Soybean color

Hou, H.J. K.C. Chang. Storage conditions affect soybean color, chemical composition and tofu qualities./. FoodProc. Preserv. 2004, 28, 473—488... 

Green coloration, present in many vegetable oils, poses a particular problem in oil extracted from immature or damaged soybeans. Chlorophyll is the compound responsible for this defect. StmcturaHy, chlorophyll is composed of a porphyrin ring system, in which magnesium is the central metal atom, and a phytol side chain which imparts a hydrophobic character to the stmcture. Conventional bleaching clays are not as effective for removal of chlorophylls as for red pigments, and specialized acid-activated adsorbents or carbon are required. 

Use of some oilseed proteins in foods is limited by flavor, color, and flatus effects. Raw soybeans, for example, taste grassy, beany, and bitter. Even after processing, residues of these flavors may limit the amounts of soybean proteins that can be added to a given food (87). The use of cottonseed and sunflower seed flours is restricted by the color imparted by gossypol and phenoHc acids, respectively. Flatus production by defatted soy flours has been attributed to raffinose and stachyose, which are removed by processing the flours into concentrates and isolates (88). 

Fig. 3. Schematic process flow diagram for an imitation cheese product having the following formulation dry ingredients, calcium caseinate (or rennet casein), 24.5 wt % tapioca flour, 3.0 wt % salt, 2.16 wt % adipic acid, 0.6 wt % vitamins and minerals, 0.1 wt % sorbic acid (mold inhibitor), 0.5 wt % fat—color blend, soybean oil hydrogenated to a Wiley melting point of 36°C, 21.3 wt % lactylated monoglycerides, 0.05 wt % red-orange coloring, 0.01 wt...

Colorant containing annatto and Ca caseinate as carrier mixed with water to be added directly to cheese milk yielding uniform colored cheese mass Water-dispersible beadlet of p-carotene is mixed with oil to attein composition that remains stable even in presence of polyphosphates and with antioxidant action even in absence of ascorbic acid Blending carotenoid pigment and soybean fiber (wifii tomato juice) as effective ingredient for dispersion stability... 

Monascus pigments have been used in Asian countries for centuries as food colorants and spices and in traditional medicine. These pigments are produced by the fungi of Monascus genus cultivated on carbohydrate-rich substrates such as rice, wheat, com, potatoes, and soybeans. Three species of Monascus identified are pilosus. 

Sinnecker, P. et al.. Relationship between color (instrumental and visual) and chlorophyll contents in soybean seeds during ripening, J. Agric. Food Chem., 50, 3961, 2002. 

The W1 locus encodes flavonoid 3 5 -hydroxylase F3 5 H) [21]. F3 5 H diverts metabolic flux into the blue delphinidin branch of anthocyanin biosynthesis (Fig. 4.1). In the absence of F3 H activity (f), Wi and recessive wl give imperfect black and buff seed colors, respectively [10]. However, in black seeds, F3 H (T) phenotypically masks Wl. In contrast to its role in seeds, Wl has a prominent role in flower colors, as delphinidin-based anthocyanins are the major pigments in purple soybean flowers [22, 23]. Interestingly, F3 5 H is expressed at very low levels in flowers and seeds [21]. This suggests that, out of the two branch-point genes (i.e., F3 H and F3 5 H), it is the strong expression of F3 H in seed coats and weak expression in the flowers that determines preferential accumulation of cyanidin-based and delphinidin-based anthocyanins in these respective tissues [21]. 

Perhaps the least understood of the five loci that control seed coat color in soybean is the O locus [10, 11]. The O locus only affects the phenotype of brown... 

Fig. 4.3 Bright field microscopy of palisade peels from soybeans at early maturation stage (400-500 mg fresh seed weight), (a) Black (Clark) with AVIs (black arrowheads), (b) Red-brown (Ml 1). Scale bar = 20 (jim. Effect of oxidation on seed coat color demonstrated by exposing immature seeds (400-500 mg fresh seed weight) (c-f) to air for 2 h (g-j). (c, g) Black (Clark), (d, h) red-brown (Mil), (e, i)brown (MlOO), and (f, j) yellow (Qark)...

Toda K, Yang D, Yamanaka N et al (2002) A single-base deletion in soybean flavonoid 3 -hydroxylase gene is associated with gray pubescence color. Plant Mol Biol 50 187-196... 

Iwashina T, Githiri SM, Benitez ER et al (2007) Analysis of flavonoids in flower petals of soybean near-isogenic lines for flower and pubescence color genes. J Hered 98 250-257... 

Iwashina T, Oyoo ME, Khan NA et al (2008) Analysis of flavonoids in flower petals of soybean flower color variants. Crop Sci 48 1918-1924... 

Instead of measuring the absorbance of the solution immediately after incubation, it is possible to determine the colored product 169 by HPLC-ELD (A.ex = 515 nm, A.fl = 553 nm). This procednre was applied for determination of MDA after oxidation of phos-phohpids catalyzed by soybean lipoxygenase . Peroxidation in the extracellular liquid of the brain cortex of rats was evaluated in vivo by microdialysis followed by reaction... 

Soybeans grow on a bushy, annual plant ranging in height from about 30 to 50 inches (75 to 125 cm). Stems have a hairlike covering and leaves are trifoliated. Flowers range in color from white to purple with variations in-between. Seedpods usually contain three spherical to oval seeds weighing 0.1 to 0.2 g. Most seeds have a yellow coat containing two oil- and protein-rich cotyledons. 

Among the naturally occurring filler materials are cellulosics, such as wood flour, alpha cellulose, shell flour, and starch, and proteinaceous fillers, such as soybean residues. Approximately 40,000 tons of cellulosic fillers are used annually by the U.S. polymer industry. Wood flour, which is produced by the attrition grinding of wood wastes, is used as a filler for phenolic resins, dark-colored urea resins, polyolefins, and polyvinyl chloride (PVC). Shell flour, which lacks the fibrous structure of wood flour, is made by grinding walnut and peanut shells. It is used as a replacement for wood flour. 

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