Influence of Lactic Acid on the Solubilization of Protein during Corn Steeping

Dailey, Oliver D.; Dowd, Michael K.; Mayorga, Julio C.

doi:10.1021/jf990866s

Cited by 28 publications

(41 citation statements)

References 13 publications

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“…It has been reported previously that much of the waterand saline-soluble proteins are lost during the steeping step of wet-milling [2,23]. The actions of lactic acid and, to some degree, SO 2 cause alterations and breakdown of the protein structure, resulting in the solubilization of fractions that are extracted, mainly from the germ, into the different product streams [23,24]. Parris et al [25] reported that the amounts of albumins and globulins were significantly less in commercial wet-milled corn germ (25% combined total) compared with that in corn kernel embryo (71%) and commercial dry-milled germ (72%).…”

Section: Protein Extraction Efficienciesmentioning

confidence: 99%

Extraction and Functional Properties of Non‐Zein Proteins in Corn Germ from Wet‐Milling

Hojilla-Evangelista

2011

J Americ Oil Chem Soc

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This study was conducted to evaluate the extractability of wet-milled corn germ protein, characterize the recovered protein and identify its potential applications. Protein was extracted from both wet germ and finished (dried) germ using 0.1 M NaCl as solvent. The method involved homogenization, stirring, centrifugation, dialysis and freeze-drying. Factors evaluated were temperature (40, 50, or 60°C) and the presence of reducing or denaturing agents. The recovered protein was analyzed for proximate composition and functional properties. Protein recovery was greater from wet germ. For both germ samples, protein recovery was not improved by using higher temperatures; thus, subsequent extractions were done at 40°C. Addition of 2% SDS and 1% b-mercaptoethanol to the solvent nearly doubled protein yield; but, SDS-PAGE indicated some protein denaturation. The recovered freezedried proteins from both germ samples were least soluble at pH 2.0-4.0, but solubility increased at higher pH values. Wet germ protein extract was more soluble than finished germ protein at all pH values; however, the finished germ protein showed much better foaming and emulsifying properties and water-holding capacity.

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Section: Protein Extraction Efficienciesmentioning

confidence: 99%

Extraction and Functional Properties of Non‐Zein Proteins in Corn Germ from Wet‐Milling

Hojilla-Evangelista

2011

J Americ Oil Chem Soc

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“…Our initial experiments using a single yellow dent hybrid showed that there was a substantial increase in steepwater nitrogen (protein) when LA was added to batch steeps (Dailey et al 2000). Since the findings for one hybrid could have been atypical, steeping studies have been performed on an additional seven hybrids to evaluate the effect across a range of corn hybrids.…”

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confidence: 99%

Effect of Lactic Acid on Protein Solubilization and Starch Yield in Corn Wet‐Mill Steeping: A Study of Hybrid Effects

Dailey

2002

Cereal Chem

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Cereal Chem. 79(2):257-260To better understand the role of lactic acid (LA) in corn wet-milling, steeping studies were performed on different yellow dent corn hybrids using four different solutions containing LA, sulfur dioxide (SO 2 ), a combination of LA and SO 2 , or no added chemicals. Although there was variation in protein solubilization among the hybrids, protein release was consistently higher when LA was included in the steepwater than when it was excluded (both with and without SO 2 ) . . Several groups have reported that starch recoveries are improved when steepwater contains LA. To explore the relationship between protein solubilization and starch yield as effected by LA, several yellow dent hybrids were steeped in 0.20% SO 2 and 0.50% LA-0.20% SO 2 solutions and milled to recover starch by a 100-g laboratory corn wet-milling procedure. In all instances, both starch yields and protein solubilization were enhanced in solutions containing LA. These results support the hypothesis that direct dissolution of the endosperm protein matrix by LA contributes to the improved starch recoveries.

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“…41 Addition of SO 2 and lactic acid enables breakage of cross-linking disulfide bonds in the endosperm protein matrix, 22,23 and possibly of the recombinant protein as well. In the case of LT-B and of most proteins, correct folding and functionality depends highly on disulfide bond formation.…”

Section: Resultsmentioning

confidence: 99%

“…This is consistent with previous findings 27 where lactic acid and sulfite treatment result in loss of biological activity of proteins, probably due to denaturing. 22 In this sense, the data are useful for future studies in which specific objectives want to be met regarding total LT-B yield or high concentration factors in particular fractions.…”

Section: Resultsmentioning

confidence: 99%

“…Traditional wet-milling involves steeping with 0.2% SO 2 , which is key in breaking the cross-linking disulfide bonds in the endosperm protein matrix, producing acidic conditions that favor Lactobacillus growth (lactic acid softens the grain for grinding) and eliminating putrefying bacterial growth. 22,23 The presence of SO 2 and lactic acid in the steep water increases release of proteinaceus material from the maize kernels 22 and enhances starch recovery. 24 Although efforts have been focused on optimizing wet-milling conditions for maize fractionation, much less has been done to study the effects of wet-milling on recombinant protein recovery from transgenic maize.…”

Section: Introductionmentioning

confidence: 99%

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Wet‐milling transgenic maize seed for fraction enrichment of recombinant subunit vaccine

Moeller

Taylor-Vokes

Fox

et al. 2009

Biotechnology Progress

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The production of recombinant proteins in plants continues to be of great interest for prospective large-scale manufacturing of industrial enzymes, nutrition products, and vaccines. This work describes fractionation by wet-milling of transgenic maize expressing the B subunit of the heat-labile enterotoxin of Escherichia coli (LT-B), a potent immunogen and candidate for oral vaccine and vaccine components. The LT-B gene was directed to express in seed by an endosperm specific promoter. Two steeping treatments, traditional steeping (TS, 0.2% SO(2) + 0.5% lactic acid) and water steeping (WS, water only), were evaluated to determine effects on recovery of functional LT-B in wet-milled fractions. The overall recovery of the LT-B protein from WS treatment was 1.5-fold greater than that from TS treatment. In both steeping types, LT-B was distributed similarly among the fractions, resulting in enrichment of functional LT-B in fine fiber, coarse fiber and pericarp fractions by concentration factors of 1.5 to 8 relative to the whole kernels on a per-mass basis. Combined with endosperm-specific expression and secretory pathway targeting, wet-milling enables enrichment of high-value recombinant proteins in low-value fractions, such as the fine fiber, and co-utilization of remaining fractions in alternative industrial applications.

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Influence of Lactic Acid on the Solubilization of Protein during Corn Steeping

Cited by 28 publications

References 13 publications

Extraction and Functional Properties of Non‐Zein Proteins in Corn Germ from Wet‐Milling

Extraction and Functional Properties of Non‐Zein Proteins in Corn Germ from Wet‐Milling

Effect of Lactic Acid on Protein Solubilization and Starch Yield in Corn Wet‐Mill Steeping: A Study of Hybrid Effects

Wet‐milling transgenic maize seed for fraction enrichment of recombinant subunit vaccine

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