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Your search keyword '"Lei, Shicheng"' showing total 18 results
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18 results on '"Lei, Shicheng"'

11. Effective synthesis of theaflavin-3,3′-digallate with epigallocatechin-3-O-gallate and epicatechin gallate as substrates by using immobilized pear polyphenol oxidase.

Author

Lei, Shicheng, Xie, Minhao, Hu, Bing, Zhou, Li, Sun, Yi, Saeeduddin, Muhammad, Zhang, Hongcheng, and Zeng, Xiaoxiong

Subjects
*THEAFLAVINS, *EPIGALLOCATECHIN gallate, *EPICATECHIN, *POLYPHENOL oxidase, *IMMOBILIZED enzymes
Abstract

In the present study, pear polyphenol oxidase (PPO) was purified, immobilized and applied for the synthesis of theaflavin-3,3′-digallate (TF3). Firstly, PPO of pear ( Pyrus bretschneideri Rehd cv. Huangguan) was purified 24.36-fold in specific activity with a recovery of 6.77% by sequential use of precipitation with 70% saturated ammonium sulfate and chromatography of DEAE-Sepharose Fast Flow column. The purified pear PPO, found to be a dimer of identical subunits of molecular mass 35 kDa, was then successfully immobilized onto Fe 3 O 4 /chitosan nanoparticles via glutaraldehyde coupling reaction. Finally, TF3 was effectively synthesized by applying the immobilized PPO as biocatalyst with epicatechin gallate (ECG) and epigallocatechin-3- O -gallate (EGCG) as substrates, and the maximum yield of TF3 was 42.23% based on the amount of ECG added. In addition, the immobilized enzyme still remained 85% of its initial ability after successive usage of 8 cycles and could be stored for 30 days with less loss of activity. All the results suggest that the developed procedure is quite useful and has great potential for synthesis of TF3 and other theaflavins. [ABSTRACT FROM AUTHOR]

Published
2017
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18. Study on combined effects of blanching and sonication on different quality parameters of carrot juice.

Author

Jabbar, Saqib, Abid, Muhammad, Wu, Tao, Muhammad Hashim, Malik, Hu, Bing, Lei, Shicheng, Zhu, Xiuling, and Zeng, Xiaoxiong

Subjects
BLANCHING (Cooking), SONICATION, CARROTS, FRUIT juices, FOOD quality, FLAVONOIDS, ANTIOXIDANTS
Abstract

This study was conducted to evaluate the combined effects of blanching and sonication on carrot juice quality. Carrots were blanched at 100 °C for 4 min in normal and acidified water. Juice was extracted and sonicated at 15 °C for 2 min keeping pulse duration 5 s on and 5 s off (70% amplitude level and 20 kHz frequency). No significant effect of blanching and sonication was observed on Brix, pH and titratable acidity except acidified blanching that decreased pH and increased acidity significantly. Peroxidase was inactivated after blanching that also significantly decreased total phenol, flavonoids, tannins, free radical scavenging activity, antioxidant capacity and ascorbic acid and increased cloud and color values. Sonication could improve all these parameters significantly. The present results suggest that combination of blanching and sonication may be employed in food industry to produce high-quality carrot juice with reduced enzyme activity and improved nutrition. [ABSTRACT FROM AUTHOR]

Published
2014
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