Sensory perception of different acidulants in flavoured sports drinks

Abstract

This study investigated the implications of substituting citric acid with other acidulants; malic acid, fumaric acid and tartaric acid and a combination thereof (Fruitaric® acid), in a flavoured sports drink. A trained sensory panel (n=10) compared the sourness intensity of the acidulants at both equal sour and equal weight concentrations in water and in a Grape and a Lemon&Lime flavoured sports drink. The sensory panel compared the temporal character of the acidulants at equal sour concentrations in water and both sports drink flavours. This included determining the rate, onset, duration and maximum intensity parameters of the perceived sourness. To determine if repeated exposure testing of sports drinks with the different acidulants added at equal sour concentrations would lead to hedonic adjustment, consumers (n=128) were repeatedly exposed to a Lemon&Lime flavoured sports drink over a period of 22 days. Citric acid, the acidulant currently used in the sports drinks, served as a reference in all the comparisons. Previously determined equal sour concentrations of tartaric and Fruitaric® acids as determined in water was found to be equally sour to citric acid when applied to water and a Lemon&Lime flavoured sports drink but less sour than citric acid when compared in the Grape flavoured sports drink. Malic and tartaric acids were found to be equal sour to citric acid in water and both sports drink flavours. The application of equal sour concentrations seemed to be flavour specific. Sourness of water and more complex solutions, such as flavoured sports drinks, seemed to be dependant on multiple factors including pH, titratable acidity, molecular weight, acidulant concentration and oBrix. The results from this study rejected anecdotal reports that acidulants differ in their temporal sensory profiles, although the lack of significant differences may be a function of the specific concentration level (0.2%) used. Repeated exposure testing of Lemon&Lime flavoured sports drinks with different acidulants resulted in hedonic adjustment. Consumer preferences post exposure could not have been predicted with a traditional consumer taste test at the start of the study. The findings of this study surely challenge the validity of sensory evaluation test strategies that rely on single exposure testing to predict long term consumer preferences.