Evaluation of antioxidative/antimicrobial potential of Oriental nutraceutical herb extracts in raw and cooked goat meat and beef products

Abstract

This study was conducted to determine the effects of alcohol extracts of several Oriental nutraceutical herbs on storage properties of raw and cooked ground goat meat and beef. White peony root, red peony root, sappanwood stem, rehmania root, moutan cortex root, angelica root, and rosemary leaves were dehydrated, extracted with 95% ethanol, and freed of the solvent. The sappanwood, moutan cortex, and rosemary samples contained the largest amounts of total phenolics. Extracts were added to ground goat meat, and treated meat samples were aerobically stored at 4°C for 6 days, with or without cooking. Each herbal extract was also added to ground beef at 0.25% (w/w), with or without adding NaCl at 2% (w/w), and stored as raw and cooked patties. Peony (red or white) root extracts, whether added at 0.5, 1, or 2% levels, showed strong antioxidant effects in cooked goat meat, decreasing TBARS content more than 90% at day 6. The extracts were less antioxidative in raw goat meat, lowering the day-6 TBARS content less than 50%. The extracts from rehmania root, sappanwood, and moutan cortex were as antioxidative as the extracts from red and white peony roots, decreasing the TBARS content in cooked goat meat more than 88% at day 6. When red peony root extract was evaluated for antimicrobial activity in raw goat meat, it decreased APCs at day 3, but not at day 6. Extracts from white and red peony roots, sappanwood, moutan cortex, and rosemary were highly antioxidative in both raw and cooked beef patties, decreasing TBARS more than 88% by day 6. However, rehmania and angelica root extracts were less inhibitory. The antioxidant activity of the herbal extracts correlated (P < 0.05) with their total phenolic content. Additionally, white and red peony roots, sappanwood, moutan cortex, and rosemary extracts counteracted a prooxidative effect of NaCl in raw and cooked beef patties. The a* (redness) values of raw-refrigerated, salted or unsalted beef patties were higher with these treatments than without. However, a* values of raw patties did not correlate (P > 0.05) with total phenolic levels. All the extracts, other than rosemary extract, showed no antimicrobial activity in raw beef patties at either day 3 or day 6, presumably due to the relatively high microbial counts found in the initial untreated meat. Rosemary extract decreased APCs only at day 3.