The Effect of Heat and Extraction Technique on beta-Lactoglobulin Hydrolysis
Whey proteins are an abundant source of biologically active peptides that have a diverse set of properties. One limitation in the production of novel peptides is the native folding of the proteins secondary and tertiary structure. β-Lactoglobulin is a barreled protein with a hydrophobic core capable of binding other proteins and fatty acids. Due to its prevalence in whey, it represents an important source of bioactive peptides. Presenting a method for the production of novel peptides by native whey protein change in conformation will bring value added products to market.
Previous studies have shown the resistance of isolated, native, β-Lactoglobulin to trypsin hydrolysis in protein-lipid emulsions. However incorporation of washed cream (40% fat) into this system (natural emulsion from cream) significantly changes the hydrolysis patterns of β-Lactoglobulin. The hydrolysis patterns of β-Lactoglobulin was evaluated using Electrospray Ionization Mass Spectrometry (ESI-MS) after three heat treatments (none, 50°C – 20 minutes, and 70°C – 20 minutes) and four extraction methods (none, Supercritical Carbon Dioxide, Hexane, and Folch). Although hydrolysis was improved compared to native β-Lactoglobulin, the degree of hydrolysis did not exceed 42% in any of the treatments.
Substitution of purified native β-Lactoglobulin with whey protein isolate (WPI) in the 40% cream solution significantly increased the number and type of β-Lactoglobulin peptides released when subjected to various heat treatments and fat extraction methods. The degree of hydrolysis reached a maximum 64% and there appeared to be sequential, predictable peptide release depending on the heat treatment and extraction technique used.
The heat treatment and extraction method change the absorption and spreading process of β-Lactoglobulin within and along the MFGM and thus, effecting which peptides are available and released by the enzymatic action.
Keywords: β-Lactoglobulin, Peptides, Mass Spectrometry