Autio Karin, Kruus Kristiina, Knaapila Antti, Gerber Nadine, Flander Laura, Buchert Johanna
VTT Biotechnology, P.O. Box 1500, FIN-02044 VTT, Finland.
J Agric Food Chem. 2005 Feb 23;53(4):1039-45. doi: 10.1021/jf0485032.
The effects of TGase in dough after 15, 30, 45, and 60 min of resting time after mixing were studied with a Kieffer test. The resistance to stretching of control dough did not change greatly during the 60 min time period after mixing. In dough, TGase decreased extensibility and increased resistance to stretching and this change was already observed after the first 15 min (first measurement). The higher the enzyme dosage was, the higher the magnitude of the rheological change was. All of the doughs that contained TGase 3.8 or 5.7 nkat/g flour had a higher resistance to stretching and lower extensibility than control dough 15 min after mixing. Resistance to stretching clearly increased at a dosage of 5.7 nkat/g flour during the 15-60 min period after mixing. Extensibility increased in the control dough and in the doughs with a low enzyme dosage almost at the same rate. The evolution of air bubbles during proofing was determined with bright field microscopy and image analysis. In the presence of 5.7 nkat/g TGase, the fermented dough contained more of the smallest and less large air bubbles in comparison to the control dough. The effect of TGase and water content on the specific volume of the conventional and organic wheat bread was studied. Water did not have a significant effect on the specific volume of bread. TGase increased the specific volume of breads baked from organic flour only, when additional water (+10% of farinogram absorption) and a small enzyme dosage were used. Microstructural characterization showed that bread baked without TGase from conventional flour had a stronger protein network than that baked from organic flour. TGase improved the formation of protein network in breads baked from either normal or organic flour but at higher dosage caused uneven distribution.
采用基弗试验研究了混合后静置15、30、45和60分钟时，转谷氨酰胺酶（TGase）对面团的影响。对照面团在混合后的60分钟内，其拉伸抗性变化不大。在面团中，TGase降低了延伸性，增加了拉伸抗性，且在最初的15分钟（首次测量）后就已观察到这种变化。酶用量越高，流变学变化的幅度就越大。所有含有3.8或5.7 nkat/g面粉TGase的面团在混合15分钟后，其拉伸抗性均高于对照面团，延伸性则较低。在混合后的15 - 60分钟内，当面粉中TGase用量为5.7 nkat/g时，拉伸抗性明显增加。对照面团和低酶用量面团的延伸性几乎以相同的速率增加。采用明场显微镜和图像分析确定醒发过程中气泡的演变。与对照面团相比，在含有5.7 nkat/g TGase的情况下，发酵面团中最小的气泡更多，大的气泡更少。研究了TGase和水分含量对传统小麦面包和有机小麦面包比容的影响。水分对面包比容没有显著影响。仅在使用额外水分（+10%粉质吸水率）和少量酶用量时，TGase才会增加用有机面粉烘焙面包的比容。微观结构表征表明，用传统面粉不添加TGase烘焙的面包比用有机面粉烘焙的面包具有更强的蛋白质网络。TGase改善了用普通面粉或有机面粉烘焙面包时蛋白质网络的形成，但用量较高时会导致分布不均。
