Role of Lactic Acid in Corn Steeping and Its Relation with Starch Isolation

Roushdi, M.; Fahmy, A. A.; Mostafa, M.Y.A.

doi:10.1002/star.19810331207

Cited by 19 publications

(10 citation statements)

References 4 publications

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“…The fiber fraction dropped from 3.1 to 13.1%, depending upon the hybrid, with the addition of 0.55% lactic acid. This increase in starch yield with decrease in the fiber fraction is in agreement with other studies (Roushdi et al 1981a, Eckhoff and Tso 1991, Du et al 1996.…”

Section: Effect Of Hybrid and Lactic Acid Level On Starch Yieldsupporting

confidence: 93%

“…Lactic acid is produced to a level of 0.6 to 2.0% during conventional counter-current steeping (Watson et al 1955). Some of lactic acid's beneficial effects observed in corn milling are: increased starch yields (Watson et al 1951, Roushdi et al 1981a, Eckhoff and Tso 1991, increased gluten filtration rate (Watson 1984), decreased evaporator fouling (Watson 1984), increased kernel softening (Cox et al 1944, Roushdi et al 1981a, Earp et al 1985, Shandera et al 1995, increased rate of water uptake (Cox et al 1944, Roushdi et al 1981a, Ruan et al 1992, and increased rate of SO 2 absorption (Shandera et al 1995).…”

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confidence: 99%

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Hybrid‐Dependent Effect of Lactic Acid on Corn Starch Yields

et al. 1997

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Cereal Chem. 74(3):249-253The effect of lactic acid on starch yields of different corn hybrids was determined by wet-milling 18 commercial corn hybrids at three levels of lactic acid. All 18 hybrid samples tested had higher starch yields when lactic acid was added to the steep solution, although the magnitude of the increased starch yields varied between 2.9 and 12.0%. The optimal lactic acid concentration for maximum starch recovery was found to be between 0.55 and 1.67% lactic acid, by wet-milling nine of the same 18 corn hybrids with seven levels of added lactic acid. Between 0.83 and 1.67% lactic acid, the starch yields of eight of the nine hybrids were constant (within ±0.5%). Results showed that the average starch yield across all hybrids decreased with a lactic acid concentration <0.55% and a lactic acid concentration >1.67%. 2 Corresponding

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Section: Effect Of Hybrid and Lactic Acid Level On Starch Yieldsupporting

confidence: 93%

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confidence: 99%

Hybrid‐Dependent Effect of Lactic Acid on Corn Starch Yields

et al. 1997

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“…Therefore, and Watson et al (1951) recommended addition of lactic acid to the steeping solution in the laboratory. Roushdi et al (1981) and Eckhoff and Tso (1991a) reported decreased starch yields of 4-6% in batch steeping corn when lactic acid was not used.…”

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confidence: 99%

Optimum Steeping Process for Wet Milling of Sorghum

et al. 2000

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Cereal Chem. 77(4):478-483Pioneer 8500, a red hard sorghum hybrid, was steeped batchwise using three steeping solutions at 50°C: SO 2 solution; SO 2 solution containing 1.25% (w/w) of a commercial multiple-enzyme preparation (Novo SP249); and SO 2 solution with the addition of 0.5% (w/w) lactic acid. Novo SP249 contained pectolytic, cellulolytic, hemicellulolytic, and proteolytic activities and small amounts of saccharolytic activities. Three SO 2 concentrations (0.1, 0.2, and 0.3% w/v) prepared by dissolving sodium bisulfite in distilled water and three steeping times (24, 36, and 48 hr) were used. Incorporation of multiple enzymes into the SO 2 resulted in an increase in starch yield with reduced protein content compared with the SO 2 solution alone. The best wet-milling performance for sorghum resulted from the SO 2 solution containing 0.5% lactic acid; it produced the whitest starch with the highest yield and the lowest protein content. Both higher SO 2 concentration of the steeping solution and longer steeping time led to higher starch yield, lower protein content in starch, and whiter starch. However, no significant differences in starch yield, protein content in starch, and starch color occurred between SO 2 concentrations of 0.2 and 0.3% for all three steeping solutions. The optimum steeping process for wet milling of sorghum was using a 0.2% SO 2 solution with 0.5% lactic acid for 36 hr at 50°C. Under these conditions, the starch yield, protein content in starch, and L value of starch color were 60.2% (db), 0.49% (db), and 92.7, respectively, which were not significantly different from the best values from the 48-hr steeping using the solution with 0.3% SO 2 and 0.5% lactic acid.Publication no. C-2000-0606-01R.

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“…The effect of the concentration of SO 2 in steepwater on the starch recovery was analyzed by Roushdi et al (1981). They found that samples steeped in low concentrations of SO 2 containing lactic acid produced high starch yields with low protein content.…”

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Effect of Chemical Pretreatments and Lactic Acid on the Rate of Water Absorption and Starch Yield in Corn Wet‐Milling

Suárez

1999

Cereal Chem

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Cereal Chem. 76(5):783-787The relative effectiveness of dehulling, potassium hydroxide dipping (alkali concentrations 0.2, 0.5, and 1.0 %), and ethyl oleate spraying (aqueous emulsion 1%, v/v) to increase the rate of water absorption by dent and flint corn during steeping was compared with untreated corn samples. These pretreatments increased the water absorption rate of both hybrids when compared with the untreated control samples. To evaluate the observed increase, the diffusion coefficients of pretreated and untreated corn samples were estimated. Corn grains steeped in SO 2 aqueous solution and variable lactic acid concentrations (0.2, 0.5, and 1.0%, v/v) were performed. Absorption rates for lactic acid concentrations were ≈0.5% higher than those steeped only in SO 2 solution. This effect was more marked for dent than for flint corn. Corn samples pretreated with potassium hydroxide had lower starch yields than the control. However, the presence of lactic acid in steepwater increased the starch yield of dent and flint corn, particularly for the samples treated with alkaline solution. This procedure was particularly beneficial for flint corn. An effective release of the starch granules was achieved within 24 hr of steeping.Since the pioneering works of Watson and Sanders (1961) and Fan et al (1965) on the function of sulfur dioxide as a steeping agent, many investigations have been conducted to reduce the time required for steeping by increasing the rate of water absorption. The effect of the concentration of SO 2 in steepwater on the starch recovery was analyzed by Roushdi et al (1981). They found that samples steeped in low concentrations of SO 2 containing lactic acid produced high starch yields with low protein content. Also the separation of hull, fiber, and protein from the steeped grains was very easy. On the other hand, Eckhoff and Tso (1991) reported that the application of gaseous SO 2 in corn wet-milling and the addition of lactic acid resulted in an increase in the starch yield.As steeping is, by far, the most time-consuming step in the wetmilling process, typically requiring 36-52 hr, various investigations were conducted to reduce the steeping time. Roushdi et al (1979) found that scratching presteeped corn grains facilitates penetration of the steeping water, reducing the steeping period by 40%. Wall and Paulis (1978) found that the treatment of corn with alkali disintegrates and disperses the matrix proteins, as well as facilitating the release of starch granules. Mistry and Eckhoff (1992) developed an alkali-debranning process where the pericarp was chemically removed and found that debranned kernels absorbed water more rapidly, reducing steeping time. More recently, Singh et al (1997) investigated the effect of sodium hydroxide, calcium hydroxide, and potassium hydroxide on corn debranning. According to those authors, the removal of the pericarp was due to total solubilization of the pericarp rather than loosening and removing by chemical action. Steinke and Johnson (1991) proposed other modifi...

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Role of Lactic Acid in Corn Steeping and Its Relation with Starch Isolation

Cited by 19 publications

References 4 publications

Hybrid‐Dependent Effect of Lactic Acid on Corn Starch Yields

Hybrid‐Dependent Effect of Lactic Acid on Corn Starch Yields

Optimum Steeping Process for Wet Milling of Sorghum

Effect of Chemical Pretreatments and Lactic Acid on the Rate of Water Absorption and Starch Yield in Corn Wet‐Milling

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