Starch Recovery Research Articles

Production of carboxylic acids from hydrolyzed corn meal by immobilized cell fermentation in a fibrous-bed bioreactor

Corn meal hydrolyzed with amylases was used as the carbon source for producing acetic, propionic, and butyric acids via anaerobic fermentations. In this study, corn meal, containing 75% (w/w) starch, 20% (w/w) fibers, and 1.5% (w/w) protein, was first hydrolyzed using amylases at 60 °C. The hydrolysis yielded approximately 100% recovery of starch converted to glucose and 17.9% recovery of protein. The resulting corn meal hydrolyzate was then used, after sterilization, for fermentation studies. A co-culture of Lactococcus lactis and Clostridium formicoaceticum was used to produce acetic acid from glucose. Propionibacterium acidipropionici was used for propionic acid fermentation, and Clostridium tyrobutylicum was used for butyric acid production. These cells were immobilized on a spirally wound fibrous matrix packed in a fibrous-bed bioreactor (FBB) developed for multi-phase biological reactions or fermentation. The bioreactor was connected to a stirred-tank fermentor that provided pH and temperature controls via medium circulation. The fermentation system was operated at the recycle batch mode. Temperature and pH were controlled at 37 °C and 7.6, respectively, for acetic acid fermentation, 32 °C and 6.0, respectively, for propionic acid fermentation, and 37 °C and 6.0, respectively, for butyric acid production. The fermentation demonstrated a yield of approximately 100% and a volumetric productivity of approximately 1 g/(l h) for acetic acid production. The propionic acid fermentation achieved an approximately 60% yield and a productivity of 2.12 g/(l h), whereas the butyric acid fermentation obtained an approximately 50% yield and a productivity of 6.78 g/(l h). These results were comparable to, or better than those fermentations using chemically defined media containing glucose as the substrate, suggesting that these carboxylic acids can be efficiently produced from direct fermentation of corn meal hydrolyzate. The corn fiber present as suspended solids in the corn meal hydrolyzate did not cause operating problem to the immobilized cell bioreactor as is usually encountered by conventional immobilized cell bioreactor systems. It is concluded that the FBB technology is suitable for producing value-added biochemicals directly from agricultural residues or commodities such as corn meal.

Study of a Small‐Scale Laboratory Wet‐Milling Procedure for Wheat

ABSTRACTThe objectives of this research were to study the effects of slurry specific gravity, starch table slope, slurry pumping rate, and their interactions on starch recovery and purity; and to propose a small‐scale laboratory wet‐milling procedure for wheat. First‐order and second‐order response surface regression models were developed to study the effects and interactions of slurry specific gravity, starch table slope, and slurry pumping rate on starch and gluten separation for a 100‐g wheat wet‐milling procedure. The starch and starch protein content data fit the first‐order models (R2 = 0.99 and 0.96) better than the second‐order models (R2 = 0.98 and 0.93). Regression results from the first‐order models indicated that specific gravity, table slope, pumping rate, and their interactions all had a significant effect on starch yield and purity. However, these effects could be simplified as the effect of the resident time of starch and gluten slurry on the starch table and the specific gravity. Starch yield increased as resident time increased and specific gravity decreased. Protein content in starch decreased as the resident time decreased and the specific gravity increased. The separation condition with specific gravity of 3 Bé, table slope of 1.04 cm/m, and pumping rate of 50 mL/min was recommended. Under this condition, starch recovery was 85.6% and protein content of starch was 0.42%, which was similar to the 1.5‐kg laboratory methods in starch recovery. Total solids recovery was 98.1%, which is similar to that from 1.5‐kg laboratory methods. These results indicated that precision of the 100‐g wheat wet‐milling procedure was similar to that of the 1.5‐kg laboratory methods.

Effect of Steeping Conditions (Sulfur Dioxide, Lactic Acid, and Temperature) on Starch Yield, Starch Quality, and Germ Quality from the Intermittent Milling and Dynamic Steeping Process (IMDS) for a Brazilian Corn Hybrid

ABSTRACTEffect of lactic acid, SO2, temperature, and their interactions were assessed on the dynamic steeping of a Brazilian dent corn (hybrid XL 606) to determine the ideal relationship among these variables to improve the wet‐milling process for starch and corn by‐products production. A 2×2×3 factorial experimental design was used with SO2 levels of 0.05 and 0.1% (w/v), lactic acid levels of 0 and 0.5% (v/v), and temperatures of 52, 60, and 68°C. Starch yield was used as deciding factor to choose the best treatment. Lactic acid added in the steep solution improved the starch yield by an average of 5.6 percentage points. SO2 was more available to break down the structural protein network at 0.1% than at the 0.05% level. Starch‐gluten separation was difficult at 68°C. The lactic acid and SO2 concentrations and steeping temperatures for better starch recovery were 0.5, 0.1, and 52°C, respectively. The Intermittent Milling and Dynamic Steeping (IMDS) process produced, on average, 1.4% more starch than the conventional 36‐ hr steeping process. Protein in starch, oil content in germ, and germ damage were used as quality factors. Total steep time can be reduced from 36 hr for conventional wet‐milling to 8 hr for the IMDS process.

Contribution of storage and structural polysaccharides to the fermentation process and nutritive value of lucerne ensiled alone or mixed with cereal grains

The low content of water soluble carbohydrates (WSC) and the high buffering capacity usually constrains lucerne ( Medicago sativa) ensilability. However, there are other sources of readily fermentable substrate and positive effects of adding cereal grains to wet silages have been reported. An experiment was carried out to study the contribution of hemicellulose, cellulose and natural or added starch to the silage fermentation process, and in vitro digestibility and gas production. A crop of lucerne (10% blooming) was chopped, inoculated with lactic acid bacteria, and ensiled in microsilos with four treatments: alone (T0), or with 50 kg/t of sucrose (SU), barley (BRL), or maize (MZ). Microsilos were incubated for 47 days. Polysaccharide recovery was determined by the mass balance technique, and starch by dacron bag. Except for SU, all treatments were apparently limited by the amount of WSC needed to sustain good silage fermentation. As expected, SU produced an excellent fermentation but despite initial WSC differences, there were no significant differences with BRL for total fatty acids, lactic and acetic acid, total acidity, pH and NH 3-N. Fermentation characteristics of MZ were generally worse than BRL’s and similar to T0’s ones. Hemicellulose was extensively hydrolysed (T0: 59.5%; MZ: 38.1%; BRL: 48.8%; and SU: 46.8%). Cellulose was almost quantitatively recovered and starch recovery averaged 70% for T0 and BRL, and approximately 100% for MZ and SU. The type of cereal added affected starch recovery using the dacron bag technique (MZ: 77%; BRL: 47%; P<0.05). True dry matter digestibility was the same for all treatments (fresh lucerne: 81.3%; T0: 80.7%; MZ: 81.8%; BRL: 80.5%; and SU: 82.1%), and neutral detergent fibre digestibility (NDF-D) of silages was reduced in relation to the fresh material (fresh lucerne: 55.1%; T0: 48.8%; MZ: 51.9%; BRL: 45.3%; and SU: 46.7%). Although all silages showed a rapid in vitro fermentation pattern, gas production (48 h) of SU and BRL (265.4 and 260.5 ml/g DM) was greater than T0 and MZ (246.0 and 244.6 ml/g DM) ( P<0.05). It can be concluded that starch hydrolysis depends on the type of grain, and that starch from barley and legume cell wall components could supply additional fermentable substrate to the ensiling process. These data also showed that ensiling reduced NDF-D and suggest that labile NDF fractions removed during the ensiling process were later accessible during the in vitro fermentation.

Heterosis in Compositional, Physical, and Wet‐Milling Properties of Adapted × Exotic Corn Crosses

ABSTRACTCompositional, physical, and wet‐milling properties of 10 corn accessions selected from the Germplasm Enhancement of Maize (GEM) project, two Corn Belt Dent inbreds (B73 and Mo17), and their crosses were compared to determine heterosis among these traits and to gain insight about their genetic control. Crossing the GEM accessions with each inbred increased protein and reduced starch contents. Mean absolute densities and test weights of the crosses were greater than for either parent. Little heterosis was observed in 1,000‐kernel weight, and the crosses had similar values to the GEM parents (relatively low). Grain protein contents were greater for the crosses than for the GEM accessions; starch and oil contents of the crosses were intermediate to both parents. The wet‐milling properties of the crosses were improved over those of the GEM accessions. Crossing the GEM accessions with B73 greatly increased residual protein content in the recovered starch, whereas values for protein in starch for the GEM × Mo17 crosses were greater than for the GEM accessions and not unlike that of Mo17. High‐parent heterosis was greater in the GEM × Mo17 crosses for absolute density, test weight, 1,000‐kernel weight, and starch content, but lower for protein and fat contents. GEM × Mo17 crosses yielded greater high‐parent heterosis for starch yield and starch recovery, and lower high‐parent heterosis for gluten and fiber yields. Mo17 expressed poor wet‐milling properties as an inbred but produced superior hybrids compared with B73, which had better wetmilling properties as an inbred.

Genetic effects of the soft starch (h) and background loci on volume of starch granules in five inbreds of maize

Larger particle volume is beneficial for many aspects of maize starch processing, and may improve the performance of some starch attributes. This study focused on the soft starch (h) locus to identify its potentially influential role in starch particle volume distribution. The objectives were to study the genetic expression of starch particle volume of the h locus in different genetic backgrounds and the gene action conditioning starch particle volume of other loci in both normal-starch and h-starch backgrounds. Forty-five populations (five intra-inbred F1s, 10 hybrid F1s 10 F2s, 10 BC1F1s to h/h parent, and 10 BC1 to h:h conversion of normal parent) were planted in 1993 at two locations and in 1995 at one location. Selfed heterozygotes (±/h) in all generations provided intra-ear comparisons of normal and h starch, and F3 and BC1F2 generations provided inter-ear comparisons. Significant differences were found between normal and h:h genotypes in all intra-ear and inter-ear comparisons. In all cases, general combining ability effects were highly significant, suggesting the presence of additive gene effects. Generation mean analysis of normal and h:h starch materials yielded similar results, indicating the predominance of additive and some dominance effects for other loci on starch particle volume. These results indicate the usefulness of the soft starch gene and additional genetic variation among inbreds in the improvement of starch particle volume for increased starch recovery in wet milling.

Effect of Mill Plate Setting and Number of Dynamic Steeping Stages for an Intermittent Milling and Dynamic Steeping (IMDS) Process for Corn

ABSTRACTEffect of corn degermination mill parameters (clearance between mill plates and rpm) were assessed on the broken germ and number of whole kernels in mash so as to optimize the cracking procedure for the intermittent milling and dynamic steeping (IMDS) process. The dynamic steep time and number of intermittent milling stages for the IMDS process were also optimized for maximum starch recovery. A comparison was made between the IMDS and the conventional steeping process for fraction yields. A clearance of 0.45–0.48 cm between the plates gave the most optimum processing conditions (minimum broken germ and least amount of whole kernels in mash after cracking). Effect of rpm on germ damage and kernel cracking was not significant when optimum clearance between the degermination plates was maintained. Two stages of intermittent milling with a dynamic steep time of 30 min or higher was recommended because it produced the highest yield of starch and germ. Comparison of the IMDS process with the conventional wet‐milling process showed that starch and gluten yield increased by 1.6 and 4.26%, respectively, in the IMDS process. Germ recovered from the IMDS process was 0.54% lower than that from the conventional steeping process.

Rice Starch Isolation by Alkaline Protease Digestion of Wet-milled Rice Flour

Alkaline protease digestion with a food-grade enzyme was used to produce rice starch from wet-milled rice flour (WMRF). In a 3×3 factorial modelling experiment, recoveries of starch and levels of protein contamination were determined at pH 8·5–10·0, protease levels of 0·5–1·5% (based on WMRF), and digestion times of 5·0–30·0 h. The following digestion conditions were kept constant; 55 °C with mild agitation, 34–37% (w/v) flour solids, and alkalinity to within ±0·2 pH units. Regression equations with the three variables explained 92% and 98%, respectively, of the variances in starch recovery and protein contamination. Upon digestion with 1·1% protease at pH 10·0 and 18·0 h, starch recovery was 95% and protein contamination was 0·5%. Most hydrolysis of rice protein occurred in the first 3–4 h of digestion as determined by the consumption of sodium hydroxide (NaOH). Rice starch also was isolated by extraction of WMRF with c. 2·5 parts of 0·05 m NaOH at c. pH 12. The recovery of starch was c. 10% higher with the protease method than with the NaOH method, and the effluents contained mostly amino acid salts as opposed to protein mixed with alkali. The rice starch isolated by protease digestion was lighter in appearance, contained more lipid, and gave a somewhat lower consistency after pasting. The raw materials used to isolate rice starch by the protease method were approximately twice as costly in 1996 as those in the NaOH method, principally because of the cost of the protease (55% of total).

Processing of cassava waste for improved biomass utilization

Cassava ( Manihot esculenta Crantz) pulp is the solid waste produced as a consequence of starch production. This pulp contains a high starch content (50–60% dry basis), causing an environmental problem with disposal. In order to recover this starch, physical or biological treatment of the material must be employed. Pulp was treated either by sonication or incubation with a multi-enzyme mixture of cellulase and pectinase. Both methods were found to improve efficiency of starch extraction by disrupting the complex structure of polysaccharides associated with and entrapping starch granules. In the enzymatic treatment, the content of cellulase and pectinase for high efficiency of starch extraction determined as the yield of liberated starch was investigated using Response Surface Methodology. Use of either cellulase or pectinase alone failed to effectively improve starch extraction. Cellulase concentration seemed to have a greater effect on efficiency of starch yield than pectinase concentration. Treatment of pulp with 15 Novo cellulase units (NCU) of cellulase and 122.5 polygalacturonase (PG) units of pectinase per g dry pulp for 60 min resulted in 40% starch recovery. Quality characteristics of the liberated starch, including paste viscosity (measured by Rapid Visco Analysis) and thermal properties (measured by Differential Scanning Calorimetry) were comparable to a primary starch obtained by root extraction. Susceptibility of the liberated starch to α-amylase was inferior to that of a primary starch. Cellulase and pectinase, however, increased α-amylase susceptibility of the starch remaining in the pulp.

Chemical Composition and Microstructure of Two Naked Waxy Barleys

Two naked waxy barley cultivars, Bz 489-30 and Prowashonupana were analysed in order to study the chemical composition and the microstructure. Prowashonupana contained more protein, fat and ash, and less starch than Bz 489-30. The content of mixed-linked β-glucan was almost three times higher in Prowashonupana (14·9%) than in Bz 489-30 (5·6%), but extractability at 40 °C was much lower. Microscopy studies showed that kernels and endosperm cells of Prowashonupana were irregular, and that cell walls were thicker with a higher content of mixed-linked β-glucan than in Bz 489-30. In both barleys the sub-aleurone layer contained black starch granules, indicating a higher amylose content in this structure compared to the rest of the kernel. Starch was isolated from both barleys using two different procedures and analysed for amylose content. The amylose content was higher, while volume % of A-granules was lower and mean diameter of A-granules was smaller in starch isolated from Prowashonupana than from Bz 489-30. Both composition and yield of starch were however influenced by the isolation procedure used. The procedure which gave higher starch yield resulted in a higher amylose content, probably because of greater recovery of starch from outer parts of the kernel with a higher amylose content.

Starch from Alberta potatoes: wet-isolation and some physicochemical properties

Starch content of six varieties of Alberta-grown potato tubers was more than 16% (wet basis). The tubers were wet fractionated in the laboratory and starch was recovered. The starch recovery ranged from 61 to 67%. The composition of the potato juice/fruit water (dry matter, protein, ash and mineral content) and starch isolations (moisture, starch, protein, lipid, ash, phosphorous and amylose content) was determined. The physicochemical characterization of the potato starch isolations were done in terms of granule size distribution, crystallinity (X-ray diffractometry), gelatinization (differential scanning calorimetry) properties, swelling factor and the changes in viscosity during heating and cooling of starch-water slurry (Brabender viscography). Substantial differences in the starch content of the tubers, fruit water composition and starch physicochemical properties were observed between potato varieties.

Paste Properties of Modified Starches from Partial Waxy Wheats

ABSTRACTProperties of modified starches from partial waxy wheats have not been examined. Protease digestion of cracked kernels of three hard winter wheats varying in amylose content led to 82–85% recovery of starch, whereas kneading of the flour‐water doughs gave 75–83% recovery. All starches had a protein content of &lt;0.3% and ash content of &lt;0.01%. Granule size distributions showed that starch from Ike kernels contained 86% A‐type granules with a peak size of ≈18μm, and Karl‐92 starch contained 77% A‐type granules with a peak size of ≈16μm. The A‐type granules (82%) from Rio Blanco starch were intermediate in size. The amylose content of Karl‐92 starch, determined by concanavalin‐A precipitation of amylpectin, was 28%, which was 17% higher than that of Ike starch (23%). The amylose content of Rio Blanco starch was 26%. The lipid content of Karl‐92 starch, determined as fatty acid methyl esters, also was 18% higher than that of Ike starch (601 vs. 488 mg/100 g of starch, respectively). Wheat starches were modified with hydroxypropyl (HP) groups to low (1.5–2.5%) and medium (≈4.0%) levels, and the HP starches were cross‐linked with phosphoryl chloride at levels of 0.003–0.075%. Pasting curves (amylograms) showed that Ike starch substituted with a low level of HP and optimally cross‐linked with 0.025% phosphoryl chloride (starch basis) had a greater paste consistency than low HP cross‐linked Karl‐92, and Rio Blanco starches. At 4% HP and optimum cross‐linking (0.003% phosphoryl chloride), the paste consistencies of the modified starches were nearly the same. The clarity of unmodified Ike starch paste was higher than that of Karl‐92 or Rio Blanco starch pastes, and the clarity of all three pastes decreased as cross‐linking was increased. Unmodified Ike starch formed a stronger gel than unmodified Karl‐92 and Rio Blanco starches, but gel properties largely converged as the starches were modified.

Colonic bacterial activity and serum lipid risk factors for cardiovascular disease

Antibiotics are being proposed for the treatment of cardiovascular disease. In the past, antibiotics were advocated for the control of hypercholesterolemia. We have therefore investigated the relation between colonic bacterial activity and serum lipids. In a four-phase randomized crossover study, we fed a different starch supplement during each 2-week phase to 24 healthy subjects. In two phases, supplements containing resistant starches were fed that reach the colon and are largely fermented by colonic bacteria. Fecal starch recovery therefore reflects the metabolic activity of colonic microflora. The control treatments were conventional starches. Blood lipid levels were obtained at the start and 4-day fecal collections at the end of each phase. Resistant starch supplements increased fecal starch excretion by 3.8 +/- 1.2 g/d more than conventional starches (P = .006). Mean starch excretion was related positively to pretreatment serum high-density lipoprotein (HDL) cholesterol (r = -.57, P = .003) and negatively to low-density lipoprotein (LDL) cholesterol (r = -.57, P = .004), apolipoprotein B:AI (r = -.56, P = .005), and fecal output of fusobacteria (r = -.73, P = .003) and bacteroides (r = -.72, P = .003). The ratio of fusobacteria to total anaerobes was also related to pretreatment LDL cholesterol (r = .56, P = .037). Differences in starch excretion between healthy subjects, as a measure of bacterial activity, accounted for 32% of the variation in pretreatment LDL cholesterol. The activity of colonic microflora therefore appears to influence serum lipid levels. Alterations of bacterial number and activity may provide an additional strategy to control serum lipid risk factors for cardiovascular disease.

Effect of Fiber Degrading Enzymes on Wet Milling and Starch Properties of Different Types of Sorghums and Maize

A factorial experiment (4 × 2 × 2) was carried out to study the effect of a fiber degrading enzyme complex on starch yield, SO2 steeping time and starch properties of normal red sorghum (RS), heterowaxy (WHWx) and waxy (WWx) white sorghums compared to regular yellow maize (YM). Starch yields and total starch recovery for the sorg-hums ranged from 53—64 % and 70—85 %, respectively. Sorghum starch recovery values were significantly lower (p < 0.05) than maize (66 % starch yield and 88 % recovery). However, the WWx yielded more starch with lower protein and ash contents (p < 0.05) than the RS and WHWx sorghums. In the RS, the fiber degrading enzymes reduced steep time while producing the same starch recovery. The WWx starch required lower temperature to initiate gelatinization and had higher peak viscosities and lower retrogradation than the other starches. The WHWx starch had intermediate viscoamylograph properties between the regular and waxy starches.

Wet-milling Factors of Sorghum and Relationship to Grain Quality

Relationships of grain sorghum quality factors (proximate composition and physical properties) to laboratory wet-milling attributes (fraction yields, protein content of fractions and recovery values) of 24 grain sorghum commercial hybrids were determined. Initial water absorption rate was positively correlated with both starch and gluten recoveries (r>0·45), thus showing the greatest significance among all quality factors. The need to understand fully protein matrix breakdown relative to obtaining optimum separation of components was indicated. Positive correlations of residual protein in starch with density and percent abraded (r>0·45) were observed. Laboratory wet-milling attributes also were correlated among themselves. The highest positive correlations were observed among yield and recovery of starch and gluten (r>0·6). These four parameters had strong negative correlations with fiber/germ yield (r<−0·6). Principal component factor analysis identified five factors (named as matrix-breakdown effect, solids-leaching effect, protein-dispersion effect, protein content of gluten effect, and washing-solids effect) that explained 91% of the total variation among wet-milling attributes.

An integrated bioconversion process for production of l-lactic acid from starchy potato feedstocks

The potential market for lactic acid as the feedstock for biodegradable polymers, oxygenated chemicals, and specialty chemicals is significant. L-lactic acid is often the desired enantiomer for such applications. However, stereospecific lactobacilli do not metabolize starch efficiently. In this work, Argonne researchers have developed a process to convert starchy feedstocks into L-lactic acid. The processing steps include starch recovery, continuous liquefaction, and simultaneous saccharification and fermentation. Over 100 g/L of lactic acid was produced in less than 48 h. The optical purity of the product was greater than 95%. This process has potential economical advantages over the conventional process.

Springiness of Pancake and Its Relation to Binding of Prime Starch to Tailings in Stored Wheat Flour

ABSTRACTWheat flours were stored at room temperature (15–25°C), 40, 60, 80, and 100°C for various times. The baking performance of these flours was then evaluated in terms of the springiness of pancakes (recovery from crushing). Baking performance improved with increased storage time at each temperature. Brabender Amylograph tests of the flours indicated that the onset temperature in viscosity decreased with increased storage time at each temperature. When the flours were fractionated by acetic acid (pH 3.5) with mortar and pestle, recoveries of the water‐solubles and gluten fractions were unchanged, but recoveries of prime starch and tailings fractions changed remarkably with increased storage time. On the other hand, those changes were not observed when flours were fractionated with a Waring blender. The binding of prime starch to tailings was correlated significantly with baking performance.

Effect of drying, initial moisture and variety in corn wet milling

A laboratory wet-milling process was used to determine starch yield and starch recovery of dent and flint corn dried under different drying conditions. A comparison with undried samples was performed. For the undried samples the starch recovery was not significantly different between both varieties. It decreased as both initial moisture content of the grains and drying air temperature increased. The reduction in starch recovery as well as the contamination by protein was greater for the flint than for the dent corn. Swelling, solubility and initial gelatinization temperatures of the starch derived from both varieties were affected by the drying conditions.

Recovery of Starch and Protein from Wet‐Milled Corn Fiber

ABSTRACTPhysical and chemical methods were used to recover starch and protein from wet‐milled corn fiber. A single milling of the fiber produced an 18% yield of mill starch. By separating the mill starch with a starch table, 68% of this material was recovered as starch with a protein contamination of 0.66%. Milling increased fine fiber from 4.5% in the starting material to 11.5% after a single grind. Successive additional milling passes modestly increased the mill starch and fine fiber yields with a corresponding decrease in the coarse fiber yield. Pretreatment with combinations of lactic and sulfurous acids had only a small effect on the distribution and composition of the recovered fractions.

Intermittent Milling and Dynamic Steeping Process for Corn Starch Recovery

ABSTRACTA procedure that reduces diffusional limitations by periodically milling the corn to reduce particle size and stirring the ground mash in the presence of sulfur dioxide (SO2) and lactic acid was developed. The process, called intermittent milling and dynamic steeping (IMDS), includes three main stages: initial soaking (a short‐time immersion in water) of whole kernels, initial cracking of the partially hydrated kernels, and dynamic steeping with interspersed milling. This study evaluated the three stages of the process separately, evaluating the effect of variables on each stage of the process. Corn fractions yield (germ, fiber, gluten, starch) were used to decide the best conditions for the soaking and steeping stages, and germ damage was used to determine the best kernel cracking method. Starch, gluten, and germ yields were not affected by soak temperatures (52–68°C) or soak time (1–3 hr). A temperature of 60°C was chosen for soaking because it increased the rate of kernel hydration without gelatinizing starch, which happens at higher temperatures. A 2‐hr soak time was preferred because there was less fiber in the germ fraction and less germ damage was observed. Although there were no advantage to using SO2 or lactic acid in the soak water, the presence of these compounds during dynamic steeping enhanced starch yield. The starch yield for 3 hr of dynamic steeping was not statistically different from the starch yield for a 7.5‐hr dynamic steep. The Bauer mill was preferred over the use of a roller mill or a commercial grade Waring blender for kernel cracking. The IMDS process produced, on an average, 1 percentage point more starch than the conventional 36‐hr steeping process. Total steep or kernel preparation time was reduced from 24–40 hr for conventional wet‐milling to 5 hr for the IMDS process.