Com steeping

Eckhoff, S.R. and Tso, C.C. 1991. Starch recovery from steeped com grits as affected by drying temperature and added commercial protease. Cereal Chem. 68, 319-320. 

Steeping and wet-milling processes are also utilized to separate soluble compounds from com. One process involves removal of soluble starch and protein from com by steeping com in a warm sulfurous acid solution for about one to two days. The undissolved com solids are then coarsely wet-milled and processed to collect the oil-containing germ for com oil production. Also, for more enzyme-resistant cellulose biomass, sulfuric acid or hydrochloric acid can be used to digest the cellulose polysaccharide into fermentable molecules. 

Anderson then developed a second screw-press, this one designed to generate lower pressure and to operate at higher capacity. It was used to prepress oilseeds and animal scraps and to dewater steeped com germ and other wet materials. The high-pressure press (The No. 1 Press) had a 15.2-cm (6-in.) diameter barrel. 

The present practice in steeping com has grown up almost of itself, that is, no one person has ever studied it enough to master it but numerous superintendents have each contributed small points. It may be said that at present the Bteeping of com is carried on in ajorude way. 

Still another method of steeping com used some years ago was... 

Steeped com Com kernels Com steep solida" Dilute HjSO] 1800-3000... 

After cleaning to remove coarse material, ie, cobs, and fines (broken com, dust, etc), the com is steeped in a sulfurous acid solution to soften the com and render the starch granules separable from the protein matrix that envelopes them. About 7% of the kernel s dry substance is leached out during this step, forming protein-rich steep-water, a valuable feed ingredient and fermentation adjunct. 

Succinic acid diesters are also obtained by one-step hydrogenation (over Pd on charcoal) and esterification of maleic anhydride dissolved in alcohols (40) carbonylation of acrylates in the presence of alcohols and Co complex catalysts (41—43) carbonylation of ethylene in alcohol in the presence of Pd or Pd—Cu catalysts (44—50) hydroformylation of acetylene with Mo and W complexes in the presence of butanol (51) and a biochemical process from dextrose/com steep Hquor, using Jinaerobiumspirillum succiniciproducens as a bacterium (52). 

A typical fermentation medium for penicillin production contains lactose, com steep Hquot, and calcium carbonate (3,153,154). In most industrial processes the carbohydrate source, glucose, beet molasses, or lactose, is continuously added to the fermentation. The rate of glucose addition must be carefully monitored, by pH or rate of oxygen depletion, because the synthesis of penicillin is markedly reduced in the presence of excess glucose. 

Microbiological Oxidation. Styrene [100-42-5] can be oxidized to PEA by aerobic cultuting with a Pseudomonas bacterium ia the appropriate medium (101). Eor a medium containing peptone, (NH 2 04, Na2HP04 12H20, KH2PO4, MgSO and com steep Hquor, the yield is 2.34 mg/mL. 

Fumaric acid can be produced in high yield by several genera of fungi, notably Aspergillus and Rhizopus, using glucose, com steep liquor and other substrates. Large amounts of caldum carbonate have to be added to neutralise the fumaric add. 

The subsequent advance was rather fortuitous and rested more with serendipity than with scientific logic. A search was made for cheaper more effective replacements for casein hydrolysate. Amongst the tested materials was com steep liquor (CSL). CSL is a by-product of the manufacture of starch from maize kemals. Whole maize is incubated in warm water, at 50°C acidified with SO2. Thermophilic bacteria hydrolyse proteins and other components of the kemals, thereby loosening the starch granules. These are removed, leaving behind the steep liquor which is used to treat further maize kemals. Ultimately, the liquor is too viscous to re-use and the liquor is concentrated and used as cattle feed. It was this material that was used for penicillin fermentation. Surprisingly, the yield of penicillin increased by a further 5-10 fold giving yields of 50-100 ig ml. 

Molasses, corn steep liquor, waste product from sugar industry, and wet milling com are used for the production of penicillin... 

In the manufacture of baker s yeast, the stock strain is inoculated into a medium that containing molasses and com steep liquor. The pH of the medium is adjusted to be slightly acidic at pH 4-5. The acidic pH may retard the bacterial growth. The inoculated medium is aerated during the incubation period. At the end, the cells are harvested by centrifuging out the fermentation broth, and they are recovered by filter press. A small amount of vegetable oil is added to act as plasticiser, and then the cell mass is moulded into blocks. The process is shown in Figure 1.2. 

Various sources of carbohydrate are used in the fermentation processes. Molasses and com steep are the most common carbon sources used to generate energy for biosynthesis. Having the correct composition and desired concentration is a necessary task in actual experimental work. 

Corn steep liquor contains 2.5% invert sugars and 50% water. The rest of the feed is considered as residual solids. Beet molasses containing 50% sucrose, 1% invert sugar, 18% water and remainder solids are mixed with corn steep liquor in a mixing tank. Water is added to produce a diluted mixture with 2% invert sugar, 125 kg com steep hquor and 45 kg molasses, which is fed into an enzymatic hydrolysis tank. 

A flow diagram for diluting carbohydrates, com steep liquor and molasses in the mixing tank is shown in Figure 9.4. 

Media name Soybean meal-glucose [26] Malt extract [58] Com Steep Liquor [62]... 

Dailey, O.D., Jr. 2000. Variability in water absorption of germ and endosperm during laboratory steeping of a yellow dent com hybrid. Cereal Chem. 77, 721-723. 

Freeman, J.E. 1973. Quality factors affecting value of com for wet milling. Trans. ASAE 16, 671-678. Hassanean, A. and Abdel-Wahed, A. 1986. A new method to short the steeping period of com grains. 

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