Chemical and morphological characterization of Mammillaria uncinata (Cactaceae) fruits

Abstract

Cacti diversity is an important feature of Mexican landscapes. Mammillaria is the largest genus and most morphologically diverse from Cactaceae family. Mammillaria uncinata is especially abundant in highlands, and its fruits are commonly consumed among local people; however there are no studies about their chemical composition and nutraceutical properties. The aim of this work was to characterize, morphologically and chemically, the fruits of Mammillaria uncinata (Cactaceae), to study their postharvest characters, as well as, quantify some of their components with nutraceutical potential. Proximate analysis and postharvest characters were determined through AOAC methods; phytochemical profile analysis was carried out through qualitative tests, betalain pigments and total phenolic compounds were quantified spectrophotometrically; and antiradical capacity was determined by DPPH method. Mammillaria uncinata fruits presented the characteristic clavate shape and size; proximate composition was similar to other cactus fruits, except for ashes (1.23%), lipids (1.79%) and crude fiber (7.03%), which were higher than those reported for Opuntia fruits. Fruit juice presented high sugar content, low acidity and a sugar-acid ratio which gives it a harmonic sensorial quality. Diverse secondary metabolites were detected in different polarity extracts (alkaloids, sterols, flavonoids, saponins, coumarins and free amino acids). Nutraceutical components were quantified, such as betalain pigments (31.61 ± 0.80 mg/100g and 16.34 ± 2.63 mg/100g, for betacyanins and betaxanthins, respectively), total phenolics (0.921± 0.07 mg gallic acid/g) and flavonoids (0.490 ± 0.05 mg catechin/g). The results show the chemical composition of Mammillaria uncinata fruits as well as their potential as a source of bioactive compounds for food industry use besides fresh consumption.