Effects of different cooking times on the sensory evaluation and flavor characteristics of soy sauce

Abstract

Changes in odor properties, key odor-active compounds (flavor dilution (FD) ≥ 81, odor activity value (OAV) ≥ 1), free amino acids, and nucleotides were explored in the four soy sauces before and after cooking. The heat-treated soy sauce scored higher for sensory attributes such as roasted, smoky, caramelized, and steaming aromas, while mellow, sour, floral, and malty aromas had lower odor intensities. Heat treatment induced an increase in the OAV of compounds with caramelized/sweet, smoky, roasted, and steaming aromas in soy sauce, while the OAV of compounds with unpleasant odors (sour and malty) decreased. The aroma of soy sauce becomes unstable during cooking. The levels of amino acids and nucleotides decreased to varying extents with increased heating time. The total free amino acid content decreased by 35 %, 36 %, and 38 % after cooking soy sauce for 10 min, 30 min, and 60 min at 100 °C, respectively. Additionally, the 5′-disodium xanthate (5′-XMP) content was the highest in all four soy sauce samples both before and after heat treatment, followed by 5′-guanylate disodium (5′-GMP) and 5′-adenylate disodium (5′-AMP).