射频处理对婴儿奶粉氨基酸、形貌和吸附特征的影响

Effect of Radio Frequency Treatment on Amino Acid Composition, Morphology and Adsorption Characteristics of Infant Milk Powder

通过对射频加热(90℃,5～10 min)前、后婴儿奶粉基本组成、氨基酸成分、原子力显微镜形貌及等温吸湿能力的研究,探讨射频加热处理对奶粉组成、形貌及吸湿特性的影响。射频处理进一步降低了奶粉的水分活度,不会对奶粉蛋白质、脂肪等基本组分产生影响。经10 min射频处理的奶粉氨基酸含量下降1.79%,蛋氨酸含量降低10.11%,b-丙氨酸的含量降低21.33%。与对照相比,射频使得奶粉空间形貌更加紧致,表面更为光滑。利用BET模型对等温吸湿数据拟合发现,经过射频处理,奶粉的单层含水量略有增加,吸湿所需能量增大。研究表明,射频处理对婴儿奶粉营养品质无明显影响,然而会改变奶粉大分子结构,影响奶粉加工性能。

The effect of radio frequency heating(90℃,5-10 min)on the basic composition,amino acid composition,atomic force microscopy morphology,and isothermal moisture absorption ability of infant milk powder was investigated in this study.Radio frequency treatment(RF)could further reduce the water activity of the milk powder,but could not affect the basic components such as protein and fat.After 10 min RF,the total amino acid content in milk powder decreased by 1.79%,but methionine content was reduced by 10.11%and the content of b-alanine was reduced by 21.33%.Compared with the control,RF promoted more compact and smooth-surface space morphology.The isothermal moisture absorption data were fitted with the BET model,which indicated that the monolayer moisture content of RF samples increased slightly and the moisture absorption energy also enhanced after RF.This study demonstrated that RF had no obvious impact on nutrition quality of infant milk powder,but changed the macromolecular structure which in turn affected the processing performance of the powder.