Effect of thermosonication on bioactive compounds and quality parameters of purui (Borojoa sorbilis) nectar

The purui (Borojoa sorbilis) is an Amazonian species with edible fruits widely consumed by the local population, but little studied and not yet economically exploited. Purui contains several biologically active compounds with potential health benefits. However, processing conditions can alter the quality attributes, including the content of bioactive compounds. In this study, the main objective was to evaluate the effect of thermosonication on physicochemical changes in purui nectars, quality parameters (pH, titratable acidity, soluble solids and cloud value), vitamin C, antioxidant activity , anthocyanins content, phenolic compounds , enzymes (PPO and POD) colour parameters (L *, a *, b * and ΔE *), organic acids and NMR. Thermosonication improved the bioavailability of bioactive compounds, increased the cloud value and maintained the physicochemical properties of the nectars. Enzyme activity was reduced with increasing time and temperature processing. From the NMR1H spectra it was observed that the chemical profiles of the nectars were similar as to signals and intensities and presented themselves rich in pectin. As minorities it was possible to observe signals of carbohydrates and organic acid. As all samples present similar chemical profiles, the sample F0 was selected as standard for the description of the chemistry of the nectars. The majority signals in H 5.40 (d, J = 3.8 Hz), H 4.20 (d, J = 8, 8 Hz), H 4.03 (t, J = 8.5 Hz), H 3.87 (m), H 3.83 (m), H 3.81 (sl), H 3.75 (t, J = 9.70 Hz), H 3.67 (sl), H 3.55 (dd, J = 10.0 and 3.8), H 3.46 (t, J = 9.2 Hz) are characteristic of pectin. The doublets at H 5.22 ppm (d, J = 3.9 Hz) and at H 4.63 ppm (d, J = 7.9 Hz) attached to carbons at C 95.2 ppm and at C 98.8 ppm are assigned to α- and β-glucose, respectively. The doublet at H 4.10 (J = 3.4 Hz) and the multiplet at H 3.99, linked to the respective carbons at C 78.5 ppm and C 72.2 ppm refer to fructose. The signal at H 4.01 linked to the carbon at C 66.7 ppm and H 2.78 (dd, 16.3:7.2) and H 2.89 (dd, 16.4 and 4.5) linked directly to the carbon at C 42.1 ppm attributed to malic acid. This study shows that thermosonication can be employed as a preservation technique for fruit nectar processing, where retention of bioactive compounds is desired. These characteristics make B. sorbilis nectar a good energy source for hypercaloric diets and supplements for physical activities that may contribute to its market potential.