Effects of the Emulsion Composition on the Physical Properties and Oxidative Stability of Sacha Inchi (Plukenetia volubilis L.) Oil Microcapsules Produced by Spray Drying

Abstract

Sacha Inchi (Plukenetia volubilis L.) oil (SIO) is one of the vegetable oils with the highest content of polyunsaturated fatty acids (about 50% α-linolenic acid, and 35% linoleic acid), thus being prone to oxidation. The aim of this study was to evaluate the effects of the emulsion composition on the physical properties and oxidative stability of SIO microencapsulated by spray drying using modified starch (Hi-Cap 100) and maltodextrin in a mass ratio of 75:25, as wall material. The processing yield (PY), microencapsulation efficiency (MEE), and some selected physical properties (moisture content, Aw, color, sorption isotherms, flowing and thermal stability) of the SIO microcapsules (SIO-M) were investigated as a function of the oil loading (10, 20, and 30%) and the concentration of wall material solids (20 and 30%). The obtained results indicated that both the PY and MEE were significantly reduced as the oil loading increased, varying from 50 to 35%, and between 96 and 82%, respectively. FTIR analyses revealed that SIO was effectively encapsulated into the wall material. SIO-M were spherical in shape, and showed high oxidation stability upon accelerated tests. According to the thermogravimetric analysis, SIO-M could resist the pasteurization and sterilization processes used in the food industry, without suffering thermal decomposition. The sorption isotherms of SIO-M fitted better with the Guggenheim-Anderson-de Boer model. These results indicate that SIO could be successfully microencapsulated by spray drying using Hi-Cap 100 and maltodextrin as wall materials, from emulsions with a concentration of 30% wall material, and 20 to 30% oil loading.