Potential sources of mouth drying in beverages fortified with dairy proteins: A comparison of casein- and whey-rich ingredients

Abstract

Oral nutritional supplement drinks (ONS) are beverages high in dairy proteins that are prescribed to individuals at risk of malnutrition. Consumption of ONS is poor in elderly care facilities, with patients commenting that the sensory attributes of these drinks reduce their enjoyment and willingness to consume. Mouth drying is an attribute of ONS found to build with repeated consumption, which may further limit liking of these products. This study investigated the sources of drying sensations by sequential profiling, with a trained sensory panel rating a range of model milk systems and ONS over repeated sips and during after-effects. Sequential profiling found that fortification of milk with both caseinate and whey protein concentrate significantly increased the perception of mouth drying over repeated consumption, increasing by between 35 and 85% over consumption of 40mL. Enrichment of ONS with either whey protein concentrate or milk protein concentrate to a total protein content of 8.7% (wt/wt) resulted in whey and casein levels of 4.3:4.4% and 1.7:7.0% respectively. The product higher in whey protein was substantially more mouth drying, implying that whey proteins may be the most important contributor to mouth drying in ONS. However, efforts to mask mouth drying of protein-fortified milk by increasing sweetness or fat level were unsuccessful at the levels tested. Increasing the viscosity of protein-fortified milk led to a small but significant reduction in mouth drying. However, this approach was not successful when tested within complete ONS. Further analysis is required into the mechanism of protein-derived mouth drying to mask negative sensations and improve the enjoyment and consumption of protein-rich ONS.

Whey protein mouth drying influenced by thermal denaturation

“…The aftertaste intensities (T30 and T60) are high for chalky, mouthcoating and drying, demonstrating that these sensations are just as prominent once the sample has been swallowed. This has been previously reported in whey-rich ingredients by Withers, Lewis, Gosney, and Methven (2014) , and could be due to mucoadhesion of the whey proteins.…”

An Investigation of the Influence of Age and Saliva Flow on the Oral Retention of Whey Protein and Its Potential Effect on the Perception and Acceptance of Whey Protein Beverages

“…The pH of WPB Low pH can cause precipitation of the protein, however, there is evidence of mouthdrying from WPB at both low and neutral pH [18,[22][23][24][25][26] Saliva and protein interactions Perception of mouthdrying has links to saliva and protein interactions [22,23,25,27,28] Reduced lubrication of saliva Increased friction within the oral cavity from reduced lubrication [29] Adhesion and binding properties Whey proteins binding to oral epithelial cells, proteins remaining on surfaces, mucoadhesive properties and increased oral retention [30][31][32][33] Heating time Mouthdrying is considered to increase with product heating time, potentially due to protein denaturation [18,34] Our research group consider the adhesion of whey protein to be a highly probable cause of whey protein derived mouthdrying. Mucoadhesion, a concept that has been utilised in drug delivery systems [35][36][37][38] and more recently considered in a food context [39].…”

Identifying Key Attributes for Protein Beverages

“…Previous studies with protein beverages have addressed specific flavors associated with whey and soy proteins (Carunchia and others ; Russell and others ; Childs and others ; Wright and others ). Other studies have addressed astringency and consumer perception of astringency in whey protein beverages (Childs and Drake ; Withers and others ). The impact of different processing parameters on whey protein flavor and comparisons with milk serum proteins have also been evaluated for impact on consumer acceptance of protein beverages (Wright and others ; Evans and others ).…”