Schober Tilman J, Bean Scott R, Boyle Daniel L
Grain Marketing and Production Research Center, Agricultural Research Service, U.S. Department of Agriculture, 1515 College Avenue, Manhattan, Kansas 66502, USA.
J Agric Food Chem. 2007 Jun 27;55(13):5137-46. doi: 10.1021/jf0704155. Epub 2007 May 31.
This study was conducted to improve the quality and theoretical understanding of gluten-free sorghum bread. The addition of 2% hydroxypropyl methylcellulose improved bread based on 105% water, 70% sorghum flour, and 30% potato starch. Nevertheless, a flat top and tendency toward a hole in the crumb remained. Sourdough fermentation of the total sorghum flour eliminated these problems. Size-exclusion high-performance liquid chromatography demonstrated that during sourdough fermentation, proteins from the dough liquid were degraded to peptides smaller than kafirin monomers (<19 kDa). Laser scanning confocal microscopy showed aggregated protein in bread crumb without sourdough fermentation, whereas with sourdough fermentation, only small isolated patches of protein bodies embedded in matrix protein remained. In oscillatory temperature sweeps, sourdough fermentation caused a significantly higher resistance to deformation (|G*|) after gelatinization of the above batter relative to batters without sourdough. Results suggest that a strong starch gel, without interference of aggregated protein, is desirable for this type of bread.
本研究旨在提高无麸质高粱面包的品质并增进对其理论理解。添加2%的羟丙基甲基纤维素可改善以105%的水、70%的高粱粉和30%的马铃薯淀粉制成的面包。然而，面包顶部仍然扁平，面包心有出现孔洞的趋势。对全部高粱粉进行酸面团发酵消除了这些问题。尺寸排阻高效液相色谱法表明，在酸面团发酵过程中，面团液中的蛋白质被降解为小于醇溶蛋白单体（<19 kDa）的肽。激光扫描共聚焦显微镜显示，未经酸面团发酵的面包心中存在聚集蛋白，而经过酸面团发酵后，仅剩下嵌入基质蛋白中的小的孤立蛋白体斑块。在振荡温度扫描中，相对于未经酸面团发酵的面糊，酸面团发酵使上述面糊糊化后对变形的抵抗力（|G*|）显著更高。结果表明，对于这类面包而言，需要一种不受聚集蛋白干扰的强淀粉凝胶。
