Tea polyphenols: prevention of cancer and optimizing health. Discussion 4.

Effects of drying and grinding in production of fruit and vegetable powders: A review

Effect of superfine grinding on the physicochemical properties and antioxidant activity of red grape pomace powders

The objective of this study was to investigate the effects of superfine grinding on the physicochemical and antioxidant properties of Lycium barbarum polysaccharides (LBP). Superfine grinding treatment could decrease the average molecular weight (changed from 834.0, 85.2 and 70.6 to 538.5, 71.2 and 2.1, respectively), the spherical particle’s heights (changed from 0.86, 0.59 and 0.51 nm to 0.74, 0.55 and 0.43 nm, respectively) and the spherical particle’s diameter (changed from 98.33, 70.67 and 86.33 nm to 88.67, 47.67 and 51.33 nm, respectively) of LBP. After being superfine grinding treated, the Δ H values of LBP changed from −154.6, −136.5 and −105.0 J/g to −220.8, −97.2 and −46.5 J/g, respectively. The IC 50 of LBP from treated materials on DPPH radical (4.96, 1.98 and 2.97 mg/mL) and ABTS radical (2.25, 0.20 and 0.25 mg/mL) were extremely lower than those of LBP from untreated materials. The results suggested that superfine grinding treatment enhanced LBP’s antioxidant activities. Molecular weight and solution behavior were key factors in polymer’s antioxidant activities.

Effects of superfine grinding on physicochemical and antioxidant properties of Lycium barbarum polysaccharides

Physicochemical properties and prebiotic activities of polysaccharides from longan pulp based on different extraction techniques.

Six Green tea powders (GTPs) were prepared from green tea with superfine grinding process. Their main quality components were determined by chemical methods and the scavenging effects of GTPs on ·OH and O2.− in vitro were evaluated by using deoxyribose assay and xanthine oxidase method, respectively. The results indicated that tea polyphenols and catechins contents decreased, while the contents of water-soluble carbohydrates in GTPs increased markedly, and no significant difference in amino acids and caffein with the decrease in particle size during superfine grinding, which benefited to reduce bitterness and preserve briskness of GTPs. Meanwhile, superfine grinding increased extraction of TPS markedly, which could lead to more potent scavenging capacity of GTPEs on ·OH. Based on the above analysis, it suggested that superfine grinding time should be controlled within 30–50 min, with ideal parameters of GTP: X: 4.93–4.75%, d50: 20.3–13.5 μm, ρbulk: 0.323–0.297 kg/m3, ρtapped: 0.666–0.614 kg/m3. Under this condition, we could prepare GTP with green and bright color, narrower and more uniform particle size distribution, as well as possessing more food processing property.

Dejiang Ni

Papers

Effect of superfine grinding on quality and antioxidant property of fine green tea powders