Characterization of physical properties and electronic sensory analyses of citrus oil-based nanoemulsions

Citrus oils and their emulsions have been widely used in food and beverage products due to their flavor, various beneficial health functions and relative high solubility for lipophilic bioactive components. However, the non digestibility and instability has limited the application of emulsions made from a single type of citrus oil. In this study, common triacylglycerol oils (i.e. corn oil and MCT oil) and citrus oils (i.e. bergamot oil and sweet orange oil) were used in combination with different mixing ratios (triacylglycerol oil:citrus oil = 1:0, 9:1, 5:1, 3:1, 1:1 and 0:1) to produce various nanoemulsions (10% oil phase), and their physical and electronic sensory properties were systematically characterized. The results demonstrated that the mixed oil nanoemulsions were much more stable than pure citrus oil emulsions. Electronic nose, electronic eye and electronic tongue were shown to be able to provide informative evaluation of the electronic sensory of the emulsions. Data-fitting of these electronic sensory devices significantly improved the effective discrimination and accuracy of sensory evaluation of the emulsions. These results provided basis for using triacylglycerol oils and citrus oils in combination to produce nanoemulsions with superior physical and electronic sensory properties. Moreover, the electronic sensory evaluation method utilized in this study provided a useful approach for evaluation of emulsion-based food and beverage products.