Optimising the sensorial and nutritional value of plant based milk alternatives.

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Plant based milk alternative (PBMA) sales increased 33% between 2015 and 2017 (Wired, 2018) andaccording to a recent Mintel report almost a quarter (23%) of Brits are using these products, with manynow choosing oat-based alternatives that are considered the most sustainable.Sensory quality (aroma, taste & mouthfeel)Oat milk-alternatives (OMAs) contain a variety of non-volatile tastants (sugars, polyphenolics) and volatilearoma compounds (predominantly lipid and Maillard derived) that contribute to the product's aroma andtaste, and that are affected by thermal treatment. However, crucial to acceptability of OMAs is the extentof astringency and mouthdrying. Oats contain aventhramides (phenolic alkaloids) and avenacosides(saponins), which may contribute to astringency through binding to salivary proteins, thus reducinglubrication. In addition, protein fortification leads to an alternative form of mouthdrying. Previousresearch at the University of Reading has shown that fortification of beverages with whey protein causesa drying sensation, building over repeated consumption, which correlates with the adhesion of protein tothe oral cavity (mucoadhesion) and is influenced by salivary flow. We propose that plant proteins mayalso cause mucoadhesion and contribute to the mouth drying phenomena.Nutritional qualityBovine milk makes a substantial positive impact on the nutritional composition of western diets,particularly through the provision of high quality protein with a complete amino acid profile, calcium in abioavailable form, and iodine. UoS have expertise in protein quality and mineral bioavailability.Protein: In comparison to plant proteins, whey and casein are complete protein sources, which lead morereadily to muscle synthesis. Bovine milk contains 3.4% protein compared to just 0.3 to 1.0 % (w/v)typically in commercial OMAs. Oat protein consists predominantly of globulin; characterised by its highlysine content making it nutritionally superior to other cereal proteins. Calcium in bovine milk is morebioavailable than from other sources because the lactose and calcium phosphopeptides in the milkpromote its absorption (as does vitamin D), whereas absorption is hindered in plant sources bysubstances such as oxalates and phytates. These anti-nutritional compounds form insoluble complexesreducing absorption. Beta-glucans: Oats are high in b-glucans, soluble fibre leading to slower absorptionof carbohydrates with benefits such as improved blood sugar control, lowering cholesterol, improvedimmune function. These benefits need to be considered alongside the known positive effect that bovinemilk proteins have on blood pressure and on insulin stimulation in relation to type 2 diabetes.Polyphenolics and Sterols: The aventhramides in oats have anti-inflammatory, antiatherosclerosis andanticancer effects whilst the avenacosides have been noted for cholesterol lowering effects.