This study assessed how the removal of specific sub-ingredients affects the quality characteristics of traditionally brewed soy sauce. Five samples were prepared using the same base formulation: a control with all ingredients (CON) and variants lacking garlic (GR), all chili peppers (CR), whole pepper (PR), or ginger wine (GWR). The sample without ginger wine (GWR) exhibited the highest moisture content and lightness, while the chili pepper-removed sample (CR) showed a darker color due to increased Maillard browning. Soy sauces without chili or pepper had significantly higher °Brix and salt contents but lower pH levels (p<0.05). Amino acid profiling revealed that the CR-removed sample had the highest levels of glutamic acid and branched-chain amino acids, whereas the GWR-removed sample had the lowest total amino acid content (p<0.05). Additionally, the CR-removed sample demonstrated the highest total polyphenol and flavonoid contents, along with the strongest DPPH and ABTS radical-scavenging activities (p<0.05). Instrumental flavor analyses conducted with an electronic nose and an electronic tongue confirmed distinct taste and aroma profiles. Overall, the removal of chili peppers enhanced antioxidant capacity and improved the instrumental flavor profile.

Abstract
Introduction
Materials and Methods
    1. Experimental materials and preparation of soy sauce
    2. Moisture content
    3. Color values
    4. Soluble solids (°Brix) and salinity
    5. pH and titratable acidity
    6. Free amino acids
    7. Reducing sugars
    8. Total polyphenol content
    9. Total flavonoid content
    10. DPPH radical scavenging activity
    11. ABTS radical scavenging activity
    12. Electronic nose analysis
    13. Electronic tongue analysis
    14. Statistical analysis
Results and Discussion
    1. Moisture content and color values
    2. Soluble solids (°Brix), salinity, pH, and titratable acidity
    3. Free amino acids and reducing sugars
    4. Total polyphenol, total flavonoid content, and radicalscavenging activity
    5. Electronic nose analysis
    6. Electronic tongue analysis
Summary
References

• Hye Kyung Cho(Graduate Student, Dept. of Foodservice and Culinary Management, Honam University, Gwangju 62399, Korea)
• Kyung Tae Jang(Assistant Professor, Dept. of Food & Cooking Science, Sunchon National University, Jeonnam 57922, Korea) Corresponding author