Pectin extraction from cv. Pink Lady (Malus pumila) apples

Abstract

The present study extracted pectin from Pink Lady apples (Malus pumila), which present at physiological maturity an average 50% of red-color coverage, to assess whether this variety is characterized by a high (HM) or low methoxyl value (LM). The raw materials were obtained from the Marengo farm, Los Niches, Curico province, in the south-central region of Chile. Acid hydrolysis was used and the material was then subjected to sensory analysis, evaluating the organoleptic characteristics of pectin. The pectin was extracted with citric acid, which was tested under three pH conditions (2.5, 3.0 and 3.5, the latter corresponding to the natural pH of apples) for 60 and 90 min and subjected to a constant temperature of 90 °C. The degree of esterification (DE) of the pectin was measured and then pectin was dehydrated to evaluate its sensory attributes, such as color, flavor, texture and acceptability (scale of 1-7). Treatment T1 (pH 3.5 for 90 min) presented the best extraction conditions (4.47 g or 7.25%), but the T0 treatment (pH 3.5 for 60 min) was the method that presented the best quality (68.27% DE) and classified the pectin as HM. The sensory evaluation results showed that the treatments gave variable attributes: the pectin samples from the T0 and T1 treatments presented the same degree of preference, 5.28 and 5.10, respectively, by 13 trained judges.