A Simple Method for Determining the Flaxseed or Fish Oil Content with <i>N</i>,<i>N</i>-dimethylformamide in Microcapsules Prepared by Spray Drying

Abstract

A simple method was developed for determination of the oil content in spray-dried microcapsules by dissolving the microcapsules in N,N-dimethylformamide (DMF). Powders containing flaxseed or fish oils were prepared by homogenization and subsequent spray drying to form coarse and fine emulsions. Sodium caseinate (SC) and maltodextrin (MD) were used as an emulsifier and wall material, respectively. The oil contents in the powders were quantified using a thin-layer chromatography-flame ionization detector after hexane extraction; the results agreed well with the initial oil contents on a dry basis in the feed emulsion, regardless of the oil-droplet size in the powders. The fatty acid compositions of the flaxseed and fish oils in the powders were obtained without an extraction process, using the proposed method. After dissolving the microcapsules in DMF, the peroxide value (POV) of the encapsulated oil was determined using the acetic acid- chloroform method. Although SC, MD, and DMF slightly increased the POV, the effect of the increase on the POV was not significant. The proposed method therefore enables easy and rapid estimation of the oil content, fatty acid composition, and POV of an encapsulated oil.