A micromethod to generate and collect odor constituents from heated cooking oils

A small stainless steel reactor about one-millionth the volume of a home kitchen, was built to generate odors from cooking oils heated to deep fat frying temperatures. This “microroom” was designed so that volatiles could be collected from 1–5 ml of heated oils (193 C) directly on a gas chromatographic column, cooled to -60 C and subsequently separated by temperature programing up to 250 C. Evaluations showed that heated oil odors from the microroom were similar to those room odors produced by heating to 193 C 300 ml of cooking oil in an open vessel; exposure to subambient conditions did not affect the separation efficiency of the gas chromatographic column. Provisions were made for three independent means of effluent monitoring: flame ionization detection, odor analyses and mass spectrometry. Presented at the AOCS Meeting, Los Angeles, April 1972. ARS, USDA.     

Effects of antioxidants,methyl silicone and hydrogenation on room odor of soybean cooking oils

Room odor characteristics produced by heated soybean oil (SBO) and soybean oils hydrogenated with copper (CuHSBO) and nickel (NiHSBO) catalysts were evaluated by a trained panel. Oils were intermittently heated to 190 C for total heating periods of 5, 15 and 30 hr. Oil additives investigated included methyl silicone (MS), tertiary butylhydroquinone (TBHQ) and a polymeric antioxidant in various combinations with citric acid (CA). In room odor tests directly comparing SBO, CuHSBO and NiHSBO, panelists rated the hydrogenated oils as having significantly less odor intensity than the SBO. The combination of CA+MS had the greatest effect in lowering odor intensity of the heated oils, followed by the mixture of CA+MS+TBHQ. The low odor intensity of the MS-treated oils remained fairly constant throughout the tests, while the higher intensity associated with all the other additive-treated oils decreased with increasing heating times, possibly as the result of formation of more volatile decomposition products in the initial heating stages. Methyl silicone had the strongest effect of any additive in decreasing objectionable room odors in the oils. Partially hydrogenated SBO treated with up to 5 ppm of MS produced cooking oils with low room odor intensity and low color development during prolonged heating.     

Salad and cooking oils

Raw materials and techniques for the production of salad and cooking oils are reviewed. Particular attention is given to oil properties that are related to end uses. Availability, local markets, and culinary practices are discussed, with particular respect to the ways these factors influence the use of oils in many countries.     

Analysis of fats and oils

Analytical information on fats and oils is required for trading, quality control, nutritional labeling and forensics. Development of analytical procedures was one of the historical reasons for the organization of the Society of Cotton Products Analysits; it continues as a major effort of the successor organization, the American Oil Chemists’ Society, through its Uniform Methods Committee and final publication of methods in the Society’s “Official and Tentative Methods.” A review of the current status of methods development will be followed by a glimpse of methodological research currently underway.     

Winterization of oils and fats

The process of winterization consists of fractional crystallization of oils and fats followed by the separation of solids to make high quality salad oils. To design a winterization process, the rate of cooling of oil, the temperature of crystallization and the mobility of triglyceride molecules in the oil mass are crucial. These variables play a significant role both in separating the solid fats as distinct crystals and facilitating their filtration from the oil. Thus, the main emphasis in this paper is on the effect of the above variables on the performance of the winterization process. Presented at the AOCS short course held April 21–23 1980, Lake Kiamesha, NY.     

Refining of oils and fats

The technique of continuous refining of oils and fats has steadily improved since the first commercial installation some 30 years ago. Refining is the most important economic factor in the overall processing of an oil from the crude to the finished product. Crude oil handling, reagent selection, mixing, heating, and centrifugal separation are all critical when an attempt is made to obtain the maximum refining efficiency. The agronomist, scientist, control laboratory and operating personnel, along with the equipment manufacturers, have all aided in obtaining more efficient and economical processing methods. In a discussion of the over-all refining process, soapstock handling must also be considered. In recent years several successful continuous soapstock acidulation plants have been installed. With this addition to a refinery, the refining operation can now truly be considered as a continuous process. Like most industrial processes, this has been an evolution from the batch system to a semicontinuous system up to the present continuous treatment of soapstock and wash water to produce a high-purity acid oil on an economical basis. Details of the various factors in refining and aeidulation on a commercial basis, along with control methods, are discussed. Presented at the AOCS Short Course, “Processing Quality Control of Fats and Oils,” East Lansing, Mich., Aug. 29–Sept. 1, 1966.     

Authenticity of fats and oils

Food authenticity has become a focal point attracting the attention of producers, consumers, and policy makers. Although in most cases adulteration of fats and oils does not pose a threat to public health, fundamental rights of consumers (right of correct information and buying “value‐for‐money”) are violated by fraudulent malpractice. Fraud is only economically viable, if a cheaper commodity can be made to resemble a genuine, more expensive product. The extent of adulteration that is possible is quite limited and, hence, the basic product that is being adulterated cannot be fundamentally different from the genuine material. Most methods to detect fraud rely on a thorough knowledge of the natural variation of characteristic constituents of the commodity concerned and make use of complex statistical procedures to derive indicators of adulteration. A range of analytical methods to detect fraud has to be developed, modified, and reappraised on a continuous basis to be a step ahead of those pursuing these illegal activities. In this article the technical merit of different analytical platforms to establish the authenticity of oils and fats is reviewed.     

Hydrogenation of oils and fats

Hydrogenation is a complex 3-phase reaction, and the end result depends largely on transport and chemical resistances. Control of these factors is of critical importance to a predictable end product and this control is possible if a fundamental understanding of the process is achieved. The basic transport steps involved to bring the hydrogen and oil together in the presence of catalyst and the effect of different process variables on the course of the chemical reaction will be the major subjects of discussion in this presentation.     

Ester content evaluation in biodiesel from animal fats and lauric oils

A modified method for the determination of ester contents of biodiesel based on EN 14103 has been developed. The method includes natural contents of heptadecanoic acid ester, which are found in animal fats and interfere with the standard method, into the calculation of ester content values. As a result, biodiesel samples prepared from waste animal fats and oils showed an increase in ester content between 2 and 7 wt‐% compared to values measured according to EN 14103. Furthermore, modifications of the GC temperature program made it possible to include also short‐chain fatty acid esters C₈–C₁₂, which can be found in coconut and palm kernel oil, into the calculation. Measurements showed that the ester content of such biodiesel differs by more than 40 wt‐% compared to EN 14103 determinations. However, also the stability of the internal standard solution methyl heptadecanoate influences the values of ester content. It can be demonstrated that after a period of 7 days, an ester content decrease of about 2 wt‐% can be observed. Therefore, the use of almost freshly prepared standard solutions should be recommended.