Investigating the Influence of Age and Saliva Flow on the Perception of Protein Fortified Foods and Beverages

To investigate whether whey protein beverages cause mouthdrying in older adults and if perception and acceptance are influenced by repeated consumption, age and individual differences in saliva flow.

To investigate whether protein fortification of cupcakes causes mouthdrying and if perception and acceptance are influenced by repeated consumption, age and individual differences in saliva flow in a home environment.

To investigate whether mucoadhesion is present within different food models, if sensitivity to mucoadhesion increases with age and to determine if a reduced salivary flow results in strengthened mucoadhesion.

• Solid Model (Behavioral): Cupcakes will be used, with the amount of protein varied to study the effect on perception of the products (using sensory methods rating drying and discrimination tests 'which is the stronger in drying'). Measuring mucoadhesion via protein content remaining in saliva samples following consumption of cupcakes.
• Liquid Model (Behavioral): To study the perception of whey protein beverages using repeated consumption sensory methods (e.g. rating mouthdrying over repeated sips of the drink).

Primary outcomes

• Mucoadhesion [Change in protein left in mouth over from baseline to after consumption (45s)]: Ex-vivo analysis using cupcakes (whey permeate and whey protein) (expectorated saliva collection to analyse protein for the extent of mucoadhesion)

Secondary outcomes

• Mouthdrying from cupcakes [Change in perceived mouthdruing from baseline over consumption (5 minutes)]: Perceived mouth drying from protein fortified lemon cupcake and whey permeate lemon cupcake using data from repeated consumption sensory methods (rating drying on line scales)
• Mouthdrying from whey protein beverages [Change in perceived mouthdruing from baseline over consumption (20 minutes)]: Perceived mouth drying from whey protein beverage using data from repeated consumption sensory methods (rating drying on line scales)
• Saliva Collection [Days 1 and 2]: Salivary flow rates from unstimulated and stimulated saliva samples
• Questionnaire [Day 1]: Dental status, mouth behaviour, attitudes and portion size data via a questionnaire

Sex: All, ages: 18 Years to any, accepts healthy volunteers

Inclusion Criteria:

* Age (18-30 years or over 65 years)
* Healthy

Exclusion Criteria:

* Cognitively impaired
* Allergies, intolerance and special dietary requirements (for example coeliac disease, lactose / gluten intolerance)
* Suffer from diabetes
* Oral surgery
* Stroke
* Smoker
* Cancer

• Bull SP, Hong Y, Khutoryanskiy VV, Parker JK, Faka M, Methven L. Whey protein mouth drying influenced by thermal denaturation. Food Qual Prefer. 2017 Mar;56(Pt B):233-240. doi: 10.1016/j.foodqual.2016.03.008. PMID 28260840
• Withers CA, Cook MT, Methven L, Gosney MA, Khutoryanskiy VV. Investigation of milk proteins binding to the oral mucosa. Food Funct. 2013 Nov;4(11):1668-74. doi: 10.1039/c3fo60291e. PMID 24092277
• Affoo RH, Foley N, Garrick R, Siqueira WL, Martin RE. Meta-Analysis of Salivary Flow Rates in Young and Older Adults. J Am Geriatr Soc. 2015 Oct;63(10):2142-51. doi: 10.1111/jgs.13652. Epub 2015 Oct 12. PMID 26456531
• Gosney M. Are we wasting our money on food supplements in elder care wards? J Adv Nurs. 2003 Aug;43(3):275-80. doi: 10.1046/j.1365-2648.2003.02710.x. PMID 12859786
• Kennedy O, Law C, Methven L, Mottram D, Gosney M. Investigating age-related changes in taste and affects on sensory perceptions of oral nutritional supplements. Age Ageing. 2010 Nov;39(6):733-8. doi: 10.1093/ageing/afq104. Epub 2010 Sep 22. PMID 20861088
• Withers CA, Lewis MJ, Gosney MA, Methven L. Potential sources of mouth drying in beverages fortified with dairy proteins: A comparison of casein- and whey-rich ingredients. J Dairy Sci. 2014 Mar;97(3):1233-47. doi: 10.3168/jds.2013-7273. Epub 2014 Jan 17. PMID 24440265

• Lisa Methven, Principal investigator, University of Reading