Publications by authors named "Kei Kumakura"

Article Synopsis
  • Takuan-zuke, a traditional Japanese pickle, is made from dehydrating and salt-aging winter radishes, leading to the accumulation of beneficial compounds like GABA.
  • A study explored how branched-chain amino acids (BCAAs) and glucosinolates (GLS) are produced during daikon dehydration, finding specific genes linked to these compounds' synthesis were upregulated.
  • The research suggests that optimizing daikon processing methods could enhance the nutritional quality of takuan-zuke, adding unique flavors and health benefits.
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Takuan-zuke is a traditional Japanese fermented pickle, prepared by dehydration of radish root (daikon) by salt-pressing or sun-drying followed by aging with salt. We previously reported that alanine, proline, and γ-aminobutyric acid (GABA) accumulate during daikon dehydration, whereas the level of glutamic acid, their precursor, decreases. We have also reported that dehydration and salt-aging markedly influence the dynamics of free amino acids.

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This study was performed to clarify the enhancement of the 4-methylthio-3-butenyl isothiocyanate induced yellowing of salted radish root (takuan-zuke) by low pH during short-term salt-aging at low temperature and low salinity. We used two different methods to prepare the dehydrated daikon prior to salt-aging: air-drying outdoors (hoshi takuan-zuke) or salting with a stone press (shio-oshi takuan-zuke). Low salt-aging at low temperature was carried out under pH control with citrate-phosphate buffer.

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Background: Mushrooms have been widely considered as health foods as their extracts have anti-hypertensive and anti-tumor activities. After a thorough literature survey, we hypothesized that enzymes in mushroom extracts play an important role in synthesizing functional molecules. Therefore, in this study, proteins extracted from reishi mushroom (Ganoderma lucidum), which is used in oriental medicine, were identified by the proteomic approach, and appropriate extraction methods for improving angiotensin-converting enzyme (ACE) inhibitory activities were investigated.

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Mastication enhances brain function and mental health, but little is known about the molecular mechanisms underlying the effects of mastication on neural development in early childhood. Therefore, we analysed the gene expression in juvenile neural circuits in rats fed with a soft or chow diet immediately after weaning. We observed that the gene expression patterns in the thalamus varied depending on the diet.

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Recently, we reported that the antihypertensive compound, γ-aminobutyrate (GABA), increases over time during the dehydration of salted radish, known as takuan-zuke, a popular pickle in Japan. The objective of this study was to clarify the antihypertensive effects of takuan-zuke. We prepared two types of takuan-zuke by sun-drying (hoshi takuan-zuke) and salt-pressing (shio-oshi takuan-zuke) using dehydration processes.

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We investigated the nutritional characteristics of salted radish roots (takuan-zuke) prepared using different methods: takuan-zuke based on sun-drying (hoshi) or salt-pressing (shio-oshi) dehydration, different salt-aging temperatures, and salting with rice bran. We examined differences in nutritional substances in salted radish using chromatographic analysis, bioassay methods, and multivariate analysis. We previously reported that the amount of γ-aminobutyrate in takuan-zuke was increased by both dehydration treatments.

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Background: To elucidate the effects of altered dietary carbohydrate and fat balance on liver and adipose tissue transcriptomes, 3-week-old rats were fed three kinds of diets: low-, moderate-, and high-fat diets (L, M, and H) containing a different ratio of carbohydrate-fat (C-F) (65:15, 60:20, and 35:45 in energy percent, respectively).

Methods: The rats consumed the diets for 9 weeks and were subjected to biochemical and DNA microarray analyses.

Results: The rats in the H-group exhibited lower serum triacylglycerol (TG) levels but higher liver TG and cholesterol content than rats in the L-group.

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2-[3-(2-Thioxopyrrolidin-3-ylidene)methyl]-tryptophan (TPMT) is a yellow pigment of salted radish roots (takuan-zuke) derived from 4-methylthio-3-butenyl isothiocyanate (MTBITC), the pungent component of radish roots. Here, we prepared salted radish and analyzed the behavior of the yellow pigment and related substances in the dehydration process and long-term salting process. All salted radish samples turned yellow, and their b(*) values increased with time and temperature.

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