• Journal of Food Hygiene and Safety
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• v.38 no.6
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• pp.537-543
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• 2023

This study monitored the caffeine content of ready-to-drink coffee and verified the appropriateness of the labeling. The caffeine content was analyzed using HPLC. The average caffeine content of cold brew coffee was 0.31-1.04 mg/mL, with an average of 0.55 mg/mL. The average content of product was 147.27 mg/bottle, and taking into account the recommended daily intake, an adult can consume 2.7 bottles. Americano coffee was 0.15-0.38 mg/mL, with an average of 0.28 mg/mL. The average content of product was 110.42 mg/bottle, and considering the recommended daily intake, an adult can consume 3.6 bottles. The caffeine content of decaffeinated cold brew coffee was 5.14 mg/bottle and compared to Americano coffee, more than 95% of the caffeine was removed. In addition, we verified the tolerance level of the total caffeine content in ready-to-drink coffee, and none of them exceeded 120%, signifying that all commercial products were effectively managed.

• The Korean Journal of Food And Nutrition
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• v.32 no.5
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• pp.504-510
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• 2019

The purpose of this study was to compare the effects of soaking and ultrasonic extraction by observing the change of contents with extraction time of physicochemical properties (solid content, colorness, caffeine, chlorogenic acid, total polyphenols, DPPH, and ABTS). As a result of the analysis, solid content increased with longer extraction time and the whiteness tended to decrease with longer extraction time. Conversely, the extraction of functional materials showed a tendency to increase as the extraction time increased. Caffeine reached the maximum value after two hours soaking, but showed the same result as one hour for sonication. Chlorogenic acid did not show difference from the content of coffee extracted for one hour soaking only by sonication extraction for 30 minutes. The total polyphenols eluted with approximately two hours of soaking even after 30 minutes of sonication. DPPH and ABTS were insignificant in their concentrations, but their antioxidative effect was more than two hours of soaking with only 30 minutes of sonication. Sonication has a short time extraction from a functional aspect (caffeine content, chlorogenic acid, polyphenol content, and antioxidant capacity) and this experiment can provide basic data for the development of innovative recipes.

• Journal of Nutrition and Health
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• v.30 no.8
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• pp.911-919
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• 1997

The purpose of this research was to investigate the effect of caffeine levels on calcium utilization in rats of different age and sex. Calcium utilization was compared in rats of different age(4 weeks and 10 months) and sex that were fed various levels of caffeine (0, 3.5, and 7mg/100g body weight) for 3 weeks. There was no significant difference in feed intake, serum calcium level, and ash content in tibia among the groups. Fecal calcium excretion was lower in young rats than in adults, Urinary calcium excretion significantly higher in the caffeine groups than that in the no-caffeine group. Daily retention and apparent absorbability of calcium in young rats were higher than those in adult rats. However, there was no significant difference among groups of different sex and caffeine levels. The results of this study suggest that caffeine consumption promotes urinary calcium excretion.

• Journal of Nutrition and Health
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• v.30 no.10
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• pp.1160-1169
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• 1997

The purpose of this research was to investigate the effects of caffeine and calcium levels on calcium utilization in female rats of different ages. Calcium utilization was compared in female rats of different age( 4 weeks and 12 months) fed various levels of caffeine(0 and 7 mg/100g body weight) and calcium (50, 100 and 200% of requirement) for 3 weeks. Feed intake of the caffeine groups were lower than that of the no-caffeine groups. body weight gain was lowest in the high-caffeine and low-calcium group. Serum calcium levels of young rats were higher than those of adult rats. There were no significant differences in tibial calcium content among the caffeine and calcium -groups. Fecal calcium excretion increased as the level of dietary calcium was increased. Urinary calcium excretion increased as the levels of caffeine and dietary calcium were increased. With increasing levels of dietary calcium , daily calcium retention was accelerated, but apparent calcium absorbability was diminished. The results of this study suggest that caffeine consumption promotes urinary calcium excretion. However, increase in dietary calcium resulted in higher calcium retention . These findings indicate that high caffeine consumption may increase dietary calcium requirements. Therefore, it could be suggested that the supplementation of dietary calcium may counteract the negative effect of caffeine intake on calcium utilization.

• Journal of the Korean Society of Food Science and Nutrition
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• v.22 no.6
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• pp.658-663
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• 1993

This study was designed to investigate the effect of dietary vitamin E levels on lipid metabolism in caffeine-fed rats. Male Sprague-Dawley rats were fed on diet containing one of three levels of vitamin E(37.5, 750, or 1,500mg/kg diet0 which was with or without 0.3% caffeine. The rats were sacrificed after 5 and 10 weeks of the feed periods. Results obtained from this study were as follows ; Net weight gain, feed intake and FER in the caffeine added groups were significantly decreased as compared to those of only vitamin E fed group. Liver and kidney weights tended to increase in the caffeine added groups, but spleen and heart weights were not affected. Total lipid contents in serum and liver tended to decrease as dietary vitamin E became increasing and caffeine diet adding. Serum total cholesterol content tended to increase in the caffeine added group. But, liver cholesterol content were decreased. And the higher the dietary vitamin E level became, the lower serum and liver cholesterol contents were. Serum and liver triglyceride contents were significantly lower in the caffeine added groups than in the only vitamin E fed groups. The degree of decrease was more evident as dietary vitamin E level became more increasing. Serum aminotransferase activity was not affected in all experimental groups.

• Journal of Nutrition and Health
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• v.41 no.3
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• pp.216-223
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• 2008

The purpose of this study was to examine the effects of dietary caffeine supplementation on bone mineral density and bone mineral content in ovariectomized rats. Twenty eight female Sprague-Dawley rats (body weight $210\;{\pm}\;5\;g$) were divided into two groups, ovariectomy (OVX) and Sham groups, which were each randomly divided into two subgroups that were fed control and control supplemented with caffeine diets (caffeine 0.03% diets). All rats were fed on experimental diet and deionized water ad libitum for 6 weeks. Bone mineral density (BMD) and bone mineral content (BMC) were measured using PIXImus (GE Lunar Co, Wisconsin) in spine and femur. Serum alkaline phosphatase activity (ALP) and osteocalcin and urinary DPD crosslinks value were measured as markers of bone formation and resorption. The results of this study indicate that body weight gain and food intake were higher in OVX groups than in Sham groups regardless of diets. There were no differences weight gain between the control and caffeine groups in both OVX and Sham groups. Within the OVX groups, serum Ca concentration was lower in rats fed caffeine than in rats fed the control diet. Serum ALP, osteocalcin, urinary Ca, and phosphate were not different in each group. Spine BMD, spine BMD/weight, and spine BMC/weight, femur BMD/weight and femur BMC/weight of ovariectomy groups were significantly lower than Sham groups. Within the OVX group, there were no differences in spine BMD and BMC and femur BMD and BMC. These results indicate that no significant differences in spine and femur BMD were found due to 0.03% caffeine intakes in diet in OVX rats for 6 weeks. No negative effect of caffeine in 0.03% diet on bone mineral density were found in the present study. Further investigation of the relation between caffeine and bone mineral density are warranted. (KoreanJNutr2008; 41(3): 2l6~223)

• Journal of Nutrition and Health
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• v.29 no.9
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• pp.950-957
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• 1996

This study was designed to investigate the effects of caffeine intake on Ca and P metabolism in ovariectomized rats. For this purpose, the ovariectomized female rats weighing 230.8$\pm$3.5g were divided into four groups, eight rats each ; control, low caffeine(LC), medium caffeine(MC)and high caffeine(HC) groups. They were supplied for six weeks with the caffeine of 0mg, 66.8mg, 167mg and 334mg per kilogram of diet, respectively, and the results are summarized as follows. 1) There were no significant differences in feed intake, feed efficiency ratio and body weight change among all of experimental groups. But liver weight(both total weight and weight/body weight) was significantly decreased by caffeine in MC group. 2) The weight of tibia was decreased by caffeine intake in MC and HC groups. But the length, Ca and P content of tibia and femur was not changed in all of caffeine groups. 3) Ca, PTH and calcitonin levels in serum were not affected by caffeine. While, serum P level in HC group was significantly increased as compared with the control. 4) The fecal excretion of Ca and P tended to be higher in the caffeine groups, and as the result, the absorption rate, retention and retention rate of Ca and P tended to be decreased. It was noteworthy that P retention was significantly lowered in HC group as compared with LC group. The results showed that, when caffeine was taken by ovarietomized rats, the weight of tibia was decreased and the retention rate of Ca and P tended to be lowered. Therefore, too much intake of caffeine for women whose bone mineral density of tibia is decreased after postmenopause seems to accelerate the decrease of bone mineral density due to the negative effect on metabolism of Ca and P.

• Korean Journal of Animal Reproduction
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• v.25 no.4
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• pp.349-357
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• 2001

This study was conducted to examine the effect of caffeine and three dietary levels of fat, i.e., 0%, 5% and 20% on mammary gland development. Mice were assigned to three groups (dietary levels 0%, 5%, 20% fat), and treated caffeine of half within the each group. Caffeine-treated mice with 0% or 20% fat levels significantly increased 4$^{th}$ mammary gland development in comparison with that of no caffeine -treated mice (P＜0.05). Caffeine-treated mice significantly increased DNA contents of 4$^{th}$ mammary gland in comparison with that of no caffeine-treated mice (P＜0.05), and DNA contents of mammary gland increased as fat levels increased within caffeine-treated or no caffeine-treated group. nteraction effect was shown between caffeine and 20% fat diet, ［(20% fat+caffeine) - (20% fat + no caffeine) vs (0% fat + caffeine) - (0% fat + no caffeine)］(P＜0.01). Conclusively, caffeine significantly increased mouse mammary gland development possibly by inhibiting phosphodiesterase activity, and dietary fat supplements increased mammary gland development as the fat content of the diet increased from 0 to 20%. The stimulatory effect of caffeine in mammary development interacted with high level of fat diet.

• Journal of the Korean Society of Food Science and Nutrition
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• v.23 no.1
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• pp.13-22
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• 1994

This study was designed to investigate the effects of dietary protein and caffeine consumption levels on Ca, P, Na and K metabolism. One hundred twenty rats were divided into twelve groups according to age, protein level and caffeine consumption such as group(120-130g young rat, 250-300g adult rat) , dietary protein group (20% normal protein , 85 low protein) , caffeine consumption group(0, 3.5mg, 7.0mg). Low protein diet containing high caffeine levels caffeine levels increased calcium, phosphorus, sodium and potassium contents of urine and fecal in rats. Young rat has higher level of calcium, phosphorus , sodium and potassium than adult rat. In the serum, calcium contents were not affected by age, dietary protein levels and caffeine consumption . However, phosphorus, sodium and potassium contents of serum in adult rat were higher than young rat. In the liver, potassium decreased with decreasing dietary protein levels. In the kidney, calcium , phosphorus and potassium contents were not different by age group, dietary protein levels and caffeine consumption , but sodium content was significantly reduced in the adult rat.

• Preventive Nutrition and Food Science
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• v.15 no.3
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• pp.229-232
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• 2010

Caffeine and catechins from the Yabukita, Yutakamidori, Saemidori, Okumidori, and Fushun varieties of tea leaves picked during different harvesting seasons from April to October were evaluated using HPLC. Total content of catechins increased greatly with the later harvesting time of tea leaves (i.e., picking the leaves in September versus in April) and decreased slightly after September. Yabukita tea leaves picked in August contained 43.1 mg% catechins including EGC, EC, ECG, and EGCG, with the ECGC levels constituting greater than 50% of those four compounds. Yutakamidori and Okumidori varieties picked in September contained the highest catechin values, at 43.6 mg% and 31.0 mg%, respectively. Fushun and Saemidori varieties contained lower catechin concentrations of 14.5 mg% (July) and 11.7 mg% (August) compared to other varieties. The EGCG levels gradually decreased in the late harvesting season, while levels of the other catechins, EC, EGC, and ECG, gradually increased. All varieties of green tea showed a gradual decrease in caffeine content toward the end of our harvesting efforts in October, with levels of 58～68 mg% in April and 28～57 mg% in October. Yabukita, Saemidori, and Okumidori varieties reached their highest caffeine levels in late spring/early summer, with Yabukita and Okumidori varieties reaching a high of 73.4% and 63.5% caffeine, respectively, in May, and Saemidori at 64.0% in June. In particular, Fushun still contained high caffeine of 66.8 mg% (September) during the late harvesting season.