Antioxidant activity and sorption characteristics of ready-made mixture with lucuma powder

Adelina Bogoeva, Albena Durakova, Radka Vrancheva and Anton Slavov

Abstract: The current scientific research is focused on a new ready-made mixture for a cream-like product with a powdered subtropical fruit Lucuma. We performed an analysis on the antioxidant activity via four analytical methods differing in their mechanism and reaction conditions, namely DPPH, ABTS, FRAP and CUPRAC. The obtained data were expressed as mM TE/g powder (3.00 ± 0.01; 7.02 ± 0.24; 4.08 ± 0.23; 15.40 ± 0.61, respectively). Equilibrium moisture content for adsorption and desorption process was determined using the static gravimetric method of saturated salt solution at three different temperatures – 10°C, 25°C and 40°C and relative humidity from 0.11 to 0.90. According to the obtained data the sorption capacity decreases when the temperature increases under the conditions of constant water activity. In order to describe the obtained sorption isotherms we used four different mathematical models – modified Chung-Pfost, modified Oswin, modified Halsey and modified Henderson. The results showed that the modified Halsey model could be recommended for a satisfactory description of the mixture sorption isotherms. The monolayer moisture content was calculated using Brunauer-Emmett-Teller (BET) equation whose results for adsorption was within the range of 2.52% to 4.41% and for desorption – from 2.15% to 3.56%

Keywords: adsorption; antioxidant activity; cream-like; desorption; lucuma; mixture; ready-made; sorption isotherms

Date published: 2020-08-31