Department of Food Science, University of Otago, PO Box 56, Dunedin 9054, New Zealand; Institute of Food Science and Technology, University of the Philippines Los Baños, College, Laguna 4031, Philippines; Riddet Institute, Massey University, Private Bag 11 222, Palmerston North 4442, New Zealand.
Department of Food Science, University of Otago, PO Box 56, Dunedin 9054, New Zealand; Riddet Institute, Massey University, Private Bag 11 222, Palmerston North 4442, New Zealand.
Food Res Int. 2020 Mar;129:108839. doi: 10.1016/j.foodres.2019.108839. Epub 2019 Dec 10.
The aim of this research was to investigate the effect of Pulsed Electric Fields (PEF) treatments (electric field strengths 2 and 4.4 kV/cm combined with specific energy inputs between 48 and 484 kJ/kg) on the thermal and pasting properties of oat flours. Colour, β-glucan content, particle size distribution, morphological characteristics, starch short-range molecular order, protein secondary structure, thermal, and pasting properties of raw (dehulled and milled) and thermally processed (kilned at 115 °C for 30 min and steamed at 100-104 °C for 18 min under industrial process condition) oat flours under the influence of PEF treatment were evaluated. Results showed that PEF treatment, applied at any intensity, led to considerable changes in the structural properties especially when applied on raw oat flour. Both types of oat flour experienced an increase in particle size (up to four-fold), damage of starch granule morphology, and modifications in starch short-range molecular order and protein secondary structures as a result of PEF treatment. These physical changes observed after PEF treatment, particularly at increasing specific energy input, coincided with the thermal and pasting behaviour of PEF-treated oat flours, which include a decrease in gelatinisation enthalpy (up to 80%), increase in thermal transition temperatures (at least 3 °C), decrease in overall viscosity profile, and reduction in pasting temperature (up to 12 °C). Overall results suggested that PEF treatment improved majorly on starch-related functionality of oat, such as increased the pasting stability of raw and thermally processed oat flours and at the same time enhanced the retrogradation property (reduced syneresis and hardness) of raw oat flour, under lower temperature requirement without affecting pasting time. This research demonstrated the potential of PEF treatment in modifying the thermal and pasting properties of oat flour, thereby offering opportunities for novel products for food industry.
本研究旨在探讨脉冲电场（PEF）处理（电场强度 2 和 4.4 kV/cm 与 48 至 484 kJ/kg 之间的特定能量输入相结合）对燕麦粉的热特性和糊化特性的影响。研究评估了未经处理（去壳和研磨）和经热处理（在 115°C 下干燥 30 分钟，在工业加工条件下 100-104°C 下蒸制 18 分钟）的燕麦粉在 PEF 处理下的颜色、β-葡聚糖含量、粒度分布、形态特征、淀粉短程分子有序性、蛋白质二级结构、热特性和糊化特性，以及 PEF 处理对这些特性的影响。结果表明，PEF 处理，无论强度如何，都会导致结构特性发生相当大的变化，尤其是在处理原燕麦粉时。两种类型的燕麦粉的粒径都增加了（高达四倍），淀粉颗粒形态受损，淀粉短程分子有序性和蛋白质二级结构发生变化，这是由于 PEF 处理的结果。PEF 处理后观察到的这些物理变化，特别是在特定能量输入增加的情况下，与 PEF 处理燕麦粉的热特性和糊化行为一致，包括凝胶化焓降低（高达 80%）、热转变温度升高（至少 3°C）、整体粘度曲线降低和糊化温度降低（高达 12°C）。总体结果表明，PEF 处理主要改善了燕麦的淀粉相关功能，例如提高了原燕麦粉和热处理燕麦粉的糊化稳定性，同时增强了原燕麦粉的回生特性（减少了收缩和硬度），同时在不影响糊化时间的情况下降低了温度要求。本研究证明了 PEF 处理在改性燕麦粉热特性和糊化特性方面的潜力，从而为食品工业提供了开发新型产品的机会。
