Page 412 - Biosystems Engineering

Extraction, Refining, and Stabilization of Edible Oils 389

Fatty Acid Analysis Loss of fatty acids due to heating was determined
from the fatty acid methyl esters of Lo/EPA/DHA. Prior to methyla-
tion, C19:0 acid was added as an internal standard to each sample. A
HP GC/DB-225 silica capillary column (30 m × 0.25 mm) used at 180
to 230°C (2°C/min), and values compared with initial and final fatty
acids remaining gave the fatty acid loss for various periods of heating
at 80°C.
Triplet oxygen lipid oxidation, a free-radical process, has been
extensively studied during the past 70 years. However, triplet oxygen
lipid oxidation does not fully explain the initiation step of lipid
oxidation. Singlet oxygen is involved in the initiation of triplet oxygen
lipid oxidation because singlet oxygen can react directly with double
bonds without forming free radicals.
Termination Antioxidants are classified into two groups—primary
and chain-breaking antioxidants and secondary antioxidants—
depending on their mechanisms of action. The former react with lipid
peroxy radicals to convert the antioxidants to stable products. These
groups include free-radical inhibitors. Secondary antioxidants such
as oxygen scavengers reduce the rate of chain initiation.

H H H H H H

AH + C C C A + + C C C
.
H

Antioxidant fat Original fat molecule

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