Research And Development Of Corn Silk Bagged Tea And Its Antioxidant And Hypoglycemic Activities

Corn silk,a by-product of corn,is rich in natural resources and low in price.Now,after harvest of corn,a large amount of corn silk was discarded.Thus,the comprehensive utilization and fine processing of corn silk need to be further investigated.Many studies have shown that corn silk has high medicinal value and health benefits,but the food development using corn silk as raw material is still in the primary stage.Aiming at the problems of low comprehensive utilization level and less development of deep processing products of corn silk,a kind of corn silk bagged tea was developed in this study.Furthermore,the physicochemical indexes,in vitro antioxidant and hypoglycemic activity of the corn silk bagged tea were determined.(1)First,taking the sensory score as the index,the formula of corn silk bagged tea was optimized by single factor test and orthogonal test.The results showed that the best formula of corn silk bagged tea was as follows:the addition amount of corn silk,semen coicis,jujube,longan,licorice,black wolfberry and yam was 1.5,0.5,1.0,1.0,0.5,0.4 and 0.4 g,respectively.Corn fiber bag(6×8 cm)was selected as the best packaging material for corn silk bagged tea.The sensory quality of the tea soup is better.Moreover,the tea soup has the fragrance of corn whiskers,and the taste is harmonious and mellow.(2)The physicochemical indexes of corn silk bagged tea were tested according to the national standard.The results showed that the moisture content,dry matter content,water extract content and ash content of corn silk bagged tea was(7.42±0.34)g/100 g,(91.43±0.04)%,(40.74±1.25)%and(6.13±0.44)g/100 g,respectively.The corn silk bagged tea was brewed with 120 m L boiling water,and the brewing time is 5 min.Under this brewing condition,the content of polysaccharides and flavonoids in tea soup was(0.6436±0.0050)mg/m L and(0.0485±0.0003)mg/m L,respectively.(3)The in vitro antioxidant activity of corn silk bagged tea was analyzed via DPPH free radical scavenging activity assay,ABTS free radical scavenging activity assay,reducing power assay,and ion chelating ability assay.The in vitro hypoglycemic activity of corn silk bagged tea was analyzed via?-glucosidase inhibitory activity assay and?-amylase inhibitory activity assay.The corn silk bagged tea was brewed with 120 m L boiling water,and the brewing time is 5 min.Under this brewing condition,the tea soup had better in vitro antioxidant capacity and hypoglycemic ability.The results showed that the tea soup could effectively scavenge DPPH free radical and ABTS free radical,and the scavenging rates were(92.98±1.04)%and(99.93±1.72)%respectively.The tea soup showed strong Fe³⁺reducing ability and Fe²⁺chelating properties,and the chelating activity of the tea soup for Fe²⁺is 40.35±1.71%.In addition,the tea soup possessed in vitro?-glucosidase and?-amylase inhibitory activity,and the inhibitory rate was12.99±1.59%and 39.01±4.64%,respectively.