Evolution of sugars and acids during the maturation of two mutations of ‘Algerí’ loquat

Abstract

One of the most appreciated characteristics of loquat flavor is the pleasant balance between sweetness and acidity. In the specific case of 'Algerí', the main variety cultivated in the Spanish Mediterranean area, such sensory equilibrium is reached when fruit has a content of total soluble solids (TSS) between 10 and 12 °Brix and titratable acidity close to 1 g acid 100 mL-1 juice. Thus, a minimum content of TSS of 10 °Brix at harvest is required to ensure high quality fruit. Recently, two spontaneous mutations of this cultivar, 'Amadeo' and 'Xirlero', have attracted growers' interest due to its late maturity period and greater fruit size, respectively. The objective of this study was to evaluate whether the minimum TSS content established for the cultivar 'Algerí' (10 °Brix) is adequate to ensure the sensory quality of these two new cultivars. Besides, we studied the changes on individual sugars (glucose, fructose and sucrose) and acids (malic and quinic acid) content during the maturity process of the three cultivars. 'Amadeo' and 'Algerí' shared a similar pattern of sugars and acids changes during maturation, and 'Amadeo' fruits reached the sensory equilibrium with 10 °Brix and 0.8 g acid 100 mL-1 juice. However, 'Xirlero' was distinguished by its high content of malic acid and the equilibrium sweetness-acidity was not achieved until fruit showed a TSS content of 11.4 °Brix and 0.9 g acid 100 mL-1 juice. Therefore, the minimum TSS established for 'Algerí' is applicable to 'Amadeo' but not to 'Xirlero'.