Physicochemical stability of colloidal systems using the cape gooseberry, strawberry, and blackberry for spray drying

Abstract

Tropical fruits have organoleptic and nutritional characteristics that are desired by consumers. The cape gooseberry (CG), strawberry (S), and blackberry concentrate (BC) contain a large number of bioactive compounds. The aim of this research was to determine the influence that a composition of a suspension based on CG, S, and gum arabic (GA) had the stability of a colloidal system. The emulsion was homogenized. A central composite experimental design was used and the independent variables were: % of cape gooseberry solids (STC) (50%–62%), strawberry solids (STS) (18%–24%), and gum arabic solids (STGA) (0.4%–0.6%). The dependent variables were viscosity (μ), zeta potential (ζ), particle size (D10, D50, D90), total solids (STCS), spectral stability index (R), and antioxidant activity (ABTS and DPPH). The suspension was experimentally optimized with the following results: STC:50%, STS:18.9%, STGA:0.6%, μ:485.27 ± 8.46, |ζ|:20.03 ± 1.04, D10:14.41 ± 1.61, D50:165.20 ± 3.36, D90:428.52 ± 17.53, STCS:11.20 ± 0.18, R:0.22 ± 0.03, ABTS:1,307.41 ± 18.71, and DPPH:1632.56 ± 73.19. Experimental validation of the optimal suspension formulation conditions showed good results, which meant that a stable suspension was obtained with high antioxidant activity. Practical applications The following research establishes the optimal formulation of a suspension based on strawberry, blackberry, and cape gooseberry. This was carried out in order to guarantee a quality feed (high in antioxidants and physicochemical stable) for the spray-drying process. It is well-known that obtaining a good product in a powder form depends largely on the good quality of the feed suspension. The cape gooseberry, strawberry, and blackberry are fruits with a great variety of bioactive compounds, although they have a short shelf life when they are in a fresh stage. Thus, it is considered important to develop products that largely preserve the nutritional properties of these fruits and at the same time extend their shelf life.