Skip to main content
Article
Influence of ensiling time and inoculation on alteration of the starch-protein matrix in high-moisture corn
Journal of Dairy Science
  • P. C. Hoffman, University of Wisconsin-Madison
  • N. M. Esser, University of Wisconsin-Madison
  • R. D. Shaver, University of Wisconsin-Madison
  • W. K. Coblentz, United States Dairy Forage Research Center-Madison
  • Marvin Paul Scott, United States Department of Agriculture
  • A. L. Bodnar, Iowa State University
  • R. J. Schmidt, Lallemand Animal Nutrition-Milwaukee
  • R. C. Charley, Lallemand Animal Nutrition-Milwaukee
Document Type
Article
Publication Version
Published Version
Publication Date
5-1-2011
DOI
10.3168/jds.2010-3562
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 buffer-soluble 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.

Comments

This article is from Journal of Dairy Science 94 (2011): 2465, doi: 10.3168/jds.2010-3562.

Rights
Works 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.
Language
en
File Format
application/pdf
Citation Information
P. C. Hoffman, N. M. Esser, R. D. Shaver, W. K. Coblentz, et al.. "Influence of ensiling time and inoculation on alteration of the starch-protein matrix in high-moisture corn" Journal of Dairy Science Vol. 94 Iss. 5 (2011) p. 2465 - 2474
Available at: http://works.bepress.com/paul-scott/16/