Hydrolysate animal protein( HAP) contains a lot of heavy metal ions which are harmful to human health. Due to its high contents of protein,HAP is used to improve the protein content in milk as an inexpensive source of protein.In this study,milk samples adulterated with different gradients of HAP were prepared. Then,the samples were scanned using near-infrared spectrometer with Fiber Optic Module and the factors influencing quantitative analysis models such as modeling methods,pretreatment methods,principal ...