Sensory analysis or tasting of dairy products as validation tool

Sensory evaluation is the primary function of man. From the earliest stages of our development, we accept or reject food according to the sensation it feels through our organs of the senses (sight, touch, smell, hearing, and taste). Through them we are able to perceive and value organoleptic properties, such as appearance, texture, smell and taste, and thus accept or reject a food on the basis of perceived sensations. In general, a food is analysed by the senses before it is put into the mouth. First, the food is examined according to the sense of sight; then the smell examines it, and if a favourable answer is accepted, it is put into the mouth, beginning with the next step of sensory analysis. Therefore, the food sector has an essential tool for controlling the sensory quality of the products it manufactures, determining the impact on the product of changes in processes or raw materials used, determining the useful life of the food, analysing the variability of the emotional response of consumers, and understanding the causes that cause it, among others.

UNE-EN ISO 5492:2010 defines sensory analysis as the “science associated with sensory evaluation of organoleptic attributes of a product”. It therefore measures, examines, and interprets the answers of the judges concerning the perception of food by the senses.

Depending on the intended purpose, sensory analysis of food, colloquially called “tasting”, can be carried out through different tests. In general, two types of tests can be defined:

  • Affective tests: aimed at consumers and assessing whether they prefer or accept a particular product. Affective tests include preferences tests, level of satisfaction or acceptance.
  • Analytical tests: Trained judges or tasters and experts are required to respond to the sensory quality of a product in a robust and reproducible manner, regardless of personal tastes or preferences. These, in turn, are divided into discriminatory or distinctive tests and descriptive tests.

The most common tests are affective tests. At LEARTIKER DAIRY CENTRE, we have been applying sensory analysis for years as a validation tool at the various stages of R&D&i projects, with the aim of validating the development of new dairy products, applying changes in processes, defining a formulation (selection of acidifying and ripening cultures, selection of types and doses of rennet, etc.) or as a tool for determining the useful life of a product.

One of the examples of external cooperation in the application of sensory analysis as a validation tool, LEARTIKER DAIRY CENTRE collaborate with NEIKER. NEIKER is a technology centre working for the Basque agricultural, livestock and forestry sectors. Its Department of Animal Nutrition is working on research to improve the food efficiency of livestock, to value local resources, to optimize food costs within the concept of circular economy, and to reduce emissions and environmental impact associated with livestock activity. In this way, it responds to the future challenges and strategies set out globally by administrations to reduce the impact of climate change.

Two of the latest projects developed by NEIKER in this field have been LIFE ECOFFEED (LIFE 19/ENV/ES/000186) and NEWFEED (Program for Research, Technological Development and Demonstration under grant agreement, 2013). In both projects, by-products created in the agri-food industry were used as a supplement to animal feed. Specifically, the experimental development of each project included coffee remains and grape scraps, respectively, in the feeding of dairy sheep. The physic-chemical and organoleptic quality of milk is directly conditioned and influenced by animal nutrition. The content and characteristics of each nutrient vary depending on the diet, among others. A clear example of this is the change in the profile of fatty acids. By supplying oil seeds rich in Omega 3 fatty acids through diet, there is evidence that the milk produced by these animals has a lipid profile rich in polyunsaturated fatty acids. So, it is to be hoped that these changes can also lead to changes in the sensory profile of milk.

In this regard, at the experimental stage of each project, at the LEARTIKER DAIRY CENTRE, we carried out sensory analyses to determine whether the introduction of these two products into sheep’s food caused a change in the organoleptic characteristics of milk produced. Since the consumption of liquid sheep’s milk is unusual, sensory analysis of modified products was chosen. In particular, it was decided to perform sensory analysis of “curds” made from sheep’s milk (a traditional Basque dairy product called “mamia”), as it is the dairy that best preserves the original characteristics of milk. Sixty people took part in the tastings, and they were taught two kinds of “curds”, one made from sheep’s milk fed on the usual diet, and the other to be examined, made from sheep’s milk fed on the supplement of coffee remains or grape scraps. In this way, hedonic tests were conducted to ascertain the degree of acceptance of both types of products by consumers, as well as triangular tests to determine whether the panel of consumers was able to distinguish between them. As a result, and brief conclusion of these two projects, it was concluded that the two types of products had a high degree of acceptance on the part of the tasters, and that there was no significant difference between the two valued curds; that is, the consumer panel did not see any difference between the control sample and the sample to be examined. Consequently, the introduction of these two by-products as a supplement to animal nutrition does not affect the sensory characteristics of sheep’s milk.

In short, sensory analysis is an essential tool for obtaining information on certain aspects of food quality that cannot be obtained from other analytical techniques, enabling full knowledge of food characteristics. So, if you want to test any of your dairy products, come to the LEARTIKER DAIRY CENTRE!