Encapsulação do óleo de linhaça marrom (Linum usitatissim L) em acetato de celulose pelo método de emulsificação/evaporação do solvente utilizando diferentes emulsificantes

Abstract

Flaxseed is one of the most important oilseeds, used for foods and textile fiber production. It has an amount of oil of approximately 40% and is a rich source of polyunsaturated fatty acids, but as a result, it is very susceptible to oxidation, which can cause undesirable taste and odor to foods. An alternative to minimize such limitations is to promote the encapsulation of linseed oil. Therefore, the objective of the study was to encapsulate the brown linseed oil in cellulose acetate by the solvent emulsification/evaporation method using different emulsifiers. Brown linseed oil was characterized for acidity, peroxide index, thiobarbituric acid reactive substances and antioxidant activity. The determination of the stability of the O/W emulsion, using linseed oil and different emulsifiers (poly (vinyl alcohol) - PVA, casein, gelatin, pea protein and rice protein) was evaluated for 24 h at 20 ºC and 50 ºC. Linseed oil particles in cellulose acetate, using the selected emulsifiers PVA, casein and gelatin, and formed by the emulsion/evaporation method, were analyzed for encapsulation efficiency, antioxidant activity, morphology, thermal stability, color and substances reactive to thiobarbituric acid. The brown linseed oil used showed a composition compatible with the legislation and the literature. Emulsifiers influenced the characteristics of linseed oil particles encapsulated in cellulose acetate by the emulsion/evaporation method. The use of gelatin as an emulsifier provided the highest values of encapsulation efficiency, spherical particles with depressions, greater thermal stability by DSC; however, high values of TBARS and intense darkening of the particles were observed with accelerated storage. With casein, intermediate values of encapsulation efficiency, irregular particles with depressions, thermal stability by DSC, lower TBARS values and darkening of the particles were obtained. PVA, on the other hand, provided low encapsulation efficiency values, spherical particles with a smooth surface with aggregates, high TBARS values and clearer particles. Regardless of the emulsifier used, the particles showed low antioxidant activity.