Using attenuated‐total‐reflection Fourier‐transformed spectroscopy to reveal molecular structural differences among willow (Salix spp.) foliage cultivars in relation to their potential as fodders

Abstract

BACKGROUND Willow trees represent a suitable species for the development of agroforestry systems, integrating bioenergy and animal feed production. However, there is a lack of information regarding the suitability of leaves and stems, considered a bioenergy by‐product, as animal feed. The aim of this study was the employment of attenuated total reflectance Fourier transform infrared spectroscopy (550–4000 cm−1) to investigate differences in the nutrient molecular structure profile of leaves and stems of selected willow cultivars to understand their utility for ruminant nutrition. RESULTS Univariate analysis of variance of leaves showed lower intensities of cellulosic compounds and higher of protein in comparison with stems, which suggests higher leaf dry matter and protein digestibility. Spectral analyses revealed differences in both plant parts between Salix cv. Terra Nova and Salix cv. Beagle, cv. Resolution, and cv. Olof. The higher α‐helix to β‐sheet ratio, which is related to a higher protein digestibility, was in correlation with the lower content of condensed tannins. Principal component and agglomerative hierarchical cluster analyses showed significant discrimination among willow cultivars in the cellulosic, structural carbohydrate, and amide regions, whereas differences were less evident for total carbohydrate and lipid‐related regions. CONCLUSION The application of attenuated total reflectance Fourier transform infrared molecular spectroscopy is an effective tool to rapidly identify spectral features related to the nutritional composition of willow foliage and to discriminate between cultivars and parts of the plant. This information would be useful to optimize the use of willow fodders in agroforestry systems. © 2021 Society of Chemical Industry.

Biochemical and protein nutritional potential of mulberry (Morus alba L.) leaf: partial substitution improves the nutrition of conventional protein

“…First, the protein amide I band was deconvolved using PeakFit software (Systat Software Inc., San Jose, CA, USA). Then, the corresponding secondary structure conformation was identified by combining the peak position of the original map and the second derivative map 37 . Figure 2(D) shows the secondary structures of the six different proteins, and the results show that the proportion of α ‐helical structures is essentially the same, ranging from 18.5% to 20.9%.…”

“…Then, the corresponding secondary structure conformation was identified by combining the peak position of the original map and the second derivative map. 37 Figure 2(D) shows the secondary structures of the six different proteins, and the results show that the proportion of ⊍-helical structures is essentially the same, ranging from 18.5% to 20.9%. However, the ⊎-turn angle content of the bean pulp-derived protein was 22.5%, which was significantly higher than that of the other proteins with a sparser structure.…”