Chocolate Almond Milk Consumption Changes Salivary Proline-Rich Protein Expression, Which Alter Astringency and Bitterness

Ciera Crawford, Purdue University


In this work we analyze how humans experience sensations from polyphenols, focusing particularly on chocolate flavonoids. First, we investigated how people use terms to describe the “astringent” sensation of these compounds, determining that the words “dry, rough” may be a feasible alternative to the poorer understood term “astringent.” Next, we investigated how human salivary proteomes may influence the sensations of chocolate flavonoids, and whether those proteomes change after exposure to the compounds in chocolate milk for a week. In this larger six-week study design, subjects alternated each week between consuming a low polyphenol diet and consuming one of three different polyphenol-rich chocolate bovine milk and almond milk beverages. At the end of each week, a salivary sample, as well as sensory intensity ratings for dry/rough, bitter, sweet, sour character, overall flavor, and overall liking were collected for the three beverages. We found that the protein concentration of several salivary proline-rich proteins (PRP, proteins implicated in the astringent sensation) were up-regulated in response to chocolate almond milk exposure (p<0.05). Several other proteins of interest to taste, flavor, and immune response were also altered over the course of the chocolate almond milk intervention, but their relationship with polyphenols have not yet been discerned (p<0.05). Further, when analyzing sensory changes over the course of the chocolate almond milk exposure, we found few changes overall until controlling for the levels of several salivary PRPs. When these were entered into the model, significant effects emerged for changes in both bitterness and astringency (p<0.05). This work indicates that exposure to polyphenols may alter saliva in ways that can then also alter the sensory experience of those polyphenols.




Running, Purdue University.

Subject Area

Food Science

Off-Campus Purdue Users:
To access this dissertation, please log in to our
proxy server