The study – published in Flavour – aimed to provide an initial evaluation of whether double (duplex) emulsion technology presents an opportunity for industry to reduce salt in emulsion-based liquid or semi-liquid foods while keeping the fat content constant.
Led by Dr Bettina Wolf of the University of Nottingham, UK, the research team revealed that the use of duplex emulsion technology – water-oil-water (WOW) emulsions in which the salt is only contained in one of the aqueous phases – resulted in a higher perception of saltiness in both simple emulsions and formulated products.
The team backed the double emulsion technology to further aid salt reduction efforts in the food industry, arguing that further lowering of salt may be possible in processed foods that utilize emulsion systems despite the fact that use of such duplex emulsions can result in increased viscosity.
“The results showed that salt reduction may be possible despite the added technology increasing the overall measured viscosity of the product,” said Wolf and her team – who noted that such changes in viscosity behavior which impact mouthfeel could be positively exploited in addition to the contribution towards salt reduction.
“In view to applying this technology to real processed foods, it needs to be tested for the product in question, but given the interesting novel data presented it should be considered as part of a salt reduction tool box,” they added.
Emulsions and a more complex emulsion-based ambient vegetable soup were tested using paired comparison tests to identify the samples perceived as saltier in each pair of single and duplex emulsions.
“Sensory assessment of saltiness of emulsion pairs indicated duplex technology enhanced saltiness perception compared to a single emulsion product at the same salt content in both simple emulsions and a formulated food product although assessors noted the increased viscosity of the duplex systems,” the researchers explained.
“The concept of enhancing saltiness perception in emulsions and a liquid food formulated with the emulsions through increasing salt concentration in the continuous phase whilst retaining the fat content of the product was evaluated,” they added.
The single and duplex emulsions and emulsion based products had comparable mean oil droplet diameters, however, viscosity of the duplex emulsion systems was considerably higher.
“The formulated food product also contained pea starch particles which may have aided product mixing with saliva and thus accelerating tastant transport to the taste buds,” they explained.
Wolf added that lowering the salt content in the duplex systems (to levels of aqueous phase salt concentration similar to the level in the single systems) resulted in duplex systems being perceived as less salty than the single system.
Volume 1, Number 13, doi:10.1186/2044-7248-1-13
“Enhancing saltiness in emulsion based foods”
Authors: Mita Lad, Louise Hewson, Bettina Wolf