Doctoral Dissertations

Myung Joo Han

Date of Award

5-1989

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Food Science and Technology

Major Professor

Sharon L. Melton

Committee Members

F. A. Draughon, John R. Mount, John T. Smith

Abstract

The objective of this study was to determine effects of cottonseed oil, soybean oil and palm olein on stability and flavor of potato chips. This study consisted of potato chips fried in 3 different oils: partially hydrogenated soybean (PHSO), cottonseed (OS) and palm olein (PO); then stored for 0, 2 or 4 weeks (3 storage times) in sealed glass jars under fluorescent light or in the dark (2 treatments) at 23°C. A single replication consisted of the 3 oils, 3 storage times and 2 treatments. Two replications were performed. The moisture and oil contents, peroxide value (PV), Hunter color values (L, "a" and "b"), sensory scores for flavor and acceptability, and volatile compounds of the potato chips were analyzed as a function of oil, storage and treatment. The fatty acid composition of the oils during use was also determined.

The PV of potato chips averaged across oil and treatment increased 57% during 2 weeks storage and 131% during 4 weeks storage, and the PV of chips stored in the light (10.8) was significantly higher than the PV of chips stored in the dark (6.5). The PV of chips fried in each of the three oils increased linearly with increasing storage time under light. The PV of chips fried in PHSO or PO and stored in the dark did not change significantly (p>0.05) during storage, but the PV of chips fried in CS increased linearly at a slower rate with increasing storage time than the same chips stored in the light. Potato chips fried in CS were lighter (Hunter color L=59.3) in color than chips fried in PHSO (57.5) or PO(57.1) and were less red (Hunter color "a"=4.2) than chips fried in PO (5.5). Potato chips fried in CS had significantly (p<0.05) more desirable flavor and were more acceptable to a sensory panel of 48 inexperienced members than chips fried in PHSO or PO. However, potato chips stored for four weeks in the light had significantly less desirable flavor and lower acceptability than fresh potato chips (0 week) or those stored for four weeks in the dark. Among the three oils, PO was the most saturated, PHSO contained the highest level of monounsaturated fatty acids and CS contained the highest level of diunsaturated fatty acids. Twenty compounds were identified in the volatiles of the potato chips and significant differences were found among the oils for five of the identified compounds and five volatiles classified only as pyrazines or aldehydes by mass spectra. In general, storage of chips for four weeks in light or dark decreased the levels of the volatile compounds isolated from tne chips (p<0.05). The most abundant volatiles found ir. the chips included 2- methyl pyrazine, 2,5-dimethyl pyrazine, 3-ethyl-2-methyl pyrazine, 2,3,5-trimethyl pyrazine, 2-ethyl-5,6-dimethyl pyrazine, phenylacetaldehyde, and t,t-2,4-decadienal. Correlation of the flavor desirability score with the levels of volatiles (n=18) indicated that higher levels of 3-ethyl-2-methyl pyrazine and t,t- 2,4-heptadienal contributed to less desirable flavor, and decanal and t,t-3,5-octadien-2-one (both found in chips fried in CS only) contributed to a more desirable chip flavor (p<0.05).

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