Search

Large amounts of utilizable by-products are produced concomitant with silver carp processing. The lipids from fish brain contain considerable essential fatty acids which however have seldom been studied. In this study, the lipids extracted from the brain of silver carp exhibited good physicochemical properties. Forty volatile compounds were identified, of which hydrocarbons and aromatics predominated. The ratios of polar lipids and phospholipids to total lipids were 22.73 and 10.95 % respectively. Phosphatidylcholine (PC), phosphatidylethanolamine (PE) and phosphatidylserine (PS) accounted for 83.9 % of the phospholipids. Major fatty acids of neutral lipids, polar lipids, PC, PE and PS differed significantly. PE had the most polyunsaturated fatty acids (PUFA), while PC, PE and PS were rich in docosahexaenoic and eicosapentaenoic acids. Moreover, the ratios of fatty acids were considered to be reasonable due to high levels of n3 PUFA. The lipids from silver carp brain have been demonstrated to be healthy and nutritious. The results herein confirm that silver carp brain lipids are a commercially and industrially feasible prospect.

One hundred nine oil samples were separated chromatographically to obtain oil fractions with a decreased TAG content but with enhanced levels of the minor components that define oil genuineness and quality. The oils, which included virgin olive oils from different cultivars and regions of Europe and north Africa and refined olive, "lampante" olive, refined olive pomace, hazelnut, rapeseed, high-oleic sunflower, corn, grapeseed, soybean, and sunflower oils, were fractionated on a silica gel column with hexane/diethyl ether as the mobile phase eluent. The method was highly reproducible, and the fraction obtained contained about 15% unmodified TAG and 85% polar compounds, which included polymeric TAG, oxidized TAG, DAG, MAG, and FFA, in addition to other minor polar components of the oils. The presence of these compounds, in an enriched fraction, should provide information about the thermal, oxidative, and hydrolytic alterations of the oils, as well as many compounds of interest in determining oil genuineness. The results indicate that these fractions can provide more information than the original oils for NMR or other spectroscopic studies used in the determination of oil quality., This study was supported in part by the European Union, the Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (Project CAO98-008), and the Comisión Interministerial de Ciencia y Tecnología of Spain (Project 1FD97-0343).

The investigation and assessment of the oil content of oilseeds are important criteria, especially for the oil milling trade. Standard methods for the determination of the oil content of oilseeds are very time consuming, with extraction periods of 4 to 8 h. Three different oilseeds—rapeseed, sunflower, and soybean—are extracted by supercritical fluid extraction (SFE), accelerated solvent extraction, microwave-assisted extraction, solid fluid vortex extraction, and Soxtherm, and the results are compared with the result of the German Fat Science Society (DGF) standard method B-I 5 (87). Besides, the extracts are analyzed regarding the content of tocopherols as a parameter for mild extraction conditions and the content of diglycerides and free fatty acids as parameters for the content of more polar lipids. The results of the determination of the oil content under optimal conditions are comparable with the results of the DGF standard method B-I 5 (87). There are no significant differences between the different methods. The content of tocopherols is dependent upon the extraction method and the type of oilseed. The highest content is obtained by SFE. The content of diglycerides and free fatty acids varied according to the oilseed.

An examination of the suitability of an alkalimetric method for the determination of free fatty acid (FFA) contents in fats, oils, and lipid extracts was conducted by comparing AOCS method Ca 5a-40 with a method based on a Chromarod-latroscan thin-layer chromatography-flame-ionization detector (TLC-FID) system. The FFA contents determined by the alkalimetric method were consistently higher than the genuine FFA contents obtained by the latroscan TLC-FID method. Phospholipids were found to be the major components that contributed to the alkali-titratable, nongenuine FFA in the total FFA determined alkalimetrically. Contributions from other polar lipid components were smaller, but they dominated as the proportion of phospholipids fell. The other alkali-titratable polar components may include oxidized lipids and their by-products bound to protein fragments. The accurate determination of FFA contents by alkalimetric methods may only be applicable to those commercially refined fats and oils that contain negligible amounts of phospholipids. Corrections for the alkalimetrically determined FFA contents should be made for those fats and oils with relatively high phospholipid contents by correlating the nongenuine FFA contents and the phospholipid contents.

The components responsible for increased stability of raw peanut oil at a high relative humidity (RH) of 91% were examined in peanut oil and methyl linoleate systems. Of the constituents, the native gums, which were mostly phospholipids and glycolipids, showed increased antioxidant activity at 91% RH. The isolated components of the gums, namely phospholipids and glycolipids, were prooxidant individually or in combination. Tocopherols did not show increased antioxidant activity at 91% RH.

A few species ofFusarium have been evaluated for their potential to produce lipids. The isolates under investigation exhibited wide variation with respect to the mycelial weight, total lipid content and percentage composition of polar and nonpolar lipids in which triglycerides were the major components (81–90%). Palmitic, stearic, oleic and linoleic acids were the major fatty acids in both the fractions. The polar lipids contained higher levels of linoleic acid, whereas nonpolar lipids contained oleic acid as the predominant acid. Nonpolar lipids were more saturated than polar lipids.

The major lipid classes and their constituent fatty acids were analyzed in maturing seeds ofHibiscus esculentus andH. cannabinus. The seeds matured in 40 and 45 days, respectively. The active accumulation period was from the 13th to 25th and 15th to 30th day after flowering, respectively. While a continuous increase in the content of triacylglycerols (TAG) was noticed inH. esculentus, TAG was at its peak inH. cannabinus on the 20th day after flowering. The contents of polar lipids were high in the immature seeds but decreased during maturation. The major fatty acids in both species were palmitic, oleic and linoleic. Cyclopropane fatty acids were present only in TAG of both species throughout maturation period. Cyclopropene and epoxy acids appeared in TAG in traces at the final stages of seed maturation. Oleic and linoleic acids were preferentially esterified at the secondary positions of TAG. The contents of palmitic and stearic acids at the secondary positions were sharply reduced as TAG accumulated.

Polar lipids having considerable antioxidant effect on linoleic acid have been isolated from nitrite-treated, laboratory-cooked ground pork and beef during and after four weeks’ storage at 4 C. The antioxidant activity of these polar lipids is 1.5–3 times greater than that of untreated meats. Antioxidatively active polar lipids have also been found in commercially processed, nitrite-containing meats, including pepperoni, ham, frankfurters and bacon. The antioxidant activity of active polar lipids was stable on storage and partially survived treatment with acids and bases and conversion to methyl esters. Separation of the active polar lipids or the active methyl esters by classes gave no fraction in which the antioxidant activity was highly concentrated; however, it seemed to be more highly associated with the polyunsaturates fraction of the methyl esters. Indications are that more than one antioxidant factor is involved and that at least one is associated with the acyl portion of the polar lipids.

Fresh cassava roots (Manihot esculenta Crantz, c.v. Algodona) were processed for lipid analysis within five hr after harvest. The total lipid content was 0.25% fresh weight, and the lipid mixture obtained was complex. Polar lipids plus sterols and steryl esters made up the major part of the extracted lipids (77.9 mol%). Seven phospholipids were identified. Those in higher amount were: phosphatidylcholine, 265.4 nmol/g fresh weight; phosphatidylethanolamine, 151.8 nmol/g fresh weight, and phosphatidylinositol, 143.1 nmol/g fresh weight. Among the six glycolipids identified, digalactosyldiacylglycerol in a content of 333.2 nmol/g fresh weight and monogalactosyldiacylglycerol in a content of 217.1 nmol/g fresh weight were the most abundant. Free sterols were at 304.3 nmol/g fresh weight and triacylglycerol was measured at 444.4 nmol/g fresh weight. Results are discussed in view of recent knowledge of the kind of lipid classes expected in plant material. This work is intended to be the starting point of further research on cassava lipids upon subjecting the roots to conditions leading to its preservation.

Fat systems for cake, Danish pastries and bread are described in terms of physical and chemical characteristics as well as performance. Results indicate that additives, such as surfactants and dough conditioners in well formulated fat systems, can increase tolerance, improve uniformity and extend storage life of baked products. The polar and nonpolar lipids naturally present in flour are shown to affect finished bread quality, with the polar lipids showing an improving effect. The apparently divergent trends in the development and use of specialized shortenings for specific baked products vs. the development and use of multipurpose bulk systems for a variety of baked products are reviewed.

The majority of palms, represented byElaeis guineensis, contained mainly neutral lipids (triglycerides) in their seed fats with lauric and myristic acids as the major acids. In certain others, symbolized by theRaphia palms, polar lipids dominated, with the unsaturated acids, oleic and linoleic acids constituting the major fatty acids. Contrary to established belief, lauric and myristic acids were not the principal fatty acids in all palms.

The lipid composition of commercially canned single-strength orange juice ranged from 84–101 mg/100 ml juice (overall mean 95 ± 6). Phospholipid phosphorus, expressed as mg/100 ml juice, showed a range of from 1.56–1.95, while phospholipid phosphorus/lipid values (as µg-P/mg lipid) were within a very narrow range, 18.9 ± 1.1. The percentage distribution of lipid classes in these juices was 24–35% neutral lipids, 18–23% resin acids and glycolipids, and 43–53% phospholipids and other polar lipids. Five fatty acids, i.e. C16, C16:1, C18:1, C18:2, and C18:3, accounted for over 93% of all fatty acids. The relative percentages of C18:2 and C18:3 differed between seasonal juices. The lipid composition does not warrant inclusion in nutritional labeling; however, lipid levels may be useful in detecting adulteration.