[关键词]
[摘要]
在直接浸渍冻结过程中,溶质渗透是影响直接浸渍冻结应用的主要因素。本文通过建立明胶模型,研究直接浸渍过程中不同溶质的渗透模型及规律,并对对虾中的溶质渗透规律进行探索。研究发现,溶质中的甜菜碱、丙二醇及氯化钠在明胶模型中的渗透深度分别为0.2 cm、0.35 cm及0.4 cm,渗透量分别为4.35±0.12 mg/g、6.15±0.12 mg/g、11.73±0.18 mg/g;在对虾中的渗透深度分别为0.25 cm、0.31 cm、0.35 cm,渗透量分别为0.86±0.07 mg/g、1.53±0.11 mg/g、1.67±0.08 mg/g。通过对直接浸渍冻结过程溶质的变化进行回归分析,溶质的渗透规律可用回归模型进行表达,并且甜菜碱、丙二醇及氯化钠在对虾中的渗透变化趋势与明胶模型相对一致,前5 min内,甜菜碱、丙二醇、氯化钠扩散速率较大,几乎呈直线增加,6 min后,扩散速率减慢。根据所建立的传质模型,甜菜碱、丙二醇、氯化钠在明胶的平均扩散系数分别为4.16×10-7 m2/s、1.27×10-6 m2/s、1.66×10-6m2/s,在对虾中的平均扩散系数分别为2.34×10-7 m2/s、9.36×10-7 m2/s、1.36×10-6 m2/s。
[Key word]
[Abstract]
During immersion chilling and freezing (ICF) process, mass transfer was a major factor directly affecting the application of ICF. The penetration model and law of different solutes during ICF was investigated by establishing the gelatin models and explored the penetration law of shrimp. The results indicated that the penetration depths of betaine, propanediol and sodium chloride in gelatin model were 0.2 cm, 0.35 cm and 0.4 cm, respectively, while the penetration depths of them in shrimps were 0.25 cm, 0.31 cm and 0.35 cm, respectively. The transfer contents of betaine, propanediol and sodium chloride in gelatin were 4.35±0.12 mg/g, 6.15±0.12 mg/g and 11.73±0.18 mg/g, respectively, and the transfer contents of them in shrimps were 0.86±0.07 mg/g, 1.53±0.11 mg/g and 1.67±0.08 mg/g, respectively. Through regression analysis of solute changes during ICF, the solute penetration regression model could express the penetration law of solute. It was found that transfer trend of betaine, propanediol and sodium chloride in shrimp and gelatin were consistent. Before 5 min, the penetration rates of betaine, propanediol and sodium chloride showed a linear increase. After 6 min, the penetration rates became slow. According to the math model, the diffusion coefficients of betaine, propanediol and sodium chloride in gelatin model were 4.16×10-7 m2/s,1.27×10-6 m2/s and 1.66×10-6 m2/s,respectively. The diffusion coefficients of three solutes in shrimps were 2.34×10-7 m2/s, 9.36×10-7 m2/s and 1.36×10-6 m2/s, respectively.
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[基金项目]
国家科技支撑计划项目(2012BAD28B00);广东省科技计划重点项目(2011A020102005)