Addition of Soybean

Figure 2.2 Oxidation of human LDL by lipoxygenase and exposure to copper. The oxidation of human LDL was monitored by the increase in absorbance at 234 nm after the addition of soybean lipoxygenase (LO) at t = 0 min (— and —) followed by the addition of Cu (10 fiM) at t = 90 min to one LO-treated sample (—) and the control (-). Other conditions were exactly as described in Jessup et af. (1991).

Follow-up studies utilized finely-milled legume flours and the addition of soybean flour as a fat-control agent in an effort to improve doughnut quality (5). The legume products and doughnuts prepared from them are shown in Figure 5. On a dry weight basis, peanut flour from solvent extracted peanuts (PF-SE) contained 0.9% fat and 54.4% protein while cowpea flour (CF) contained 1.4% fat and 25.5% protein. Peanut flour from partially defatted untoasted peanuts (PF-PD-U) contained 34.5% fat and 34.9% protein while peanut flour from partially defatted peanuts toasted at 160°C contained 34.4% fat and 37.6% protein. 

A toluene dioxygenase (TOD) operon was isolated from a Pseudomonas strain which can grow on toluene through expression of the TOD operon, and cloned into E. coli. The TOD complex can convert both toluene and indene to the corresponding cis-dihydrodiols but has to be induced by toluene, which is toxic to the microorganism above a certain concentration. One measure to reduce toxicity is addition of soybean oil to the biotransformation to form a second, hydrophobic solvent phase to partition the toxic toluene from the aqueous biocatalyst solution. Expression of the operon in E. coli and process optimization lead to a titer of 1 g L-1 product with over 99% e.e. after 24 h of fermentation. However, the titer was not high enough for commercially attractive levels. 

Lecithins as antioxidants. The literature is replete with references to the antioxidant properties of lecithins. For example, Pokomy (102) claimed that the addition of soybean phospholipids reduced the rate of autoxidation of sunflower oil and prolonged the induction period. Hudson and Ghavani (103) published data showing that the addition of 0.3% dipalmitoyl phosphatidylethanolamine (DPE) to refined soybean oil increased the induction time during Rancimat analysis from 8.8 hours to 19.3 hours. Hildebrand et al. (104), and Jung et al. (105), also published data demonstrating the antioxidant properties of various phospholipids and commercial lecithins. 

Lipoxygenases will also catalyse co-oxidation reactions. This is used both in assay methods for the enzyme and in commercial applications. An example of the latter is the addition of soybean or broad bean flours (both rich in lipoxygenase activity) to wheat flour in order to bleach pigments for white bread production. Enzymes from different sources differ in their co-oxidation ability, e.g. soybean type-I enzyme has poor activity in this regard while soybean type-II enzyme has high co-oxidation activity. The reaction probably proceeds by a free-radical process (Veldink et al., 1977) and requires the presence of a substrate (e.g. linoleic acid) as well as the co-substrate. The extent of the cooxidation may depend on the lifetime of the radical intermediates and the relative efficiency of the lipoxygenase-mediated radical reduction (Weber and Grosch, 1976). 

As preliminary experiments, the influence of the addition of different amounts of lipids excluded from the DEAE-column ("leek lipids") on the CI8-C0A elongase activity was studied (Table 2). The phospholipid composition of the lipid extract was determined by TLC densitometry as 3.31, 0.86 and 0.35 pg for PC, PS and PE respectively. The role of PC was chiefly studied and the influence of the addition of soybean PC vesicles on CI8-C0A elongation was checked. In the presence of 19.8 pg of PC, the activity increased from 0.4 to 1.2 nmoles/mg/h. The highest activities were observed in the presence of 4.6 pg "leek lipids" with 13.2 pg of PC. Under these conditions the CI8-C0A elongation was increased 6.5-fold. These results indicated that the addition of PC alone, which was the predominant lipid in the microsomes, is not sufficient to completely restore the acyl-CoA elongase activity.The ad-... 

Since feeds contain other substances than those required by the animals of interest, studies have also been conducted on antinutritional factors in feedstuffs and on the use of additives. Certain feed ingredients contain chemicals that retard growth or may actually be toxic. Examples are gossypol in cottonseed meal and trypsin inhibitor in soybean meal. Restriction on the amount of the feedstuffs used is one way to avoid problems. In some cases, as is tme of trypsin inhibitor, proper processing can destroy the antinutritional factor. In this case, heating of soybean meal is effective. 

The nutritional value of a proteia can be improved by the addition of amino acids of low abundance ia that proteia. Thus the fortification of plant proteias such as wheat, com, and soybean with L-lysiae, DL-methionine, or other essential amino acids (L-tryptophan and L-threonine) is expected to alleviate some food problems (11). Such fortification has been widespread ia the feedstuff of domestic animals. 

Free substitution of protein meals ia feeds is much more restricted than interchange of oils ia foods. Because of a good balance of essential amino acids, soybean meal is an indispensable ingredient for efficient feeding of nonmminants, eg, poultry and swine. Soybeans provide ca 60% of the world s protein meals, including fish meal (Table 14). Of the 30.0 x 10 t of soybean meal produced in the United States in 1994—1995, 24.2 x 10 t was used domestically, primarily in feeds, and 5.7 x 10 t was exported (50). In the United States, poultry consume the largest share of soybean meal, followed by swine. Lesser amounts are fed to beef and dairy catde. Soybean meal is a principal ingredient in many pet foods (see Feeds and feed additives). 

Pea.nuts, The proteins of peanuts are low in lysine, threonine, cystine plus methionine, and tryptophan when compared to the amino acid requirements for children but meet the requirements for adults (see Table 3). Peanut flour can be used to increase the nutritive value of cereals such as cornmeal but further improvement is noted by the addition of lysine (71). The trypsin inhibitor content of raw peanuts is about one-fifth that of raw soybeans, but this concentration is sufficient to cause hypertrophy (enlargement) of the pancreas in rats. The inhibitors of peanuts are largely inactivated by moist heat treatment (48). As for cottonseed, peanuts are prone to contamination by aflatoxin. FDA regulations limit aflatoxin levels of peanuts and meals to 100 ppb for breeding beef catde, breeding swine, or poultry 200 ppb for finishing swine 300 ppb for finishing beef catde 20 ppb for immature animals and dairy animals and 20 ppb for humans. 

Polyunsaturated fatty acids in vegetable oils, particularly finolenic esters in soybean oil, are especially sensitive to oxidation. Even a slight degree of oxidation, commonly referred to as flavor reversion, results in undesirable flavors, eg, beany, grassy, painty, or fishy. Oxidation is controlled by the exclusion of metal contaminants, eg, iron and copper addition of metal inactivators such as citric acid minimum exposure to air, protection from light, and selective hydrogenation to decrease the finolenate content to ca 3% (74). Careful quality control is essential for the production of acceptable edible soybean oil products (75). 

The yield was highest with starch or dextrin, intermediate and about the same with sucrose, glucose, maltose and lactose and poorest with glycerol. Kanamycin was produced by media containing soybean meal, peanut meal, cottonseed meal, corn steep liquor, peptone, yeast extract or meat extract, with or without sodium nitrate. Commercially available soybean meal was recognized to be one of the best nitrogen sources. The addition of corn steep liquor, peptone, yeast extract or nitrate to the soybean meal promoted the production of kanamycin. 

Einhellig and Rasmussen (17) reported that In addition to ferulic and p-coumaric acids, vanillic acid reduced chlorophyll content of soybean leaves but did not affect chlorophyll In grain sorghum fSorghum bicolor (L.) Moench.]. It Is not known whether these reported mechanisms are primary or secondary events In the Inhibition of plant growth by allelochemlcals. 

The purple speck disease of soybeans is caused by the fungus Cercospora kikuchii, and additional cash crops such as tobacco, com, sugar, and coffee are damaged by fungi from the genus Cercospora [3]. Cercosporin (3, Chart 7.1), initially isolated in 1957 from Cercospora kikuchii and subsequently from other Cercospora species, was found to be the phototoxin responsible for the destructive nature of the pathogen [4]. For these reasons, the natural product was extensively studied, yet its structure was not elucidated until the 1970s [5]. 

Other pharmaceutical applications have seen the SdFFF applied successfully to monitor droplet size distributions in emulsions, together with their physical state or stability. Some examples are fluorocarbon emulsions, safflower oil emulsions, soybean oil emulsions, octane-in-water emulsions, and fat emulsions. SdFFF is also able to monitor changes in emulsion caused by aging or by the addition of electrolytes. SdFFF has been used to sort liposomes, as unilamellar vesicles or much larger multilamellar vesicles, the cubosom, and polylactate nanoparticles used as drug delivery systems [41]. 

Most of the applications of HPLC for protein analysis deal with the storage proteins in cereals (wheat, corn, rice, oat, barley) and beans (pea, soybeans). HPLC has proved useful for cultivar identihcation, protein separation, and characterization to detect adulterations (illegal addition of common wheat flour to durum wheat flour) [107]. Recently Losso et al. [146] have reported a rapid method for rice prolamin separation by perfusion chromatography on a RP POROS RH/2 column (UV detection at 230nm), sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (PAGE), and molecular size determination by MALDl-MS. DuPont et al. [147] used a combination of RP-HPLC and SDS-PAGE to determine the composition of wheat flour proteins previously fractionated by sequential extraction. 

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