Masters Theses

Date of Award

12-2001

Degree Type

Thesis

Degree Name

Master of Science

Major

Food Science and Technology

Major Professor

Marjorie P. Penfield

Committee Members

Clark Brekke, Sharon Melton

Abstract

Time-intensity profiles were utilized to study the perceived heat intensity of cheese biscuits formulated at 3 fat reduction levels (0. 25, and 30%) and 4 cayenne pepper levels (0.0, 0.1, 0.2, and 0.4%). The design used for the experiment was an incomplete block with a block on panelists and days. Trained panelists evaluated the heat intensity of 3 cheese biscuits per testing session at 5, 15, 30, 45, 60, 90, 120, 150, 180, 210, 240, 270, and 300 s using a 150-point unstructured line scale. On a scorecard, panelists also evaluated the hardness. Sensory data were collected 9 times per wk for 4 wk. Four testing sessions were held within each of 3 replications. Percentages of moisture and fat, hardness, and brittleness were also measured. Based on the parameters measured on the time-intensity curves, total heat intensity and maximum heat intensity increased as the cayenne pepper level increased from 0.0 to 0.4% in the cheese biscuits regardless of the fat level (p < 0.0001). Panelists found cheese biscuits formulated with 0.4% cayenne pepper to be more intense in heat than those made with 0.0, 0.1, and 0.2% pepper. The time it took in seconds to reach the maximum heat measurement for cheese biscuits made with 0.1, 0.2, and 0.4% cayenne pepper was less than the time it took for cheese biscuits made with no cayenne pepper (p < 0.0001). Full-fat cheese biscuits (0% reduction) contained less moisture than did the 25 and 30% reduced-fat cheese biscuits (p < 0.0001). As the fat reduction in the cheese biscuits increased from 0 to 30% reduced-fat, the percentage of fat decreased from 33.07 to 23.99% (p < 0.0001). Based on the textural analysis of hardness and brittleness, the 25 and 30% reduced-fat cheese biscuits were harder and more brittle than were the fullfat cheese biscuits. Cheese biscuits formulated with 0.2% cayenne pepper were not as hard as those containing 0.0, 0.1, and 0.4% cayenne pepper. Panelists perceived full-fat cheese biscuits to be less hard than those containing 25 and 30% reduced-fat. A strong, positive correlation, 0.92, (n=12) existed between the sensory evaluation and the instrumental analysis of hardness (p < 0.0001). In a low water activity food such as cheese biscuits, the perception of heat caused by capsaicin is dependent upon the concentration. Reducing the fat in cheese biscuits affected the textural parameters. Because of mastication differences among individuals, textural parameters such as hardness and brittleness can influence the rate at which the heat induced by capsaicin is perceived by trigeminal nerve endings.

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