Taste-aroma interactions as a sugar reduction strategy in flavored milk

Restricted (Penn State Only)
Wang, Gloria
Graduate Program:
Food Science
Master of Science
Document Type:
Master Thesis
Date of Defense:
June 15, 2018
Committee Members:
  • Helene Hopfer, Thesis Advisor/Co-Advisor
  • Gregory Ray Ziegler, Committee Member
  • Robert F Roberts, Committee Member
  • milk
  • vanilla
  • flavored milk
  • dairy
  • taste-aroma interactions
  • cross-modal interactions
  • flavor enhancement
  • sweetness enhancement
  • sugar reduction
  • analytical
  • synthetic
  • dose-response
  • matching test
  • ABX test
  • sensory evaluation
  • congruency
  • real food application
  • isobole method
  • sugar
  • scaling method
  • non-scaling method
  • vanilla flavor
  • sweetness
  • milk flavor
  • thickness
  • liking
  • consumer acceptance
  • flavor perception
  • flavor
  • incongruent
Food manufacturers are actively seeking methods for reducing sugar in products without compromising flavor, functionality, and consumer acceptability. The use of alternative sweeteners is the most common strategy; however, consumers have become wary of these for various reasons. Cross-modal interactions, in particular taste-aroma interactions, have been proposed as another strategy for sugar reduction, as it has been shown that the addition of a congruent aroma to a sweetened matrix may enhance the matrix’s perceived sweetness and vice versa. Currently there are two underlying factors that make this phenomenon difficult to accept as a real occurrence: 1) most studies have been done in model solutions or model foods and not real foods, and 2) enhancement is either present or disappears depending on the sensory testing method and consequently the perceptual strategy used. Enhancements thus have been attributed to what is known as the “dumping effect” i.e., when panelists are given a limited ballot of attributes to rate, they will “dump” any similar perceptions into one category, causing what seems to be an enhancement. When panelists are given an extended ballot of salient product attributes, they are then able to separate these perceptions into individual components, causing enhancements to disappear. However, this method of rating is not representative of a typical eating situation for the average consumer. Instead of this analytical mindset that is employed when rating scales are used, consumers’ perception of food is more often holistic and hedonic. This integration of perceptions is known as the synthetic strategy and methods that encourage such behavior have been proposed as an alternative approach when testing for enhancements in taste-aroma interaction studies. The following chapters outline studies to answer the following questions: 1) Can enhancements of either aroma or taste be elucidated in a typical rating study of vanilla flavored milk when controlling for response biases? 2) Can these enhancements be assessed by testing mathematically for synergistic, antagonistic, or no interaction effects with the isobole method? 3) Can sweetness enhancement be found in vanilla flavored milk using a non-scaling testing approach, i.e., a modified ABX test? First, a dose-response study was conducted to induce panelists to use the analytical mindset when rating sucrose milk and vanilla flavored milk samples. Here, interaction effects of taste and aroma were found as measured by the isobole approach. Vanilla flavor and liking scores were best fit by a second-order model, while sweetness, milk flavor, and thickness were best modeled by a first-order model (both as a function of sucrose and vanilla extract concentration). The addition of vanilla had significant effects on perceived sweetness (p < 0.05), and similarly, sugar had a significant effect on vanilla flavor perception (p < 0.05). Based on the isobole method, skim milk samples containing both vanilla and sugar were found to act synergistically for perceived sweetness at the low to medium sugar concentrations (I < 1), demonstrating that taste aroma enhancement occurs even in a rating setting when using an extended ballot and encouraging an analytical mindset. To further test the feasibility of a non-scaling method for assessing sweetness enhancement, the ABX test was modified to create a set of matching experiments (ABCX and ABCDX). All matching experiments demonstrated greater interaction between vanilla flavor and sugar in skim milk samples than was found in the dose-response study: a greater proportion of panelists matched a vanilla-sucrose milk to a sucrose-milk reference higher in sugar than that of the aroma-spiked sample. All observed proportions of matched samples were significantly above the expected probabilities (p < 0.05). This enhancement was repeatedly observed for both a congruent vanilla flavor and incongruent beef flavor. Further, it appears that congruency is proportional to the degree of enhancement, as more panelists matched the congruent vanilla-sugar milk to a higher sugar reference than in the case of the beef-sugar milk. Overall, synergistic interactions between vanilla flavor and sugar were found with both scaling (i.e., analytical strategy) and non-scaling (i.e., synthetic strategy) testing methods in skim milk, with the effect being greater when using a non-scaling method. The effect was small but was still found in the analytical rating task even after controlling for the dumping effect, over a range of concentrations, and using a real food. Thus, taste-aroma interactions seem to be robust and should be further investigated in other real food applications.