Quality Characteristics and Antioxidant Activity of Soy Sauce with Added Levels of Black Garlic Extract

Abstract

Purpose: In order to develop soy sauce and increase its functionality, by adding black garlic extract. Methods: We compared quality characteristics and antioxidant activity of 20 days aging black garlic soy sauce from mixed manufacturers with raw soy sauce (commercial fermented soy sauce) and different ratio of black garlic extract (65 Brix, 0.3-5.0%). Results: The salt content of the black garlic extract (0.3-5.0%) added soy sauce were 12.35-12.77%. The pH was lowered to 4.99, and acidity was increased to 2.12%, depending on the increase in black garlic extract added ratio. The crude protein and total nitrogen contents were 6.23-6.62% and 1.10-1.16%, respectively, and content of amino form nitrogen was 0.52-0.53%, without significant differences between experimental groups. Contents of reducing sugar and free sugars (fructose and glucose) tended to be higher with higher mixing ratios of black garlic extract. Total phenolic compounds and flavonoids contents were significantly increased in the 3% and 5% black garlic extract addition group. At concentrations of 62.5, 125, 250, 500, 1,000 and 2,000 µg/mL, the DPPH and ABTS radical scavenging activity of the polysaccharides isolated from control soy sauce and 5% black garlic extract added soy sauce showed higher correlation with their concentration. Conclusion: These results, confirmed that the soy sauce produced by adding more than 3% of black garlic extract has high antioxidant activity.

Development of a low‐salt soy sauce with enhanced flavor and functionality with soy residue andTenebrio molitorlarvae powder

“…In contrast, the change in the reducing sugar content was related to changes in the browning index (Figure 2b). The reducing sugar content increased sharply in all soy sauces on day 10 because of the glucoamylase produced by Aspergillus oryzae (Choi et al, 2016) and decreased significantly after 10 days of fermentation (p < 0.05). This continuous depletion of reducing sugars is related to its reaction with amino acids that darkens the color of soy sauce through non‐enzymatic browning (Song et al, 2015).…”

“…Figure 1 shows the changes in the salinity, pH, and total acidity of soy sauce during fermentation. Salt plays an important role in inhibiting the excessive growth of microorganisms in fermented foods, as well as the progress of ripening and storage stability (Choi et al, 2016). Moreover, salty taste can mask the metallic and bitter taste and improve the umami taste of soy sauce (Zhao et al, 2016).…”