Influence of ensiling time and inoculation on alteration of the starch-protein matrix in high-moisture corn

Abstract

The fates of hydrophobic zein proteins, which encapsulate corn starch to create vitreous endosperm, have not been investigated in high-moisture corn (HMC). To assess influences of ensiling time and inoculation on zein proteins in HMC, quadruplicate samples of 2 random corn hybrids (A and B), containing 25.7 and 29.3% moisture, were ground, inoculated with (I) or without 600,000 cfu/g of Lactobacillus buchneri 40788 (Lallemand Animal Nutrition, Milwaukee, WI), and ensiled for 0, 15, 30, 60, 120, and 240 d. Nutrient composition [crude protein (CP), starch, acid detergent fiber, and neutral detergent fiber], fermentation (pH, lactate, and acetate), and protein degradation markers (buffer-soluble CP, isopropanol-soluble CP, and NH3-N) were evaluated. At 0 and 240 d, α, γ, δ, and β zein subunits were profiled using HPLC. Data were evaluated as a split-split plot using the PROC MIXED procedures of SAS. Ensiling time and inoculation decreased pH, and altered lactate and acetate contents of HMC. Lactate and acetate contents of A, AI, B, and BI at 240 d were 0. 40, 0.32, 1.11, 0.73, and 0, 0.35, 0.30, and 0.87% of DM, respectively. Buffer-soluble CP in HMC increased from 1.5 to 2.0% of DM at 0 d to >4.0% of DM at 240 d. Inoculation had no effect on buffersoluble CP but increased NH3-N content of HMC. Corn A contained more isopropanol-soluble CP than did corn B and peak areas for 6 α, and all γ and δ zein regions were greater for corn A. Ensiling (0 vs. 240 d) decreased all zein subunits with the exception of 2 α and 1 δ subunit. Ensiling decreased (42.2-73.2%) γ zeins, which are primarily responsible for cross-linking in the starch-protein matrix. Despite altering lactate and acetate contents, inoculation had no effect on degrading hydrophobic zein proteins in HMC. Data suggest that hydrophobic zein proteins in the starch-protein matrix of HMC are degraded by proteolytic activity over an extended ensiling time. RightsWorks produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted. ABSTRACTThe fates of hydrophobic zein proteins, which encapsulate corn starch to create vitreous endosperm, have not been investigated in high-moisture corn (HMC). To assess influences of ensiling time and inoculation on zein proteins in HMC, quadruplicate samples of 2 random corn hybrids (A and B), containing 25.7 and 29.3% moisture, were ground, inoculated with (I) or without 600,000 cfu/g of Lactobacillus buchneri 40788 (Lallemand Animal Nutrition, Milwaukee, WI), and ensiled for 0, 15, 30, 60, 120, and 240 d. Nutrient composition [crude protein (CP), starch, acid detergent fiber, and neutral detergent fiber], fermentation (pH, lactate, and acetate), and protein degradation markers (buffersoluble CP, isopropanol-soluble CP, and NH 3 -N) were evaluated. At 0 and 240 d, α, γ, δ, and β zein subunits were profiled using HPLC. Data were evaluated as a split-split plot using the PROC MIXED procedures of SAS. Ensiling time and inoculat...

Effect of the ensiling time of hydrated ground corn on silage composition and in situ starch degradability

“…The effect of the ensiling time on starch degradability and protein integrity of the endosperm matrix was previously described for silage of grains harvested with high-moisture corn (HOFFMAN et al, 2011). However, as far as we know, no studies reported the effect of longer ensiling periods on the composition and degradability of corn with medium vitreousness and high levels of DM.…”

“…Increases in corn grain starch and DM digestibility evaluated by in vitro and in situ assays, respectively, were reported after increasing the storage period of the entire crop, high-moisture corn grain and hydrated corn grain silages (BENTON et al, 2005;DER BEDROSIAN et al, 2012). The effect of ensiling time on silage degradability is probably due to the degradation and/or solubilization of zein subunits over the ensiling period (LAWTON, 2002;HOFFMAN et al, 2011).…”

“…These proteins are hydrophobic and have low solubility in alcoholic solution. Because proteins of corn endosperm are composed of up to 79% zein, these proteins may limit the degradability of the starch granules (HOFFMAN et al, 2011). Ensiling of ground corn grain increases ruminal degradability of starch, which may suggest that the process of silage fermentation can increase the access of rumen bacteria to starch granules by removing the protein barrier (PHILIPPEAU; MICHALET-DOREAU, 1998).…”

Evaluación física, química y microbiológica del ensilaje de yuca con caupí y cultivo microbiano

“…En tal sentido, se hace apremiante la búsqueda de soluciones y alternativas que logren dar respuesta a las necesidades básicas en la producción animal (Hoffman et al, 2011). Un método económico y de fácil acceso es el ensilaje, el cual permite conservar productos de rápido deterioro.…”

“…Asimismo, Miranda et al (2014) reportaron extender el tiempo de conservación sin afectar al contenido nutritivo y con reducción de las partes fibrosas de la yuca al inocular cultivo mixto de bacterias ácido lácticas y levaduras. De igual manera, Hoffman et al (2011), Dadvar et al (2013) y Lyncha et al (2014, con el uso de un cultivo mixto se lograron controlar el crecimiento de microorganismos toxigénicos como clostridium, S. aureus, C. botulinum, Salmonella sp. y Listeria monocytogenes, así como de los microorganismos asociados al deterioro directo del alimento.…”