全营养乳液贮藏期品质变化及动力学研究

Quality change and kinetics of total nutrient emulsion during storage

为探究全营养乳液在贮藏过程中的品质变化规律,将其置于不同温度(20、30、40℃)下贮藏,对粒径、电位、离心沉淀率、色差、p H、维生素C、维生素E和感官评分变化情况进行回归性分析并研究了稳定动力学。结果表明,贮藏温度是影响全营养乳液品质变化的重要指标。随着贮藏时间的延长,平均粒径增加了77.19%~156.74%,电位绝对值减小了27.36%~48.31%。a^(*)、b^(*)值增加,亮度减弱。维生素C对温度的敏感性高且降解符合一级反应,半衰期从144 d降低至81 d,反应活化能E_(a)为21.75 k J/mol。p H、粒径和离心沉淀率遵循零级反应动力学,色差、电位、维生素C含量的变化遵循一级反应动力学。热力学参数ΔH>0,ΔS<0,属于非自发进行的吸热反应。ΔG依赖于温度变化,随温度的增加呈上升趋势。该研究为全营养乳液的贮藏保质提供了理论参考依据。

To investigate the quality change pattern of total nutrition emulsion during storage,the changes of particle size,potential,centrifugal sedimentation rate,chromatism,pH,vitamin C,vitamin E,and sensory score were regressed and the stability kinetics were investigated at different temperatures(20,30,40℃).Results showed that the storage temperature was an important index affecting the quality of the total nutrient emulsion.With the extension of storage time,the average particle size increased by 77.19%to 156.74%and the absolute potential value decreased by 27.36%to 48.31%.The a and b values increased and the brightness decreased.The temperature sensitivity of vitamin C was high and the degradation was consistent with a primary reaction.The half-life decreased from 144 days to 81 days and the reaction activation energy E_(a) was 21.75 kJ/mol.The pH,particle size and centrifugal precipitation rate followed zero-level reaction kinetics,while the chromatism,potential and vitamin C content follow first-level reaction kinetics.Thermodynamic parametersΔH>0 andΔS<0 indicated that the reaction belonged to non-spontaneous endothermic reaction.ΔG depended on the temperature variation and showed an upward trend with increasing temperature.This study provides a theoretical basis for the storage and quality assurance of total nutrient emulsion.