Masters Theses

Hung-Wei Lin

Date of Award

12-1993

Degree Type

Thesis

Degree Name

Master of Science

Major

Food Science and Technology

Major Professor

Sharon L. Melton

Committee Members

Marjorie Penfield, John Mount

Abstract

The objective of this study was to determine the effects of canola (CA), high oleic acid sunflower (HOSU), regular sunflower (SU), and cottonseed (CS) oils on the characteristics, flavor, and stability of potato chips. Oil degradation during frying was monitored also by peroxide value (PV), free fatty acid (FFA) levels, and fatty acid compositional changes. Chips were fried in the different oils and stored 0 wk (fresh) and under fluorescent light or in the dark at 23°C for 2 and 4 wk. Chips were analyzed for color, moisture and oil contents, PV of chip oil, concentrations of volatile components, flavor desirability, and acceptability.

The PV of each frying oil increased then decreased with increasing use. Free fatty acid content of frying oils increased with increasing use (4 hr frying) from 0.022 to 0.071% oleic acid. SU, CS, CA, and HOSU contained, respectively, 66.1, 57.4, 22.4, and 12.4% linoleic (C18:2) and 21.7, 16.4, 57.9, and 77.6% oleic (C18:l) acids. CS was most saturated containing 22.0% palmitic (C16:0). CA contained 9.7% linolenic acid (C18;3), and other oils, <1%. The percentages of C16:0, C18:0, and C18:l increased with increasing oil use, but the levels of C18:2 and C18:3 decreased. Chips contained 1.26% moisture and 44.6% oil and had a mean L value of 54.3, chroma of 27.2, and hue angle of 88.3(yellowcolor). Oil from fresh chips had a mean PV of 4.4. Storage in dark did increased PV of oil in SU fried chips,butnotinCA,HOSUorCSfriedchips. Storage in light increased PV of oil in chips fried in all oils, but of SU fried chips the most. Twenty-four compounds were identified in chip volatiles, which included, 7 pyrazines, 3 alkanals, 4 alkenals, 3 alkadienals, 2-pentylfuran, 2-furaldehyde, benzaldehyde, 1-octen-3-ol, and phenyl- acetaldehyde. Concentrations of many aldehydes increased during storage in light but not in the dark. SU fried chips were most acceptable (like moderately to very much) of all chips. CA fried chips were less acceptable than CS fried chips but HOSU fried chips were just as acceptable as the CS fried chips. Storage in light or dark decreased flavor desirability in SU chips, and storage in light decreased flavor desirability in CS and CA chips but not in HOSU chips. SU and CS chips had higher levels of t,t-2,4- decadienal and CA chips higher levels of t,t-2,4-heptadienal. Increases in levels of hexanal, 2-furaldehyde and 2-nonenal in SU and CA chips during storage may have decreased flavor desirability while increasing concentrations of t,t-2,4-decadienal resulted in a less desirable flavor in the CA chips.

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