频率、温度和大豆分离蛋白对南极磷虾虾肉糜介电特性的影响

Effects of frequency,temperature and soy protein isolate on dielectric properties of minced antarctic krill

为探索微波加热作为虾肉糜复合物加工方式的可行性,以南极磷虾虾肉糜和大豆分离蛋白粉末及其复合物为研究对象,采用同轴探针技术测定了在25℃下不同压力(0~4.96 N)和堆积密度下大豆分离蛋白粉末的介电特性,以及大豆分离蛋白含量(0%~4%)、温度(20~80℃)和频率(300 M^3 000 MHz)对南极磷虾虾肉糜介电特性的影响。结果表明,随着压力的增大,大豆分离蛋白粉末的介电常数增加,而介电损失率无显著变化(p>0.05),但在堆积密度下略大于其他压力下的介电损失率。虾肉糜复合物的介电常数随着温度的升高而降低,介电损失率在小于2 500 MHz时增大而大于2 500 MHz时减小,穿透深度随温度的升高而降低。一定温度和频率下,随着大豆分离蛋白含量的增加,南极磷虾虾肉糜的介电常数降低,而对介电损失率无显著影响(p>0.05)。对20~80℃时虾肉糜复合物的介电特性值的进行拟合,拟合系数均大于0.93。调节频率和温度,可改变南极磷虾虾肉糜复合物的介电特性;大豆分离蛋白的添加可降低其介电常数。

The practicality of microwave heating as a food thermal processing method in processing shrimp surimi-soybean product was studied. Minced Antarctic krill and soy protein isolate were raw material. The open-ended coaxial probe technique was used to study the effects of pressure （0 -4.96 N） and bulk density on dielectric properties of soy protein isolate powder. The effects of frequency （300 M -3 000 MHz）, temperature （20 -80℃） and concentrations of soy protein isolate （0% - 4% ） on dielectric properties of Antarctic krill were investigated. The results showed that the dielectric constant of soy protein isolate increased as pressure increased. No significant （p 〉 0.05） of dielectric loss was found. However, the dielectric loss was bigger than other pressures under the bulk density. The dielectric constant and penetration depth of shrimp surimi-soybean compound decreased as the temperature increased. The dielectric loss was increased when the frequency was lower than 2 500 MHz, and decreased when the frequency was more than 2 500 MHz. Dielectric constant was decreased with the increase of the temperature. And the penetrating was decreased with the increase of the temperature. At a given temperature and frequency, the dielectric constant of Antarc- tic krill decreased as the concentrations of soy protein isolate increased,and had no significant influence on dielectric loss factor （p 〉 0.05 ）. The regression equations between temperature （20 -80℃） and dielectric properties of shrimp surimi-soybean compound were established, the regression coefficient was greater than 0.93. Control the frequency and temperature could change the dielectric properties of shrimp surimi-soybean compound; adding soy protein isolate could decrease the dielectric constant of shrimp surimi-soybean compound.