The effect of steaming on the free amino acid contents and antioxidant activity of Panax ginseng

• Published in: Food chemistry Vol. 107; no. 2; pp. 876 - 882
• Main Authors: Cho, Eun Jung, Piao, Xiang Lan, Jang, Moon Hee, Baek, Seung Hoon, Kim, Hyun Young, Kang, Ki Sung, Kwon, Sung Won, Park, Jeong Hill
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 15.03.2008; Elsevier
• Subjects: Amino acid; amino acid composition; Antioxidant activity; Biological and medical sciences; chemical analysis; chemical composition; Food industries; free amino acids; free radical scavengers; Fundamental and applied biological sciences. Psychology; General pharmacology; Maillard reaction; Maillard reaction product; Medical sciences; Panax ginseng; Pharmacognosy. Homeopathy. Health food; Pharmacology. Drug treatments; Steam treatment; steaming; β-ODAP; β-ODAP; Amino acid; Steam treatment; Panax ginseng; Maillard reaction product; Antioxidant activity; Heat treatment; Reaction product; Maillard reaction; Antioxidant; Water vapor; Medicinal plant; Dicotyledones; Angiospermae; Spermatophyta; Araliaceae
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2007.09.007

This study was carried out to investigate changes in the free amino acid contents and antioxidant activity of Panax ginseng induced by steaming at different temperatures. For this purpose, white ginseng (WG), red ginseng (RG, ginseng steamed at 100 °C) and ginseng steamed at 120 °C (SG) were prepared using an autoclave. Most free amino acids were decreased significantly by steam treatment, with the greatest reduction observed in SG. Total content of free amino acids, 17.9 mg/g in WG was reduced to 12.2 mg/g in RG and 2.79 mg/g in SG. As for Arg which is the most predominant amino acid in ginseng, the content, 10.4 mg/g in WG, decreased significantly to 1.38 mg/g in SG. In particular, β- N-oxalyl- L-α,β-diaminopropionic acid (β-ODAP), a well-known neurotoxin, was reduced by 92.9% in SG. In contrast, the level of Maillard reaction products (MRPs) increased with steam treatment, which indicates that the reduction of most amino acids is attributed to the extent of the Maillard reaction. Based on MRPs being useful antioxidants, we assayed the scavenging activity against free radicals produced by 2,2′-azobis-(2-amidinopropane) dihydrochloride (AAPH). The radical scavenging activity of a ginseng extract increased with steam treatment, with the most potent activity in SG. Further, MRPs-rich fraction in SG showed powerful antioxidant activity, which indicates MRPs are major contributors to antioxidant activity enhanced by steam treatment.