Microwave Irradiation Induced Changes in Protein Molecular Structures of Barley Grains: Relationship to Changes in Protein Chemical Profile, Protein Subfractions, and Digestion in Dairy Cows

作者：Yan Xiaogang; Khan Nazir A; Zhang Fangyu; Yang Ling; Yu Peiqiang^*

来源：Journal of Agricultural and Food Chemistry, 2014, 62(28): 6546-6555.

DOI：10.1021/jf501024j

• barley grain
• microwave irradiation
• heat processing
• nutrient availability
• protein molecular structure

The objectives of this study were to evaluate microwave irradiation (MIR) induced changes in crude protein (CP) subfraction profiles, ruminal CP degradation characteristics and intestinal digestibility of rumen undegraded protein (RUP), and protein molecular structures in barley (Hordeum vulgare) grains. Samples from hulled (n = 1) and hulless cultivars (n = 2) of barley, harvested from four replicate plots in two consecutive years, were evaluated. The samples were either kept as raw or irradiated in a microwave for 3 min (MIR3) or 5 min (MIR5). Compared to raw grains, MIR5 decreased the contents of rapidly degradable CP subfraction (from 45.22 to 6.36% CP) and the ruminal degradation rate (from 8.16 to 3.53%/h) of potentially degradable subfraction. As a consequence, the effective ruminal degradability of CP decreased (from 55.70 to 34.08% CP) and RUP supply (from 43.31 to 65.92% CP) to the postruminal tract increased. The MIR decreased the spectral intensities of amide 1, amide II, alpha-helix, and beta-sheet and increased their ratios. The changes in protein spectral intensities were strongly correlated with the changes in CP subfractions and digestive kinetics. These results show that MIR for a short period (5 min) with a lower energy input can improve the nutritive value and utilization of CP in barely grains.

• 出版日期2014-7-16
• 单位天津农学院; 吉林省农业科学院