Optimization of spray drying process of buriti oil-loaded bilayer emulsions

Abstract

Buriti oil is extracted from the fruits of a palm tree (Mauritia flexuosa L.) native to the Amazon rainforest, having one of the highest levels of β-carotene found in nature. The emulsification of buriti oil contributes to protecting the bioavailability of its bioactive compounds during processing. Drying oil-loaded emulsions is a way to produce microcapsules that have higher storage stability and expand the application possibilities of buriti oil. The objective of this work was to evaluate the impact of spray drying conditions on the microencapsulation of buriti oil, using response surface methodology. Bilayer emulsions were stabilized by whey protein isolate and high-methoxyl pectin and spray dried. The effects of inlet air temperature (154–196 °C) and feed flow rate (1.2–6.8 mL/min) on different properties of the microcapsules were evaluated. Higher air temperatures caused a positive effect on process yield but affected the color and encapsulation efficiency, while the increase in feed flow rate had a positive effect on the color of microcapsules. The higher drying rates negatively affected the microcapsules, resulting in larger and agglomerated particles, with the presence of holes in their surface. Surface models were obtained to predict color parameters of the microcapsules, which can be used as tools to quality control during processing. In general, the low drying rate resulted in microcapsules with suitable characteristics to ensure oil protection. The optimized spray drying process allows the production of buriti oil microcapsules with potential for application as natural pigments in the food industry.