Department of Food Science and Technology, Ferdowsi University of Mashhad, Mashhad, Iran.
Department of Food Science and Technology, Ferdowsi University of Mashhad, Mashhad, Iran.
Food Res Int. 2022 Aug;158:111520. doi: 10.1016/j.foodres.2022.111520. Epub 2022 Jun 17.
In this study the effect of different high intensity ultrasound (HIU) amplitudes (25, 50 and 75%) and sonication times (5, 10 and 20 min) on the structure and functional properties of grass pea protein isolate (GPPI) was investigated. A higher sonication amplitude and longer time improved the protein solubility and surface hydrophobicity and reduced the particle size of GPPI. These physicochemical alterations in GPPI enhanced the protein adsorption at the oil-water interface, reduced the interfacial tension and increased the EAI and ESI values. SDS-page demonstrated that sonication did not change the primary structure of the protein. However, CD spectroscopy indicated a reduction in α-helix and an increase in the content of β-sheet and random coil structures in the sonicated GPPI. The free SH groups content and UV-vis absorbance intensity increased after the sonication. However, prolonged sonication up to 20 min reduced the free SH content in GPPI due to the oxidation of susceptible SH groups. HIU increased the thermal degradation of GPPI and lowered the least concentration needed for gelatinization of GPPI (LGC). Therefore, less protein powder was needed to form a strong gel compared to the non-sonicated GPPI. Sonicated GPPIs showed higher gel strength especially when 75% amplitude used for 10 min. These results showed that the HIU is a promising approach for modification of the functional properties of GPPI for food applications.
本研究考察了不同高强度超声（HIU）幅度（25%、50%和 75%）和超声时间（5、10 和 20 分钟）对草豌豆分离蛋白（GPPI）结构和功能特性的影响。更高的超声幅度和更长的时间提高了 GPPI 的蛋白质溶解度和表面疏水性，并减小了 GPPI 的粒径。这些对 GPPI 的物理化学改变增强了蛋白质在油水界面的吸附，降低了界面张力，并增加了 EAI 和 ESI 值。SDS-page 表明，超声并未改变蛋白质的一级结构。然而，圆二色谱（CD）光谱表明，在超声处理的 GPPI 中，α-螺旋减少，β-折叠和无规卷曲结构的含量增加。自由 SH 基团含量和 UV-可见吸收强度在超声后增加。然而，长时间的超声（长达 20 分钟）会由于易受氧化的 SH 基团的氧化而降低 GPPI 中的自由 SH 含量。HIU 增加了 GPPI 的热降解，并降低了 GPPI 的凝胶化最低浓度（LGC）。因此，与未经超声处理的 GPPI 相比，形成强凝胶所需的蛋白质粉更少。超声处理的 GPPIs 表现出更高的凝胶强度，尤其是当使用 75%幅度处理 10 分钟时。这些结果表明，HIU 是一种有前途的方法，可以修饰 GPPI 的功能特性，用于食品应用。
