This study aims to investigate whether protein fortification of foods and beverages causes mouthdrying and mucoadhesion and whether this is influenced by age and saliva flow.

1. To investigate, by using protein fortified foods and beverages, whether mucoadhesion to the oral cavity is greater for older adults compared to younger adults and determine whether it is related to salivary flow rate.
2. To determine whether protein fortification of foods and beverages causes mouthdrying and whether perception and acceptance are influenced by age and individual differences in saliva flow.

These aims will be investigated using two different models: a liquid model using whey protein and a solid model using protein fortified biscuits and cakes.

Inclusion Criteria:

• Age 18-30 years or over 65 years
• Self reported as healthy (no specific disease states)

Exclusion Criteria:

• Cognitively impaired
• Allergies or intolerances that include coeliac disease, lactose or gluten intolerance
• Diabetic
• Had oral surgery
• Had stroke
• Smoker

No personal identification data will be shared. The study is not under an obligation to share data, however it is possible that some of the individual (unliked / non identifiable) data will be useful in a meta analysis and, hence sharing individual participant data (IPD) will be considered.

All samples provided to the participant are labelled with 3 digit random codes