Soybean cotyledons

Fig. 1. Transmission electron micrograph of a section of a mature, hydrated soybean cotyledon. Protein bodies (PB), lipid bodies (LB), and cell wall (CW)...

Tempeh. DehuUed cooked soybeans are inoculated with the mold, Thi pus oligosporus packed in perforated plastic bags, and allowed to ferment for 18 h. The mold mycelium overgrows the soybean cotyledons and forms a compact cake. When sHced and deep-fried in oil, a crisp and golden brown product is obtained. Although native to Indonesia, tempeh has become popular with vegetarians in the United States and other Western countries (93). 

Feung, C. S.. Hamilton, R.H., and Witham, F.H. Metabolism of 2,4-dichlorophenoxyacetic acid by soybean cotyledon callus tissue cultures. J. Agric. Food Chem., 19(3) 475-479,1971. 

Soybean cotyledons -source of dietary fiber [DIETARY FIBER] (Vol 8)... 

Bray, E.A. Beachy, R.N. (1985). Regulation by ABA of P-congly-cinin expression in cultured developing soybean cotyledons. Plant Physiology 79, 746-50. 

Ihl, M. Indole-acetic acid binding proteins in soybean cotyledon. Planta, 1976, 131, 223-228. 

Relatively few detailed studies have been performed on the GDH s of plants. An enzyme active with NAD but not NADP has been purified 1250-fold from pea roots (4S)- When assayed by reductive amination, however, the rate of reaction is 1.8 times faster with NADPH than NADH. An NAD-linked enzyme has been isolated from soybean cotyledons (47), and a similar enzyme from com leaves (4 ) has been shown not to be affected by purine nucleotides (17). 

Fornaroli, S. S. Petrussa E. Braidot A. Vianello F. Macri. Purification of a plasma membrane-bound lipoxygenase from soybean cotyledons. Plant Sci. 1999, 145, 1—10. 

Kato, T H. Ohta K. Tanaka D. Shibata. Appearance of new lipoxygenases in soybean cotyledons after germination and evidence for expression of a major lipoxygenase gene. Plant Physiol. 1992, 98, 324 330. 

Wilson, R.F. H.H. Weissinger J.A. Buck G.D. Faulkner. Involvement of phospholipids in polyunsaturated fatty acid synthesis in developing soybean cotyledons. Plant Physiol. 1980, 66, 545-549. 

Soybean proteins are packaged in discrete spherical subcellular structures called protein bodies in the palisade-like cells of the soybean cotyledons (Bair Snyder, 1980). The soybean storage protein structures for glycinin and P-conglycinin are apparently highly conserved to maximize protein packaging in the protein bodies (Shewry et ah. 

It is desirable to remove the hull (seed coat) that covers the soybean cotyledon or meat. Soybean hulls contain much less oil and protein than do the meats. Soybean hulls account for about 8% of the bean dry matter but contain less than 1% lipid. Removing the hull reduces the amount of material that must be further processed, thus increasing downstream plant capacity and reducing energy consumption per unit processed. However, removing the hull is usually done to raise the protein level of the meal. The protein content of soybean meal increases by about 4 percentage points... 

Frietas et al. (1997) improved oil recovery by extruding dehulled soybean cotyledons prior to enzyme-assisted AEP, but extruding dehulled soybeans without flaking does not achieve as extensive cell distortion as does extrusion of flaked soybeans. AEP of extruded full-fat soy flakes gave 68% extraction of the total available oil without using enzymes but, with a protease enzyme treatment, oil extraction increased to >90% (Lamsal et al., 2006). Treating with cellulase did not enhance oil extraction either alone or in combination with protease. Low levels of proteolysis do not seem to affect protein precipitation as SPI. 

Storage proteins in soybean cotyledon cells are deposited in discrete protein bodies. Attempts were made to separate them from other cellular constituents by fine milling and density flotation using glycerin, other polyhydric alcohols, sodium chloride, sucrose, and metal salts of organic acids. A density of 1.2 to 1.5 g/mL is required to float protein bodies, and water activity must be maintained at less than 0.85 to prevent hydration from occurring. The separated bodies contain >80% protein mfb (Kolaretal., 1985). 

FIGURE 2.1 SEM micrograph of soybean cotyledon cells. Protein bodies (p), lipid bodies (1), cytoplasmic network (c). 

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