Investigation of structure interaction to nutrient properties and utilization in co-products after pellet processing at various conditions using advanced molecular spectroscopy

The molecular infrared (micro)spectroscopy, developed as a rapid, non-destructive and non-invasive analytical technique, is able to reveal structure features at a molecular level and provide tissue structure and chemistry information simultaneously. However, to date, this analytical technique is seldomly used in study processing induced structure change in relation to nutrient properties, utilization, and delivery in livestock. The objective of this article was to review the inter-relationship between molecular structures with nutritive properties and nutrient delivery in co-products from bioenergy production after pelleted processing using vibrational molecular spectroscopy. First, this article reviews recent progress in pelleting process research, related to physical quality of pellets, utilization for animals, processing quality, and current nutrition evaluation methodologies for pelleting. The emphasis of this study focused on the effect of conditioning temperature and time of the pellet processing on molecular structure changes and nutrient properties and nutrient delivery. The methods for nutritive properties and nutrient delivery were reviewed, which included various in vitro, in situ, in vivo, and nutrient modeling techniques. The molecular spectroscopic techniques included globar-sourced and synchrotron-sourced molecular spectroscopic techniques. The molecular spectra analysis included univariate and multivariate molecular spectral analyses. The relationship between molecular structural changes and truly absorbed nutrient supply was quantified. The research provides an insight how inherent structure changes induced by pellet processing on a molecular basis affected nutrient properties, utilization, and availability.