Encapsulation of flaxseed oil in the tertiary conjugate of oxidized tannic acid-gelatin and flaxseed (Linum usitatissimum) mucilage.

Flaxseed oil, due to high amount of unsaturation, is susceptible to oxidation which could reduce oil nutritional value and cause off-flavor. In this study, flaxseed oil was encapsulated in new wall materials of tertiary conjugate of gelatin-flaxseed mucilage (FM)-oxidized tannic acid (OTA) which are available and food grade with nutritional value, controlled-release ability. The effect of different percentages of oil (15, 30 and 50% w/w concentration of total dry matter) on encapsulation efficiency (EE) and loading (EL) was investigated. Then, the microcapsules were evaluated by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), oxidative stability and release profile of flaxseed oil. The data showed that the treatment containing 50% (w/w) oil had the highest oil loading. The oil was surrounded by physical link into the complex and the final powder was fine with low porosity. Also, oxidative test exhibited an improved stability of the oil encapsulated in triple complex. During storage, the peroxide value of encapsulated oil increased from 3.0 to 5.3 meq O/kg while in free oil, higher oxidation rate was recorded. According to the results, this tertiary complex can be used as wall material in encapsulation and delivery system of functional and sensitive oils.