Sensory Perception and Chemical Analysis of Oat Snack Bars Fortified with Encapsulated EPA and DHA Rich Oils

Abstract

Exposure to factors like oxygen, light and heat cause nutritional degradation and unpleasant flavour in fortified products containing omega-3 oils. Microencapsulation protects omega-3 oils from oxidation; mask flavours and controls their release. This thesis investigates the fortification of oat snack bars with microencapsulated omega-3 oils at a level which fulfils omega-3 health claims. Differences between omega-3 oils, encapsulation materials and formulation with non- and encapsulated oil were investigated based on fatty acid composition, profiles of volatiles and consumer preferences. Six fortified foods using non- and encapsulated fish and microalgae oil as omega-3 sources were prepared. Combination of either pea protein or Arabic gum with maltodextrin were used as wall material for microencapsulation by spray-drying. A sample with the same formula but without the omega-3 oils was prepared as a control. Fatty acids were analysed by gas chromatography with flame ionization and volatile profiles with solid-phase microextraction with gas chromatography-mass spectrometry. A consumer trial was conducted to study the impact of fortification and different treatments on the sensory attributes of the products. The results show that no significant fatty acid degradation took place during the encapsulation and food processing. The fatty acid composition also verifies that the food models met the omega-3 content requirements of the European Commission. Most acceptable sample in consumer trial was control followed by the sample fortified with nonencapsulated microalgae oil, however they were not significantly different. A same trend was observed when considering flavour results, where the sample fortified with nonencapsulated microalgae oil showed the most similar results to control. The overall comparison also highlights the advantage of using pea protein for fish oil encapsulation as observed in increased acceptability of the sample fortified with encapsulated fish oil. The findings of the volatile profile of the samples show that treatments containing fish oil encapsulated by pea protein and microalgae oil encapsulated with Arabic gum most closely resembled the control, with limited association with volatile compounds arising from lipid oxidation. All in all, the snack bar fortified with encapsulated fish oil using pea protein demonstrated both oxidative stability and high consumer acceptance, making it the most promising treatment in this study.