High Quality Green Tea Extract Production from Enzyme Treated Fresh Green Tea Leaves

이란숙,; 차환수,; 박종대,; 이성훈,; 김상희,

doi:10.3746/jkfn.2008.37.8.1025

Cited by 3 publications

(1 citation statement)

References 15 publications

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“…The content of glucose was the highest in the FHD-treated sample, followed by the HD-, SFHD-, SHD-treated samples. These effects of SHD and FHD may be explained by the inhibition and promotion of sucrose hydrolysis by steaming and freezing, respectively (Lee et al 2008). This freezing effect appear to have been caused by tissue destruction developed by freezing, similar to the case of browning mentioned above.…”

Section: Comparison Of Free Sugarsmentioning

confidence: 79%

Effect of freezing treatment in tea preparation using Camellia sinensis leaves

Chung

Youn

2020

J Food Sci Technol

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This study was conducted to examine the effect of freezing in the tea preparation using Camellia sinensis leaves in order to develop new technology for improving tea quality. Effects of single and combined treatments of freezing (F: -20 °C, 15 days), steaming (S: 100 °C, 3 min), and hot-air drying (HD: 50 °C, 12 h) on the physicochemical characteristics of tea (powder and hotwater leachate) prepared from treated Camellia sinensis leaves were investigated. The L * , b * , and C * values of the powder were the highest in SHD-treated leaves, followed by HD-, SFHD-, and FHD-treated leaves. Redness (?a * value) was only seen in FHD-treated leaves and greenness (a * value) was the highest in SHD-treated leaves. Browning index of the leachate was significantly lower in SHD-and SFHD-treated leaves than in FHD-treated leaves (p \ 0.05). Soluble solids, acidity, and phenolic compounds of FHD-treated leaves were significantly lower than in SHD-and SFHD-treated leaves (p \ 0.05). Sucrose was highest in SHD-treated leaves and glucose was highest in FHD-treated leaves. Sensory preference was better evaluated in FHD-treated leaves than in SHD-and SFHD-treated leaves. These results suggest that freezing treatment in tea processing promotes browning and component decomposition and enhances sensual preference. Therefore, freezing has a potential application in the tea manufacturing.

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Section: Comparison Of Free Sugarsmentioning

confidence: 79%

Effect of freezing treatment in tea preparation using Camellia sinensis leaves

Chung

Youn

2020

J Food Sci Technol

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Quality characteristics of Aster glehni extract depending on the concentration and time of enzyme treatment

Kim,

Yoon,

Jeong

2023

Korean J. Food Preserv.

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The Aster glehni extract has many therapeutic and medicinal values. Therefore, it is essential to set appropriate conditions for enzyme treatment to efficiently extract A. glehni. In this study, changes in the quality of A. glehni extract depending on the concentration and time of enzyme treatment was investigated to increase its effective utilization. Compared to the control, the pH of the extract of A. glehni its soluble solid content increased with the enzyme treatment. The color of the A. glehni extract changed from green-yellow to reddish-yellow with the increase in treatment duration. The fructose and sucrose contents of the extract were the highest at 7.73% and 6.78%, respectively, in the control group without the enzyme treatment. Glucose and maltose contents were 6.91% and 4.44% in the C group (3.2% enzyme concentration and 60 min for enzyme treatment), respectively. Total polyphenol content, which shows antioxidant activity, was the highest at 7.38 mg GAE/g in the E group (1.6% of enzyme concentration and 120 min for enzyme treatment). 2,2-diphenylpicrylhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS) showed the highest radical scavenging activity in the C group (3.2% of enzyme concentration and 60 min for enzyme treatment). These results enable setting appropriate conditions of enzyme treatment in terms of enzyme concentration and time for the production of dry powders using A. glehni extract.

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Physicochemical characteristics of hot-water leachate prepared from persimmon leaf dried after steaming or freezing treatment

Chung,

Youn,

Kim

2023

Korean J. Food Preserv.

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This study was conducted to develop a preservation technology that can induce changes in physicochemical properties to effectively utilize of persimmon leaves. The application effects of steaming or freezing technique were investigated. Astringent persimmon leaves were steam-blanched (100°C, 30 sec) or frozen (−20°C, 15 d), followed by hot-air drying (50°C). The physicochemical properties of the extract obtained by hot-water leaching from the dried leaves were compared. The extract of leaves dried without pretreatment was used as a control. L* value was higher in steamed than in control and frozen. a* value was highest in the control. The browning index was higher in the frozen and lower in the steamed than in the control. Soluble solids were the highest in the steamed and the lowest in the frozen. Sucrose content was relatively high in the steamed, and the glucose and fructose contents were relatively high in the frozen. Total polyphenol content and DPPH radical scavenging activity were higher in steamed and lower in frozen than in control. Thus, it was confirmed that steam or freeze pretreatment after harvesting persimmon leaves affects the extraction yield, color, antioxidant capacity and component changes of dried persimmon leaves. Unlike steaming, freezing pretreatment showed the effect of promoting decomposition and browning reactions, and it is considered useful when such an effect is needed.

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High Quality Green Tea Extract Production from Enzyme Treated Fresh Green Tea Leaves

Cited by 3 publications

References 15 publications

Effect of freezing treatment in tea preparation using Camellia sinensis leaves

Effect of freezing treatment in tea preparation using Camellia sinensis leaves

Quality characteristics of Aster glehni extract depending on the concentration and time of enzyme treatment

Physicochemical characteristics of hot-water leachate prepared from persimmon leaf dried after steaming or freezing treatment

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