• Korean Journal of Food Science and Technology
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• v.47 no.5
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• pp.556-560
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• 2015

This study was aimed at investigating the natural occurrence of caffeine, theobromine, and theophylline in tea leaves. Sample clean-up was based on a simple solid phase extraction (SPE) treatment, and simultaneous analysis was performed by high performance liquid chromatography (HPLC). This method showed good results in terms of linearity, recovery, precision, limit of detection (LOD), and limit of quantitation (LOQ). The caffeine, theobromine, and theophylline contents of tea leaves (n = 228) ranged from 5.4 to 58.2 mg/g, from not detected to 11.2 mg/g, and from not detected to 0.7 mg/g, respectively. The results obtained in this study can be used as fundamental data of caffeine, theobromine, and theophylline contents in tea leaves.

• Korean Journal of Food Science and Technology
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• v.44 no.3
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• pp.356-361
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• 2012

Caffeine is a xanthine alkaloid derivative found in many foods and beverages. Dietary caffeine may interact with commonly-consumed over-the-counter (OTC) drugs in body. In this study, cytotoxic effects on the intestinal cells by combined treatment of caffeine with several OTC drugs, including ibuprofen, aspirin, and acetaminophen. Cytotoxic effect of caffeine was more potent in normal intestinal INT 407 cells than in colon cancer HCT 116 cells. Relative toxicity of caffeine and the OTC drugs was significantly enhanced in INT 407 cells when treated together. Intracellular thiol levels of the cells treated with the OTC drugs increased in the presence of caffeine. When HCT 116 cells were incubated with each OTC drug after or before caffeine treatment, the relative cytotoxicity of the OTC drugs increased. The present study may provide basic information about possible health effects through the interactions between caffeine and OTC drugs in the intestinal cells.

• Journal of Food Hygiene and Safety
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• v.36 no.4
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• pp.342-346
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• 2021

Cold brew coffee extracted from cold water for a long time has drawn public concern over hygiene. This study was carried out to investigate the microbiological contamination levels and caffeine contents in cold brew coffee. A total of 75 cold brew coffees were purchased from offline and online sources. As a result, the average number of bacteria in samples purchased online was 1.14 log CFU/mL (0-6.57 log CFU/mL), while bacteria were not detected in samples purchased offline. Therefore, stricter surveys are required to avoid the food contamination. However, Esherichia coli and nine types of foodborne pathogens were not detected in all samples. The average caffeine content of the samples was 1.6 mg/mL (384 mg/240 mL), so the caffeine almost reached to acceptable daily intake levels (400 mg for adults). However, ten products did not provide any precautions for consumer safety, so improvement of the system is needed. This monitoring data can contribute to the protection of consumer rights and improvement in the safety of cold brew coffee.

• Journal of the Economic Geographical Society of Korea
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• v.25 no.1
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• pp.131-146
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• 2022

The purpose of this study is to examine the locational characteristics of cafes in Jeju Island and the changes. For the purpose, we identify the spatial distribution patterns of openings and closings by period from the first opening of cafes in Jeju Island to the present. In particular, we analyze the spatial distribution characteristics found in the locations of cafes that have been opened and closed after the outbreak of COVID-19, in which new stores have significantly increased. In addition, we identify the regional attributes and the influence of online that have affected the distribution of currently open cafes and cafes that have opened or closed during the COVID-19 outbreak. As a result of empirical analysis, Jeju Island is a tourist destination and island region with the characteristics of determining major destinations through information search, showing a different distribution form from the location of cafes in inland cities. In particular, as a result of frequency analysis by extracting keyword search volume for cafes in Jeju Island, online accessibility such as information search for new areas and places in Jeju Island has become more diversified and expanded after COVID-19. In addition, as a result of calculating the distance to cafes by road size, the relationship between physical location and road accessibility, which has traditionally been an important factor, was relatively low. This study is meaningful in that it revealed the distribution patterns and characteristics of cafe locations in Jeju Island by reflecting the influence of online and offline.

• 건강소식
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• v.31 no.11 s.348
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• pp.22-23
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• 2007

• 베이커리
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• no.4 s.345
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• pp.82-83
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• 1997

• Journal of agriculture & life science
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• v.46 no.2
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• pp.49-61
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• 2012

This study was carried out to investigate the chemical composition and the inorganic constituents of the green tea at the 3 picking periods (Ujeon, Sejag, Jungjag) in Hadong. The results as follows ; The contents of chlorophyll, tannin, vitamin-c and total catechin were increased as picking periods increased but the contents of total nitrogen, total free amino acids, theanine and caffeine were decreased on the reverse. The inorganic constituents Mg, Ca and Mn were increased as picking periods getting late but the Na, K, B contents were decreased on the reverse. The contents of the total nitrogen, chlorophyll, total free amino acid, theanine, caffeine and total catechin and Na, Mg, Ca, B and Se were insignificant differences between Ujeon and Sejag.

• Journal of the Korean Chemical Society
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• v.34 no.4
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• pp.325-330
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• 1990

The solubilities of caffeine in supercritical ammonia were measured at various temperatures and pressures to represent the relationship between the solubility and the density of ammonia at desired temperature and pressure by means of a simple equation. Using the equation, the interaction virial coefficient between ammonia and caffeine has been determined to give the parameters of Lennard-Jones potential function for the system. Furthermore, there are comparisons and discussions of the interaction virial coefficients and Lennard-Jones potential functions determined by the same techniques from the solubility data of naphthalene in supercritical ammonia and of caffeine and naphthalene in supercritical carbon dioxide from existing data sources others.

• The Journal of the Convergence on Culture Technology
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• v.9 no.4
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• pp.693-697
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• 2023

As of 2022, dessert cafe trends are changing faster, customers' needs are becoming more demanding, and Koreans' consumption tendencies are changing rapidly, so this study investigates servicescape and customer engagement factors for dessert cafes through big data to identify servicescape and customer engagement factors.

• Proceedings of the Korea Information Processing Society Conference
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• 2023.05a
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• pp.404-406
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• 2023

본 논문은 맞춤형 카페 추천 서비스를 제안한다. 대중적인 포털 사이트의 카페 정보와 사용자 리뷰를 크롤링 하여 지역별, 키워드별 카페 데이터를 수집한다. 사용자가 원하는 지역과 임의의 키워드를 기준으로 데이터셋 내의 키워드와 비교하여 가장 유사한 키워드를 추출한다. spaCy 라이브러리의사전 학습된 모델 중 similarity method를 사용하여 추출된 키워드를 바탕으로 해당하는 카페를 추천한다. 이를 통해 사용자는 불필요한 정보를 걸러내고 쉽게 원하는 정보를 얻을 수 있다.