The variation in fatty acid composition between the "bound" and
"free" lipid in stored anchovy meal was determined using gas-liquid
chromatographic analysis. A model system of fresh anchovy oil on
powdered lactalbumin was also studied to determine the changes in
extractability and fatty acid composition which occur during oxidation.
All of the lipid-protein systems examined were first extracted
with hexane. The extracted protein was then extracted with choroform::
methanol (2:1 v/v), and finally digested in HCl and the hydrolysate
extracted with diethyl ether. The chloroform : methanol extract
and HCl digestion represented oil which was bound to the
protein.
Each lipid extract was interesterified with methanol to yield
the corresponding methyl esters, and these esters were then analyzed by gas-liquid chromatography. Both quantitative and qualitative
analysis was carried out using a diethylene glycol succinate
packed column in a gas chromatograph equipped with a hydrogen
flame detector.
The results of these investigations showed that the oil from
anchovy meal differed markedly in fatty acid composition from the
corresponding fresh oil. Although the types of fatty acids found were
identical to those in the fresh oil, there was considerable quantitative
variation. These differences were characterized by smaller
amounts of polyunsaturated fatty acids in the meal, and correspondingly
larger amounts of saturated and monoenoic fatty acids. The
greatest change occurred in the acid, 20:5.
Anchovy meal contained a "bound" lipid fraction which varied
in quantitative fatty acid composition with the readily extractable
lipid. The fractions associated with the protein had higher proportions
of 22:4, 22:5, and 22:6, with the acid digest fraction considerably
lower in the monoenoic fatty acids.
The oxidation of anchovy oil and anchovy oil methyl esters on
lactalbumin produced a reduction in hexane extractable lipid with a
corresponding increase in lipid which was soluble only in chloroform
: methanol or after HCl hydrolysis. These changes were more
drastic when untreated anchovy oil was used. The oxidation of
anchovy oil methyl esters on lactalbumin produced a reduction in the amounts of polyunsaturated fatty acids present in the hexane extract.
The other solvent extractions, however, yielded only higher
molecular weight compounds which could not be analyzed by GLC.
These observations led to the conclusion that the fatty acids formed
compounds which interacted before being bound to the protein. / Graduation date: 1966
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/26785 |
| Date | 08 October 1965 |
| Creators | Roehm, Jeffrey Noyes |
| Contributors | Sinnhuber, Russell O. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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