Biofunctional characterization of puffed red ginseng

Abstract

Ginseng (Panax ginseng C.A. Meyer) has been cultivated and consumed as a medicinal herb in East Asia for a long time. Ginseng has a lot of bioactive components including ginsenosides, polyacetylenes, polysaccharides, and phenolic compounds. Among them, ginsenosides have been regarded as major active components of ginseng and used as index component for the quality control. Many researches have been conducted to develop methods for increasing the pharmacological effect of ginseng by conversion of the dammarane-based saponin by high temperature and high pressure thermal processing. However, it is complicated and time-consuming to extract the active components of ginseng because of its dense texture. Thus, researchers have conducted the studies on the production of expanded ginseng using an extruder and explosive puffing process. This study was designed to examine the effect of puffing process on the biofunctional property of red ginseng. Red ginseng was puffed using a rotary puffing machine at 0.30 MPa. After puffing, the changes in physicochemical properties, antioxidant activity and volatile components in puffed red ginseng were investigated. Puffing process increased the total ginsenoside content including ginsenoside Rg3 with anticancer activity. Extraction yields (16.7-42.2%) from puffed red ginseng were higher than those from non-puffed red ginseng (9.0-32.7%) at all extraction times. When comparing the free sugars and amino acids, the contents of maltose and arginine drastically decreased because puffing process accelerated the reaction of maltose and arginine to produce maltulosyl arginine. Effects of explosive puffing on the changes of volatiles in red ginseng were investigated using headspace-solid phase microextraction (HS-SPME)-gas chromatograph (GC) with a mass selective detector (MS). Formation of porous structures and smaller pieces were clearly observed on the surface of puffed red ginseng by scanning electron microscopy. Total volatiles in puffed red ginseng increased by 87% compared with those in red ginseng. Hexanal, Δ-selinene, and β-panasinsene were major volatiles in red ginseng, whereas α-gurjunene, β-panasinsene, and calarene were main volatiles in puffed red ginseng. Puffing process decreased volatiles from lipid oxidation including aldehydes, ketones, and 2-pentylfuran and increased terpenoids in red ginseng. Selective ion monitoring (SIM) mode for GC/MS results showed that 2-furanmethanol and maltol were present at the concentrations of 0.20 and 0.24%, respectively, in red ginseng and 5.86 and 3.99%, respectively, in puffed red ginseng. Explosive puffing process increased 2-furanmethanol and maltol in puffed red ginseng significantly (p<0.05) with the changes of microstructure. The antioxidant properties of extracts of red ginseng and puffed red ginseng were determined in bulk oil and oil-in-water (O/W) emulsions. Bulk oils were heated at 60°C and 100°C and O/W emulsions were treated under riboflavin photosensitization. In vitro antioxidant assays, including 2,2-diphenyl-1-picrylhudrazyl (DPPH), 2,2-azinobis-3-ethyl-benzothiazoline-6-sulfonic acid (ABTS), ferric reducing antioxidant power (FRAP), total phenolic content (TPC), and total flavonoid content (TFC), were also performed. The total ginsenoside contents of extract from red ginseng and puffed red ginseng were 42.33 and 49.22 mg/g, respectively. All results from these in vitro antioxidant assays revealed that extracts of puffed red ginseng had significantly higher antioxidant capacities than those of red ginseng (p<0.05). Generally, extracts of puffed red and red ginseng had antioxidant properties in riboflavin photosensitized O/W emulsions. However, in bulk oil systems, extracts of puffed red and red ginseng inhibited or accelerated rate of lipid oxidation, depending on the treatment temperature and the type of assay used. These results suggest that the puffing process can provide us with an alternative means to produce functional red ginseng products with the additional advantage of reduced processing time.

Keywords: puffed red ginseng, volatile component, ginsenoside, antioxidant property, bulk oil, oil-in-water emulsion, radical scavenging activity.

Student Number: 2000-30738