Use of a dry fractionation process to manipulate the chemical profile and nutrient supply of a coproduct from bioethanol processing.

With an available processing technology (fractionation), coproducts from bioethanol processing (wheat dried distillers grains with solubles, DDGS) could be fractionated to a desired/optimal chemical and nutrient profile. There is no study, to the author's knowledge, on manipulating nutrient profiles through fractionation processing in bioethanol coproducts in ruminants. The objectives of this study were to investigate the effect of fractionation processing of a coproduct from bioethanol processing (wheat DDGS) on the metabolic characteristics of the proteins and to study the effects of fractionation processing on the magnitude of changes in chemical and nutrient supply to ruminants by comparing chemical and nutrient characterization, in situ rumen degradation kinetics, truly absorbed protein supply, and protein degraded balance among different fractions of coproduct of wheat DDGS. In this study, wheat DDGS was dry fractionationed into A, B, C, and D fractions according to particle size, gravity, and protein and fiber contents. The results showed that the fractionation processing changed wheat DDGS chemical and nutrient profiles. NDF and ADF increased from fraction A to D (NDF, from 330 to 424; ADF, from 135 to 175 g/kg DM). Subsequently, CP decreased (CP, from 499 to 363 g/kg DM), whereas soluble CP, NPN, and carbohydrate increased (SCP, from 247 to 304 g/kg CP; NPN, from 476 to 943 g/kg SCP; CHO, from 409 to 538 g/kg DM) from fraction A to D. The CNCPS protein and carbohydrate subfractions were also changed by the fractionation processing. Effective degradability of DM and CP and total digestible protein decreased from fraction A to D (EDDM, from 734 to 649; EDCP, from 321 to 241; TDP, from 442 to 312 g/kg DM). Total truly absorbed protein in the small intestine decreased from fraction A to D (DVE value, from 186 to 124 g/kg DM; MP in NRC-2001, from 193 to 136 g/kg DM). Degraded protein balance decreased from wheat DDGS fractions A-D (DPB in the DVE/OEB system, from 245 to 161 g/kg DM; DPB in NRC-2001, from 242 to 158 g/kg DM). The fractionation processing had a great impact on the chemical and nutrition profiles. Total truly digested and absorbed protein supply and degraded protein balance were decreased. The processing relatively optimized the protein degraded balance of the coproducts to dairy cattle. Compared with the original wheat DDGS (without fractionation), fractionation processing decreased truly absorbed protein supply of DVE and MP values. In conclusion, fractionation processing can be used to manipulate the nutrient supply and N-to-energy degradation synchronization ratio of coproducts from bioethanol processing. Among the fractions, fraction A was the best in terms of its highest truly absorbed protein DVE and MP values. Fractionation processing has great potential to fractionate a coproduct into a desired and optimal chemical and nutrient profile. To the author's knowledge, this is the first paper to show that with fractionation processing, the coproducts from bioethanol processing (wheat DDGS) could be manipulated to provide a desired/optimized nutrient supply to ruminants.