Metabolic characteristics of proteins and biomolecular spectroscopic profiles in different batches of feedstock (wheat) and their co-products (wheat distillers dried grains with solubles) from the same bioethanol processing plant

The objectives of this study were (1) to reveal the metabolic characteristics of proteins in different batches of feedstock (wheat) for bioethanol production and their co-products (wheat distillers dried grains with solubles, wDDGS) from the same bioethanol processing plant, and (2) to characterize biomolecular spectral profile associated with nutrient digestion in the rumen and intestine of dairy cattle. The metabolic characteristics of proteins were determined using the DVE/OEB system (where DVE = total truly absorbed protein supply, and OEB = degraded balance of protein) based on chemical profiles and rumen and intestinal digestion data from dairy cattle. The biomolecular spectral characteristics were investigated by using the molecular spectroscopy technique attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FT/IR). Multivariate molecular spectral analyses-agglomerative hierarchical cluster analysis (AHCA), and principal component analysis (PCA)-were conducted to identify the spectral differences in biomolecular inherent structure among the wheat and wDDGS batches. The results showed that (1) the metabolic characteristics of proteins in the wheat and wDDGS from the same bioethanol processing plant were significantly affected by batch, with total truly absorbed protein supply (DVE value) ranging from 101 to 116 g/kg of dry matter (DM) in wheat and from 153 to 182 g/kg of DM in wDDGS; (2) the degraded balance of protein (OEB value) in the wDDGS (but not the wheat) from the same bioethanol processing plant was significantly affected by batch, with the OEB value ranging from −19 to −26 g/kg of DM in the wheat and from 145 to 181 g/kg of DM in the wDDGS; and (3) the biomolecular spectral analyses with AHCA and PCA revealed biomolecular spectral profiles and differences among the wheat and wDDGS samples.