两种酶制剂对非发酵面团冻融循环后品质的影响

    Effects of two enzymes on qualities of non-fermented dough after freeze-thaw circles

    • 摘要: 为了探究酶制剂对非发酵面团在冻融循环后的品质的影响,该文比较了2种酶制剂转谷氨酰胺酶(TGase)与木聚糖酶(xylanase)对非发酵面团冻融品质的改良效果。结果表明,与对照组相比,添加转谷氨酰胺酶和木聚糖酶均能改变冻融后面团蛋白各组分的含量。添加转谷氨酰胺酶使醇溶蛋白以及谷蛋白含量显著下降(P<0.05)、谷蛋白大聚合体含量有所上升。添加木聚糖酶则使醇溶蛋白含量上升,使谷蛋白含量显著降低(P<0.05)。转谷氨酰胺酶对面团中戊聚糖含量影响不显著(P>0.05),而添加木聚糖酶使面团中可溶性戊聚糖含量显著上升(P<0.05)。转谷氨酰胺酶的添加加速了冻融循环后非发酵面团的失水,木聚糖酶则显著降低了其失水率(P<0.05)。除在10 g/kg转谷氨酰胺酶显著降至1.32 ms外,弛豫时间T2 (1)基本维持在1.75 ms,而弛豫时间T2(2)均有所减小;添加转谷氨酰胺酶后,深层结合水相对含量呈逐渐上升趋势;而木聚糖酶则反之。木聚糖酶使冻融面团强韧性与对照组相比显著增强(P<0.05),剪切力小幅下降,硬度显著下降(P<0.05);与转谷氨酰胺酶相比,木聚糖酶更能缓解冻融面团的质构劣变;转谷氨酰胺酶改善冻融熟面坯的黏性、弹性与内聚性,木聚糖酶则改善"硬度上升,弹性下降"的劣变现象。在改善冻融面团流变特性方面,转谷氨酰胺酶效果更为显著(P<0.05)。因此,添加转谷氨酰胺酶与木聚糖酶均能在一定程度上改善冷冻非发酵面团在冻融条件下的品质劣变,但它们的作用方面有所差异。研究结果为两者能够在冷冻非发酵面制品中被广泛地应用提供理论基础。

       

      Abstract: Abstract: In order to explore the effect of enzymes on the quality of non-fermented dough after freeze-thaw cycles, the transglutaminase and xylanase were chosen and their effects on the quality of non-fermented dough after freeze-thaw circles were investigated. The low-field nuclear magnetic resonance (LF-NMR), texture profile analyzer and a rheometer were used to observe the changes of frozen non-fermented dough in quality during freeze-thaw cycles. The water loss rate, water distribution and mobility, protein fraction content, textural and rheological properties of the dough samples were evaluated in the experiment. The results showed that: compared with the control group, the additions of transglutaminase and xylanase could change the contents of different protein fractions. Transglutaminase addition could reduce the gliadin and gluten content (P<0.05), and raise the glutenin macropolymer content in the dough, while adding xylanase could increase the gliadin content but reduce glutenin content. The effect of transglutaminase on water extractable arabinoxylan content was not significant (P>0.05), however, the effect of xylanase was significant (P<0.05) compared with the control group, and with the increase of addition dose, the water extractable arabinoxylan content increased. Though transglutaminase addition could accelerate dehydration of the non-fermented dough after freeze-thaw cycles, xylanase significantly reduced water loss rate (P<0.05). Relaxation time T2(1) remained at 1.75 ms except the addition of 10 g/kg transglutaminase which significantly decreased T2(1) to 1.32 ms, and relaxation timeT2(2) were all reduced with the addition of two enzymes. The addition of transglutaminase gradually increased the relative content of deep bound water of the non-fermented dough after freeze-thaw cycles, and its content became to 33.05% when the addition of transglutaminase was 10 g/kg; while the effect of xylanase was opposite. The firmnness, toughness and hardness of samples were significantly decreased (P<0.05) with the addition of xylanase when compared with the control group. The xylanase improved the sample's texture profile better than the transglutaminase. The transglutaminase improved the sample's adhesiveness, elasticity and cohesiveness, and the xylanase decreased hardness and improved elasticity. To optimize the rheological properties of dough, the transglutaminase significantly increased the storage of moduliand the loss of moduli (P<0.05), and more addition more increased. On the contrary, the xylanase had a negative impact. Therefore, the addition of transglutaminase and xylanase played the roles in different aspects to improve the quality of non-fermented dough after freeze-thaw circles. The results provide the theoretical basis for the two enzymes widely application to the frozen non-fermented flour products.

       

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