Sensory Evaluation and Consumer Perceptions of Grassfed Dairy

In Ireland, grass feeding of cattle is common due to the temperate climate. Indoor grain feeding systems also known as Total Mixed Ration (TMR), are more common globally. This thesis investigated the sensory characteristics of dairy products from a 95% grass fed (GF) system, a partial mixed ration (PMR) and a TMR feeding system. The impact of the stage of lactation (SOL) on, and global consumer perceptions of GF dairy products were also explored. In chapter 2, a sensory panel was trained, and a lexicon was generated to evaluate dairy products from different diets and SOLs. This trained panel and consumers, evaluated WMP from 95% grass and TMR and across SOL. The results indicated that diet and SOL did not significantly affect trained panel ratings. Diet did not influence consumer ratings. Mid lactation WMP was liked most overall and for taste/flavour. In chapter 3, the trained panel and consumers evaluated butter samples. Diet did not influence trained panel ratings, but SOL did. Consumers liked GF butter more than TMR butter overall, and for appearance, and taste/flavour. Consumers rated GF butters as more intense than TMR for flavour, saltiness, creaminess, spreadability and colour intensity. Colour and spreadability were influenced by diet, with GF butter rated higher than TMR. Consumer liking was affected by SOL, with late lactation butters being liked most overall, and for taste/flavour. Distinct liking groups were identified with n=46 consumers preferring GF and n=19 consumers preferring TMR butter. Flavour intensity was a predictor of overall liking for both cohorts, highlighting the importance of flavour in consumer preferences. In Chapter 4 the use of instrumental measurements was introduced for texture, volatile organic compounds, and colour of Cheddar cheese. Toluene was the only volatile compound that was significantly affected by diet. The trained panel rated early lactation cheeses as stronger than mid and late for cowy/barny flavour and rated late cheeses as sweeter than early and mid lactation cheese. Mid lactation cheese was liked least overall. Diet affected consumer ratings, with GF and PMR cheese rated as more intense than TMR for flavour, aftertaste, and saltiness. Consumers reported that TMR cheese was lighter in colour compared to GF cheese, which was supported by instrumental analysis. Texture Profile Analysis indicated that TMR cheese was harder than GF cheese. For consumers, taste/flavour appeared to be the main driver of liking, reiterating findings from chapter 3. In Chapter 5, we aimed to understand consumer perceptions and sensory expectations of Cheddar cheese with nutrition (fat content) and GF claims, on the front of pack label. The study involved consumers from Ireland and the US. Results showed that the inclusion of a lighter fat (LF) claim on the packaging may negatively affect the sensory expectations of cheese. A GF claim did not influence sensory perceptions, but perceived healthiness and naturalness of the cheese were higher in both cohorts. The findings showed that consumers have a positive perception of GF Cheddar cheese, while the expectations of sensory qualities are not compromised. Chapter 6 investigated Chinese consumer perceptions of dairy. The expected aftertaste and flavour intensity of regular fat (RF) milk was rated higher than LF milk while participants expected to like LF Cheddar more than RF Cheddar. Fat claim influenced the perception of healthiness of milk and Cheddar, with the LF being perceived as healthier than RF. Including a GF claim on a label increased expected liking of cheese products. The GF claim increased perceptions of naturalness in all three products, as well as the perceived healthiness of Mozzarella and Cheddar cheese. Adding a GF claim to a label may positively affect the Chinese consumers perceptions of dairy products. Overall, the research presented makes a significant contribution to the sensory and consumer research in GF dairy products.