The Evaluation of the Physico-Chemical Qualities of Blueberry Fruits

Abstract

In last years, highbush blueberry (Vaccinium corymbosum L.) has gained great popularity, mainly due to its appreciated taste and multiple uses. The biochemical composition of blueberries has an important role in health and nutrition. Studies have shown that bioactive compounds can reduce the risk of many diseases. This study was conducted over a period of three years to assess the size of the fruit average weight per fruit, diameter, firmness, total titratable acidity, color, total soluble solids (°Brix), pH, but also the total content of bioactive compounds such as polyphenols, flavonoids, anthocyanins, tannins and carotenoids, along with vitamin C and total sugar. Three blueberry genotypes ('Azur', 'Delicia', and 'Northblue') and two advanced selections ('4/6', and '6/38') were studied. The plants were grown at the Research Institute for Pomiculture Pitesti - Maracineni, Romania, in open field studies in randomized block with three repetitions (5 plants/ genotype/ repetition). The researches showed the following: the average weight / plant recorded values between 2.07 g ('Northblue' cv.) and 2.64 g ('6/38'); the size of the fruit varied between 12.10 mm ('4/6') and 17.45 mm ('Azur' cv.); the firmness had values between 15.33 N ('Northblue' cv.) and 18.45 N ('Azur' cv.); total titratable acidity of highbush blueberry increased from 0.625% for '4/6' elite to 0.960% for 'Northblue' cv.); total soluble solids varied between 12.9 °Brix ('6/38') and 15.59 °Brix ('Delicia' cv.); colorimetry ranged from 27.19 (L*), 0.19 (a*), -2.66 (b*) ('Azur' cv.) to 34.23 (L*), 0.72 (a*), -3.13 (b*) ('Delicia' cv.). Total polyphenols recorded values between 284.4 mg gallic acid equivalent (GAE) g/ 100 g fresh weight (fw) ('Azur' cv.) and 481.6 mg GAE/100 g fresh weight ('Northblue' cv.); total flavonoids had values between 110.6 mg catechin equivalents/100 g) CE /100 g ('Delicia' cv.) and 160.8 mg CE/100 g ('6/38'); total anthocyanins recorded values between 10.35 mg cyanidin-3-O-glucoside equivalents (C 3-G)/100 fresh weight ('Azur' cv.) and 56.03 mg cy3GE/100 g ('6/38'); total tannins varied between 160.5 mg GAE/100 g ('6/38') and 335.2 mg GAE/100 g ('4/6'); total sugar varied between 21.14 g glucose/100 g ('Northblue' cv.) and 30.67 g glucose /100 g ('Azur' cv.), and vitamin C content had values between 2.27 mg/100 g ('Azur' cv.) and 5.85 mg/100g ('Delicia' cv. and '6/38'). These genotypes having highest physico-chemical qualities could be used in blueberry breeding programs in order to obtain new genotipes.