ITALIAN JOURNAL OF FOOD SCIENCE, cilt.21, sa.1, ss.65-72, 2009 (SCI-Expanded)
Several characteristics of Arbutus andrachne L. fruit harvested at four maturation stages (green, green-orange, orange-red and red) have been examined. Soluble solids, pH, acidity, organic acids, specific sugars, and several nutrient element concentrations (N, P, K, Ca, Mg, Fe, Zn, Mn, Cu) have been determined. The total phenolic content along with antioxidant activity, determined by FRAP and TEAC methods, were also measured. There were significant differences among most of the traits tested. The average soluble solids increased from 16.0 to 20.6% going from the green to the red stages, while the acidity decreased from 0.54 to 0.45%. All of the element concentrations were statistically different among the various stages, with N and Ca being the most variable. The total acidity was found to be the highest in the orange-red and red stages (0.52 and 0.50 g/100 g, respectively). The main organic acid was malic acid (0.32 g/100 g) followed by ascorbic and citric acids (0.09 and 0.03 g/100 g) respectively. The red (17.84 g/100 g) and orange-red (16.25 g/100 g) stages had the highest total sugar values. Fructose was the main sugar in the fruit with an overall average of 8.91 g/100 g. The total phenolic content was highest at the red stage (3,904 mg gallic acid (GA)/kg fresh weight (fw)), followed by the green stage (3,589 mg GA/kg fw). The antioxidant activities were highest at the red stage as determined by both the TEAC and FRAP methods (26.5 and 21.8 mu mol TE/g fw).