Quality characteristics and antioxidant activity of traditional Korean soy sauce based on the proportion of onion juice

Abstract

The aim of this study was to improve the quality and functionality of Korean soy sauce made with onion juice. At the end of fermentation, the titratable acidity of the soy sauce containing 100% onion juice was the highest at 2.90%. The salt (NaCl) content was highest and lowest in the samples without and with onion juice supplementation, respectively. The protein content ranged from 11.09-12.50%. The sensory evaluation revealed that the soy sauce sample containing 70% onion juice had the highest scove at 5.0-5.8 levels in terms of sweetness, salty taste, delicate flavor, and overall preference. Quercetin content was 1.73 mg/100 g and 1.68 mg/100 g in soy sauce containing 70% and 100% onion juice, respectively. However, quercetin was not detected in the soy sauce without onion juice supplementation. Total polyphenol and flavonoid contents, as well as antioxidant activity, increased proportionally to the amount of onion juice added. Overall, it was confirmed that the addition of onion juice improved the quality and functionality of Korean soy sauce.

Fermentation Characteristics of Unripe Citrus unshiu Vinegar Production Using Acetic Acid Bacteria Isolated from Traditional Fermented Vinegars

“…The high FRAP values were attributed to the high content of quercetin derivatives and polyphenols. In another study that analyzed the FRAP activity of commercially available fruit juices, Lee et al (2008) reported high FRAP values in orange and grapefruit juices (117.62 and 115.72 μM TE, respectively). In addition, these juices contained significantly higher DPPH radical scavenging activity and FRAP antioxidant activity compared with others, noting that the two values were significantly correlated.…”

Physicochemical and organoleptic properties of hot-air dried oriental melon slices prepared using different physical pretreatments

“…Additionally, it contains cucurbitacins, which are representative functional components with high anti-cancer activity and particularly good effectiveness against prostate cancer (Kim et al, 2014a;Shin et al, 2008). Despite these benefits, oriental melon poses challenges for long-term storage and distribution because it is intensively produced during the summer and is susceptible to coldinduced injuries at low storage temperatures (Lee et al, 1999;Lee et al, 2005b;Park et al, 2000). Therefore, improvements are needed in the storability of oriental melon through appropriate processing, along with the development of new products using the fruit.…”