Publications by authors named "Kyu Hang Kyung"

Aged garlic extract (AGE) contains a significant amount of bioactive compounds, including -allyl-l-cysteine (SAC), which is associated with various health benefits. Among different AGE products, black garlic extract (BGE) is widely consumed and a common product in the Korean market. BGE products do however contain different levels of SAC and S1PC.

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The biochemistry and microbial ecology of 2 similar types of watery (mul) kimchi, containing sliced and unsliced radish and vegetables (nabak and dongchimi, respectively), were investigated. Samples from kimchi were fermented at 4, 10, and 20 °C were analyzed by plating on differential and selective media, high-performance liquid chromatography, and high-throughput DNA sequencing of 16S rDNA. Nabak kimchi showed similar trends as dongchimi, with increasing lactic and acetic acids and decreasing pH for each temperature, but differences in microbiota were apparent.

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Cysteine was found to form pigments with garlic thiosulfinates in this investigation, in contrast to previous reports. Pigments were formed only when the molar concentration ratios of cysteine to total thiosulfinates were smaller than 2:1. Cysteine does not form pigments with thiosulfinates in the same manner as other pigment-forming amino compounds because it has a sulfhydryl (SH) group.

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The antimicrobial activity of Allium species has long been recognized, with allicin, other thiosulfinates, and their transformation products having antimicrobial activity. Alliums are inhibitory against all tested microorganisms such as bacteria, fungi, viruses, and parasites. Alliums inhibit multi-drug-resistant microorganisms and often work synergistically with common antimicrobials.

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A nonvolatile and slightly water-soluble antimicrobial sulfur compound newly isolated from heated garlic extract was characterized. The compound was generated most when heated at 120°C for 30 minutes and completely disappeared after 90 minutes of heating. It has a molecular mass of 225 daltons with an elemental ratio of C₆H₁₁N₁O₂S₃, and the interpretation of ¹H- and ¹³C-nuclear magnetic resonance and Fourier transform-infrared data showed that the compound was CH₂=CH-CH₂-S-S-S-CH₂-CH(NH₂)COOH, 3-(allyltrisulfanyl)-2-aminopropanoic acid, a derivative of cysteine, presumably derived from alliin (S-allyl-L-cysteine sulfoxide).

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