Preliminary studies to determine the chaperoning properties of bovine casein and crystallin proteins at reducing beef muscle protein aggregation during heating

The ability of small heat shock proteins (sHSP) at preventing the aggregation and precipitation of unfolded and misfolded proteins because of changes in pH and temperature is widely recognised. The performance of sHSP from bovine lens extract at protecting sarcoplasmic proteins from heat induced denaturation and aggregation was compared with other chaperones including bovine serum albumin, alpha(s)-casein, beta-casein and a synthetic peptide based upon alpha A-crystallin (AAC). Beef sarcoplasmic proteins were heated in the presence or absence of exogenous chaperone and the solubility, surface hydrophobicity and enzymatic activities of the sarcoplasmic proteins was determined. Lens extract prevented the aggregation of sarcoplasmic proteins, maintaining solubility and clarity up to 65 degrees C relative to 60 degrees C for beta-casein. By contrast, alpha(s)- and beta-casein proteins protected the activity of endogenous enzymes at temperatures between 37 degrees C and 52 degrees C, unlike lens sHSP. Our findings support the addition of casein proteins as potential thermal stabilisers of meat proteins in food systems.