The objective of this study was to conduct comprehensive aroma analyses of fermented soybean paste (doenjang) using descriptive sensory analysis and μ-CTE-TD-GC-MS. Four doenjang samples were analyzed for its aroma using μ-CTE-TD-GC-MS. Descriptive analysis was carried out with a highly trained panel (n = 6). A total of 38 volatile compounds were identified and significant differences in concentrations were noted especially between traditionally manufactured doenjang (S1) and commercially manufactured doenjang (S2-S4) samples. Authentically produced traditional doenjang samples (S1) characterized with meju, fish sauce, and roasted bean aromatics and these are previously reported as typical aromatics associated with traditional doenjang. Higher concentrations of Streker aldehydes and 3-hydroxy-2-butanone, 2-hydroxy-3-pentanone, and butanoic acid were exclusively found in S1.Commercially manufactured doenjang samples were characterized with high alcohol and fruity aromatics and volatile compounds in alcohol and ester compounds were found in higher concentration than S1. Addition of different flavor enhancer also influenced the aroma characteristics of commercially manufactured doenjang, which seems irrelevant to soybean fermentation. Practical applicationsThis study provides the most abundant list of sensory descriptors for traditional doenjang, which can be used as a baseline for doenjang aroma wheel. In addition, this study confirms the use of μ-CTE-TD-GC-MS for volatile aroma analysis to provide same or superior extraction efficiency for volatile aroma analysis. Overall, this study confirms the aroma differences between "traditionally made" doenjang and "commercially made" doenjang. Interestingly commercial doenjang advertised as "traditionally made doenjang" had different aroma characteristics than authentic, traditionally made doenjang. Finding from current study can assist the doenjang industry to strategically designing the traditional doenjang aroma development targeting for different consumer segments.

Gluten is an insoluble protein produced when glutelins and prolamins, which are found in grains such as wheat, barley, and oats, combine to form an elastic thin film. This dietary gluten can cause severe contraction of the intestinal mucous membrane in some people, preventing nutrient absorption. This condition, called celiac disease (CD), affects approximately 1% of the world’s population. The only current treatment for patients with CD and similar diseases is lifelong avoidance of gluten. To analyze the gluten content in food, various enzyme-linked immunosorbent assay (ELISA) tests are currently used. In this study, the gluten content in various food products was analyzed using different kinds of ELISA test kits. For gluten-free food, three different ELISA test kits mostly yielded values below the limit of detection. However, gluten was detected at 24.0–40.2 g/kg in bread, 6.5–72.6 g/kg in noodles, and 23.0–86.9 g/kg in different powder food samples. A significant difference (p < 0.05) in gluten content was observed for these gluten-containing food products. Reproducibility issues suggest that it is necessary to use several ELISA kits for the accurate detection and quantification of gluten in various food products rather than using one ELISA kit.

The inner shell of the chestnut (Castanea crenata) has long been used in Asia as a medicinal herb for improving digestion and blood circulation, and treating diarrhea. However, most chestnut shells are now treated as waste materials in industrial peeling processes. In this study, we examined the metabolite variation among major cultivars of C. crenata shells using mass spectrometry. Among five representative cultivars, Okkwang, Porotan, and Ishizuuchi had higher levels of bioactive compounds, such as ellagic acid derivatives, ellagitannins, flavonoids, and gallic acid derivatives. Their antioxidant capacity was positively correlated with their chemical composition. The byproducts (whole shells) from the industrial peeling process were re-evaluated in comparison with the inner shell, a rich source of phenolic compounds. The phenolic acids and flavonoid glucoside derivatives were significantly higher in the whole shells, whereas the levels of flavonoids were higher in the inner shells. In addition, the whole shell extracts significantly reduced cellular reactive oxygen species production compared to the inner shell extracts. This study demonstrated the different biochemical benefits of different C. crenata cultivars through metabolic profiling and suggests that the whole shell could be used as a functional ingredient, as it has the highest levels of bioactive products and antioxidant effects.

Chestnuts are an important food crop commonly used as a food ingredient due to their nutritional properties and potential health benefits. In Korea, chestnuts have been crossbred to develop cultivars with insect resistance and high productivity, producing multiple chestnut varieties. This study classified 17 Castanea crenata cultivars produced in Korea according to origin and harvest time and determined the metabolites in chestnut kernels using 1H nuclear magnetic resonance spectroscopy. The 17 C. crenata cultivars were divided into four groups based on their geographic origin: Korean native, Korean hybrid, Japanese native, and Japanese hybrid. The cultivars were also divided into three groups depending on their harvest period: early-ripening cultivar, mid-ripening cultivar, and late-ripening cultivar. The partial least squares-discriminant analysis score plot revealed differences among the groups. Identified metabolites, including amino acids, organic acids, and sugars, contributed to discriminating the origin and harvest time of the C. crenata chestnut kernels. Significant differences were observed, mainly in amino acids, which suggests that the composition of amino acids is one factor influenced by both the origin and harvest time of C. crenata. These results are useful to both growers and breeders because they identify the nutritional and metabolic characteristics of each C. crenata cultivar.