Masters Theses

Date of Award

5-1990

Degree Type

Thesis

Degree Name

Master of Science

Major

Food Science and Technology

Major Professor

Sharon L. Melton

Committee Members

Marjorie Penfield, Rabindra Biswal

Abstract

The flavor of 4 different cookies was investigated by sensory and chemical analyses. Cookies were made from 2 different formulas, a conventional chocolate chip cookie base (CON) and a cookie formula optimized for spread and texture during microwave baking (MW). The cookies from the CON and MW formula were both baked in a conventional oven (CON CON and MW CON, respectively), and the cookies from the MW formula were baked in the microwave oven (MW MW). Also, commercial color and flavoring additives (ADD) were added to the MW formula before baking in the microwave oven (MW MW ADD). Two paired-comparison tests using selected pairs of cookies were conducted. Panelists were blindfolded and asked if there were a flavor difference and to describe any detectable difference. Test 1 consisted of the following pairs of cookies: CON CON/MW MW, CON CON/MW CON and MW CON/MW MW and test 2, MW MW ADD/CON CON, MW MW ADD/MW MW and MW CON/MW MW. Each of the 4 cookies also was analyzed for acceptability (8-point scale were 8 = like extremely and 1 = dislike extremely) by a consumer panel of 92 people. Headspace volatile compounds from each of the 4 cookies (replicated twice) and the color-flavoring additive were trapped on Tenax GC precolumns and analyzed by gas chromatograph-mass spectroscopy (GC-MS).

Results of test 1 indicated flavor differences (P < .05) between members of the CON CON/MW CON and CON CON/MW MW cookie pairs. The difference in flavor in test 1 was attributed primarily to a difference in perceived sweetness with the CON CON cookie being sweeter. Results from test 2 showed flavor differences (P < .05) between members of the MW MW ADD/MW CON and the MW MW ADD/MW MW cookie pairs. The flavor difference in test 2 was due to a burnt sugar, overbaked, and burnt marshmallow flavor in the MW MW ADD cookies compared with bland, flour-like, flavorless MW MW or MW CON cookies. Consumers liked (P < .05) the CON CON cookies more than the MW CON, MW MW and the MW MW ADD cookies. They also liked (P < .05) the MW CON cookies better than the MW MW and MW MW ADD cookies. Twenty-four volatiles were isolated from the headspace of the cookies, 13 of which were identified. Seven volatiles (6 identified) were isolated from ADD and were also found in the MW MW ADD cookies. Two of the volatiles, diacetyl and furfural, in ADD were also isolated from the CON CON and MW CON cookies. In general, except for these 7 volatiles, cookies baked in a conventional oven had more volatiles and a higher concentration of those volatiles than cookies baked in a microwave oven. The majority of these volatiles were formed by nonenzymatic browning reactions and contributed to consumers liking the CON CON and MW CON cookies more than the MW MW and MW MW ADD cookies.

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