Studies On Novel Production Technologies For CPP And Its Functional Properties

Casein phosphopeptide (CPP) was produced by hydrolyzing casein using proteases. Thepeptides containing phosphoseryl cluster are responsible for the functional properties of CPPin enhancing the absorption of calcium and iron in the human small intestine, where pH isneutral or slightly alkaline. CPP can retard the formation of calcium phosphate precipitation.Therefore, CPP can enhance the absorption and utilization of soluble calcium. The CPP wasdivided into three grade products by N/P(molar ratio), namely higher CPP with N/P(molarratio) above 24, middle CPP with N/P(molar ratio) between 15-24 and lower CPP withN/P(molar ratio) under 15. The main objective of this work was to investigate a novel production technology forhigher CPP The kind of enzyme for hydrolyzing casein and the method for controlling the DH ofcasein were investigated and selected. Nanofiltration was employed to decrease the content ofshort peptides and free amino acids, resulting in improvement of the quality of CPP. Theresults showed that DH of casein could reach 16% using Alcalase2.4L, addition of base waseliminated while casein was hydrolyzed without control with TNBS method used to monitorthe DH of casein. The quality of CPP was improved by using nanofiltrarion membrane with150Da of molecular weight interception, which was responsible for the decrease of shortpeptides and free amino acids in casein hydrolysates solution. The recovery rate of N wasabove 80%, most part of P could be recovered. The quality of CPP produced by currenttechnology was near to that of CPP produced by DMV corporation in content of CPP(bothabove 20%) and ash (both 5.7%-6.0%). The functional properties of CPP with different grades in enhancing the absorption ofcalcium were studied in vitro. The content of the binding calcium of CPP, the effect of CPP onretarding the formation of calcium phosphate and synergism of citric acid with CPP weretested. The results showed that the content of binding calcium of CPP decreased with theincrease in temperature and increased with the increase in pH. Additionally the effect of CPPon retarding the formation of calcium phosphate decreased with the increase in temperature,molar ratio of Ca to P and N to P, CPP could also inhibit the precipitation of iron. When CPPwas used with citric acid, the effect of CPP on retarding the formation of calcium phosphateobviously increased. Permeated solution from nanofiltration of casein hydrolysates solution was analyzed byusing Sephadex G-15. The results showed that short peptides and free amino acids were partly IIAbstract removed by using nanofiltration. The mean relative molecular weight of CPP before andafter nanofiltration was 660.76Da and 1150.85Da respectively. Compared HPLC graphs ofCPP before and after nanofiltration, it could be concluded that the peak of CPP beforenanofiltration with relative mean molecular weight of 240Da obviously decreased afternanofiltration. CPP after nanofiltration was separated and purified by using Sephadex G-25 ,The result showed that mean relative molecular weight of active CPP was relatively high. Ethanol extraction technology for production of middle CPP was studied, and thetechnological conditions were optimized. Concentration of ethanol for extraction of CPP was85%. The ratio between the volume of ethanol and the weight of CPP before extraction was10:1. The results showed that the N/P(molar ratio)of CPP produced by ethanol extractiontechnology was between 19-24, the recovery rate of N and P was 74.54% and 98.37%respectively, the ash content of extracted CPP was relatively low (6.79%), the ash content ofNPP, which was the by-product of ethanol extraction technology, was 4.42%. In conclusion,ethanol extraction technology can be employed in production of middle CPP and NPP inindustrial scale.