Lipids from Wastewater-Activated Sludge Cultivated on Acetic Acid as Potential Alternatives to High-Value Oils and Fats

This study focuses on new interpretations of the published literature by statistically evaluating the potential of microbial lipids from activated sludge (AS) as alternatives to high-value oils and fats. There are two data analysis stages involved in this study after compilation and organization of fatty acid profiles from the literature databases: (1) comparison of fatty acid profiles of the cultivated AS lipids with that of oils and fats found in the literature databases, and (2) hierarchical cluster analysis of the fatty acids of the combined dataset of literature oils and fats, and the AS lipids. Results show that fatty acid profiles of lipids from cultivated AS were similar to the fatty acid profiles of some oils and fats of plant, animal, single-microbial cultures, and algal origins; hence, lipids from AS could be potential alternatives to specialty oils and fats. The cultivation conditions of AS during lipid content enhancement may influence lipid application.     

Analysis of sterol content and composition in fats and oils by capillary-gas liquid chromatography using an internal standard. Comments on the German sterol method

The advantages and disadvantages of various approaches to the capillary-gas liquid chromatography (GLC) of sterols in fats and oils with internal standards are discussed. The German method F-III 1²(,3) for sterol analysis in fats and oils, which uses betulin as an internal standard, was reformulated and translated. A number of further improvements and alterations were also made, and the procedure used is described more precisely below in English in order to give detailed explanations, e.g. regarding the role of the aluminium oxide column and of the internal standard betulin. The method is applicable to a wide range of oils and fats, including mixtures of vegetable and animal fats, cereal lipids, and partially hydrogenated fats.     

The formation of oxo- and hydroxy-fatty acids in heated fats and oils

A fast-food fat (mostly tallow), olive oil and safflower oil were heated in air for 4 d and periodically analyzed for oxofatty acids (OFA), monohydroxy-fatty acids (HFA) and polyhydroxy-fatty acids (PHFA). After transmethylation, the OFA were estimated as 2,4-dinitrophenylhydrazones, and the HFA and PHFA were quantitated as pyruvic acid 2,6-dinitrophenylhydrazone esters. At least half of the maximum concentration attained for OFA, HFA and PHFA was generated between 16–24 h of heating of each oil. Safflower oil contained greater concentrations of HFA and PHFA than either olive oil or the fast-food fat. The fastfood fat sample contained a greater concentration of OFA than did the other oils. The sum of the concentrations of OFA, HFA and PHFA at the time of maximum formation in the oils was approximately 260 μmoles/g at 48–72 h for safflower, 200 μmoles/g at 48–72 h for olive and 170 μmoles/g at 72 h for the fast-food fat. Presented at the 79th Annual AOCS Meeting, Phoenix, Arizona, May 8–12, 1988.     

Medium chain triglycerides and structured lipids

Lipids are an essential component of our body composition and necessary in our daily food intake. Conventional fats and oils are composed of glycerides of long chain fatty acids and are designated as long chain triglycerides (LCT). Body fat as well as the fats and oils in our daily intake fall into this category. In enteral and parenteral hyperalimentation, we can identify such LCT fats and oils. Soy, corn, safflower and sunflowerseed oils are typical of the LCT oils. In the search for alternative noncarbohydrate fuels, medium chain triglycerides (MCT) are unique and have established themselves in the areas of malabsorption syndrome cases and infant care and as a high energy, rapidly available fuel. Structure lipids with a MCT backbone and linoleic acid built into the triglyceride molecule have been developed to optimize the triglyceride structure that is best for patients, particularly the critically ill. Structured lipids with built-in essential fatty acid components or other polyunsaturated fatty acids promise greater flexibility in patient care and nitrogen support.     

Fats and other Lipids from Single Cell Cultures,Plants, and Animals

Through the ages, a major portion of fats and oils produced by man has been used as human food and animal feed. For little more than a century, most of the inedible fats, together with substantial proportions of edible fats and oils, have served as raw material for the production of bulk commodities such as soaps and detergents, paints and varnishes, as well as lubricants and plastics. These products are beneficial on account of their physical and chemical properties. The biological properties of some naturally occurring lipids are being recognized and appreciated since the 1930ies. As a result of intensive research efforts, the structures of these substances, notably of the fat-soluble vitamins, hormones, essential fatty acids and oxylipids derived therefrom, pheromones, platelet activating factor and other ether lipids, are now known. Both naturally occurring lipids and semisynthetic or synthetic analogues are being applied in agriculture, bio-medical research and clinical therapy. A ‘fat tree’ devised in 1958 by the late H. P. Kaufmann illustrates the wide applicability of fats and oils at that time. The present article includes a figure showing further ramifications of Kaufmann's tree. The structures, properties, and uses of the substances added recently are outlined in a series of publications that appeared in a special issue of the journal Fat Science Technology.     

The Antioxidant Functions of Tocopherol and Tocotrienol Homologues in Oils,Fats, and Food Systems

This review paper is focused on the relative antioxidant activities of tocopherols and tocotrienols in oils and fats and certain food systems. α-Tocopherol generally showed better antioxidant activity than γ-tocopherol in fats and oils, but at higher concentrations γ-tocopherol was found to be a more active antioxidant. The results of studies on the optimum antioxidant concentrations of tocopherols in oils and fats indicated that the optimal level for α-tocopherol is usually lower than other tocopherols, meaning less α-tocopherol is needed for maximum antioxidant protection. There are comparatively very few studies related to the antioxidant activities of tocotrienols in oils and fats. It has been stated that generally γ-tocotrienol has higher antioxidant effect than α-tocotrienol, and tocotrienols may be better antioxidants than their corresponding tocopherols in certain oils and fats systems. Studies on the antioxidant activity of various tocopherols in food systems are varied and cannot be uniformly evaluated because experiments have generally focused on different foods and used various methods for the detection of antioxidant activities. Depending on the food system, in certain cases tocopherols were better antioxidants than synthetic antioxidants such as butylhydroxy toluene (BHT) or butylhydroxy anisole (BHA). However, in certain other food systems the synthetic antioxidants were more effective to increase the shelf life and the stability of foods than those containing tocopherols.     

Fatty alcohols in capelin,herring and mackerel oils and muscle lipids: I. Fatty alcohol details linking dietary copepod fat with certain fish depot fats

It is shown that the shorter chain (C₁₄-C₁₈) minor fatty alcohols in copepods, fish body lipids, and commercial fish oils are all qualitatively present, and quantitatively similar in proportions to acids found in the depot fats of capelin and mackerel, and in some herring. Although these fatty acids can be formed de novo in fish, copepod alcohols offer an alternative dietary source. Monoethylenic fatty alcohol details, especially for the 22∶1 isomers, are reviewed, and the latter are discussed as precursors of the 22∶1 fatty acids of fish depot fats, specifically of the dominant 22∶1ω 11 isomer.     

Relative nutritional value of various dietary fats and oils

The dietary and nutritional role of fats and oils is quite complex, as evident in the new biological findings about some of their components that are essential to man. Fats and oils must be considered for both their quantitative and qualitative aspects, their fatty acid compositions and relationships with average diets in different countries should be emphasized. Because of some adverse physiological effects ascribed to saturated fatty acids, a tendency to increase the intake of polyunsaturated vegetable oils has occurred to provide a good source of essential fatty acids, mainly linoleic acid. However, saturated fats still are an important part of the diet in developed countries, especially “invisible” fats. Research must continue that is related to modifications fats and oils undergo during industrial processes which affect their nutritional value. Compositions of many fats and oils are provided.     

Monitoring the oxidation of edible oils by Fourier transform infrared spectroscopy

Edible fats and oils in their neat form are ideal candidates for Fourier transform infrared (FTIR) analysis, in either the attenuated total reflectance or the transmission mode. FTIR spectroscopy provides a simple and rapid means of following complex changes that take place as lipids oxidize. Safflower and cottonseed oils were oxidized under various conditions, and their spectral changes were recorded and interpreted. The critical absorption bands associated with common oxidation end products were identified by relating them to those of spectroscopically representative reference compounds. The power and utilty of FTIR spectroscopy to follow oxidative changes was demonstrated through the use of “real-time oxidation plots.” A quantitative approach is proposed in which standards are used that are spectroscopically representative of oxidative end products and by which the oxidative state of an oil can be defined in terms of percent hydroperoxides, percent alcohols and total carbonyl content. By using either relative absorption as a basis or calibrating on representative standards, FTIR analysis provides a rapid means of evaluating the oxidative state of an oil or of monitoring changes in oils undergoing thermal stress.     

Preparation and analysis of some food fats and oils for fatty acid content by gas-liquid chromatography

The fatty acid compositions of some food fats and oils were determined by gas-liquid chromatography (GLC) before and after application of reagents and conditions of some extraction procedures. The extraction procedures studied had a nonsignificant effect on the fatty acid compositions. Procedures leading to methyl ester formation through a series of room temp reactions were selected over procedures requiring higher temp reactions, on the basis of yield of products, fatty acid compositions of food lipids of simple composition, or both. These procedures were then used to prepare some food fats and oils for analysis by GLC and the fatty acid compositions determined in this manner are presented. Food Composition Laboratory, ARS, USDA.     

Die antioxidativen Eigenschaften von Lecithin

Antioxidizing Properties of Lecithin In various storage trials with sunflower oil and lard the antioxidizing properties of crude soybean lecithin as well as of its alcohol soluble and alcohol insoluble fraction could be proved. The addition of a very small quantity of these phospholipids to the oil after the refining process (prior to this process crude oil contains approx. 2–3% lecithin) improves the stability of these oils. The antioxidizing properties of phospholipids depend on: 1. composition of phospholipids, 2. tocopherol content of the oil. In our trials the alcohol soluble fraction of soybean lecithin performed the best antioxidizing results in sunflower oil by adding not less than 1%. In lard the same effect could already be reached with 0.1% of this fraction. As shown before, lecithin with a special phospholipid composition has antioxidizing properties and its addition in small quantities is beneficial to increase the stability of oils and fats. In new Japanese literature soybean saponines are the most favoured antioxidizing agents. Our trials did not confirm the results of these publications.     

Thermochemical applications for fats and oils

Fats and oils are well established in food, surfactant and coatings applications. Historically, fats and oils were employed to provide lighting and warmth. Increasing production of fats and oils and increasing uncertainties regarding the reliability of petroleum resources make it desirable to reconsider thermochemical applications of fats and oils. Difficulties associated with the use of fats and oils for vehicular applications are discussed, and use in stationary diesel engines is suggested. Conventional kerosene space heaters are designed to make use of the vaporization behavior of this fuel. Changes in heater design are required to take into account the pyrolytic degradation of the fuel when fats and oils are used, and a traveling grate burner was designed for this purpose. Pyrolysis of fatty acids at temperatures exceeding 500 C yields a mixture of gaseous and liquid products. The gaseous products include ethylene, but little propylene. The liquid product is primarily a mixture of substituted styrenes. Further development is needed for these thermochemical applications of fats and oils. Fuel and olefin markets present valuable cushions to keep the price of fats and oils from fluctuating as during the early 1980’s, when soybean oil has varied from $0.15 per pound to $0.40 per pound. The triglycerides can provide a future source of feedstocks for petrochemicals, if petroleum prices and availabilities change dramatically. Most of the development work needed consists of down-to-earth large-scale experiments in semi-commercial or commercial equipment to determine the best methods of fuel storage, feeding and conditions for combustion and steam cracking.     

Medium chain length fatty acid esters and their medical and nutritional applications

Caprylic and capric acid esters and their applications in medical, nutritional and dietetic uses are described. Medium chain triglycer-ides (MCT) as a tool in the control of obesity, control in the choles-terol deposition in the tissues as well as a means of lowering serum cholesterol are cited as unique characteristics of such lipids. MCT as a source of quick energy and high energy is suggested as an alterna-tive to the conventional fats and oils (LCT). Dietetic and nutritional application utilizing the unique characteristics of caprylic and capric acid esters is indicated as alternatives to conventional fats and oils. The mono-diglycerides of caprylic and capric acid as cholesterol dis-solving agents in treating of patients having cholesterol gallstones is described to illustrate the unique solvency properties of such mono esters in medical applications. The possibility of such mono esters of di- and polyhydric alcohols to act as co-solvents for oil and water systems is suggested which can be applied in medical, pharmaceuti-cal and allied fields. Structured lipids with a predominance of capry-lic and capric acid to modify the properties of triglycerides is described for hyperalimentation uses as well as the special nutri-tional and dietetic needs.     

A highly sensitive method for the micro-determination of lipid hydroperoxides by potentiometry

A modified method for peroxide value (POV) determination of lipids was developed through the application of potentiometry to conventional POV tests such as the official method of the Japan Oil Chemists’ Society (JOCS). The new method permits a simple and reliable determination of low hydroperoxide levels in the initial stages of lipid autoxidation when only very small amounts of sample are available, even when those levels are measured on less than 10 mg of lipid. Using the present method, hydroperoxide levels as low as 20 nanoequivalents (neq) were determined with reasonable precision. This method is applicable to all lipids tested including oils and fats, free fatty acids, phospholipids, glycolipids and cholesterol esters.     

Differentiation of Lard From Other Edible Fats and Oils by Means of Fourier Transform Infrared Spectroscopy and Chemometrics

Fourier transform infrared (FTIR) spectra at mid infrared regions (4,000–650 cm⁻¹) of lard and 16 edible fats and oils were compared and differentiated. The chemometrics of principal component analysis and cluster analysis (CA) was used for such differentiation using FTIR spectra intensities of evaluated fats and oils. With PCA, an “eigenvalue” of about 90% was achieved using four principal components (PCs) of variables (FTIR spectra absorbances at the selected frequency regions). PC1 accounted for 44.1% of the variation, while PC2 described 30.2% of the variation. The main frequency regions that influence the separation of lard from other evaluated fats and oils based on PC1 are 2,852.8 followed by 2,922 and 1,464.7 cm⁻¹. Furthermore, CA can classify lard into its group based on Euclidean distance.     

Natural oils and fats — Prospects for the 1980s

All fats and oils are more or less interchangeable in varying degrees. Therefore, shortages or surpluses of one type of oil or fat have some effect on the whole supply and demand effect on a freely operating market. The trend in long term for real prices of soapmaking fats and oils is down — because it is projected that supplies are likely to increase faster than global demand. Inflation rates affecting production costs of soybean and palm oils are not expected to be large but probably the most important of any of the fats. The price of coconut oil, as an example, was relatively stable until ca. 4 years ago — 5 years ago it was $200/ton, 3% years ago it was $1,400/ton, 6 months ago it was $700/ton, and now (August 1977) it is $470/ton. It is projected, for example, that it will be at a level of $750/ton in 1990.     

Improved method for quantitating and obtaining the unsaponifiable matter of fats and oils

A quantitative method for saponifying and isolating the unsaponifiable matter (UM) from fats and oils is detailed. The method, which is a modification of a previously described procedure, is faster, uses about half the solvent, and is easier to execute. The minimum time needed to completely saponify a large number of fats and oils is established and conditions for removing contaminating soap from the extracted UM are described. Evidence presented shows some fats and oils to be incompletely saponified using previously indicated time-temperature conditions. The method compares favorably with the AOAC method, but is not applicable to the analysis of marine oils.     

Comparative nutritional study of enzymatically and chemically interesterified palm oil products

A comparative evaluation of the nutritional value of palm oil, which was interesterified by lipozyme and by chemical catalysis, has been done with albino rats (Charles Foster strain). The two interesterified fats have identical coefficients of digestibility, and rats fed the two fats exhibit similar patterns of growth response and food efficiency ratio. The total lipid and total cholesterol levels in serum of rats of the two interesterified fats are nearly the same, but there is a significant difference in free cholesterol level. The lipozyme-catalyzed product creates a higher level of free cholesterol. Liver lipids of rats are identical in amount for the two groups, but the total cholesterol level of the lipozyme-catalyzed group is significantly less than the chemically catalyzed group. The positional distribution of fatty acids differs between the two interesterified products. The nutritional attributes of interesterified oils can vary depending on the specificity of the catalyst employed.     

A review of methods for determining pesticide residues,contaminants and adulterants in fats and oils

Sensitive chromatographic methods are available for determining chlorinated pesticide residues and chick edema factor contaminants in fats and oils. Determination of chlorinated pesticide residues in fats and oils generally involves acetonitrile extraction, Florisil column cleanup, and analysis by electron capture gasliquid chromatography (ECGLC). However, other procedures are available including dimethyl sulfoxide extraction and sweep codistillation. Sensitive screening tests for chick edema factor involve alumina column fractionation of isolated unsaponifiable matter, sulfuric acid cleanup, and examination by ECGLC. Admixtures of animal and vegetable fats are detected by the gasliquid chromatography (GLC) of isolated sterols, and individual vegetable oils can be characterized by GLC analysis of the sterols as well as of the other unsaponiflable constituents. Presented at the AOCS Short Course, “Processing Quality Control of Fats and Oils,” East Lansing, Mich., Aug. 29–Sept. 1, 1966.     

What else besides commodity oils and fats?

For over 40 years Oil World publications of Hamburg have provided business data on 17 commercial oils. These include 4 animal fats and 13 vegetable oils from 12 species. But natural oils are seldom optimum for their ultimate human use. This review refers briefly to the technological methods of modifying lipids and describes in more detail five biological procedures by which a wider range of lipids is being developed. These include the domestication of wild crops, the modification of existing crops by seed breeding and by genetic modification, the use of microbial lipids particularly as a source of PUFA, and the modification of triacylglycerol composition by lipase-mediated reaction.