title: Molecular spectroscopic investigation on fractionation-induced changes on biomacromolecule of co-products from bioethanol processing to explore protein metabolism in ruminants.
abstract: Fractionation processing is an efficient technology which is capable to redesign/redevelop a new food or feed product with a specified chemical and nutrient profile. This processing technique was able to produce four different fractions (called "A", "B", "C", "D" fractions/treatments) with different nutrient profile form a co-product of bioethanol processing [wheat dried distillers grains with soluble (DDGS)]. To date, there is no study on the effect of fractionation processing on inherent molecular structure of different fractions and how the processing-induced structural change affect the metabolic characteristics of protein and nutrient availability. The objectives of this experiment were to: (1) investigate the effect of fractionation processing on changes of protein functional groups (amide I, amide II, and their ratio) and molecular structure (modeled α-helix, β-sheet, and their ratio), and (2) study the relationship between the fractionation processing-induced changes of protein molecular structure and nutrients availability as well as the metabolic characteristics of protein. The hypothesis of this study was that the fractionation processing changes the molecular structure and such changes affect the metabolic characteristics of protein. The protein molecular structure spectral profile of the fractions A, B, C and D were identified by Fourier-transform infrared attenuated total reflection spectroscopy (FT/IR-ATR). The results showed that the fractionation processing significantly affected the protein molecular spectral profiles. The differences in amide I to amide II peak area and height ratios were strongly significant (P<0.01) among the treatment fractions, ranging from 4.98 to 6.33 and 3.28 to 4.00, respectively. The difference in the modeled protein α-helix to β-sheet ratio was also strongly significant (P<0.01) among the treatment fractions. Multivariate molecular spectral analysis with cluster (CLA) and principal component analyses (PCA) showed that there are no clear distinguished clusters and ellipses among the fractions (A, B, C and D) in the protein amide I and II region ca. 1726-1485 cm(-1). The correlation study showed that the modeled α-helix to β-sheet ratio tended to have a negative correlation with truly absorbed rumen undegraded protein (ARUP(DVE): r=-0.944, P=0.056<0.10) and total truly absorbed protein in the small intestine (DVE: r=-0.946, P=0.054<0.10), but there was no correlation between the α-helix to β-sheet ratio and the degraded protein balance (DPB(OEB): P=0.267<0.10). In conclusion, the fractionation processing changed the molecular structural spectral profiles in terms of amide I to II ratio and α-helix to β-sheet ratio. These changes negatively affected the metabolic characteristics of protein and true protein supply. These results indicated that spectral features of different fractions could be used as a potential tool to predict true protein nutritive value.
authors: Department of Animal Science, Tianjin Agricultural University, Tianjin 300384, China; Department of Animal and Poultry Science, College of Agriculture and Bioresources, University of Saskatchewan, Saskatoon, SK S7N 5A8, Canada.
authors: Xuewei
authors: X
authors: Zhang
authors: Department of Animal and Poultry Science, College of Agriculture and Bioresources, University of Saskatchewan, Saskatoon, SK S7N 5A8, Canada; The Branch Academy of Animal Science, Jilin Academy of Agricultural Science, Gongzhuling, Jilin 136100, China.
authors: Xiaogang
authors: X
authors: Yan
authors: Research and Innovation Division, Alberta Agriculture and Rural Development, Edmonton, AB T6H 5T6, Canada.
authors: Eduardo
authors: E
authors: Beltranena
authors: Department of Animal Science, Tianjin Agricultural University, Tianjin 300384, China; Department of Animal and Poultry Science, College of Agriculture and Bioresources, University of Saskatchewan, Saskatoon, SK S7N 5A8, Canada. Electronic address: peiqiang.yu@usask.ca.
authors: Peiqiang
authors: P
authors: Yu
mesh_terms: D000821:Animal Feed / Q000032:analysis*; D000818:Animals; D004044:Dietary Proteins / Q000737:chemistry / Q000378:metabolism*; D002523:Edible Grain / Q000737:chemistry / Q000378:metabolism; D017433:Protein Structure, Secondary; D012417:Rumen / Q000378:metabolism*; D012418:Ruminants / Q000378:metabolism*
chemical_list: D004044:Dietary Proteins
keywords: Co-products from bioethanol processing; Fractionation processing; Metabolic characteristics of protein; Protein molecular structure