CONICET | Buscador de Institutos y Recursos Humanos

Coronary heart disease is one of the major public health problems. The daily intake of phytosterols helps to reduce seric cholesterol and, thus, to improve the coronary health. However, phytosterols are only found in vegetables in lesser quantities than required and their inclusion in processed foods is limited by their waxy nature, water insolubility and high melting point. To overcome these problems, phytosterols microencapsulation by spray drying in arabic gum/maltodextrin/sodium lauryl sulphate matrices was proposed. The process yield determines the spray drying economic feasibility. In particular, the aim of this work is to analyze the influence of formulation and operating parameters on the process yield for the microencapsulation of phytosterols in order to identify the optimal set. In this context, 54 experimental runs were performed in a Büchi B-290 lab-scale spray dryer following a Box-Behnken statistical design. Six factors were evaluated at 3 levels: drying temperature (110-135-160ºC), atomization rate (30- 45-60 mm), feed flow rate (5-10-15%), phytosterols feed content (2-5-8 g/100mL), solids feed content (15-25-35 g/100mL), arabic gum:maltodextrin mass ratio (1:19-9.5:1-19:1) for a fixed content of sodium lauryl sulphate (2 g/100mL). The experimental yields were between 26.5 and 86.7%. Taking into account the lab-scale of the spray dryer and the high stickiness of the phytosterols, the maximum value of 86.7% (obtained at 135ºC, 45mm, 5%, 2 g/100 mL, 25 g/100 mL and 1:19) is considered excellent. A second order model was derived (R2=0. 9097). Except for the drying temperature, all the factors were found to have a significant effect on the process yield, which increases as the phytosterols and total solids feed contents and the feed flow rate increase. According to this model, an optimum yield of 92.37% could be attained at 160ºC, 50.7 mm, 5%, 2 g/100mL, 15 g/100mL and 1:19. In summary, an appropriate selection of the formulation and operating factors can significantly enhance the process performance for a sticky product.