Improvement of Oil Quality in Soybean [<Emphasis Type="Italic">Glycine max </Emphasis>(L.) Merrill] by Mutation Breeding

Low oxidative stability, off-flavor and rancidity are the major drawbacks of soybean oil. Modification of the fatty acid composition of soybean [Glycine max (L.) Merrill] oil can improve its quality and value for processors and acceptability among consumers. Mutation breeding of soybean was therefore initiated with the objective of identifying stable soybean mutants with altered fatty acid composition for improved oxidative stability and nutritional quality. Seeds of soybean cultivar ‘MACS 450’ were treated with γ-radiation and/or ethyl methane sulfonate (EMS). The harvest of M₁ plants was evaluated for fatty acid composition by gas chromatography. Highly significant variation in all the fatty acids except palmitic acid was observed. Treatment of EMS in higher concentrations as well as combined treatment of both the mutagens, i.e., γ-radiation and EMS were effective in increasing the variability for the fatty acid content in soybean oil. The variability was skewed towards high levels of oleic (35–42%) and low levels of linolenic acid (3.77–5.00%). M₃ and M₄ generations of desirable variants were analyzed for the stability of the mutated trait_. Only high oleic variants were stable in M₃ and M₄ generations. Based on fatty acid values, oxidative stability index (OSI), nutritional quality index (NQI) and ratio of essential fatty acids (ω₆/ω₃) were calculated for the control and M₂, M₃ and M₄ generations. The ω₆/ω₃ ratio in all the high oleic mutants was within the World Health Organization (WHO) recommended value (5–10%). A significant positive correlation between OSI and oleic acid content (P < 0.001) indicated improved oxidative stability of the oil while retaining nutritional quality. These high oleic lines could be utilized further in breeding programs for improvement of soybean oil quality.     

Alteration of soybean oil composition by plant breeding

Experimental lines selected from the cross PI 90406 × PI 92567 are being used in an attempt to improve soybean (Glycine max [L.] Merr.) oil by altering fatty acid composition through plant breeding. Preliminary evidence shows that the concentration of linolenic acid in soybean oil is reduced by selection for high levels of oleic acid. Levels of poly-unsaturated acids in “high oleic” selections are lower, to various degrees, but the concentration of saturated fatty acids is not different from that of the variety Dare, a representative southern commercial cultivar. In triglyceride from the “high oleic” selection, N70-3436, levels of palmitic, stearic, oleic, linoleic, and linolenic acid are 9.5, 2.0, 40.1, 43.3, and 5.1 mol %, respectively. The types of triglyceride structures observed in the experimental lines which were examined also are changed. The combined level of triolein, monooleyl-dilinolein, and dioleyl-mono-linolein in seed from N70-3436 is doubled and constitutes ca. 50% of the oil.     

Effects of deodorization and steam-refining parameters on finished oil quality

Deodorization and steam-refining parameters have significant impact on the quality of finished oil. Hence, optimization of parameters is critical for the production of acceptable oil. Temperature, time, throughput rate, sparging steam rate and pressure must be optimized to produce edible oil with desirable characteristics. Process optimization modeling in the laboratory, pilot plant and refinery is utilized to obtain predictive equations correlating product characteristics with deodorization parameters and feedstock properties. This optimization technique is demonstrated on model feedstocks and typical commercial oil. Finished corn and soybean oil quality are expressed by tocopherols and free fatty acid levels and sensory attributes during accelerated storage.     

Stability of Essential Fatty Acids and Formation of Nutritionally Undesirable Compounds in Baking and Shallow Frying

During cooking oils and fats are exposed to high temperatures that may affect the nutritional quality of foods that are prepared in this way. Concerns have been raised about the degradation of polyunsaturated fatty acids and the formation of potentially harmful compounds during deep frying, but relatively little is known about these changes in other cooking processes. In the present study sponge cakes and fried potatoes were prepared via standardised baking and shallow frying procedures by using different oils and fats (sunflower oil, rapeseed oil, various margarines or butter). The effect of cooking on the retention of two essential fatty acids (linoleic acid and α-linolenic acid) and the formation of trans fatty acids (TFA) and polymerised triacylglycerols (PTG) was evaluated by analyzing fat extracted from the cooked food. It was found that over 95 % of essential fatty acids were retained upon completion of both cooking techniques. The formation of TFA was not significant. Polymerisation was noticeable only in shallow frying, although the final levels of PTG were negligible (<1.3 %). Overall, in contrast to deep frying, oil-based media high in polyunsaturated fatty acids seem to be a good alternative for domestic cooking techniques as they increase the nutritional value of the prepared food.     

Chemical inactivation of cyclopropenoid fatty acids in cottonseed meals and their physiological evaluation

Chemical inactivation of cyclopropenoid fatty acids in commercial cottonseed meals was explored with three classes of compounds: anhydrous gases, organic acids and sulfhydryl compounds. Of the reagents screened, sulfur dioxide reduced the cyclopropenoid content by over 90% while free cottonseed fatty acids and thioglycollic acid reduced the cyclopropenoid fatty acid content by over 30%. Large batches of the above three selected meals, as well as a control commercial screw-pressed meal, were then incorporated at 20 wt % levels in the rations of laying hens. A negative control containing 25% soybean meal and a positive control containing a 2% refined cottonseed oil of known CPA content were also employed. During a four-week feeding period, eggs were collected during the third and fourth week and stored at 35 F for periods of 3 and 6 months. Overall egg quality and the fatty acid distribution of the yolk lipids were determined after the 3 and 6 months’ storage periods.     

Participation of free fatty acids in the oxidation of purified soybean oil during microwave heating

Effects of 0 to 1.0% levels of caprylic, capric, lauric, myristic, palmitic or stearic acid on the oxidative stability of purified soybean oil were investigated under microwave heating conditions. A prooxidative effect of the fatty acids introduced into the systems was established. The extent of this effect depended on the acyl chin and levels of added fatty acids. During microwave heating, the oxidative rate of purified soybean oil by the fatty acids was rapid compared to the addition of their corresponding hydrocarbons; the shorter the chainlength and the higher the levels of fatty acids, the more accelerated was the thermal oxidation in the oil. The results are explained on the basis of the catalytic effect of the carboxylic group on the formation of free radicals by the decomposition of hydroperoxides. Therefore, particular attention should be paid to the free fatty acid content, which affects the oxidative stability of purified soybean oil.     

Nutritional qualities of soya protein as affected by processing

The nutritional qualities of soybean proteins are basically determined by amino acid patterns, amino acid availabilities (digestibility) and contents of biologically active components. Of these factors, the last two are most affected by processing conditions, whereas amino acid analysis is least affected, although it too may be modified in those cases in which soybean proteins are fractionated. In the preparation of the large variety of soya products presently available, soybeans are subjected to many different processes, all of which are discussed. Heat treatment appears to be the process which most affects protein nutritional quality; generally, quality first increases with heat treatment due to inactivation of biologically active factors, passes through a maximum and then decreases due to destruction and/or inactivation of essential amino acids such as cystine and lysine. Other processes affect protein nutritional quality to different degrees, inasmuch as they affect amino acid analysis, digestibility and content of biologically active components. When soybean proteins are used to extend animal proteins, supplement other vegetable proteins, or in vegetable protein mixtures, nutritional quality of the combined proteins appears to be affected in the same manner as that of soya proteins alone.     

Effects of refining on chemical and physical properties of palm oil products

Some chemical changes in the composition and physical properties of palm oil products are discussed. The effects of bleaching and deodorization on oxidative properties and possible isomerization and interesterification of the fatty acids were indicated from laboratory refining experiments. Investigation of commercial samples of refined palm oil products showed that the conjugated dienes and trienes formed are minimal, indicating the use of good quality raw materials and mild processing conditions. Very little isomerization occurred in commercial refined products as indicated from the level oftrans acids, and changes in the POP to PPO triglycerides due to possible interesterification were insignificant. Changes in physical properties were inevitable due to the removal of free fatty acids and diglycerides and to minor impurities.     

Sunflower oil processing from crude to salad oil

World-wide use of sunflower oil is second only to soybean oil. Interest in domestic use as a premium salad oil is very recent. The high ratio of polyunsaturated-to-saturated fatty acids makes sunflower oil a premium salad oil. Sunflower oil, however, contains a small amount of high melting wax which must be removed to avoid settling problems. It is possible to produce a brilliant, dewaxed, deodorized sunflower oil with over a 100-hr cold test at 0 C. This quality oil can be produced by conventional caustic refining, dewaxing, bleaching and deodorization. A quality finished oil may also be produced by dewaxing and steam refining. This paper reviews various methods for processing sunflower oil from the crude state through the finished, dewaxed, deodorized salad oil. Presented at the ISF/AOCS Meeting, New York, April, 1980.     

Nutritional and microbiological profile of soybean sausages available in Costa Rica

The nutritional and microbiological quality of 80 soybean sausage samples (50% frankfurter and 50% sausage mortadela) was studied. On average, the protein content was 17.5 g/100 g in sausage mortadela and 20 g/100 g in frankfurter. The mean total fat content was 5.5 g/100 g for both products. However when products of different manufacture industries were compared, a highly significant difference (p = 0.0000) in the fatty acids speciation between both groups and between samples of the same product were found. Bigger differences were found in the content of palmitic acid (C16:0), oleic acid (C18:1) and linoleic acid (C18:2). Cholesterol was not detected in samples analyzed. On average the atherogenicity index was 0.55 for sausage mortadela and 0.59 for frankfurter. A consumption of 25 grams of of soybean protein from these sausages can bring an intake of saturated fatty acids between 20-90% of the daily recommendation. Likewise, they can supply between 12-70% of the recommended daily polyunsaturated fatty acids. These variations are owing to the big difference in fatty acids speciation in each sausage brand. Around 20% of soybean sausages studied showed total coliform levels above 10(4)/g, being more frequent in sausage mortadela. Also 60% of this product and 10% of frankfurters showed psychrotroph levels of 10(6)/g. Clostridium perfringens, in levels above 10(2)/g was evidenciated in 5% of samples, Escherichia coli was not isolated from them. The findings of this study suggest the urgent need for implementing a quality control system for soybean sausages, before national health authorities consider to support nutritional campainings that promote their consumption.     

Electrochemical hydrogenation of edible oils in a solid polymer electrolyte reactor. Sensory and compositional characteristics of low Trans soybean oils

Soybean oils were hydrogenated either electrochemically with Pd at 50 or 60°C to iodine values (IV) of 104 and 90 or commercially with Ni to iodine values of 94 and 68. To determine the composition and sensory characteristics, oils were evaluated for triacylglycerol (TAG) structure, stereospecific analysis, fatty acids, solid fat index, and odor attributes in room odor tests. Trans fatty acid contents were 17 and 43.5% for the commercially hydrogenated oils and 9.8% for both electrochemically hydrogenated products. Compositional analysis of the oils showed higher levels of stearic and linoleic acids in the electrochemically hydrogenated oils and higher oleic acid levels in the chemically hydrogenated products. TAG analysis confirmed these findings. Monoenes were the predominant species in the commercial oils, whereas dienes and saturates were predominant components of the electrochemically processed samples. Free fatty acid values and peroxide values were low in electrochemically hydrogenated oils, indicating no problems from hydrolysis or oxidation during hydrogenation. The solid fat index profile of a 15∶85 blend of electrochemically hydrogenated soybean oil (IV=90) with a liquid soybean oil was equivalent to that of a commercial stick margarine. In room odor evaluations of oils heated at frying temperature (190°C), chemically hydrogenated soybean oils showed strong intensities of an undesirable characteristic hydrogenation aroma (waxy, sweet, flowery, fruity, and/or crayon-like odors). However, the electrochemically hydrogenated samples showed only weak intensities of this odor, indicating that the hydrogenation aroma/flavor would be much less detectable in foods fried in the electrochemically hydrogenated soybean oils than in chemically hydrogenated soybean oils. Electrochemical hydrogenation produced deodorized oils with lower levels of trans fatty acids, compositions suitable for margarines, and lower intensity levels of off-odors, including hydrogenation aroma, when heated to 190°C than did commercially hydrogenated oil.     

Effects of processing on quality of soybean oil

The fate of major and minor components of soybean oil is examined at each stage of processing. Relationships are then drawn upon the effect on the quality of finished oil. General topics covered are (a) triglycerides and polyunsaturated fatty acids, (b) free fatty acids, (c) mono- and diglycerides, (d) phospholipids, (e) minor constituents, such as tocopherols, color bodies, and metal ions, (f) rearrangement and decomposition products, (g) foreign or toxic compounds not native to soya and (h) other additives, such as refining aids.     

Occurrence of Conjugated Linolenic Acids in Purified Soybean Oil

A high-performance liquid chromatographic (HPLC) method is described for the determination of conjugated linoleic acids (CLA) and conjugated linolenic acids (CLN). Methyl esters prepared from purified lipid fractions of soybean oil were analyzed using an HPLC system equipped with photodiode-array detector to detect peaks having maximum absorption around 233 and 275 nm. These peaks were concentrated by AgNO₃-silicic acid column chromatography and reversed-phase HPLC. The structural analysis, of dimethyloxazoline (DMOX) derivatized methyl esters, using gas chromatography–mass spectrometry (GC–MS) showed the occurrence of 9,11- and 10,12-CLA and 8,10,13-, 8,10,12-, and 9,11,13-CLN. The comparison of these conjugated fatty acids with authentic isomers by HPLC revealed the presence of isomeric mixtures of CLA [cis (c),trans(t) or t,c and t,t] and CLN (c,t,t or t,t,c and t,t,t). Traces of 9,11- and 10,12-CLA (c,t or t,c) were found in crude oil. CLN isomers (8,10,12-18:3 and 9,11,13-18:3) were found to be forming during the bleaching phase of soybean oil processing. 8,10,13-CLN and 9,11- and 10,12-CLA (t,t) were only found in soybean oil after the deodorization step. CLN contents in commercial soybean oil varied from 387 to 1,316 mg/kg oil. A decreased level of bleaching earth and temperature resulted in a reduced CLN content. It is possible that CLN would be derived from the linoleate hydroperoxides formed during the processing and storage of soybean oil.     

Use of SDA soybean oil in bakery applications

Stearidonic acid (SDA) soybean oil is a sustainable, land‐based source of omega‐3 fatty acids. SDA soybean oil can be formulated directly into baked products or incorporated into shortening blends for use in a variety of baking applications. Little has been published in the scientific and other literature concerning the functional and sensory performance of baking applications comprising SDA soybean oil. In this article, we review work that has been done to evaluate the performance of SDA soybean oil in an array of bakery applications. Consumer acceptance data showed that incorporation of SDA soybean oil in application models such as bagels, breakfast bars, pastries, cookies, icings and chocolate coatings resulted in acceptable product functionality and flavor. The results also indicated that SDA soybean oil imparted functional and sensory attributes in baked products that were similar to commercial soybean oil.     

Effect of low intake of n−3 fatty acids during development on brain phospholipid fatty acid composition and exploratory behavior in rats

The effect of dietary restriction of n−3 fatty acids during development on brain phospholipid fatty acid composition and exploratory behavior has been studied in male Sprague Dawley rats. Female rats were fed semipurified diets containing either 5.5% safflower oil or 6% soybean oil for 6 wk prior to mating and throughout gestation and lactation. Control rats were maintained on laboratory chow. The male pups were weaned to the diets of the dams except for one group which was switched from safflower to soybean oil at weaning. Behavioral studies and brain phospholipid analyses were conducted at 16–18 wk of age. Rats fed safflower oil showed significantly lower levels of 22∶6n−3 in phospholipids of synaptic membranes and myelin than rats fed soybean oil or chow. The decrease in 22∶6n−3 was compensated for by an increase in 22∶5n−6, the total content of polyunsaturated fatty acids remaining approximately constant. The brain phospholipid fatty acid composition of rats switched from safflower to soybean oil at weaning was similar to that of rats fed soybean oil throughout the experiment. There was no difference in spontaneous locomotor activity among the different dietary groups. However, rats raised on safflower oil displayed a significantly lower exploratory activity (horizontal movements and rearings) in a novel environment than rats fed soybean oil or chow. In contrast to the brain phospholipid fatty acid composition, there was no recovery of exploratory behavior in rats raised on safflower oil and switched to soybean oil at weaning suggesting a specific requirement of n−3 fatty acids during development.     

Effect of Extraction Method on the Yield and Quality of Mullet Roe Oil

Striped mullet (Mugil cephalus) roe is used for the production of high nutritional and added-value delicacies. Its lipid fraction is rich in polyunsaturated fatty acids (PUFA) and bioactive compounds. This study examines scalable oil extraction methods for mullet roe oil extraction. Namely, solvent extraction (SE) using ethanol in two different temperatures, supercritical fluid extraction (SFE) using CO₂-ethanol mixture (SFE-E) in two different temperatures, expeller oil press (EP) extraction, expeller oil press combined with ethanol extraction (EP-SE) and wet reduction (WR) are examined. The methods are evaluated with regard to the oil yield and recovery, the oil oxidation and the composition in fatty acids, and polar compounds and unsaponifiable matter. EP-SE and SE provide the highest oil recovery for tested extraction temperatures (76% and 65% respectively), followed by SFE-E (46%) and EP (36%). Extracted oils present high PUFA content (28.5–33.9%). The type of extraction process and the process variables affect oil oxidation as well as the concentration of polar compounds and unsaponifiable matter. In terms of oxidation levels, 85% of the extracted oil samples were within the limits set by the Codex Alimentarius Commission. The potential of the examined methods for industrial mullet roe oil production is discussed. Practical applications : Oil rich in polyunsaturated fatty acids was extracted from stripped mullet roe. The work proposes several scalable extraction methods using mild conditions which could be applied to obtain edible and high nutritional value mullet roe oil with high recovery reaching up to 76%. The same methods could be employed also for mullet roe by-products. The obtained results improve the knowledge regarding the potential of roe valorization for oil extraction as well as the effect of the extraction method on the oil yield, main composition features and the quality characteristics of oil extracted by mullet roe. This research could offer new opportunities for the food industry for fish roe valorization for high nutritional quality oil production.     

Influence of dietary fatty acids on the glycerophospholipid composition in organs of cod (gadus morhua)

Cod (mean start weight of 26 g) were fed three diets for 15 months, each based on a dry pellet coated at a level of 9g/100 g with soybean oil, capelin oil or sardine oil. The fatty acid compositions of neutral lipids and four glycerophospholipids of white muscle, liver, gills and heart were determined. The fatty acid composition of dietary lipids influenced the composition of neutral lipids in all organs. Linoleic acid (18∶2n−6) from soybean oil was selectively incorporated into phosphatidylcholine of the four tissues. Similar levels of 20∶5n−3 and 22∶6n−3 in phosphatidylcholine and phosphatidylethanolamine were found in all organs from cod fed capelin oil and sardine oil in spite of highly differentiated feed fatty acid levels. The polyunsaturated fatty acid (PUFA) composition of phosphatidylinositol was least influenced by dietary lipids. The preferred monoenic fatty acid in phospholipids of cod was 18∶1n−9, independent of dietary intake, whereas the longer chain monoenoic acids seemed to be preferentially catabolized. The results suggest that 20∶4n−6 as well as 20∶5n−3 and 22∶6n−3 fatty acids are essential for cod.     

Lipid Composition of Wheat Germ and Wheat Germ Oil

Information available in the literature concerning the composition of lipids in wheat germ and in wheat germ oil is critically reviewed. After a brief introduction to the botanical and technological aspects of wheat germ, the yield of oil and its physico-chemical properties are described followed by the composition of fatty acids, acyl lipids and non-saponifiable components. The importance of distinguishing between dissected germ and commercial wheat germ and between germ oil and germ lipids is emphasised. The triglycerides account for the major part of the fatty acids, of which linoleic acid is the principal component, and the content of free fatty acids depends on the rancidity of the germ and also on possible post-extraction processing in the case of commercial oil. Polar lipids consist mainly of phospholipids and available information suggests that glycolipids are present only at very low concentration and that galactosyl glycerides may be absent from the embryo of the quiescent wheat grain. Most reports of tocopherol composition concern wheat germ oil and there is less information about the tocopherols of dissected wheat germ. α- and β-tocopherols are found in wheat germ but tocotrienols are probably absent from dissected germ and only occur in commercial germ as a result of bran and endosperm contamination. Wheat germ oil exhibits a range of sterols. 4-methyl sterols and triterpenoid alcohols, and β-sitosterol and campesterol are the major components. The hydrocarbon composition of wheat germ oil has been reported but the significance of the results is uncertain. Flavonoid pigments, xanthophyll and xanthophyll esters have been shown to be present in wheat germ. Most of the studies of the non-saponifiable fraction were based on germ oil and commercial wheat germ and little is known of the nature of this fraction in dissected wheat germ.     

Multidimensional Proton Nuclear Magnetic Resonance Relaxation Morphological and Chemical Spectrum Graphics for Monitoring and Characterization of Polyunsaturated Fatty-Acid Oxidation

Polyunsaturated fatty acids (PUFA) are components of many commercial products such as edible oils, foods, cosmetics, medication, and in biological systems such as phospholipids of cellular membranes. Although PUFA aggregates are important functional components, they are also related to system degradation, because PUFA are susceptible to oxidation via their multiple double bonds and allylic carbons. Current technologies are not effective in characterizing the morphological and chemical structural domains of saturated, monounsaturated fatty acids (MUFA) and PUFA materials, or how the morphological structures of fatty acids, at the mesomolecular, nanomolecular, and molecular levels, affect their oxidation mechanisms. In this article, the ¹H low-field (LF) NMR energy relaxation time technology is proposed as a tool to analyze PUFA oils undergoing thermal oxidation. This technology generates two-dimensional (2D) chemical and morphological spectra using a primal-dual interior method for the convex objectives (PDCO) optimization solver for computational processing of the energy relaxation time signals T₁ (spin–lattice) and T₂ (spin–spin). The 2D graphical maps of T₁ vs. T₂ generated for butter, rapeseed oil, soybean oil, and linseed oil show that the different degrees of unsaturation of fatty-acid oils affect their chemical and morphological domains, which influences their oxidative propensity. The technology of the ¹H LF-NMR energy relaxation time proved to be an effective tool to characterize and monitor PUFA oxidation.     

Einfluß der Hydrierung auf Haltbarkeit und ernährungsphysiologische Eigenschaften von Qualitätsrapsölen

Effect of Hydrogenation on Stability and Nutritional Properties of Low-Erucic Rapeseed Oils Low-erucic rapeseed oils, Lesira and Erglu, were converted to more stable edible oils by selective hydrogenation of the linolenic acid moieties while retaining most of the linoleic acid groups. Feeding Lesira oil, hydrogenated Lesira oil, soybean oil and hydrogenated soybean oil to rats did not result in any appreciable differences in growth rates, whereas feeding conventional rapeseed oil caused extensive depression of growth. Among all the groups of animals the group fed conventional rapeseed oil showed the highest weights of heart and liver. The fatty acid patterns of depot and organ lipids did not show any major difference between the groups fed hydrogenated fats and those fed the corresponding unhydrogenated oils. The fatty acid composition of the organ lipids did not reveal deficiency in essential fatty acids. In the groups fed Lesira oil and hydrogenated Lesira oil half of the animals investigated exhibited myocardial lesions of light degree, probably due to the relatively high residual level of long-chain monoenoic fatty acids, whereas in the groups fed soybean oil and hydrogenated soybean oil only one-eighth of the rats examined exhibited such effects. The occurrence and severity of these myocardial lesions are known to be much higher in rats fed conventional rapeseed oils.