Correlation Analysis between Properties and Calcium-holding Capacity of Different Casein Phosphopeptide Products

In order to investigate the influence of the properties of casein phosphopeptide(CPP) on its calcium-holding capacity, the content of CPP, nitrogen and phosphorus content, molecular weight distribution, amino acid composition and content were determined using 7 kinds of commercial CPP products. The correlation between physical and chemical properties and calcium holding capacity was analyzed. The results showed that the CPP content and N/P of 7 kinds of CPP products were 1.30%~18.50% and 12.70~46.80, respectively. The content of total amino acid of 7 kinds of CPP products were 70.50~901.00 mg/g, and proline was the most abundant amino acid among those CPP products. The molecular weight of those CPP products were <5000 Da(except for No.7 CPP products). Meanwhile, the amount of CPP added to the simulated reaction system at different levels(0.05, 0.1, 0.2 g/L) were also determined using those commercial CPP products, No. 1, No. 2 and No. 6 products showed better calcium holding capacity, while No.7 products showed the worst calcium holding capacity. Then the above mentioned results were subjected to principal component analysis(R1=0.674, R2=0.167), the results showed that there was a correlation between the molecular weight distribution, amino acid content and the calcium-holding capacity of CPP products. Further correlation analysis was found that the content of molecular weight >10 kDa showed a highly significant negative correlation with the calcium-holding capacity of CPP samples(correlation coefficient −0.985~−0.975, P<0.01), while CPP samples with similar molecular weight distribution and higher content of isoleucine(correlation coefficient 0.766~0.768, P<0.05) and phenylalanine(correlation coefficient 0.758~0.759, P<0.05) showed a stronger calcium-holding capacity. This study provided a theoretical basis for evaluating and improving the quality of CPP products.