Home-made soy sauces with or without Hovenia dulcis Thunb (Hutgae) originated from different parts such as fruits, stems, and twigs were prepared according to the Korean traditional procedure. Soy sauces supplemented with Hutgae were evaluated for their activities of 2,2-diphenyl-1-picrylhydrazyl radical scavenging (DPPH) and alcohol dehydrogenase (ADH), free amino acid profiles, and sensory quality. All soy sauce types containing Hutgae had a strong DPPH activity as compared to the general type of soy sauce without Hutgae (GSC). Among Hutgae groups, DPPH activities of soy sauce supplemented with Hutgae stems was higher than that of soy sauces with either Hutgae fruits or twigs. ADH activities of soy sauces with Hutgae ranged from 14% to 55%, thus indicating that the functional activity of Hutgae was not altered during soy sauce preparations. Total free amino acid content of GSC was 295.5 ㎎%, and that of soy sauce with Hutgae fruits (346.8 ㎎%) was the highest when compared to Hutgae stems (272.3 ㎎%) and Hutgae twigs (225.6 ㎎%). In amino acid profiles, aspartate, arginine, histidine, and lysine levels were higher in soy sauces with Hutgae compared to GSC, whereas isoleucine, leucine, and phenylalanine levels were lower. Particularly, high levels of aspartate, glutamate, threonine, and lysine were presented in Hutgae twigs, whereas for Hutgae fruits and Hutgae stems, the levels of serine, glycine and arginine, and proline and methionine were high, respectively. According to sensory evaluations, Hutgae stems were preferred than GSC, due to the lower offensive smell and higher umami tastes. These findings demonstrate that soy sauce with Hutgae stems has potential protective effects against hangovers, improves the taste, and implies a possible functional ingredient.

The objective of this study was to investigate the sensory quality attributes for the development of soy sauce containing Hutgae(Hovenia dulcis Thunb). Aqueous extracts of Hutgae were prepared from different parts such as trunk, twig, and fruit. These extracts were used for determining the antioxidant effect by 2, 2-diphenyl-1-picrylhydrazyl(DPPH) radical scavenging activity and sensory evaluation. Hutgae twig and fruit extracts had a strong DPPH scavenging effect compared to Hutgae trunk extract. In sensory analysis, high intensities of roast smell, bitter taste, and astringent taste were observed in Hutgae twig extract, whereas those of sweet smell and sweet taste were predominated within Hutgae fruit extract. Hutgae trunk and fruit extracts obtained higher overall acceptability. Various seasoning items such as anchovy, dried-pollack, katsuobushi, shiitake, radish, and kelp were used to determine the suitable type of soy sauce containing Hutgae extracts regarding the different parts. Hutgae fruit and trunk extracts were evaluated for use as a good source of seasoned soy sauce, and the dried-pollack and radish among the seasoning items were well-matched with Hutgae extracts. From these results, soy sauce containing Hutgae trunk and fruit extracts added to dried-pollack soup may be used as a functional seasoning in order to remove hangovers.