Encapsulation of Allyl Isothiocyanate by Freeze- and Spray-Drying: Effects on Retention and Sensory Perception in Sodium-Reduced Soups

Allyl isothiocyanate (AITC) has been shown to enhance perceived saltiness in food products; however, it is also associated with a pungent and spicy flavour. The objective of this study was to assess the encapsulation of AITC with maltodextrin (MD) and gum Arabic (GA) using spray-drying (SD) and freeze-drying (FD) techniques, with and without the addition of a surfactant. Furthermore, the different encapsulated formulations were evaluated for their impact on sensory properties when added to soups. In total, twelve different treatments were investigated. The physicochemical characteristics (i.e., encapsulation efficiency, surface oil content, capsule morphology, and moisture content) and sensory properties (i.e., hedonic scales and rate-all-that-apply) of the encapsulated AITC particles were analyzed. Gas chromatography revealed low AITC retention in all FD formulations, while SD formulations with surfactants achieved up to 136.71 mg AITC/g powder. Sensory trials were conducted on eight formulations added to tomato soup (0.500 mg AITC/100 mL) (SD trial: <i>n</i> = 79, and FD trial: <i>n</i> = 93). FD resulted in relatively low AITC retention (with and without surfactants), while SD with surfactants led to higher AITC retention. None of the formulations significantly impacted the saltiness perception of the soups. FD soups significantly enhanced thickness, creaminess, and tomato flavour, increasing overall liking. This is the first study to evaluate the sensory properties and cross-modal interactions of encapsulated AITC. Further studies are needed to continue exploring the sensory properties, its release behaviour, overall stability, and shelf life of encapsulated AITC.