Department of Food Science, Alma Mater Studiorum, University of Bologna, Campus of Food Science, Piazza Goidanich 60, I-47521 Cesena (FC), Italy.
J Sci Food Agric. 2011 Sep;91(12):2140-5. doi: 10.1002/jsfa.4430. Epub 2011 Jun 8.
The aim of this work was to study the influence of steam cooking on pectin methylesterase (PME) and endogenous α- and β-amylase activities in different tissues (cortex and pith) of raw and heat-treated potatoes cv. Agria. Three different cooking temperatures were chosen (55, 70 and 85 °C). For each cooking trial, time-temperature profiles were recorded and the degree of cooking was expressed in terms of cooking factor.
Steam cooking contributed to significantly activate PME at 55 °C and to reduce its activity at the final processing temperature (85 °C), with the highest amount in the cortex (0.3745 ± 0.0007 µmol galacturonic acid (GA) g(-1) fresh weight (FW) min(-1) ) compared with the pith (0.2617 ± 0.0012 µmol GA g(-1) FW min(-1) ). The presence of heat-labile and heat-stable isoforms of PME in the considered potato tissues was also assumed. Heat treatment by steam resulted in a significant decrease in endogenous α- and β-amylase activities in both tissues compared with the raw potato, though without complete deactivation. Starch-degrading enzymes were also found to be differently distributed in the raw tuber.
Steam cooking affected in different ways the assessed residual enzymatic activity in the considered tissues of potatoes cv. Agria. Further research is needed to confirm the results obtained.
本研究旨在探讨蒸汽烹饪对生食和热处理的爱瑞卡马铃薯不同组织（皮层和髓部）中果胶甲酯酶（PME）和内源性α-和β-淀粉酶活性的影响。选择了三种不同的烹饪温度（55、70 和 85°C）。对于每种烹饪试验，记录了时间-温度曲线，并以烹饪因子的形式表示烹饪程度。
蒸汽烹饪显著促进了 PME 在 55°C 时的活性，并降低了其在最终加工温度（85°C）时的活性，在皮层中活性最高（0.3745±0.0007 µmol 半乳糖醛酸（GA）g(-1) 鲜重（FW）min(-1)），而在髓部中活性较低（0.2617±0.0012 µmol GA g(-1) FW min(-1)）。还假设在所考虑的马铃薯组织中存在热不稳定和热稳定的 PME 同工酶。与生食相比，蒸汽热处理导致两种组织中内源性α-和β-淀粉酶活性显著降低，但并未完全失活。还发现淀粉降解酶在生薯中分布不均。
蒸汽烹饪以不同的方式影响了爱瑞卡马铃薯不同组织中评估的残余酶活性。需要进一步的研究来证实所获得的结果。
