Abstract

Cultivated potato purple flesh (Solarum tuberosum) has high nutritional value, containing starch and anthocyanins (AT). Anthocyanins are responsible for the purple color and antioxidant activity. However, the stability of AT has been shown to be affected by environmental, food and gastrointestinal conditions, limiting their application as food ingredients. Therefore, the stabilization of AT could be improved by microencapsulation technology as spray-drying. The aim of this work was to study the microencapsulation of concentrated potato purple flesh by spray-drying using a mixture of maltodextrin (MD) and starch (S) as encapsulating agent on the AT encapsulation efficiency and bioaccessibility in in-vitro digestion model. Concentrated potato purple flesh (CPP) was obtained by separation of starch and then concentration of AT solution until 65Brix. Delphinidin-3-glucoside and petunidin-3-glucoside were the main AT identified by HPLC. The microencapsulation of CPP with MD-S by spray drying was performed applying Taguchi L9 experimental design. The air inlet temperature (100–180 °C), MD-S content (8–23%) and starch content (0–25% respect to MD) were evaluated as independent variables. AT encapsulation efficiency (EE) and yield (Y) were the response variables. A linear regression analysis was applied to each response variable, and then Response Surface Methodology was used to determine the optimal conditions maximizing responses variables using desirability function. The AT EE and Y ranged from 60 to 93% and 24 to 81%, respectively. The optimal conditions were 100 C, 21 % MD-S and 25% starch. Microparticles obtained under optimal condition were characterized according to EE (94%), moisture (3.5%), AT (1.6 mg equivalent to cy-3-glu/g) and morphologically by scanning electron microscopy (SEM). The bioaccessibility (BA) of AT was evaluated for CPP-MD-S; CPP-MD; CPP non-encapsulated (control) in in-vitro digestion model. The BA of AT was significantly higher for encapsulated AT than nonencapsulated AT.