Whey Protein Derived Mouthdrying Found to Relate Directly to Retention Post Consumption but Not to Induced Differences in Salivary Flow Rate

Abstract

Whey protein is fortified into beverages to provide functional benefits, however, these beverages are considered mouthdrying. To date whey protein derived mouthdrying has not been quantified using a 'physical measure' in parallel with rated perception. Saliva flow could also relate to whey protein derived mouthdrying, however this has not been previously tested as an intervention. Accordingly, volunteers (n = 40) tested mouthdrying in different whey beverages and the sensory profile was evaluated by a trained sensory panel (n = 10). Volunteers also rated mouthdrying combined with collection of saliva samples post beverage consumption to measure retention to the oral cavity. To modulate saliva flow rate, volunteers both chewed on parafilm (to increase saliva flow) and used cotton wool (to remove saliva) before tasting beverages and rating mouthdrying. Both the volunteers and sensory panel rated whey protein beverages (WPB) as significantly more mouthdrying than the control beverage (whey permeate). The significantly higher rating of mouthdrying from the volunteers coincided with significantly higher protein concentration in saliva samples post WPB consumption, supporting mucoadhesion as the mechanism. Modulating saliva flow did not lead to any difference in rated mouthdrying and future work would be beneficial to evaluate further the influence of natural variation in salivary flow rate.

Keywords: mouthdrying; mucoadhesion; saliva flow; whey permeate; whey protein.

Figure 1

Study Overview (2-AFC: two alternative forced choice).

Figure 2

Brief overview of modulating saliva flow and mouthdrying perception protocol.

Figure 3

Summary of protocol for saliva sample collection and mouthdrying perception rating post beverage consumption.

Figure 4

Volunteers’ attribute perception mean ratings (±standard error) of whey beverages (n = 40; anti-logged data). Sample significant differences denoted by differing small letters.

Figure 5

Volunteers’ liking (left axis; measured on a 9-point hedonic scale) and easiness to consume (drink or swallow) (right axis; measured on a 5-point category scale) mean ratings (±standard error) of whey beverages (n = 40). Sample significant differences denoted by differing small letters.

Figure 6

Volunteers’ perceived mouthdrying (±standard error) post beverage (WPeBS: whey permeate beverage sweetened; WPBS: whey protein beverage sweetened) consumption over time following saliva flow (SF) being modulated (increased: chewing on parafilm and decreased: by placing cotton wool rolls within the mouth). Sample significant differences are represented by differing small letters (between samples) and capital letters (within samples).

Figure 7

Protein concentration in saliva samples post beverage consumption (SSPBC) (left axis) and perceived mouthdrying (right axis; measured on gLMS (0–100)) (±standard error). WPeBS: whey permeate beverage sweetened and WPBS: whey protein beverage sweetened. Sample significant differences are represented by differing small letters (between samples) and capital letters (within samples).