Lecture: sensory science
Sensory evaluation = is a scientific discipline used to evoke, measure, analyse and interpret
responses to those characteristics of foods and materials as they are perceived by the senses of sight,
smell, taste, touch and hearing. Some things to highlight in this definition:
- Evoke: eliciting and isolating certain responses by minimizing certain kinds of bias like brand
labels info or other people in environment etc. To avoid these kinds of bias, the research is
mostly conducted in sensory booths and samples are labelled with a random code. Also,
products are offered in different sequences between panellists. Always the same
temperature, serving size, volume is standardizes because it could influence perception.
- Measure: people give a numerical response about attributes or liking, with these numbers
you can conduct statistical analysis.
- Foods and materials: can be used in food, raw materials but also for non-food stuff such as
in toilet paper, medicines, soaps etc.
- You can try to isolate senses, but it is difficult, you have to keep in mind that the sensory
perception is a whole and integrated.
Sensory evaluation applies broad spectrum of methods and techniques that include physiology,
statistics, product sciences (food science or cosmetic chemistry) and physics among others.
The role of sensory evaluation:
- Consumers
o Provide insights into human behaviour and perception
o Set consumer acceptability limits for specific attributes (how spicy do we like sauce
or how stringent tea?). Of course, it also depends on location of consumers.
- Market
o Analyse competitor products and evaluate new concepts. How does our product
differ from competitor?
o Support marketing claims such as “most preferred” or “most creamy”
- Product
o Identify important sensory attributes driving acceptability across a product category.
o To determine products shelf-life and product variability through supply chain.
- Science
o Combining sensory data with instrumental measurements provides insights to
chemical and physical properties driving sensory attributes. They do this because
most panellists are trained and payed, but sometimes for instance the hardness of a
product is correlated with physical measurements, so sometimes it is cheaper and
faster to use lab tools than using a panel.
Two branches of sensory methods:
- Hedonic methods: how well are products liked or which one is preferred? So, refers to liking
or liking responses and they are collected on a scale and this can be done with only one
product. Another alternative is assessing which product is preferred over another, you then
usually use two products.
o Acceptance: it can help to (i) evaluate the overall performance of a product and (ii)
this info can be related to sensory properties.
, The scale below is the golden standard. The scale is used to assess the overall
acceptability but is can also be used to evaluate the overall flavour acceptability, or
just texture or just appearance. The scale needs samples size 75-100. Since you use
consumers the instructions should be very simple and very clear. However, the scale
is a little bit criticized because:
it has the central tendency bias, this means that people tend to use only the
central part of the scale.
the data is categorical, this limits the possibilities to do parametrical tests.
However, due to the sample size the data can be robust and analysed
through ANOVAS, so it doesn’t seem a big product.
sometimes people feel safe to answer the neutral option because they don’t
know what to answer.
Due to the critics another scale was developed namely the labelled magnitude scale,
it was quite similar, but is was allowed for participants to mark in the scale anywhere
in the line. So, there is more continuous data. Nevertheless, some researchers say
that in this type of scale participants tend to mark in the categories, so even though
the scale is meant to be continuous participants use it as a categorical scale. A good
point is that the scale has 11 points, and therefore people use more broad options
and extreme points are more used.
