Research On Inner Quality Evaluation Of Northern Highbush Blueberry

Blueberry(Vaccinium spp.)is among one of the most comprehensive berries because of its huge market and nutritional value.Northern highbush blueberry(Vaccinium corymbosum L.)has the highest economic value and the largest planting area among all blueberry species.Due to regular increase in blueberry production and consumption,its quality has gained primitive attention throughout the world.However,there is no systematic study on the inner quality evaluation standard for specific blueberry varieties.In this research work,inner quality of 73 northern highbush blueberry samples were evaluated,including their physiochemical properties including,firmness,titratable acidity,soluble solids content,vitamin C,and soluble solid/titratable acidity,flavor characteristics(soluble sugar and organic acid),functional factors(anthocyanins)and antioxidant activity(total antioxidant capacity assay with ABTS and FRAP methods).This study aim to provide a scientific basis and technical support for blueberry quality evaluation.In the scenario of our work,conclusions are summarized as follows:1.There were significant variations in soluble solids and vitamin C among regions and cultivars.Titratable acidity was significantly varied among cultivars.There was significant correlation between indexes,except of fruit firmness.Soluble solid/titratable acidity ratio had also a significant power function concerning titratable acidity.2.In the total soluble sugars contents of northern highbush blueberries,glucose and fructose has a major contribution,and citric acid and quinic acid were the prominent organic acids components.Significant differences were found in term of glucose,fructose,and total sugar content among regions,and quinic acid,shikimic acid and citric acid content also varied significantly among cultivars,and regions.There was a linear relationship among glucose,fructose and total soluble sugar and a linear relationship among citric acid,total organic acid and titratable acidity.3.The main anthocyanins of northern highbush blueberries were delphinidin-3-O-galactoside,delphinidin-3-O-arabinosid,petunidin-3-O-galactoside,malvidin-3-O-galactoside and malvidin-3-O-arabinosid.Significant differences were found in the contents of 14 anthocyanins and total anthocyanins among cultivars.In addition to the contents of cyanidin-3-O-arabinoside,peonidin-3-O-glucoside and total anthocyanins,the other 12 anthocyanins content also had significant variations among regions.Significant divergence was found in the total antioxidant capacity with ABTS and FRAP methods among regions and cultivars.ABTS was positively correlated with total anthocyanins contents.4.Northern highbush blueberries inner quality could be evaluated by 9 indexes,including fruit firmness,glucose and titratable acidity,delphinin-3-O-galactoside,malvidin-3-O-glucoside,malvidin-3-O-arabinosid,cyanidin-3-O-galactoside and antioxidant capacity with ABTS and FRAP methods.The typical inner quality evaluation indexes of northern highbush blueberries were divided into five grades.The discriminant function of inner quality evaluation was established,and 73 northernhighbush blueberry samples were divided into five grades.