Physicochemical characterization, phenolic compounds and antioxidant capacity of uvilla (Pourouma cecropiifolia)

The uvilla (Pourouma cecropiifolia) is a fruit found throughout the Peruvian Amazon region. It resembles a table grape, but is larger in size, has a dark purple skin, and has a pleasant flavor. The harvest season runs from April to July, and it is consumed by the population living near the production areas. To enhance the value of the fruit, as well as promote and expand its consumption, we decided to generate initial information related to its bioactive potential, since to date there is very limited information on the subject. Thus, the main objective was to characterize the biometric and physicochemical properties of ripe uvillas, as well as the total phenolic compounds (TPC), total anthocyanin (TA), and antioxidant activity (AAOX) of freeze-dried uvilla in its components: pulp, pulp + skin, and skin. Therefore, the fruit was harvested under optimal conditions at three sampling points in Loreto (Iquitos, Peru). The fresh ripe fruits were measured for morphometric parameters and physicochemical properties, such as pH, soluble solids, titratable acidity, ripeness index, and surface color. The pulp, pulp + peel, and freeze-dried peel components were analyzed for TPC and TA content, as well as AAOX by ABTS and FRAP. The fruits weighed 11.71-12.47 g, and according to the CIELAB scale, they had a dark blue-purple color, pH values between 4.74 and 4.86, soluble solids from 11.00 to 14.48 °Brix, suggesting a balance between sweetness and acidity, and a ripeness index between 9.4-9.7. The pulp accounted for the majority of the weight (52-56%), followed by the seed (22-29%) and the skin (17-20%). The CTF content in the peel reached 158.45 mg gallic acid equivalent (GAE)/g, exceeding that of the pulp (max. 18.6 mg GAE/g). This same trend was observed in the TA content, where the peel had concentrations of up to 27.9 mg of cyanidin-3-glucoside/g. AAOX, ABTS, and FRAP were mainly found in the peel, with a maximum value of 2013.0 µmol Trolox equivalent/g. The high concentration of bioactive phenolic compounds in the peel reveals the underestimated potential of this fraction, which is often discarded during consumption. The results demonstrate the functional potential of the gooseberry and the importance of valuing all its parts. Meanwhile, studies to identify and quantify the phenolic compounds in the gooseberry are ongoing.