Ripening of Pithecellobium dulce (Roxb.) Benth. [Guamúchil] Fruit: Physicochemical, Chemical and Antioxidant Changes

The fruit of Guamúchil is an excellent source of bioactive compounds for human health although their natural occurrence could be affected by the ripening process. The aim was to evaluate some physicochemical, chemical and antioxidant changes in guamúchil fruit during six ripening stages (I to VI). A defined trend (p ≤ 0.003) was observed for color [°Hue, 109 (light green) to 20 (dark red)], anthocyanins (+571 %), soluble solids (+0.33 ^oBrix), ash (+16 %), sucrose (-91 %), proanthocyanidins (63 %), ascorbic acid (-52 %) and hydrolysable PC (-21 %). Carotenoids were not detected and chlorogenic acid was the most abundant phenolic compound. Maximal availability of these bioactives per ripening stage (p ≤ 0.03) was as follows: I (protein/ lipids/ sucrose/ proanthocyanidins/ hydrolysable phenolics), II (total sugars/ascorbic acid), III (total phenolics), IV (flavonoids/ chlorogenic acid) and VI (fructose/ glucose/ anthocyanins). Color change was explained by sucrose (β = 0.47) and anthocyanin (β = 0.20) contents (p < 0.001). Radical scavenging capacity (ORAC, DPPH and TEAC) strongly correlated with total PC (r = 0.49-0.65, p ≤ 0.001) but 89 % of ORAC's associated variance was explained by anthocyanin + sucrose + ascorbic acid (p ≤ 0.0001). Guamúchil fruit could be a more convenient source of specific bioactive compounds if harvested at different ripening stages.