Application Potential of ATR-FT/IR Molecular Spectroscopy in Animal Nutrition: Revelation of Protein Molecular Structures of Canola Meal and Presscake, As Affected by Heat-Processing Methods, in Relat

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• 作者：Katerina Theodoridou ; Peiqiang Yu
• 刊名：Journal of Agricultural and Food Chemistry
• 出版年：2013
• 出版时间：June 12, 2013
• 年：2013
• 卷：61
• 期：23
• 页码：5449-5458
• 全文大小：368K
• 年卷期：v.61,no.23(June 12, 2013)
• ISSN：1520-5118

文摘

Protein quality relies not only on total protein but also on protein inherent structures. The most commonly occurring protein secondary structures (伪-helix and 尾-sheet) may influence protein quality, nutrient utilization, and digestive behavior. The objectives of this study were to reveal the protein molecular structures of canola meal (yellow and brown) and presscake as affected by the heat-processing methods and to investigate the relationship between structure changes and protein rumen degradations kinetics, estimated protein intestinal digestibility, degraded protein balance, and metabolizable protein. Heat-processing conditions resulted in a higher value for 伪-helix and 尾-sheet for brown canola presscake compared to brown canola meal. The multivariate molecular spectral analyses (PCA, CLA) showed that there were significant molecular structural differences in the protein amide I and II fingerprint region (ca. 1700鈥?480 cm^鈥?) between the brown canola meal and presscake. The in situ degradation parameters, amide I and II, and 伪-helix to 尾-sheet ratio (R_a_尾) were positively correlated with the degradable fraction and the degradation rate. Modeling results showed that 伪-helix was positively correlated with the truly absorbed rumen synthesized microbial protein in the small intestine when using both the Dutch DVE/OEB system and the NRC-2001 model. Concerning the protein profiles, R_a_尾 was a better predictor for crude protein (79%) and for neutral detergent insoluble crude protein (68%). In conclusion, ATR-FT/IR molecular spectroscopy may be used to rapidly characterize feed structures at the molecular level and also as a potential predictor of feed functionality, digestive behavior, and nutrient utilization of canola feed.

Keywords:

canola; protein secondary structure; ATR-FT/IR molecular spectroscopy; 伪-helix; protein nutritive value; heat-processing condition