Detectable Odor Thresholds of Selected Lipid Oxidation Compounds at Various Temperatures in a Gelatin Model System

Abstract

ABSTRACT. This study was undertaken to determine detection thresholds of selected volatile organics known to be produced during the oxidation of food lipids. Gelatin was chosen to simulate a complex thermally‐sensitive food system. Stock solutions of pentanal, hexanal, t‐2‐hexenal, heptanal, t‐2‐octenal, and t,t,‐2,4‐decadienal were prepared using distilled water. A gelatin (3%) dispersion was prepared with distilled water, cooled (22C) then organic stock solutions were added to it at parts per billion (ppb) concentrations. A 16‐member panel was acquainted with the use of the sniffing apparatus with suprathreshold concentrations of the organics used in the study. Samples were presented in ascending order of concentration; judges indicated detectable point of specified stimulus. Odor characters are reported for these organics at each temperature. The detectable odor thresholds (DOT) were positively correlated with viscosity, and negatively correlated with temperature. DOT values ranged from 22 to 170 ppb. DOT values increased in the order of pentanal < hexanal < heptanal < t,t‐2,4‐decadienal < t‐2‐hexenal < t‐2‐octenal.

Detectable Odor Thresholds of Selected Lipid Oxidation Compounds in a Meat Model System

“…DETECTION ODOR THRESHOLD DIFFERENCES were three orders of magnitude for pentanal, hexanal, t-2-hexenal, t-2-octenal, and two orders of magnitude for heptanal and t,t-2,4-decadienal in a beef system compared to the same compounds in a gelatin system (Vega and Brewer, 1994) (Table 1). Cooked beef DOT values ranged from 0.23 ppm for heptanal to 7.87 ppm for t-2hexenal.…”

“…Differences in odor detection thresholds of several lipid oxidation products (aldehydes) have been reported using different media (air, water, milk, vegetable oil, mineral oil, paraffin oil, and gelatin); odor thresholds differed widely among different media (Fazzalari, 1978;Lillard et al, 1962;Lillard and Powers, 1975;Salo, 1970;Vega and Brewer, 1994). These studies indicated the different degrees of variation the matrix may cause for odor thresholds.…”

Chemical and Stability Characteristics of Structured Lipids from Borage (Borago officinalis L.) and Evening Primrose (Oenothera biennis L.) Oils

“…In our study, the hexanal derived from n-6 fatty acids in modified oils increased from 0 to 7.3 to 189.1 to 316.4 ppm during a 96 h storage at 60°C. LA (n-6) may be expected to produce pentane, hexanal, malondialdehyde, octanal, and 2,4-decadienal upon oxidation (Vega and Brewer 1994). Shahidi and others (1987) found a direct relationship between hexanal content and sensory scores of cooked ground pork which contains a high amount of LA.…”

Oxidative stability of structured lipids produced from borage (Borago officinalis L.) and evening primrose (Oenothera biennis L.) oils with docosahexaenoic acid

“…Similarly, n-6 PUFA, especially LA, produce more of the 13-hydroperoxides as their primary product of oxidation and produce hexanal upon homolytic cleavage (37). LA, which is n-6, can be expected to produce pentane, hexanal, malondialdehyde, octanal, and 2,4-decadienal upon oxidation (38). Shahidi et al (39) found a direct relationship between hexanal content and sensory scores of cooked ground pork, which contains a high amount of LA.…”