Master's thesis: A study of sensory assessors sensitivity - how objective is a trained sensory panel?

Transcription

1 Master's thesis: A study of sensory assessors sensitivity - how objective is a trained sensory panel? 3. MAY 2018 NORDIC WORKSHOP, REYKJAVIK Josefine Skaret Laboratory leader / projectleader, sensory analyses

2 Background Quality of food - focus in today's society Sensory analysis important - product development Important to be aware of factors that may affect Consideration for this - trained panels can be considered as an objective instrument (Skorbakk, 2006b).

3 What can affect sensory analyzes? Experience and food culture (may affect the recognition and identification of flavours)(hersleth et al., 2013). Knowledge of and how well a product is preferred (Y.-K. Kim, Jombart, Valentin & Kim, 2015). Experience with and exposure of basic tastes (Bitnes et al., 2007). Training (Hoehl, Schoenberger & Schwarz, 2013).

4 Research Questions Is it possible for sensory assessors to set aside all personal experiences and perceptions when they work as sensory assessors? Does the frequency of use affect the assessors objective assessment of the products? Will high usage frequency lead to a more accurate assessment?

5 Issue for the master thesis The main objective of the study is to investigate certain factors that might affect sensory sensitivity of trained assessors. Secondary objectives: 1. To study the relationship between frequency of use and sensory sensitivity for selected products. 2. To study the relationship between the results of basic tests and sensory sensitivity.

6 Materials and methods - The structure of the study

7 Methods Questionnaire - Frequency of use - 65 products Coffee Never 1-3 t/ year 4-6 t/ year 1 t/ month 2-3 t/ month 1-3 t/ week 4-6 t/ week 1 t/ day 2-3 t/ day 4 t/ day or more QDA, Quality descriptive analyses, ISO Sweet taste None Clear Triangle test, ISO difference test (more sensitive method)

8 Methods Basic Test and PROP Test (obtained from tests performed at Nofima in 2013).

9 Instrument - Sensory panel Instrument: Sensory panel consisting of 10 assessors at Nofima AS, Ås. Ideally, more assessors, more assessors in each group for frequency of use. Recruit new external assessors?

10 Overview of samples Beer Blue cheese Caviar Low-fat milk

11 Statistical analysis

12 Results - Sub-goal 1 The structure of the study

13 Sub-goal 1 Results Overview of assessors usage frequency for the four selected products Beer Frequency of use Number of assessors 1-3 t/ week t/ month high t/ year - Never low 4 Blue cheese 4-6 t/ week t/ week high t/ month - Never low 4 Caviar 1-3 t/ week - 1 t/ month high t/ year - Never low 6 Low-fat milk 1 t/ day - 1 t/ month high t/ year - Never low 5

14 Sub-goal 1. Results - Frequency of use Percent low frequency of use BEER high frequency of use

15 Sub-goal 1. Results - Frequency of use L O W BEER HIGH

16 Sub-goal 1. Results - Frequency of use Beer Yeast flavour BEER Acidic flavour This was studied for all four products and the result showed the same. low frequency of use

17 Sub-goal 1. Results - Frequency of use Triangle test low-fat milk and beer No difference between assessors with high and low frequency of use, either in the assessment of low fat milk or beer

18 Results - Sub-goal 2 The structure of the study

19 Sub-goal 2. Results: Basic tests Average Water Umami Bitter Acid Salty Sweet In total Percent

20 Sub-goal 2. Results: Basic tests Blue cheese Sweet taste Salty taste Umami taste

21 The benefit of this study Even with a small number of assessors, interesting results were found regarding the objectivity of the trained assessors. The results found in this study should, however, be confirmed in similar and preferably larger study. Useful information for sensory environments that work with trained panels both nationally and internationally. Weaknesses with the study Number of assessors. Relatively small differences between high and low frequency of use between the assessors.

22 Conclusion No correlation between frequency of use or performance in basic taste tests and sensitivity. Sub-goal 1: The assessments in Nofima's sensory panel are an objective instrument. There are no affect of frequency of use of food products. Sub-goal 2: Results from basic tests do not necessarily affect sensory sensitivity in other sensory analyzes. General training is important to maintain sensory sensitivity. Basic tests are only one of many quality control indicators for trained assessors.

23 Thank you for your attention!