，发生了由金枪鱼红肌肉的滴水损失或变色引起的变质。然而，我们证明，通过保持表面温度低于10摄氏度，冷冻金枪鱼可以解冻，而不会出现滴水损失和变色。这是通过间歇性照射能量或在表面温度达到7摄氏度时降低加热器温度来实现的。