Showing papers in "Journal of the American Oil Chemists' Society in 1971"
TL;DR: In this article, a procedure for rapid evaluation of antioxidants was described for dilute aqueous emulsions of an antioxidant, carotene and lipid were prepared in spectrometer tubes.
Abstract: A procedure is described for rapid evaluation of antioxidants. Dilute aqueous emulsions of an antioxidant, carotene and lipid were prepared in spectrometer tubes. The oxidative destruction of carotene in the emulsion was observed directly with a colorimeter. The antioxidants were then evaluated according to their effect on the rate of carotene decolorization.
619 citations
TL;DR: In this article, a new process was described whereby polyunsaturated oil droplets were protected from ruminal hydrogenation by encapsulation with formaldehyde-treated protein, and when these protected oils were fed to ruminants the formaldehydeprotein complex is hydrolyzed in the acidic conditions of the abomasum and the fatty acids are absorbed from the small intestine.
Abstract: Polyunsaturated fatty acids are normally hydrogenated by microorganisms in the rumen. Because of this hydrogenation ruminant triglycerides contain very low proportions of polyunsaturated fatty acids. A new process is described whereby polyunsaturated oil droplets are protected from ruminal hydrogenation by encapsulation with formaldehyde-treated protein. The formaldehyde-treated protein resists breakdown in the rumen thereby protecting the fatty acids against microbial hydrogenation. When these protected oils are fed to ruminants the formaldehydeprotein complex is hydrolyzed in the acidic conditions of the abomasum and the fatty acids are absorbed from the small intestine. This results in substantial changes in the triglycerides of plasma, milk and depot fats, in which the proportion of polyunsaturated fatty acids is increased from 2–5% to 20–30%. These effects are observed in the plasma and milk within 24–48 hr of feeding while a longer period is necessary to alter the composition of sheep depot fat. The implications of these findings are discussed in relation to human and ruminant nutrition.
205 citations
TL;DR: In this article, the variability of jojoba seed oil composition was investigated with five different seed samples and the results indicated that oil from smaller leaved prostrate plants growing along California's oceanside showed a slight tendency toward higher molecular size than oils from the California desert and Arizona specimens.
Abstract: HCl-catalyzed ethanolysis followed by saponification readily surmounts the resistance of long chain wax esters to direct hydrolysis by alkali. Additionally, choosing ethyl instead of methyl esters allows baseline separations between long-chain alcohols and corresponding esters in gas liquid chromatographic (GLC) analysis of total alcohol and acid components before saponification. Liquid wax esters were analyzed on a temperature-programmed 3% OV-1 silicone column. Geographical and genetic effects on the variability of jojoba oil composition were investigated with five different seed samples. Major constituents in jojoba seed oil from shrubs in the Arizona deserts, as indicated by GLC analyses of oil, ethanolysis product, isolated fatty alcohols and methyl esters of isolated fatty acids, were C40 wax ester 30%, C42 wax ester 50% and C44 wax ester 10%; octadecenoic acid 6%; eicosenoic acid 35%, docosenoic acid 7%, eicosenol 22%, docosenol 21% and tetracosenol 4%. Oil from smaller leaved prostrate plants growing along California’s oceanside showed a slight tendency toward higher molecular size than oils from the California desert and Arizona specimens. The wax esters are made up of a dispro-portionately large amount of docosenyl eicosenoate and are not a random combination of constituent acids and alcohols.Lunaria annua synthetic wax ester oil was used as a model for evaluating the analytical procedures.
203 citations
TL;DR: In this paper, Ferric heme pigments have been implicated as the major prooxidants in tissue lipid oxidation, and ferric hemes are believed to promote lipid oxidation.
Abstract: Lipid oxidation is a major cause of deterioration in the quality of meat and meat products Oxidation can occur in either the stored triglycerides or the tissue phospholipids Ferric heme pigments have been implicated as the major prooxidants in tissue lipid oxidation Pigment and lipid oxidation are interrelated, and ferric hemes are believed to promote lipid oxidation The resulting oxidation destroys the hemes Nonheme iron and ascorbic acid may also function as prooxidants in meat Sodium chloride accelerates oxidation of the triglycerides, although the mechanism of salt catalysis is not completely known Cooked meat undergoes rapid deterioration due to tissue lipid oxidation The meat pigment in the cured pink ferrous form does not promote the rapid oxidation undergone by cooked uncured meat Refrigerated and frozen fresh meats are also susceptible to lipid oxidation Protein denaturation and cross-linking may result from lipid oxidation in stored freeze-dried meat With increased consumption of prepackaged raw meat and precooked convenience meat items, control of oxidation has become increasingly important Antioxidants and chelating agents are the most effective inhibitors of lipid oxidation
174 citations
TL;DR: In this paper, the polymorphic behavior and thermal properties of cocoa butter have been investigated by means of programmed temperature x-ray diffraction and differential scanning calorimetry, and the relationship of this polymorphism to the technical problems of "tempering" and "bloom" development is discussed.
Abstract: The polymorphic behavior and thermal properties of cocoa butter have been investigated by means of programmed temperature x-ray diffraction and differential scanning calorimetry. The relationship of this polymorphism to the technical problems of “tempering” and “bloom” development is discussed. Cocoa butter containing, respectively, milk fat and a bloom inhibitor, and some alternatives to cocoa butter have been studied. These results have provided information that will help determine process conditions for these particular fats.
148 citations
TL;DR: In this article, an experimental investigation of the conditions under which non-hydratable phospholipids (Mg/Ca-phosphatidates) are removable from water degummed soybean oil was carried out.
Abstract: On the basis of the literature concerning the chemical and physicochemical properties of phosphatidic acid and phosphatidates, an experimental investigation of the conditions under which nonhydratable phospholipids (Mg/Ca-phosphatidates) are removable from water degummed soybean oil was carried out. The experiments were carried out by mixing water-degummed oil at different fixed pH values with buffer solutions with and without admixture of Ca++, Mg/Ca-binding reagents and surfactants. The results indicate that the nonhydratable phospholipids can be removed in a chemically nonconverted state as a component of micelles or of mixed emulsifiers. Furthermore, the nonhydratable phospholipids are removable by conversion into dissociated form, i.e., by removal of Mg and Ca from the phosphatidates, which can be accomplished by acidulation or by treatment with Mg/Ca-complexing or Mg/Ca-precipitating reagents. Alkali-refining experiments have shown that removal or chemical conversion of the nonhydratable phospholipids result in reduced emulsion formation and in improved separation of the deacidified oil from the emulsion layer and the soapstock.
86 citations
TL;DR: As a growing amount of research attention has been diverted from the traditional protein foods to the so-called unconventional food proteins, an awareness has increased of the need to understand the functional properties of these proteins, including their solubility in aqueous solution.
Abstract: As a growing amount of research attention has been diverted, for a number of reasons, from the traditional protein foods to the so-called unconventional food proteins, an awareness has increased of the need to understand the functional properties of these proteins. Some empirical functionality tests have been devised, but it is submitted that many of these could yield misleading information, inasmuch as they often ignore or even run counter to the environmental interactions to which proteins are exposed in food systems. Some examples are given of the influence of the ionic environment upon one basic functional property of proteins, their solubility in aqueous solution.
86 citations
TL;DR: In this paper, it was shown that a fraction of the potential that exists for commercial exploitation of high erucic oils in the United States is fulfilled with 10 million pounds of rapeseed oil imported annually.
Abstract: Vegetable oils rich in erucic acid have desirable properties for a variety of applications. At present, only a fraction of the potential that exists for commercial exploitation of high erucic oils in the United States is fulfilled with 10 million pounds of rapeseed oil imported annually. Though rape is not a crop in the United States, another member of the mustard family, crambe, has been recommended by the USDA as a practical crop for domestic cultivation. Compared to rapessed oil, crambe oil is more suitable for industrial use because it consistently contains a higher percentage of erucic acid. High erucic oils, as examplified by crambe, can be employed as lubricants in continuous steel casting, in formulated lubricants and in the manufacture of rubber additives. Both the hydrogenated oil and derived wax esters have properties comparable to commercial waxes. Useful nitrogen derivatives can be prepared from either the erucic acid or mixed acids from the oil; behenyl amine is used in a corrosion inhibitor, disubstituted amides are effective plasticizers and erucamide is an excellent slip and antiblocking agent for plastic films. Oxidative ozonolysis of erucic acid produces the dibasic acid, brassylic, and the monoacid, pelargonic. Mixed diacids, mainly brassylic and azelaic, can be obtained by ozonolysis of fatty acids from the oil. Alkyl diesters of brassylic, or of the mixed diacids, are excellent low temperature plasticizers. Two new nylons (13 and 1313), which are derived from C-13 difunctional products of erucic acid ozonolysis, contain repeating units that have longer uninterrupted polymethylene chains than other nylons. Moderate melting points and exceptionally low water absorption are a consequence of this structure. The low-melting characteristic is an advantage in adhesive uses and facilitates fluidized-bed coating, molding and extrusion; low moisture affinity contributes to excellent electrical properties and dimensional stability.
84 citations
TL;DR: The chemistry of castor oil and its derivatives is reviewed with particular reference to work done in India in general and at the Regional Research Laboratory in Hyderabad in particular.
Abstract: The chemistry of castor oil and its derivatives is reviewed with particular reference to work done in India in general and at the Regional Research Laboratory in Hyderabad in particular. Topics covered are the structure of castor oil, preparation of ricinoleic acid and its glycerides, monoglycerides, surfactants from castor oil, diverse hydrogenations, dehydration, preparation and properties of estolides, alkali fusion or oxidation to dibasic acids, hydroxylation and acetoxy-epoxies, urethanes and polymerisable monomers.
82 citations
TL;DR: Aflatoxins in peanut and cottonseed meal can be inactivated by treatment with gaseous ammonia and under optimum processing conditions, aflatoxin content of this meal was reduced to below 5 ppb and non-detectable levels.
Abstract: Aflatoxins in peanut and cottonseed meal can be inactivated by treatment with gaseous ammonia In pilot plant runs, contaminated peanut meal was ammoniated at two levels each of moisture content, reaction time, temperature and ammonia pressure Thin layer chromatography indicated that ammoniation inactivated the aflatoxins (121 ppb) in the meal to a nondetectable level With a similar treatment, total aflatoxins (350 ppb) in cottonseed meal were reduced to 4 ppb A series of runs was made with large scale equipment using cottonseed meal containing an average of 519 ppb total aflatoxins Under optimum processing conditions, aflatoxin content of this meal was reduced to below 5 ppb and non-detectable levels
79 citations
TL;DR: Several improvements and extensions of the Udy dye method for estimating protein content in natural products are discussed, and it is suggested that the amount of dye bound by the protein’s BAA offers a better nutritional index than conventional nitrogen procedures.
Abstract: Several improvements and extensions of the Udy dye method for estimating protein content in natural products are discussed. The many outstanding physical and chemical properties of the monosulfonic azo dye, acid orange 12, are presented. This dye is used in a stablizing pH 2 buffer system to react with the protein’s basic groups that originate from the basic amino acids (BAA) histidine, arginine and lysine. A complete analysis requires less than 5 min. The ionic reaction rate is limited to the exposure rate of each binding site. Regression equations relating nitrogen content and bound dye are presented for several oilseeds, grains, legumes and animal products. Random mixtures of products, having wide dif-ferences in dye-binding capacity, are not amenable to this method of protein estimation. Because nonpro-tein nitrogen is not measured, and the critically essential amino acid, lysine, is measured only when it is nutritionally available, it is suggested that the amount of dye bound by the protein’s BAA offers a better nutritional index than conventional nitrogen procedures.
TL;DR: A mutant formed after UV irradiation of a potent a flatoxin producing strain of Aspergillus parasiticus elaborated 80% less aflatoxin than did the parent strain and produced an orange-red pigment.
Abstract: A mutant formed after UV irradiation of a potent aflatoxin producing strain ofAspergillus parasiticus elaborated 80% less aflatoxin than did the parent strain and produced an orange-red pigment. This new metabolite which represents 1% of the mycelial mass has been identified as 2-hexanoyl-1,3,6,8-tetrahydroxyanthraquinone (norsolorinic acid), mol wt 370, mp 256–257 C, and molecular formula C20H18O7.
TL;DR: In this paper, the fatty acid composition of each group of triglycerides was calculated and the experimental and random distributions were compared to the random distributions calculated from the fatty acids composition, for groups with carbon numbers 38 and 40, the experimentally found distributions in each group were very similar but for most other groups, the distributions found were much different from calculated random distributions.
Abstract: Triglycerides of coconut oil were fractionated by GLC into 13 groups based on their carbon numbers of 28 to 52. These groups represent 99.8% of the total glycerides of coconut oil. With the fatty acid composition of each group, it was possible to calculate the composition of 79 types of triglycerides. These types are defined by the nature of their constitutive fatty acids but the position of the acids on glycerol is unknown. Each group usually has only one major type of triglyceride. For example, group 36 has 52% of trilaurin. Also four types of triglycerides comprise 42.4% of the total glycerides and 24 types comprise 85%. The experimentally found distributions in each group are compared to the random distributions calculated from the fatty acid composition. For groups with carbon numbers 38 and 40, the experimental and random distributions were very similar but for most other groups, the distributions found were much different from the calculated random distributions.
TL;DR: In this paper, a highly selective catalyst system was proposed for the hydroformylation of methyl oleate into methyl 9(10)-formylstearate in high yields.
Abstract: A highly selective catalyst system has been discovered for the hydroformylation of methyl oleate into methyl 9(10)-formylstearate in high yields. A rhodium catalyst in the presence of triphenylphosphine is used with oleic esters, acids or triglycerides. Hydroformylation proceeds smoothly at 95-110C with a 1:1 mixture of H2 and CO at 500 to 2000 psi with or without a solvent, such as toluene. The formylstearate obtained in 90% to 99% conversion from oleate can be either hydrogenated (Raney Ni) or reduced (NaBH4) to hydroxymethylstearate or oxidized (KMnO4) to carboxystearate. According to TLC and mass spectrometry, the methylated carboxystearate consists of about equal proportions of the 9 and 10 isomers. Addition of triphenylphosphine inhibits isomerization of the double bond and leads to the formation of a rhodium carbonyl triphenylphosphine complex, which is apparently the active catalyst. Other known methods for hydroformylation (cobalt carbonyl) and carboxylation (Koch’s method) of oleate give a wide distribution of isomers.
TL;DR: In this paper, a 2,4-decadienal was autoxidized by purging a purified sample with oxygen and an analysis of the autocidative degradation products was made with tandem gas chromatography-mass spectrometry.
Abstract: 2,4-Decadienal was autoxidized by purging a purified sample with oxygen. An analysis of the autoxidative degradation products was made with tandem gas chromatography-mass spectrometry. Additional information was obtained from the determination of the melting point of the dinitrophenylhydrazone derivatives and IR absorbency data. Pentane, furan, ethanal, hexanal, acrolein, butenal, 2-heptenal, 2-octenal, benzaldehyde, glyoxal,trans-2-buten-1,4-dial, acetic acid, hexanoic acid, 2-octenoic acid, 2,4-decadienoic acid and benzene were identified.
TL;DR: In this paper, the autoxidation of organic compounds, RH, occurs by a radical-catalyzed chain reaction to give hydroperoxides, RO2H, as primary products.
Abstract: The autoxidation of organic compounds, RH, occurs by a radical-catalyzed chain reaction to give hydroperoxides, RO2H, as primary products. The initial rate is -d[O2]/dt = kp[RH] {ki[Cat]/kt}1/2, or in the presence of an inhibitor, (In), kp[RH](ki[Cat]/kI[In]), where kp is the chain propagation rate; ki[Cat], the rate of radical catalysis; kt chain termination rate; kI[In] rate of inhibitor action. As oxidation proceeds the hydroperoxides break down to give further catalytically active radicals and eventually an autoxidation may reach a maximum rate of k
p
2
[RH]2/fkt, independent of the concentration or nature of the catalyst. Photosensitization, by forming singlet oxygen, can catalyze autoxidation by forming peroxides. Compounds of many transition metals, e.g., Co, Mn, Fe, act as secondary catalysts by promoting the rapid formation of radicals from RO2H molecules by a one-electron transfer reaction RO-OH + M2+→RO· + M3+ + OH− and the M3+ ions are then reconverted to M2+ ions giving further radicals. The overall catalytic activity of a metallic ion is controlled by the slower step of the M2+⇌M3+ + e redox cycle and depends on the electronic structures of the two ions concerned and on the ligand groups attached to them. These effects are discussed in detail since ligand molecules for transition metal ions can be selected so as either to promote or inhibit autoxidation. Special reference is made to biological catalysts, such as the porphyrins, found in food products. Direct activation of oxygen by metallic complexes rarely seems to occur, but direct oxidation of substrates by metallic compounds is possible. This leads to another redox cycle which is utilized in copper-containing enzymes.
TL;DR: Factors limiting Crambe development are the high cost of seed transportation due to the high volume to weight ratio of the threshed seed and the need for extra seed processing steps to render the meal suitable as a high protein feed supplement for livestock and poultry.
Abstract: Oilseed crops of the Cruciferae are widely adapted and are of particular importance to countries in the northern latitudes. Cruciferous seed oils from the crops, rapeseed, mustard, Camelina, oilseed radish and Crambe, enter edible or industrial markets, or both. The oil-seed meal can be used either as a high protein feed supplement or as an organic fertilizer. The spring and winter forms of the two species of rapeseed,Brassica napus andB. campestris, are commercially the most important. Advances in crop management and plant breeding have resulted in a 40% to 50% increase in seed yield over the past 25 years. In the next 10 to 15 years, application of newer plant-breeding techniques will result in varieties even higher in yield and seed with improved oil and meal quality. Some of the quality improvements will be new patterns in fatty acid composition, higher oil and protein content, lower fiber content, and removal of the undesirable glucosinolate compounds from the meal. The mustard cropsBrassica juncea andB. hirta are important condiment crops which have considerable potential as edible oil sources. Oilseed radish,Raphanus sativus, yields significantly less seed and oil than other cruciferous oil crops but its oil, which contains a low level of erucic acid (3.7%) and a relatively high content of 16-carbon fatty acids (9.3%), may be useful in blending with normal or zero erucic acid rapeseed oils.Camelina sativa or false flax has many desirable agronomic characteristics but the oil of camelina seed contains too high a level of linolenic acid (36%) to penetrate the edible oil market and too low to compete industrially with linseed oil.Crambe abyssinica andC. hispanica are potentially important producers of high erucic acid industrial oils. Factors limiting Crambe development are the high cost of seed transportation due to the high volume to weight ratio of the threshed seed and the need for extra seed processing steps to render the meal suitable as a high protein feed supplement for livestock and poultry.
TL;DR: The major components of the sunflower seed hull, lipids, proteins and carbohydrates were studied in this paper, where they represented 5.17% of the total hull weights, 2.96% of which is wax composed of long chain fatty acids (C14-C28, mainly C20) and fatty alcohols (C12-C30, mainly c22, C24, C26).
Abstract: The major components of the sunflower seed hull, lipids, proteins and carbohydrates were studied Lipids represent 5.17% of the total hull weights, 2.96% of which is wax composed of long chain fatty acids (C14–C28, mainly C20) and fatty alcohols (C12–C30, mainly C22, C24, C26). Hydrocarbon, sterol and triterpene alcohol fractions were also examined. The rest of the lipid fraction is an oil with a composition relatively similar to that of the kernel oil. The protein fraction (4% of the total hull weight) is similar to the protein fraction of the oil cake, although it contains hydroxyproline. The carbohydrate fraction is composed mainly of cellulose, but also of reducing sugars (25.7%), mainly pentoses.
TL;DR: In this paper, the odor threshold was determined for a series of unsaturated ketones, secondary alcohols, hydrocarbons and substituted furans added to bland edible oil, and the odour threshold was taken as the point where 50% of a 15 to 18-member taste panel could detect an odor difference from the control oil.
Abstract: The odor threshold was determined for a series of unsaturated ketones, secondary alcohols, hydrocarbons and substituted furans added to bland edible oil. Odor thresholds were taken as the point where 50% of a 15- to 18-member taste panel could detect an odor difference from the control oil. These additives are oxidative products of fats, but the concentrations investigated were far below any level associated with an identifying odor or taste of the additive per se. Odor, rather than flavor, was selected as the starting basis because of greater acuity and ease of handling a large number of samples with less taster fatigue. Oil samples containing additive concentrations near the odor threshold levels were evaluated by flavor score and flavor descriptions. Taste panel members were experienced oil tasters and were allowed free choice in selecting terms to describe the flavor quality of the oil samples. The propyl and butyl members of the homologous series of vinyl ketones had the lowest odor thresholds, whereas the difference in odor threshold was small between homologs in the unsaturated alcohols and in the 2 substituted furans. Vinyl propyl ketone, vinyl propyl carbinol (1-hexen-3-ol) and 2-propyl furan had odor thresholds of 0.005, 0.5 and 6 ppm, respectively. Odor thresholds of the unsaturated hydrocarbons are markedly lower than those of the saturated isologs. The odor of nonane can be detected at 650 ppm. However, at 1000 ppm it cannot be tasted and oils containing it were scored equal to the control oil. 1-Nonene, 1-nonyne and other tested C-9 unsaturated hydrocarbons, including a number of dienes, have odor thresholds of about 10 ppm. The hydrocarbons 1-hexyne, 1-nonyne and 1-decyne had odor thresh-olds of 0.2, 5 and 4 ppm, respectively.
TL;DR: New Hampshire chicks and turkey poults were highly susceptible to aflatoxin in contrast to the resistance of Barred Rock and Australop chickens and guinea fowl, and Hybrid chicks from a New Hampshire-White Leghorn cross were highly resistant to a flatoxin.
Abstract: Feeding trials were conducted with swine, beef cattle, dairy cattle and poultry to determine adverse effects, if any, of graded levels of aflatoxins in rations. In addition, samples of meat, eggs and milk from these animals were analyzed chemically to determine if aflatoxin was transmitted into these products. In growing-fattening swine, no evidence of toxic effects was observed when the aflatoxin level fed was 233 ppb or less. In a swine reproduction experiment, no adverse effects were detected in pigs produced from sows fed 450 ppb aflatoxin. No toxic effects were observed at levels of 300 ppb or lower in cross-bred beef steers fed aflatoxin rations for 4.5 months. Using recognized chemical methods, we detected no aflatoxin in meat from swine and cattle fed rations containing 800 and 1000 ppb of aflatoxin, respectively. In dairy cows, weekly intakes of 67 to 200 mg of aflatoxin B1 per cow produced 70 to 154 ppb aflatoxin M1 in lyophilized milk. Rapid disappearance of aflatoxin M1 in the milk took place after withdrawal of aflatoxin from the ration. No adverse effects were discernible in broilers fed from one day to eight weeks of age a ration containing 400 ppb aflatoxin. Lyophilized meat from broilers fed 1600 ppb aflatoxin for eight weeks contained no detectable aflatoxin. Striking differences in aflatoxin susceptibility were observed in 17 different breeds and strains of poultry and game birds fed from two to six weeks of age a ration of 800 ppb aflatoxin B1. New Hampshire chicks and turkey poults were highly susceptible to aflatoxin in contrast to the resistance of Barred Rock and Australop chickens and guinea fowl. Hybrid chicks from a New Hampshire-White Leghorn cross were highly resistant to aflatoxin. Eggs and meat from White Leghorn hens fed a ration containing 2700 ppb aflatoxin contained no detectable aflatoxin.
TL;DR: In this article, a study of the oxidation rate of methyl linoleate in protein and cellulose systems, a prooxidant effect was found at intermediate moisture contents, where water hydrates metals and hydrogen bonds with peroxides, and an overall decrease in the rate of lipid oxidation results.
Abstract: In the study of the oxidation rate of methyl linoleate in protein and cellulose systems, a prooxidant effect was found at intermediate moisture contents. At low water content, water hydrates metals and hydrogen bonds with peroxides, and an overall decrease in the rate of lipid oxidation results. With an increase in the water content to the region with a water activity of 0.6 to 0.7, the water predominantly acts as a solvent to dissolve and mobilize previously unavailable trace metals with the result of increased oxidation rates. Use of chelating agents such as ethylenediaminetetraacetic acid and citric acid reduced oxidation significantly although some antioxidant activity was also observed for butylated hydroxyanisole. These results have important implications in the preparation of intermediate moisture foods.
TL;DR: In this article, the behavior of two types of catalysts, a complex of ferrous ion [Fe(II)] and EDTA, a non-heme iron model, in a 1:1 ratio accelerated peroxidation at lower pH; no catalysis took place above pH 6.4.
Abstract: Hemoprotein and non-heme iron components are active catalysts of lipid peroxidation. The behavior of these two catalysts under a number of conditions was compared as a basis for a study of their activities in meats. In model systems, MetMb accelerated linoleic acid peroxidation in a pH range from 5.6 to 7.8; it catalyzed especially rapidly at higher pH. A complex of ferrous ion [Fe(II)] and EDTA, a non-heme iron model, in a 1:1 ratio accelerated peroxidation at lower pH; no catalysis took place above pH 6.4. Most chelating agents eliminated Fe(II)-EDTA catalysis, but had no effect on MetMb catalysis. Reducing agents, on the other hand, accelerated Fe(II)-EDTA catalysis but inhibited MetMb catalysis. In model systems in which fresh dilute (1.2%, w/v) meat homogenate was the catalyst, the effect of the heme predominated. An exception was ascorbic acid; it accelerated oxidation at pH 5.6. The pattern of linoleate peroxidation catalyzed by heme-free (H2O2-treated) beef homogenate and shrimp homogenate was similar to that in the Fe(II)-EDTA model system. Again, ascorbic acid accelerated the catalysis and the acceleration could be eliminated by adding chelating agents. The presence of a non-heme iron catalyst in meat is thus indicated. Evidence is presented for both types of catalytic activity in meats. In cooked meats, heme was the dominant catalyst, but significant lipid oxidation, apparently catalyzed by a non-heme iron-type catalyst, occurred in cooked meats in which the heme had been destroyed by H2O2. In raw meats, lipid oxidation was inhibited at high pH because of removal of oxygen by enzymatic reducing systems. Both heme and non-heme iron were active at lower pH values. EDTA inhibited lipid oxidation during storage, presumably by its demonstrated effect on non-heme iron catalysis. Ascorbic acid also inhibited lipid oxidation, probably indirectly by keeping the heme pigment in the catalytic inactive ferrous state.
TL;DR: Several species of the Cruciferae family are presently used as oilseed crops, viz.,Brassica campestris (turnip rape and sarson), B. juncea (brown or yellow mustard),B. napus (rape), Crambe abyssinica (crambe), andSinapis alba (white oryellow mustard) as mentioned in this paper.
Abstract: Several species of the Cruciferae family are presently used as oilseed crops, viz.,Brassica campestris (turnip rape and sarson),B. juncea (brown or yellow mustard),B. napus (rape),Crambe abyssinica (crambe), andSinapis alba (white or yellow mustard). Seed oils of these species are characterized by variable but generally large amounts of erucic acid (22:1) in the triacylglycerols, which make up 95–98% of the total lipids of high quality, viable seeds. In addition to erucic acid, the major fatty acids are oleic (typically 10–25%), linoleic (10–20%), linolenic (7–11%) and eicosenoic (5–10%). However cultivars of rapeseed lacking erucic acid and having about 55–60% oleic, 20–25% linoleic and ca. 10% linolenic acid have been developed. The eicosenoic and erucic acids are located exclusively at the 1 and 3 positions of the triacylglycerol. As a consequence, major triacylglycerol types have carbon numbers 54, 56, 58, 60 and 62. The phospholipids of rapeseed are essentially devoid of erucic acid and have palmitic, oleic and linoleic acids as major fatty acids. Sterols generally amount to about 0.5% of the oil with β-sitosterol, campesterol and brassicasterol as major constituents (about 55%, 25% and 15%, respectively, of the total sterols). A few per cent of the total sterol fractions is cholesterol. The tocopherol content of rapeseed oil is about 800 ppm with α- and γ-tocopherol as major components. Cruciferous seeds contain a fairly large number of storage proteins. Thus approximately 50 components have been detected in alkaline extracts ofBrassica napus, a major portion of which are in the molecular weight range 120–150,000. The protein spectrum ofB. napus (rape) is more complex than that ofB. campestris (turnip rape) since the former species is an allotetraploid withB. oleracea (kale, cabbage, etc.) andB. campestris as parents. Approximately 5% of the fat free seed meal is composed of glucosinolates, which are split upon enzymatic hydrolysis to antinutritional factors: isothiocyanates, oxazolidinethiones and nitriles. The different crucifers discussed have both qualitative and quantitative differences with respect to glucosinolate content.
TL;DR: In this paper, the effect of metals on the other components of the muscle was examined and it was shown that removing the dark lateral muscle from the fillets before freezing reduced the production of DMA and formaldehyde during storage and resulted in less loss of extractable protein.
Abstract: The addition of metals to pure fats and model systems has given us a picture of the part they play in lipid oxidation. But in complex substrates such as fish flesh the same metal ions catalyze reactions in other components of the muscle as well. A more complete picture of deterioration is obtained when we also examine the effect of metals on the other components of the muscle. Although lean fish muscle contains 0.5% to 1% unsaturated lipids, during frozen storage it rarely goes rancid, as indicated by thiobarbituric acid (TBA) values or rancid odors. The lipids do oxidize, but instead of forming carbonyls and other compounds associated with rancidity, they become bound up in lipid-protein complexes, which accounts for the toughened texture of overstored or poorly stored frozen fish. It has been generally accepted that the formation of these lipid-protein polymers is brought about by a reaction between the proteins and oxidizing fatty acids. For fish of the gadoid or cod family, this is further complicated by the enzymic production of formaldehyde, which forms in the muscle during cold storage. The direct addition of formaldehyde to give concentrations of 0.001% to 0.05% caused marked reductions in the extractable protein of cod muscle. Because formaldehyde and dimethylamine (DMA) are produced in the stored muscle by the same reaction, the accumulation of the DMA can be used as a measure of this process which leads to protein insolubility. Removal of the dark lateral muscle from the fillets before freezing reduced the production of DMA and formaldehyde during storage and resulted in less loss of extractable protein.
TL;DR: The best approach to contain the problem of aflatoxin is prevention and enough is now known about prevention to reduce contamination drastically.
Abstract: The best approach to contain the problem of aflatoxin is prevention and enough is now known about prevention to reduce contamination drastically. Guidelines for preventing mycotoxins in farm commodities have been suggested by the U.S. Department of Agriculture. Moisture is the single most important parameter and prompt drying to safe levels is essential for control of toxigenic molds. Foreign matter and damaged seed should be removed. Provision of clean, dry, adequately cooled and ventilated storage is important and good sanitation is essential to minimize mold contamination during storage and processing: Genetic approaches which may result in resistance to elaboration of aflatoxins are under investigation. When aflatoxin is found in a sample of oilseeds the contamination generally resides in only a small proportion of the kernels, commonly less than 1%. Sorting or separation can concentrate the vast majority of aflatoxin-contaminated kernels into relatively small fractions and only a small loss is incurred as a result of their removal. Aflatoxin is frequently found deeply imbedded within individual kernels so removal by simple washing does not seem feasible. However, extraction with polar solvents such as alcohols and ketones to achieve essentially complete removal of aflatoxins appears technically feasible. Heat is relatively ineffective for destruction of aflatoxin although normal roasting, as of peanuts for the preparation of peanut butter, results in considerable reduction in aflatoxin content. Treatment withFlavobacterium aurantiacum removes aflatoxin and may be useful for beverages. Oxidizing agents readily destroy aflatoxin, and treatment with hydrogen peroxide may be useful. Treatment of defatted oilseed meals with ammonia can reduce aflatoxin content to very low or undetectable levels with only moderate damage to protein quality.
TL;DR: In this paper, the results obtained on the various samples by SFI, NMR and differential scanning calorimetry (DSC) techniques were compared according to fat composition.
Abstract: Dilatometry (SFI) has gained wide acceptance for the characterization of solid-liquid contents of fats over approximately the past 15 years. In more recent times, wide-line nuclear magnetic resonance (NMR) has been used for this purpose. Still more recently the differential scanning calorimetry (DSC) technique has been used to determine solid-liquid contents. These three techniques were used to determine the properties of seven fats and oils which represent a cross section of commercially available materials. These products were blended into 14 different compositions and the solid-liquid contents were determined by the three methods. A comparison is made on the results obtained on the various samples by SFI, NMR and DSC techniques. The results of each procedure are compared according to fat composition.
TL;DR: By polarographic oxygen analyzer, the rate of oxidation of linoleate solutions was catalyzed by low concentrations of heme and heme-proteins and inhibited by higher concentrations, which may reflect the oxidative synthesis of antioxidants from heme compounds.
Abstract: By polarographic oxygen analyzer, the rate of oxidation of linoleate solutions was catalyzed by low concentrations of heme and heme-proteins and inhibited by higher concentrations. High concentrations of these substances also inhibited lipoxygenase catalysis of linoleate oxidation. Manganese and cobalt salts inhibited heme-catalyzed linoleate oxidation. These combined effects may reflect the oxidative synthesis of antioxidants from heme compounds.
TL;DR: The phase behavior of a homologous series of saturated even 1-monoglycerides, starting with monomyristin, has been reviewed and their study extended to monoarachidin and monobehenin this article.
Abstract: Phase behavior of a homologous series of saturated even 1-monoglycerides, starting with monomyristin, has been reviewed and their study extended to monoarachidin and monobehenin. The occurrence of sub α, α, β' and β polymorphs was confirmed for all compounds, except in the case of β' for monomyristin. It has been firmly established that there is a reversible sub α2 ⇄ sub α1 transition, (indicated by Malkin for monostearin) below the reversible sub α (sub α1)⇄α transition, for C18 through C22 compounds; it occurs at about 50 C and is apparently almost independent of chain length. The sub α2 to sub α1 transformation is particularly sensitive to impurity and disappears for 1-monobehenin at about 10% 2-monobehenin as produced by heating at 96 C. Heats of transformation are, for β' and β crystal melting, about 50 cal/g; for α melting, about 35; for sub α → α transition, about 15 and for sub α2 to sub α1 transition about 3, which is several times as large as typical heats of melting of mesomorphic states. Diffraction data confirm the essential identity of all long spacing values and the occurrence of tilted chains for all polymorphs of a given compound. Much similarity is encountered between sub α and β' patterns. Sub α2 and sub α1 are difficult to distinguish by diffraction pattern.
TL;DR: Urea-denatured hemoprotein possessed increased nonenzymatic activity due to increased exposure of the protein-bound heme, however, peroxidase increased less than catalase which is consistent with the fact that per oxidase is the more heat stable enzyme.
Abstract: Purified catalase and peroxidase were denatured by heat, acid and urea. Denaturation resulted in up to 22-fold increase in nonenzymatic lipid oxidation activity concomitant with loss of enzymatic activity. It is proposed that the increased nonenzymatic activity is due to increased exposure of the heme group. Acid-splitting of the hemoproteins into apoprotein and hemin had the greatest influence on both of the catalytic activities and recombination reversed the effect. Urea-denatured hemoprotein possessed increased nonenzymatic activity due to increased exposure of the protein-bound heme, however, peroxidase increased less than catalase which is consistent with the fact that peroxidase is the more heat stable enzyme. Nonenzymatic activity of the heat denatured hemoproteins was maximum when catalase was treated at 90 C for 2 min and peroxidase at 100 to 125 C for 5 to 30 min.
TL;DR: In this paper, the embryo, endosperm, testa and pericarp from seeds of three buckwheat species were analyzed for total lipid content and fatty acid composition and the average lipid content of these tissues was 8.2%, 0.4%, 2.0% and 0.5%, respectively.
Abstract: The embryo, endosperm, testa and pericarp from seeds of three buckwheat species were analyzed for total lipid content and fatty acid composition. The average lipid content of these tissues was 8.2%, 0.4%, 2.0% and 0.5%, respectively. Eighteen fatty acids were tentatively identified in buckwheat oil. The following eight constituted an average of more than 93% of the total acids: palmitic, stearic, oleic, linoleic, linolenic, arachidic, behenic and lignoceric acids. The embryo tissue of cultivated and Tartary buckwheats contained the fewest minor acids with an average of 95% of the acids containing either 16 or 18 carbons. The pericarp, or hull, had a unique composition with higher levels of saturated acids, odd carbon acids and acids of 20 or more carbons than any other tissues. The compositions of the testa and endorsperm were intermediate.