Abstract:

Whey protein isolate (WPI) was hydrolyzed with alcalase and its hydrolysates were added to raw pork patties for evaluating their antioxidant activity. WPI hydrolysates at the concentration levels of 1.0%, 1.5% and 2.0% were added to pork patties. During the storage period, a* value, thiobarbituric acid-reactive substances (TBARS), pH, Metmyoglobin (MetMb) were measured and sensory evaluation was conducted. The pork patties without the addition of WPI hydrolysates and with the addition of nonhydrolyzed whey at the concentration of 2.0% or BHA at the concentration of 0.02% were used as controls. Results showed that WPI hydrolysates had a significant inhibitory effect on lipid oxidation of pork patties during 7-day storage period when compared with the controls. The most obvious effect was observed in pork patties with the addition of 2.0% WPI hydrolysates. Compared to the control without the addition of hydrolysates, 2% WPI hydrolysates resulted in the decrease of TBARS and the increase of a* value (P < 0.05). The MetMb level in pork patties with the addition of 2.0% WPI hydrolysates was only 79% level of the control group without the addition of hydrolysates. The similar results were observed in BHA group. Therefore, WPI hydrolysates have a higher inhibitory effect on lipid oxidation than nonhydrolyzed whey protein. These investigations demonstrate that enzymatically hydrolyzed whey protein can retard the peroxidation of lipids.

Key words: raw pork patties, whey protein hydrolysates, antioxidant activity