Date of Graduation

8-2018

Document Type

Thesis

Degree Name

Master of Science in Food Science (MS)

Degree Level

Graduate

Department

Food Science

Advisor/Mentor

Han-Seok Seo

Committee Member

Philip Crandall

Second Committee Member

Andy Mauromoustakos

Keywords

Coffee, Consumer Testing, Sensory Science, Temperature

Abstract

Coffee continues to be one of the most widely consumed beverages worldwide. How an individual perceives a cup of coffee is impacted by a plethora of factors including origin, growing climate, roasting level, and consumption habits. This thesis utilized both trained descriptive panelists and untrained consumer panelists to analyze how serving/consumption temperature modulates sensory perception of brewed coffee in regards to appearance, aroma, flavor, taste, and mouthfeel. Three varieties of coffee (Colombia, Ethiopia, and Kenya) were brewed and served to panelists at four temperatures: 70, 55, 40, and 25 °C. In one study (Study 1, Chapter 3), results from descriptive analysis showed that product temperature had a larger effect in modulating sensory perception than did coffee variety. In another descriptive analysis study (Study 2, Chapter 3), trained panelists found that serving temperature had a more significant effect on perception than freshness, up to 90 minutes, of the brewed coffee sample of Ethiopian variety. Utilizing an untrained consumer panel and a Check-All-That-Apply (CATA) method to assess these same coffee samples, results showed that both serving temperature and coffee variety largely contributed to the variation in sensory perception. While these consumer panelists were more effective in differentiating between coffee varieties when assessing the samples at a lower (40 °C) temperature, liking of the sample was highest when served at hot temperatures (55 and 70 °C). This indicates that subtle attributes of brewed coffee may be easier to identify when served at lower temperatures. In a final study using CATA, additions of cream and sugar were added to the brewed coffee sample and served at four temperatures. Results showed that temperature is a significant modulator of sensory perception in enhanced coffee (i.e., brewed coffee with cream and/or sugar). The findings of this thesis show the importance of controlling temperature for the sensory evaluation of coffee products, since significant variations in both qualitative and quantitative sensory perception arise from changes in product temperature.

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