Soybeans INDEX

Biodiesel is normally produced by starting from vegetable oils having an IV of <130, that is, having a low unsaturation index, such as rapeseed oil (IV = 110-115), sunflower oil (IV = 120-130) and soybean oil (IV = 125-135). 

The correlation between the TEARS assay and MDA dnring oxidation of edible oils may be complicated by the presence of tocopherols (e.g. Vitamin E, 21) . An evaluation was carried of MDA, determined by an independent method , and TEARS as indices for direct oxygen uptake of edible oils and unsatnrated fatty acids. The linear increase of MDA and TEARS with oxygen consumption of soybean oil, in a closed vessel at 170 °C, stops when the latter value reaches 500 p.molL, when both MDA and TEARS start to decrease on further O2 consumption. The same process carried out at 40 °C, using 2,2 -azobis(2,4-dimethylvaleronitrile) (171) as initiator, shows linearity up to 1500 p,molL O2 consumption . A similar behavior is observed for nnsatnrated fatty acids snch as oleic, linoleic and linolenic acids . On the other hand, depletion of Vitamin E (a-tocopherol, 21) and its analogs y- and 5-tocopherol (172, 173) present in the oil show a linear dependence on O2 consumption of the oil, np to 1800 p,molL . This points to the consumption of these antioxidants, and especially 21, as a good index for the O2 uptake in oils at high temperature. The determination of the tocopherols is carried ont by HPLC-FLD (Xex = 295 nm, Ah = 325 nm) . ... 

Two saponins from soybean seeds having soyasapogenol as aglycone were shown to have a partial inhibitory effect on HIV-induced cytopathology in infected human MT-2 lymphocytes cultures [158], The major constituent of group of B saponins from soybean seeds completely inhibited HIV-induced cytophatic effects and virus-specific antigen expression 6 days after infection at concentration > 0.25 mg/ml. Saponins isolated from soybean seeds inhibited HIV-1 replication in MT-4 cells at 0.5 [tg/ml (Nakamura et al. 1992) [159]. These saponins had a narrow therapeutic index and did not inhibit HIV-1 RT. One of them was found to inhibit HIV-induced cell fusion in MOLT-4 cells. 

Fig. 41 Separation of triacylglycerols on Supelcosil-LC 8 with acetone-acetonitrile (70 30, v/v) as the mobile phase and refractive index detection. Flow rate, 1.0 ml/min. (a) Olive oil, (b) soybean oil, (c) sunflower oil, (d) corn oil.

Dunn, R. O. 2005a. Oxidative Stability of Soybean Oil Fatty Acid Methyl Esters by Oil Stability Index (OSI). /. Am. Oil Chem. Soc., 82, 381-387. 

Fig. 34.25. Solid Fat Index (SFI) profiles for six hydrogenated soybean oil (H-SBO) base stocks. (From O Brien, R. D., Shortening technology, in Introduction to Fats and OilsTechnology, 2nd edn., R. D. O Brien,W. E. Farr, and R J.Wan (Eds.), pp. 421-451, AOCS Press, Champaign, IL, 2000. With permission.)...

Fig. 34.33. Solid Fat Index (SFI) profiles for hard stick, soft stick and tub margarines, and for all-purpose shortening and heavy duty frying oil. (Data plotted from Erickson, D. R., and M. D. Erickson, "Hydrogenation and Base Stock Formulation," in Practical Handbook of Soybean Processing and Utilization, D. R. Erickson (Ed.), pp. 218-238, AOCS Press, Champaign, IL, 1985.)...

Active Oxygen Method for Fat Stability (AOM) (Cd 12-57) determines the time (in hours) for a sample of fat or oil to attain a predetermined peroxide value (PV) under the conditions of the test. The method is used to estimate the comparative oxidative stability of fats and oils. The method has been placed in surplus, in favor of Cd 12b-92 (Oil Stability Index), but retains official status and is still used in domestic industry. p-Anisidine Value (AV) (Cd 18-90) determines the amount of aldehydes (principally 2-alkenals and 2,4-dienals) in animal and vegetable fats and oils. These are degradation products of peroxides, which are not removed by bleaching. Some fats and oils chemists propose increased use of this method in purchase specifications. Bleaching Test for Soybean Oil (Cc 8e-s63) determines the color of a sample of soybean oil after treatment with a specified bleaching earth. Specific methods exist for other oil species. 

List, G. R., Steidley, K. R., Palmquist, D., and Adlof, R. O., Solid fat index vs. solid fat content A comparison of dilatometry and pulsed nuclear magnetic resonance for solids in hydrogenated soybean oil, in Crystallization and Solidification Properties of Lipids, N. Widlak, R. Hartel, and S. Narine (Eds.), pp. 146-152, AOCS, Champaign, IL, 2001. 

Linoleic Acid occurs as a colorless to pale yellow, oily liquid that is easily oxidized by air. It is an essential fatty acid and the major constituent of many vegetable oils, including cottonseed, soybean, peanut, corn, sunflower seed, safflower, poppy seed, and linseed. Its specific gravity is about 0.901, and its refractive index is about 1.469. It has a boiling point ranging from 225° to 230° and a melting point around -5°. One milliliter dissolves in 10 mL of petroleum ether. It is freely soluble in ether soluble in absolute alcohol and in chloroform and miscible with dimethylformamide, fat solvents, and oils. It is insoluble in water. 

The original soybean oil (SBO), the processed soybean oil under similar conditions without catalyst (SBO control), and polymers of soybean oil (PSBO) were dissolved in THF. Molecular weights and molecular weight distribution were measured by GPC with a differential refractive index detector using THF as an eluent. The flow rate was 1.00 mL/min at 40 C. The injection volume was 100 pL. Linear polystyrene standards (Polymer Laboratories (PL), Mn = 580-lOOK, Mw/Mn = 1) were used for calibration of molecular weights of all polymers of PSBO. 2 PL gel 3 pm mixed E columns (300 mm x 7.5 mm) in series were used to resolve the samples. 

Peroxide value, expressed as milliequivalents of peroxide per kilogram of oil, measures the primary oxidation products of oils— the hydroperoxides. The peroxide value has shown a particularly good correlation with sensory flavor scores of soybean oU, and its use during storage is quite common. The peroxide value is an index to the oxidative state of an oU. Soybean oU is considered fresh with a peroxide value <1.0 mEq/kg, to have low oxidation with 1.0-5.0 mEq/kg, to have moderate oxidation at 5.0-10.0 mEq/kg, to have high oxidation at > 10.0 mEq/kg, and to have poor flavor quality at >20 mEq/kg (6). Several methods (300-303) can be used to measure the peroxide value of an oil depending on the specific circumstance. 

Laboratory tests such as urease activity, protein dispersibility index (PDI), nitrogen solubility index (NSI), thiamine, and water absorption have been found valuable in monitoring daily production for protein quality. But biological chick and/or rat assays are the only reliable means currently available for predetermining the nutritional value of whole soybean protein they must be conducted periodically to verify results of chemical tests (31). If whole soybeans are to be used in a mixture containing 20% or more soybean meal, 5% or more urea, and 20% or more molasses, or an equivalent mixture, and exposed to hot, humid storage conditions, it is advisable that the urease activity of the whole soybeans not exceed 0.12 increase in pH (31). Extruded or roasted soybeans properly treated for cattle to increase bypass protein should have urease values of less than 0.05 pH rise. A urease rise of 0.05-0.20 is an indication of proper treatment for swine and poultry. 

The protein concentration and amino acid composition of sunflower meal also vary with the source of seed, and high-temperature processing may have a deleterious effect on its lysine content. Generally, however, sunflower meal exhibits a well-balanced amino acid composition with an essential amino acid index of 68, compared to 79 for soybean meal and 100 for whole egg (35). 

High nitrogen solubihty index (NSI), soy protein for manufacture of meat analogs is prepared in flash desolventizers. Some soybean extraction plants send part of their marc through a flash desolventizer to serve the high NSI soy flour market and the balance of their marc through desolventizer/toasters to serve the animal feed soy meal market. The first flash desolventizer was commissioned by EMI Corporation (Em. Corp., Des Plaines, Illinois) in 1960 (214). 

John et al. (70) studied and compared the properties of polyurethane foam obtained from soybean oil-based polyols and synthetic polyols and found that the soybean-based polyols showed enhanced reactivity and that the foaming reactions proceeded in a very similar way to synthetic polyols. It was also found that their properties were sensitive to several variables such as water content, isocyanate index, and catalysts. The reaction rate was mainly controlled by the water and isocyanate content. As the water content increased, the reaction was faster and the amount of the hard segment increased. In addition, MDl yielded more rigid foams than TDL... 

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