April 8/Prague/Technology Business Journal --  "Four microbial proteases (Alcalase, Flavourzyme, Neutrase and Protamex) were used for the preparation of whey protein hydrolysates. The aim of this research was to find out whether these hydrolysates can be used as a source of whey-derived antioxidants," investigators in Prague, Czech Republic, report.

"Hydrolyzed samples, including their unhydrolyzed protein solutions were tested by the ABTS (2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) decolorization assay, by the total radical-trapping potential method and by the assay of liposomes peroxidation (fluorescence photometry). Antioxidant properties were enhanced by hydrolysis in most of cases. Alcalase hydrolysates were found as the most effective antioxidants as determined by ABTS assay (similar to 50% of antioxidant activity at 0.1 mg ml(-1) of hydrolysate in reaction) and fluorescence photometry. Liposomes were oxidized similar to 50% less (1.1 mc M of alpha-tocopherol equivalent) with Alcalase hydrolysates additive (at 5.85 mg ml(-1) of hydrolysate in reaction). Hydrolysates did not inhibit the oxidation of liposomes at concentrations below 1.0mg ml(-1) in reaction. On the contrary, results of total trapping potential method did not agree with findings observed in other tests. In this assay, Neutrase hydrolysates showed the best antioxidant properties. Pro-oxidant properties were observed in solutions containing (prior to the enzyme Protamex addition only) intact whey protein as determined by the measurement of the liposome peroxidation. The ABTS assay was optimized for the evaluation of the antioxidant activity in whey protein hydrolysates," wrote A. Dryakova and colleagues.

The researchers concluded, "The reaction time should be prolonged to avoid underestimation of the antioxidant activity."

Dryakova and colleagues published their study in European Food Research and Technology ("Antioxidant Properties of Whey Protein Hydrolysates as Measured by Three Methods." European Food Research and Technology, 2010;230(6):865-874).

For additional information, contact A. Dryakova, Inst Chem Technol, Technical 5, CR-16628 Prague 6, Czech Republic.

From the April 12, 2010, Prepared Foods E-dition