Influence of unit operations on immunoglobulins and thermal stability of colostrum fractions

Abstract

Colostrum-based ingredients are gaining significance in the global nutraceutical market as dietary supplements, but compositional variation, bioactive heat sensitivity and lack of appropriate preservation technologies hamper commercial colostrum processing. The effect of commonly employed unit operations on the physicochemical and nutraceutical components of skim colostrum was determined, and effects of membrane processing on its thermal gelation temperature, key to further liquid processing, were monitored. Homogenisation and high-shear mixing did not alter immunoglobulin content. However, commercial thermal pasteurisation (72 °C, 15 s) and batch pasteurisation (63 °C, 30 min) led to 56.4% and 24.6% denaturation of IgG, respectively. Microfiltration eliminated microbial load of diluted skim colostrum to render it practically sterile, while ultrafiltration concentrated the proteins of colostrum fractions. Concentration of protein, particularly immunoglobulins, resulted in lowering of thermal gelation temperature. Skim colostrum and colostrum whey can, therefore, be preserved by employing microfiltration and concentrated with simultaneous purification by ultrafiltration.