Determination Of Antioxidant Capacities And Antimicrobial Activities Of Different Cultivated Blueberry Cultivars Obtained In China

Twenty cultivated blueberry cultivars from Q ingdao, Hangzhou and Shanghai were chosen in this paper as the objects of study. Many techniques were involved in the process of the research, such as extraction of bioactive components of blueberries, colony identification technology of microbes, antibacterial test in vitro, antioxidant capacity in vitro and cellular antioxidant activity and so on. The research contained antioxidant activities in vitro of different blueberry extracts, comparing the antibacterial difference of twenty blueberry cultivars. The cellular antioxidant activities(CAA) of the extracts were also explored in this study.Five kinds of methods, including DPPH assay, Hydroxyl radical scavenging assay, ABTS assay, reducing power and ORAC(Oxygen radical absorbance capacity) were used in this paper. The results of the antioxidant activities in vitro test showed that different blueberry cultivars had different a ntioxidant capacities. Highest scavenging capacity was found in the Gardenblue(52.09%) from Hangzhou, which was followed by Primer and Centurion of Hangzhou. However, the highbush blueberry cultivars obtained in Q ingdao exhibited relatively lower DPPH sca venging abilities. The scavenging ability of Nelson was only 16.48%. There was no difference found according to the ABTS assay. Nelson had the highest Hydroxyl radical scavenging ability, with the value of 53.07%. Centurion and Gardenblue from Hangzhou stood in the medium level. Centurion(Hangzhou) had the best ORAC, with the highest value 7583μmol TE/100 g FW. Furthermore, relatively good ORAC were also found in Primer and Gardenblue of Hangzhou. Pariot from Q ingdao possessed the lowest ORAC value. Reducing power determination indicated that Centurion of Hangzhou had the strongest reducing power.Generally, the results showed that the antioxidant capacity of Centurion from Hangzhou was significantly higher than the other cultivars. And blueberry cultivars from Hangzhou showed higher antioxidant activies compared to cultivars from Shanghai and Qingdao. Different growth conditions and blueberry genotypes are likely contribute to the difference.In recent years, a cell- foundation biology method, called cellular antioxidant activity was established and widely applied in a wide range of areas. In this assay, Hep G2 was used as the cell tool. The results demonstrated that different blueberry cultivar had different CAA values. CAA values were expressed as μmol Q E/100 g blueberry sample. The cultivar Dellite had the highest C AA value at 1302±28.35μmol QE/100 g. CAA values were also found in Centurion, C limax and Gardenblue of Hangzhou and Primer of Shanghai. The values were 553±19.70μmol QE/100 g, 739±5.03μmol Q E/100 g, 771±12.17μmol Q E/100 g and 580±8.58μmol Q E/100 g, respectively.Gardenblue of Shanghai and highbush blueberry Nelson of Q ingdao had the lowest CAA values, the values were 284±19.52μmol QE/100 g and 289±21.34μmol QE/100 g, respectively, what was about one quarter of Del ite’s value.Two- fold dilution method was used to determine the antibacterial activity of twenty blueberry cultivars. The results showed that different blueberry cultivars showed different microbes inhibitory effects. The minimal inhibitory concentration(MIC) and minimal bactericidal concentration(MBC) of blueberry extracts against L. monocytogenes, S. aureus, P. aeruginosa, and V. parahaemolyticus were determined in the paper. Among the four pathogens, V. parahaemolyticus was most susceptible to Climax and Powderblue of Hangzhou and Baldwin and Powderblue of Shanghai with the lowest MIC at 15.625 mg/m L, indicating that these cultivars had the most potent activity against V. parahaemolyticus. V. parahaemolyticus was most resistant to Centurion, C hoice, and Bluebelle of Hangzhou(MIC at 250 mg/m L). For P. aeruginosa and S. aureus, Gardenblue and Baldwin of Shanghai extracts showed the lowest MIC and MBC at 31.25 mg/m L and 125 mg/m L, respectively. Bluebelle of Hangzhou had the highest MIC and MBC, both at 1000 mg/m L. For L. monocytogenes, there was no obvious difference between different cultivars. L. monocytogenes was most resistance to the antimicrobial activities of berry extracts with MIC and MIB for all extracts at ≥125 mg/m L. Generally, the antimicrobial activities of different blueberry cultivars against different foodborne pathogens were different as observed in the present study. The antibacterial effects of blueberry against Gram- negtive bacteria were better than that of Gram-positive bacteria. Blueberries of Shanghai had the better antimicrobial activities against V. parahaemolyticus, P. aeruginosa, S. aureus, and L. Monocytogenes than those from Hangzhou. Bluebelle had the worst inhibitory effects against four kinds of pathogens.