Chemical Analysis and Antioxidant Activity <em>in vitro</em> of Polysaccharides Extracted from Lower Grade Green Tea

Abstract

Tea is a well-known and important agricultural product in the world. The Crude Polysaccharides from tea leaves (CP) probably have good antioxidant activities. However, whether or not the antioxidant abilities of CP depend on tea polyphenols in the CP is not understanded. In this study, four CP fractions (TPF30, TPF50, TPF70 and TPF90) were isolated from CP and their antioxidant activities were compared. Meanwhile, Chemical and physical characteristics of CP and four CP fractions were investigated by the combination of chemical and instrumental analysis methods. Their antioxidant activities were investigated in vitro systems, including hydroxyl radical assay, 1, 1-Diphenyl-2-Picrylhydrazyl (DPPH•) scavenging activity, reducing power and chelating activity. Among CP and these four polysaccharides, TPF90 showed more significant DPPH• scavenging activity and highest reducing power, chelating activity and inhibitory effects on hydroxyl radical. Thus, it can be concluded that polysaccharides extracted from the lower grade green tea might be employed as ingredients in healthy and functional food to alleviate the oxidative stress.

Effect of Temperature, pH and Some Salts on Physicochemical and Rheological Properties of &lt;i&gt;Nettle seed gum (NSG)&lt;/i&gt;

“…Nettle seed gum was provided under the optimized conditions [12] In summary, Nettle seeds were soaked in the distilled water at a water/seed ratio of 40:1 and a fixed temperature of 59±1.0°C for a period of 3.4 h. Then, Separation of mucilage from the swollen seeds was achieved through the scraping technique. The seeds were passed through an extractor (model 402, Pars-Khazar Com., Iran) equipped with a rotating plate that scraped the mucilage layer on the seed surface.…”

A Review on the Extraction, Bioactivity, and Application of Tea Polysaccharides

“…Chen et al isolated crude TPS and four CTPS fractions (TPF30, TPF50, TPF70, and TPF90) from green tea and compared their antioxidant activities. TPF90 had significant DPPH-scavenging activity and the highest inhibitory effect on hydroxyl radicals, reducing power, and chelating activity, showing stronger antioxidant capacity than crude TPS [ 64 ]. Shu et al explored the antioxidant activity of green tea powders (GTPs) with different particle sizes using a simulated in vitro gastrointestinal digestion model and showed that the particle size significantly affects the antioxidant activity of the polysaccharides.…”

Tea Diversification Products and Value Addition

“…Catechin candy, green tea ice cream, catechin tea bar, matcha powder, vitamin fortified unsweetened high antioxidant enriched flavored catechin beverages are popular amongst the confectionaries serving the purpose of nutraceuticals [5,16]. Amongst the value-added tea diversified products commercialized in China include the green tea polyphenolbased products, tea saponin based products, theanine and tea polysaccharide added nutraceuticals, micro tea power as an ingredient in confectonaries, dental products and cosmetics [5,17,18]. Tea cola, tea toffee, tea ice cream, a wide range of herbal teas (tulsi tea, ginger tea, turmeric tea, cinnamon tea etc), tea wine, tea based confectionary products and cosmeceuticals have occupied significant places in Indian market [19,20].…”