Surface oil was then determined gravimetrically, after heating the beaker at 105 C for 30 min to remove any residual solvent. Due to the porous nature of the biopolymer wall, it is assumed that minor amounts of interior oil may have been extracted during the process. In contrast, total oil (encapsulated and surface) was determined using the Ro¨se-Gottlieb method [14]. Briefly, 1 g of capsules was initially dispersed in 20 mL of water at 65 C under constant mechanical stirring for 15 min, followed by the addition of 2 mL of 28–30% (w/w) NH4OH for an additional 15 min. The mixture was then cooled to room temperature, and transferred to a separatory funnel. Ten milliliters of 95% ethanol was added and mixed gently. Gas was released before adding 25 mL each of diethyl ether and hexane. The flaxseed oil was extracted into the organic phase by inverting the separatory funnel for 30 s. After separation, the lower aqueous phase was removed. The extraction step was subsequently repeated an additional two times with a mixture of 5 mL of ethanol and 15 mL each of diethyl ether and hexane. The organic phases were combined and filtered through anhydrous Na2SO4 to removed residual water, and then evaporated under a steady stream of nitrogen to a constant weight. Total oil was then determined gravimetrically. Encapsulation efficiency (EE) was determined based on the ratio between surface to total oil [EE = (Total-Surface)/ Total) 9 100%] [16]. Three replicates were measured on duplicate batches of capsules.