title: Characterization of protein and carbohydrate mid-IR spectral features in crop residues.
abstract: To the best of our knowledge, a few studies have been conducted on inherent structure spectral traits related to biopolymers of crop residues. The objective of this study was to characterize protein and carbohydrate structure spectral features of three field crop residues (rice straw, wheat straw and millet straw) in comparison with two crop vines (peanut vine and pea vine) by using Fourier transform infrared spectroscopy (FTIR) technique with attenuated total reflectance (ATR). Also, multivariate analyses were performed on spectral data sets within the regions mainly related to protein and carbohydrate in this study. The results showed that spectral differences existed in mid-IR peak intensities that are mainly related to protein and carbohydrate among these crop residue samples. With regard to protein spectral profile, peanut vine showed the greatest mid-IR band intensities that are related to protein amide and protein secondary structures, followed by pea vine and the rest three field crop straws. The crop vines had 48-134% higher spectral band intensity than the grain straws in spectral features associated with protein. Similar trends were also found in the bands that are mainly related to structural carbohydrates (such as cellulosic compounds). However, the field crop residues had higher peak intensity in total carbohydrates region than the crop vines. Furthermore, spectral ratios varied among the residue samples, indicating that these five crop residues had different internal structural conformation. However, multivariate spectral analyses showed that structural similarities still exhibited among crop residues in the regions associated with protein biopolymers and carbohydrate. Further study is needed to find out whether there is any relationship between spectroscopic information and nutrition supply in various kinds of crop residue when fed to animals.
authors.affiliation: College of Animal Science and Technology, Northeast Agricultural University, Harbin 150030, China. Electronic address: xinhangshu@163.com.
authors.forename: Hangshu
authors.initials: H
authors.lastname: Xin
authors.affiliation: College of Animal Science and Technology, Northeast Agricultural University, Harbin 150030, China.
authors.forename: Yonggen
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: College of Animal Science and Technology, Northeast Agricultural University, Harbin 150030, China.
authors.forename: Mingjun
authors.initials: M
authors.lastname: Wang
authors.affiliation: College of Animal Science and Technology, Northeast Agricultural University, Harbin 150030, China.
authors.forename: Zhongyu
authors.initials: Z
authors.lastname: Li
authors.affiliation: College of Animal Science and Technology, Northeast Agricultural University, Harbin 150030, China.
authors.forename: Zhibo
authors.initials: Z
authors.lastname: Wang
authors.affiliation: College of Animal Science and Technology, Northeast Agricultural University, Harbin 150030, China; Department of Animal and Poultry Science, College of Agricultural and Bioresources, University of Saskatchewan, Saskatoon, SK S7N 5A8, Canada; Department of Animal Science, Tianjin Agricultural University, 22 Jinjin Road, Tianjin 300384, China.
authors.forename: Peiqiang
authors.initials: P
authors.lastname: Yu
mesh_terms: D010367:Arachis / Q000737:chemistry; D002241:Carbohydrates / Q000032:analysis*; D018556:Crops, Agricultural / Q000737:chemistry*; D012275:Oryza / Q000737:chemistry; D008897:Panicum / Q000737:chemistry; D018532:Pisum sativum / Q000737:chemistry; D010940:Plant Proteins / Q000032:analysis*; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods*; D014908:Triticum / Q000737:chemistry
chemical_list: D002241:Carbohydrates; D010940:Plant Proteins
keywords: Carbohydrate; Crop residue; Molecular structures; Protein