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Title: Novel approaches to reduce dietary sodium
Author: Rama, Ruben Rama
ISNI:       0000 0004 6350 9058
Awarding Body: University of Nottingham
Current Institution: University of Nottingham
Date of Award: 2016
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There has been a big input within the food industry to look at novel ways to achieve salt reduction in a food product without compromising the sensory profile and reducing the saltiness perception by consumers. The aim of this thesis was to understand if by optimising the sodium release from the food matrix, sodium reduction could be achieved without affecting the saltiness perceived by the consumers. In order to do that, three approaches were tri­alled: firstly, it was hypothesised that a reduction in the size of the salt crys­tal could accelerate dissolution in saliva and that by blending salt crystals of different sizes, sodium reduction could be achieved without compromising overall saltiness; secondly, it was hypothesised that the inclusion of plant- based polyphenols at subthreshold concentrations for astringency and bit­terness that precipitate salivary proteins could modify the rheological prop­erties of saliva and ultimately change saltiness perception; and finally it was hypothesised that sodium could be delivered in a hydrocolloid matrix and if this matrix is optimised for hydrateability, sodium may be more avail­able for perception. Results showed that a reduction of 25 % sodium can be achieved by using blends of salt crystals with different size without any loss of saltiness, as expressed by naive consumers. Subthreshold concentra­tions for astringency and bitterness for the four polyphenols used (tannic acid, gallic acid, rutin and EGCG) showed salivary protein precipitation, but had no impact on saltiness perception of solutions. Superthreshold concentrations for astringency and bitterness using the same polyphenols caused a decrease in saltiness perception of solutions. Out of the three different polymers (pullulan, chitosan and HPMC) studied to create orally dissolving films, HPMC showed the best film forming properties, and the fastest dissolution rate. In summary, optimisation of the food matrix and the salt crystal may offer a direct route to reducing sodium in the diet, and of the approaches evaluated the use of complex salt crystal size blends and the optimisation of sodium-biopolymer interaction are proposed as viable strategies for sodium reduction for the food industry.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available