From pasture to palate: Exploring the sensory qualities of milk

Have you ever considered how your senses perceive food – or even something as simple as a glass of milk? That’s what tasters were asked to explore at a recent experiment to determine whether cows fed different types of pasture produce milk that varies in taste and mouthfeel. 

The sensory evaluation is one stage of Grassfed 2.0, a collaborative research programme

between Te Whare Wānaka o Aoraki Lincoln University and Yili Oceania Dairy. The programme, led by Lincoln’s Professor Pablo Gregorini, aims to understand the impact of diverse pasture grazing methods on milk metabolomics and sustainability. One group of cows grazed a specific set of diverse forages, while a second group were offered the traditional perennial ryegrass/white clover forage. 

This research brought in the expertise of Lincoln Lecturer in Food & Sensory Science, Dr Shaoyang Wang, who supervised Bachelor of Science in Food Innovation student Brooke McNamara as she led the trials. The aim of the study was to assess if differences in cow feeding practices influence the sensory characteristics of milk—aroma, flavour, taste, mouthfeel and aftertaste—as perceived by trial panellists.

“Sensory science is becoming of much greater interest to food producers,” says Dr Wang. “Consumers, more than ever, are demanding products that offer improved nutritional health and uncompromised sensory quality.

“Whenever we talk about sensory evaluation, people think that’s simply tasting food and sharing their thoughts. But there is much, much more to sensory science. Aside from the methodologies we re-create from psychology and quantitative social sciences, we draw knowledge from food science, including ingredients, composition and processing, to explain the sensory profiles of foods.” 

The study investigated the sensory attributes of the fresh milk, such as sweet, salty, buttery, green, viscous and mouthcoating. Next, the trials examined whether these attributes varied when cows were fed different pastures and linked these findings to the metabolomics results.

To achieve this depth of understanding, the research team recruited expert panellists of varying ages and backgrounds to participate in the tastings. For panellists, the experience is both fun and educational, helping them appreciate the many senses at play when tasting food and beverages. 

During the trial, they scored each sensory attribute on a scale to confidently reflect the sensation they experienced. Dr Wang is quick to point out that with the use of cutting-edge evaluation methods and statistics, the panellists give accurate answers after only a little training. 

“By collating these results, researchers can develop a sensory profile of the product and estimate the size of the difference between treatments,” says Dr Wang. 

Dr Philip Wescombe, Head of Yili Innovation Centre Oceania, says Yili Oceania Dairy is keen to learn whether differences between the milks could be detected, which sensory attributes differed and the magnitude of those differences. The findings will ultimately be of great value to the New Zealand dairy industry.

To bring this research to life, many complementary aspects were brought together by combining industry, research and teaching.

“We combined our relationship with Yili Oceania Dairy with our specialised knowledge in sensory science, and by doing so, gave Brooke a real-life scenario and hands-on experience completing research for an industry collaborator. 

“This project is a great example of the value sensory science offers the food industry. Our research helps them identify which sensory attributes are altered by farming practices, whether consumers can detect these differences and how it may influence their purchase intentions,” says Dr Wang.