Search

There is no analytical system to directly and simultaneously detect taste- and odor-active compounds. Graphite carbon black (GCB) nanoparticles, a chemical adsorbent for a variety of compounds, including gaseous molecules, which consists of nanoparticles made from multilayered sheets of sp^2-conjugated atomic carbon, have the characteristics required for a surface-assisted laser desorption ionization−mass spectrometry (SALDI-MS) material. Thus, in this study, GCB-LDI-MS was developed for the simultaneous detection of taste- and odor-active compounds. The proposed GCB-LDI-MS successfully detected volatile compounds, including ethyl esters, alcohols, fatty acids, and aldehydes with up to 16 carbons (maximum carbon number of the tested compounds), which could not be detected by conventional matrix-assisted-LDI-MS. Moreover, a series of taste-active compounds (e.g., amino acids and sugars) and various volatile compounds (e.g., ethyl esters, aldehydes, alcohols, fatty acids, and lactones) as a mixture in liquid samples were also detected by the present GCB-LDI-MS. Thus, the proposed simple and rapid detection technique can digitize the analysis of flavor compounds, which provides an analytical concept for flavor scanning to evaluate the palatability of food products.

The cooked meat-like aroma compound, 2-methyl-3-furanthiol (2M3F), was detected in fermented soy sauce (FSS) by GC-olfactometry and GC-MS. 2M3F was present in FSS at a concentration considerably greater than the perception threshold, and the 2M3F concentration increased with heating temperature. Sensory analysis indicated that with the addition of only 0.2 μg/L of 2M3F to the soy sauce sample, the cooked meat-like aroma is significantly stronger than that of sample without the addition of 2M3F. Hence, 2M3F contributes to the cooked meat-like aroma of FSS, which constitutes the key aroma component of FSS. In addition, 2M3F was generated from the addition of ribose and cysteine in FSS by heating at 120 °C, but it was not detected in a phosphate buffer under the same condition. Furthermore, 2M3F was not detected in acid-hydrolyzed vegetable-protein-mixed soy sauce (ASS) and heated ASS. These results indicated that fermentation by micro-organisms facilitates the generation of 2M3F in FSS.

Although soy sauce is a globally used seasoning, its sensory properties have not been fully revealed. Here, the sensory characteristics of 149 soy sauces were examined using descriptive analyses. Eighty-eight attributes were identified and integrated them into a flavor wheel. Aroma was the sensory modality described most often, suggesting that soy sauce's aroma is likely important in characterizing its sensory quality. Nineteen out of 88 attributes were found in all soy sauces implying their importance in representing a soy sauce-like quality. These 19 attributes allowed the discrimination of manufacturing methods and the successful generation of a comparison map. Other attributes appeared infrequently, indicating that all soy sauces are unique and that these attributes can be utilized to describe subtle differences in their characters. Practical application Since soy sauce has become a globally used seasoning, it is meaningful to define its attributes for sensory evaluation. Establishing the sensory attributes of soy sauce allows us to describe each soy sauce objectively and share sensory perceptions among consumers, producers, and researchers. A flavor wheel would facilitate people's systematical understanding of the sensory characteristics of soy sauce. Also sensory evaluation using a flavor wheel would be helpful in finding previously unrecognized attractive or non-attractive characteristics in soy sauces, which ultimately affects purchase decisions. Defining the minimum attributes required for creating a soy sauce positioning map would save a great deal of time and money for product development. Finally, knowledge about the relationship between sensory qualities and the manufacturing process and/or production area would be helpful in regards to product development and purchasing decisions.

In order to clarify the aroma characteristics of raw soy sauce (RS), the application of gas chromatography−olfactometry analysis to the aroma concentrate from a RS revealed 76 aroma peaks, of which 25 peaks showed fruit-like aromas. Furthermore, the head space aromatic compounds of RS were analyzed with 32 peaks detected. Ethyl 2-methylpropanoate, ethyl butanoate, ethyl 2-methylbutanoate, ethyl 3-methylbutanoate, and ethyl 4-methylpentanoate were detected with higher flavor dilution factor (FD factor) than other aroma compounds by aroma extract dilution analysis. Quantitative analysis suggested that these compounds were common in all RS samples tested in this study, and were present at higher concentrations than their perception thresholds. The concentrations and the FD factors of these compounds were significantly decreased during the heating of the RS. Fruitiness is one of the key aroma characteristics of RS and the ethyl esters identified in this study are the key components contributing to this distinct aroma.