Evaluation of the antioxidant potential of natural food/plant extracts as compared with synthetic antioxidants and vitamin E in raw and cooked pork patties.

Antioxidant potential for previously identified optimum levels of aloe vera (AV), fenugreek (FGK), ginseng (G), mustard (M), rosemary (R), sage (S), soya protein (SPI), tea catechins (TC) and whey protein concentrate (WPC) were evaluated in raw and cooked patties manufactured from frozen pork. The optimum levels determined were: AV (0.25%), FGK (0.01%), G (0.25%), M (0.10%), R (0.10%), S (0.05%), SPI (0.10%), TC (0.25%) and WPC (4%). Test ingredients were evaluated against synthetic antioxidants butylated hydroxyanisole/butylated hydroxytoluene (BHA/BHT) (0.01%) and a supplemented meat containing natural antioxidant, α-tocopherol (1000 mg α-tocopheryl acetate/kg feed). Ranking the decreasing antioxidant effectiveness of added ingredients in raw patties on day 9 showed that: Control>G>SPI>FGK>AV>M>WPC>S>α-tocopherol>R>TC>BHA/BHT. Cooking resulted in a four-fold increase in TBARS values over raw patties with TC being the most effective antioxidant having significantly (P<0.001) lower TBARS values than the cooked control on days 3, 6 and 9. Ranking of decreasing antioxidant effectiveness of added ingredients showed that: M>SPI>G>FGK>α-tocopherol>AV>control>S>BHA/BHT>R>WPC>TC. BHA/BHT had the most beneficial effect on cooked meat redness with Hunter 'a' values being significantly (P<0.05) higher than the control on days 3, 6 and 9. Ranking of Hunter 'a' values for added test ingredients showed that FGK>WPC>control>R>BHA/BHT>α-tocopherol>TC>AV>SPI>M>G>S on day 9. Hunter 'L' and 'b' values showed no significant trend over the storage period in either raw or cooked patties. The pH values of both raw and cooked pork control patties and products containing added test antioxidants were variable and while a number of trends were observed, no significant differences were recorded between samples.