• Journal of Biosystems Engineering
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• 제41권4호
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• pp.365-372
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• 2016

Purpose: Tea is the most frequently consumed drink worldwide, next to water. About 75% of the total world tea production includes black tea, and withering is one of the major processing steps critical for the quality of black tea. There are two types of tea withering methods: physical and chemical withering. Withering can be achieved by using tat, tunnel, drum, and trough withering systems. Of these, the trough withering system is the most commonly used. This study focuses on the different types of withering, their effect on the various quality attributes of tea, and other aspects of withering methods that affect superior quality tea. Results: During physical withering, tea shoots loose moisture content that drops from approximately 70-80% to 60-70% (wet basis). This leads to increased sap concentration in tea leaf cells, and turgid leaves become flaccid. It also prevents tea shoots from damage during maceration or rolling. During chemical withering, complex chemical compounds break down into simpler ones volatile flavor compounds, amino acids, and simple sugars are formed. Withering increases enzymatic activities as well as the concentration of caffeine. Research indicates that about 15% of chlorophyll degradation occurs during withering. It is also reported that during withering lipids break down into simpler compounds and catechin levels decrease. Improper withering can cause adverse effects on subsequent manufacturing operations, such as maceration, rolling, fermentation, drying, and tea storage. Conclusion: Freshly harvested leaves are conditioned physically and chemically for subsequent processing. There is no specified withering duration, but 14-18 h is generally considered the optimum period. Proper and even withering of tea shoots greatly depends on the standards of plucking, handling, transportation, environmental conditions, time, and temperature. Thus, to ensure consumption of high quality tea, the withering step must be monitored carefully.

• Food Science and Biotechnology
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• 제17권4호
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• pp.687-691
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• 2008

This study was performed to investigate the taste composition and biological activities of cheonggukjang containing Rubus coreanum to improve cheonggukjangs' flavor and consumption. In R. corenum cheonggukjang (RCC), the total content of soluble sugars, including glucose, fructose, maltose, and sucrose, was 1,052.1 mg/100 g. Glutamic acid, phenlylalanine, leucine, cystine, and tyrosine were the major amino acids, and the ratio of sweet to bitter components was higher in RCC than in general cheonggukjang (GC). The 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activities of the extracts, in decreasing order, were found to be: ethanol extract> water extract> chloroform extract, at all concentrations. The water extract had the highest SOD-like activity (10.2%) at a concentration of 0.5 mg/mL, whereas the chloroform extract showed the highest SOD-like activity (19.1%) at a concentration of 2 mg/mL. The nitrite scavenging ability was higher at pH 1.2 than at pH 3.0 or 6.0, and had a positive correlation with the extract concentration. The chloroform extract had the highest nitrite scavenging ability (84.6%) at a concentration of 2 mg/mL and pH 2.0.

• 한국식품저장유통학회지
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• 제6권4호
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• pp.475-480
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• 1999

한국산 작두콩을 부위별(종자, 자엽, 껍질, 깍지, 잎, 줄기 및 뿌리)로 구분하여 화학성분을 분석한 결과는 다음과 같다. 작두콩의 부위별 일반성분 중 총당과 조단백질은 다른 부위에 비해 자엽에서 높게 나타났으며, 무기성분은 뿌리에서 칼륨, 잎에서는 칼슘의 함량이 높게 나타났으며, 유기산은 잎의 경우 oxalic acid가 2.556 mg%, 깍지는 citric acid가 573 mg%로 가장 높았다. 유리당은 껍질에서 sucrose가 3.80%, 줄기의 경우 fructose가 2.17%로 각각 높게 나타났다. 구성 아미노산은 자엽과 잎에서 glutamic acid가 각각 592 mg%와 429 mg%, 깍지에서 proline 497 mg%, 줄기에서 lysine 328 mg% 및 뿌리에서는 arginine이 714 mg%로 가장 높게 나타났다. 껍질과 깍지의 지방산 함량은 포화지방산인 경우 palmitic acid가 각각 32.75%와 21.93%이었으며, 불포화지방산의 경우는 linoleic acid가 각각 39.15%와 43.03%로 높게 나타났다.

• Journal of Ginseng Research
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• 제43권4호
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• pp.654-665
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• 2019

Background: Panax ginseng Meyer has widely been used as a traditional herbal medicine because of its diverse health benefits. Amounts of ginseng compounds, mainly ginsenosides, vary according to seasons, varieties, geographical regions, and age of ginseng plants. However, no study has comprehensively determined perturbations of various metabolites in ginseng plants including roots and leaves as they grow. Methods: Nuclear magnetic resonance ($^1H$ NMR)-based metabolomics was applied to better understand the metabolic physiology of ginseng plants and their association with climate through global profiling of ginseng metabolites in roots and leaves during whole growing periods. Results: The results revealed that all metabolites including carbohydrates, amino acids, organic acids, and ginsenosides in ginseng roots and leaves were clearly dependent on growing seasons from March to October. In particular, ginsenosides, arginine, sterols, fatty acids, and uracil diphosphate glucose-sugars were markedly synthesized from March until May, together with accelerated sucrose catabolism, possibly associated with climatic changes such as sun exposure time and rainfall. Conclusion: This study highlights the intrinsic metabolic characteristics of ginseng plants and their associations with climate changes during their growth. It provides important information not only for better understanding of the metabolic phenotype of ginseng but also for quality improvement of ginseng through modification of cultivation.

• Journal of Microbiology and Biotechnology
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• 제33권2호
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• pp.151-166
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• 2023

Yeast extract is a product prepared mainly from waste brewer's yeast, which is rich in nucleotides, proteins, amino acids, sugars and a variety of trace elements, and has the advantages of low production cost and abundant supply of raw material. Consequently, yeast extracts are widely used in various fields as animal feed additives, food flavoring agents and additives, cosmetic supplements, and microbial fermentation media; however, their full potential has not yet been realized. To improve understanding of current research knowledge, this review summarizes the ingredients, production technology, and applications of yeast extracts, and discusses the relationship between their properties and applications. Developmental trends and future prospects of yeast extract are also previewed, with the aim of providing a theoretical basis for the development and expansion of future applications.

• Animal Bioscience
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• 제36권6호
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• pp.908-919
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• 2023

Objective: Information about the chemical composition of cassava-based feed ingredients is needed to accurately formulate animal diets. A study was conducted to determine the chemical composition of cassava-based feed ingredients and to test the hypothesis that there is variation in chemical composition among cassava products originating from different South-East Asian countries. Methods: Sources of dried peeled and unpeeled cassava roots, cassava chips, cassava meal, high-ash cassava meal, and cassava residue were used. All samples were analyzed for dry matter, gross energy, nitrogen, amino acids (AA), acid-hydrolyzed ether extract (AEE), ash, minerals, total starch, insoluble dietary fiber, and soluble dietary fiber. Samples of peeled and unpeeled cassava roots, cassava chips, and cassava meal were also analyzed for sugars. Results: High-ash cassava meal had greater (p<0.05) dry matter and ash, but lower (p<0.05) total starch and gross energy than all other cassava products. Peeled cassava roots, unpeeled cassava roots, and cassava chips had greater (p<0.05) total starch than the other cassava-based ingredients. Cassava residue had greater (p<0.05) concentrations of lysine, insoluble dietary fiber, and soluble dietary fiber compared with the other cassava products, but tryptophan and glutamic acid were greater (p<0.05) in peeled cassava roots, cassava chips, and cassava meal samples compared with the other ingredients. Concentration of most minerals was greater (p<0.05) in high-ash cassava meal than in the other cassava products. Conclusion: Cassava-based ingredients sold as peeled roots, unpeeled roots, chips, or meal have chemical compositions that are not different from each other, and peeling has little impact on chemical composition. High-ash cassava meal has lower nutritional quality compared with other cassava products due to low starch and gross energy. The high fiber content in cassava residue makes this ingredient more suitable for ruminants and sows than for younger pigs or poultry.

• Animal Bioscience
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• 제36권10호
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• pp.1568-1577
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• 2023

Objective: A study was conducted to determine the chemical composition of banana meal and rice bran from Australia or South-East Asia and test the hypothesis that there are no differences in rice bran produced in different countries, but there are differences between full-fat and defatted rice bran. Methods: Two sources of banana meal and 22 sources of rice bran (full-fat or defatted) from Australia or South-East Asia were used. All samples were analyzed for dry matter, gross energy, nitrogen, amino acids (AA), acid hydrolyzed ether extract (AEE), ash, minerals, total starch, insoluble dietary fiber, and soluble dietary fiber. Banana meal was also analyzed for sugars including glucose, fructose, maltose, sucrose, stachyose, and raffinose. Results: Chemical analysis demonstrated that banana meal from the Philippines is primarily composed of starch. Full-fat rice bran from Australia had greater (p<0.05) concentrations of AEE, lysine, and glycine than samples from the Philippines and Vietnam. Full-fat rice bran from Australia and Thailand had greater (p<0.05) concentrations of gross energy and most AA than rice bran from Vietnam. Full-fat rice bran from Australia had greater (p<0.05) concentrations of tryptophan and manganese than all other sources, but full-fat rice bran from the Philippines contained less (p<0.05) zinc than all other sources of rice bran. Gross energy, AEE, and copper were greater (p<0.05) in full-fat rice bran compared with defatted rice bran, but defatted rice bran contained more (p<0.05) crude protein, ash, insoluble dietary fiber, total dietary fiber, AA, and some minerals than full-fat rice bran. Conclusion: Banana meal is a high-energy source that can be used as an alternative ingredient in livestock diets. Full-fat rice bran from Australia and Thailand contained more concentrations of AEE and AA than samples from the Philippines or Vietnam. Full-fat rice bran had more gross energy and AEE than defatted rice bran, whereas defatted rice bran contained more crude protein, ash, and total dietary fiber.

• The Plant Pathology Journal
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• 제39권1호
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• pp.123-135
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• 2023

Previously, Pseudomonas plecoglossicida YJR13 and Pseudomonas putida YJR92 from a sequential screening procedure were proven to effectively control Phytophthora blight caused by Phytophthora capsici. In this study, we further investigated the anti-oomycete activities of these strains against mycelial growth, zoospore germination, and germ tube elongation of P. capsici. We also investigated root colonization ability of the bacterial strains in square dishes, including cell motility (swimming and swarming motilities) and biofilm formation. Both strains significantly inhibited mycelial growth in liquid and solid V8 juice media and M9 minimal media, zoospore germination, and germ tube elongation compared with Bacillus vallismortis EXTN-1 (positive biocontrol strain), Sphingomonas aquatilis KU408 (negative biocontrol strain), and MgSO₄ solution (untreated control). In diluted (nutrient-deficient) V₈ juice broth, the tested strain populations were maintained at >10⁸ cells/ml, simultaneously providing mycelial inhibitory activity. Additionally, these strains colonized pepper roots at a 10⁶ cells/ml concentration for 7 days. The root colonization of the strains was supported by strong swimming and swarming activities, biofilm formation, and chemotactic activity towards exudate components (amino acids, organic acids, and sugars) of pepper roots. Collectively, these results suggest that strains YJR13 and YJR92 can effectively suppress Phytophthora blight of pepper through direct anti-oomycete activities against mycelial growth, zoospore germination and germ tube elongation. Bacterial colonization of pepper roots may be mediated by cell motility and biofilm formation together with chemotaxis to root exudates.

• 한국식품저장유통학회지
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• 제30권4호
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• pp.617-629
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• 2023

Reactive oxygen species are the byproducts of metabolic processes in the body, However, excessive amount may cause side effects such as cancer. Therefore, to reduce the production of these species, but their long-term administration at high doses may induce side effects. Hence, natural materials with antioxidant activities are attracting attention. Two of these natural materials are soybean sprouts and Hovenia dulcis Thunb. fruits, but few studies have evaluated the effects of their combination. Thus, we prepared a soybean sprout extract containing 1.5% H. dulcis Thunb. fruit concentrate (BHM) to develop a functional food material derived from natural products and then confirmed its physicochemical properties and physiological activity. Among the organic acids detected in BHM, malic acid exhibited the highest content of 1,451.03 ppm, and the main free sugars were glucose (645.48 ppm) and fructose (738.11 ppm). Taurine was the most abundant free amino acid at a concentration of 11.95 ppm, followed by those of arginine (10.97 ppm) and glutamic acid (10.16 ppm). Analyses of the mineral components revealed large amounts of Zn and Fe in BHM, and the respective total polyphenol and flavonoid contents in BHM were 957.16 and 601.93 ppm. The DPPH radical and H₂O₂ scavenging activities and reducing power indicated excellent antioxidant efficacy compared to the positive controls. Furthermore, blood alcohol and acetaldehyde concentrations were measured to confirm the hangover-relieving effects of BHM, with both significantly decreased (p<0.05). BHM displays potential for development as a functional food, and the results of this study may be used as basic data in further research.

• 한국축산식품학회지
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• 제44권3호
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• pp.662-683
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• 2024

Thai-Native×Anglo-Nubian goat meat cooked by grilling (GR), sous vide (SV), and microwave (MW), was compared to fresh meat (Raw) in terms of flavor development. Non-volatile [i.e., free amino acids, nucleotide-related compounds, taste active values (TAVs) and umami equivalency, sugars, lipid oxidation, Maillard reaction products] and volatile compounds, were investigated. Notably, inosine monophosphate and Glu/Gln were the major compounds contributing to umami taste, as indicated by the highest TAVs in all samples. Raw had higher TAVs than cooked ones, indicating that heat-cooking removes these desirable flavor and taste compounds. This could be proportionally associated with the increase in aldehyde, ketone, and nitrogen-containing volatiles in all cooked samples. GR showed the highest thiobarbituric acid reactive substances (1.46 mg malonaldehyde/kg sample) and browning intensity (0.73), indicating the greatest lipid oxidation and Maillard reaction due to the higher temperature among all cooked samples (p<0.05). In contrast, SV and Raw exhibited similar profiles, indicating that low cooking temperatures preserved natural goat meat flavor, particularly the goaty odor. The principal component analysis biplot linked volatiles and non-volatiles dominant for each cooked sample to their unique flavor and taste. Therefore, these findings shed light on cooking method selection based on desirable flavor and preferences.