Department of Animal and Poultry Science, College of Agricultural and Bioresources, University of Saskatchewan, Saskatoon, SK, Canada S7N 5AB.
Spectrochim Acta A Mol Biomol Spectrosc. 2013 Mar 15;105:304-13. doi: 10.1016/j.saa.2012.11.096. Epub 2012 Dec 12.
The objectives of this experiment were to detect the sensitivity and response of protein molecular structure of whole canola seed to different heat processing [moisture (autoclaving) vs. dry (roasting) heating] and quantify heat-induced protein molecular structure changes in relation to protein utilization and availability. In this study, whole canola seeds were autoclaved (moisture heating) and dry (roasting) heated at 120 °C for 1h, respectively. The parameters assessed included changes in (1) chemical composition profile, (2) CNCPS protein subfractions (PA, PB1, PB2, PB3, PC), (3) intestinal absorbed true protein supply, (4) energy values, and (5) protein molecular structures (amide I, amide II, ratio of amide I to II, α-helix, β-sheet, ratio of α-helix to β-sheet). The results showed that autoclave heating significantly decreased (P<0.05) but dry heating increased (P<0.05) the ratio of protein α-helix to β-sheet (with the ratios of 1.07, 0.95, 1.10 for the control (raw), autoclave heating and dry heating, respectively). The multivariate molecular spectral analyses (PCA, CLA) showed that there were significantly molecular structural differences in the protein amide I and II fingerprint region (ca. 1714-1480 cm(-1)) among the control, autoclave and dry heating. These differences were indicated by the form of separate class (PCA) and group of separate ellipse (CLA) between the treatments. The correlation analysis with spearman method showed that there were significantly and highly positive correlation (P<0.05) between heat-induced protein molecular structure changes in terms of α-helix to β-sheet ratios and in situ protein degradation and significantly negative correlation between the protein α-helix to β-sheet ratios and intestinal digestibility of undegraded protein. The results indicated that heat-induced changes of protein molecular structure revealed by vibration molecular spectroscopy could be used as a potential predictor to protein degradation and intestinal protein digestion of whole canola seed. Future study is needed to study response and impact of heat processing to each inherent layer of canola seed from outside to inside tissues and between yellow canola and brown canola.
本实验的目的是检测全油菜籽蛋白质分子结构对不同热加工（水分[高压灭菌]与干燥[烘焙]加热）的敏感性和响应，并定量研究热诱导的蛋白质分子结构变化与蛋白质利用和可获得性的关系。在这项研究中，分别将全油菜籽在 120°C 下进行高压灭菌（水分加热）和干燥（烘焙）加热 1 小时。评估的参数包括：（1）化学成分谱；（2）CNCPS 蛋白质亚组分（PA、PB1、PB2、PB3、PC）；（3）肠道吸收的真蛋白供应；（4）能量值；（5）蛋白质分子结构（酰胺 I、酰胺 II、酰胺 I 与酰胺 II 的比值、α-螺旋、β-折叠、α-螺旋与β-折叠的比值）。结果表明，高压灭菌加热显著降低（P<0.05），而干燥加热显著增加（P<0.05）蛋白质的α-螺旋与β-折叠的比值（对照组（生）、高压灭菌加热和干燥加热的比值分别为 1.07、0.95、1.10）。多元分子光谱分析（PCA、CLA）表明，在蛋白质酰胺 I 和 II 指纹区（约 1714-1480cm(-1)），对照、高压灭菌和干燥加热之间的蛋白质分子结构存在显著差异。这些差异表现为处理之间单独类（PCA）和单独椭圆群（CLA）的形式。Spearman 法的相关性分析表明，热诱导的蛋白质分子结构变化与α-螺旋与β-折叠比值以及原位蛋白质降解之间存在显著的正相关（P<0.05），并且α-螺旋与β-折叠比值与未降解蛋白质的肠道消化率之间存在显著的负相关。结果表明，振动分子光谱法揭示的热诱导蛋白质分子结构变化可作为全油菜籽蛋白质降解和肠道蛋白质消化的潜在预测因子。未来的研究需要研究热加工对油菜籽从外向内组织以及黄油菜籽和褐油菜籽之间每个固有层的响应和影响。
