College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, China.
State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Synergetic Innovation Center of Food Safety and Nutrition, Jiangnan University, 1800 Lihu Avenue, Wuxi 214122, Jiangsu Province, PR China.
Food Chem. 2017 Apr 15;221:482-488. doi: 10.1016/j.foodchem.2016.10.108. Epub 2016 Oct 24.
The present study comparatively evaluated the evolution of yeast and chemical leavened steamed bread dough (YLD/CLD) quality during freeze/thaw (FT) cycles. The steamed bread quality of CLD was more freeze-stable than that of the YLD after 3 FT cycles. Decreased yeast viability contributed to the loss of gassing power in YLD while no significant differences were observed for CLD during FT cycles. However, faster gas release rate in frozen CLD indicated gas retention loss due to the distortion of gluten network. Glutenin macropolymers (GMP) depolymerization via breakage of inter-chain disulfide (SS) bonds and conversions of α-helix and β-turn to β-sheet structures were the main indicators of gluten deterioration. Gluten network was more vulnerable in frozen YLD, resulting in detectable loss of viscoelasticity. The results suggested that supplement of chemical leavener contributed to a more freeze-tolerant gluten network besides its stable gassing power.
本研究比较了在冻融（FT）循环过程中酵母和化学膨发面团（YLD/CLD）品质的演变。经过 3 次 FT 循环后，CLD 的馒头品质比 YLD 更耐冻融。酵母活力下降导致 YLD 的产气能力下降，而在 FT 循环过程中，CLD 则没有明显差异。然而，冷冻 CLD 中更快的气体释放速度表明，由于面筋网络的变形，气体保持能力下降。通过打破链间二硫键（SS）和将α-螺旋和β-转角转化为β-折叠结构，麦谷蛋白大聚合物（GMP）的解聚是面筋劣化的主要指标。在冷冻 YLD 中，面筋网络更容易受到破坏，导致明显的粘弹性丧失。结果表明，化学膨松剂的添加除了稳定产气能力外，还有助于形成更耐冻融的面筋网络。
