Lipid Hydrolysis in Unblanched Frozen Peas (Pisum sativum)

Abstract

SUMMARY Data on hydrolytic changes in the lipids of unblanched (enzymatically active) peas in the range –5 to –20°C are presented. The Q10 value for the formation of free fatty acids between these temperatures is about 2.5. The corresponding value for development of off‐flavor is about 3.0. Both values are considerably lower than those typical for deteriorative non‐enzymatic reactions in blanched vegetables. Gas chromatographic analysis of the free fatty acid fraction demonstrates further that there is an apparent preference for hydrolysis of polyunsaturated acids. This tendency is especially evident in the lower part of the temperature range studied. A corresponding increase of the proportion of saturated acids in the unhydrolyzed fat can be shown. No net change of any single acid in the combined lipid fractions is observed, except for linoleic and linolenic acids, which decrease somewhat after long storage at the higher temperatures. This indicates a substantial breakdown into smaller molecules.

Pea Lipoxidase, Distribution of Enzyme and Substrate in Green Peas

“…The results are in good agreement with those reported earlier (Bengtsson and Bosund, 1966). The values obtained for free fatty acids-98 mg per 250 g of peascorrespond to an average degree of hydrolysis of 7.2%.…”

“…About 40% of the fatty acids are bound in triglycerides and the rest in phospholipids. The composition of the fatty acid pool in green peas is shown in Table 1 (Bengtsson and Bosund, 1966). Thus, the unsaturated fatty acids, mainly linoleic acid, are abundant in the fatty material of peas.…”

Fatty acid composition of pea (<i>Pisum sativum</i> L., var. Citrina) during seed growth

“…Two-way ANOVA (Table IV) showed that during seed growth 18:2 increases and 18:0 and 18:3 decrease (Table II). These variations are similar to those obtained from the 7.0 mm to more than 9.5 mm growth period in Govorov variety, where oleic acid does not vary significantly with maturation and linoleic acid apparently increases, while palmitic and linolenic acids decrease (Bengtsson and Bosund, 1966).…”

“…It is known that the enzymes involved in fatty acid biosynthesis depend on agroclimatic factors (Harwood and Stumpf, 1970), and lipid content varies with climatic and environmental conditions (Worthington et al, 1972), For this reason, a significant decrease in temperature values during the four weeks before harvest must be taken into account (Figure 1). In adition, it was shown that the total fatty acid content of Manuela pea is partly determined by modifications in the cotyledon/testa ratio during seed growth (Murcia and Rincón, 1991), because the fatty acid composition of lipids from cotyledons and testas revealed great differences (Bengtsson and Bosund, 1966;Welch and Griffiths, 1984;Savage and Deo, 1989). Both temperature and cotyledon/ testa ratio factors can explain the differences in fatty acid composition during pea seed growth obtained here and those obtained by Bengtsoon and Bosund (1966), mainly in relation to oleic and linoleic acids.…”

Quality of home frozen vegetables

“…These authors found, as did Eheart & Gott (1965), that chlorophyll a was more easily degraded than chlorophyll 6 and that chlorophyll retention was closely linked with the pH of the cell sap. Bengtsson & Bosund (1969) blanched peas in tap water and in concentrated blanching water and obtained the same flavour for the two treatments, but a poorer coloured product when concentrated blanching water was used. They attributed this to the lower pH of the concentrated blanching water.…”