Impacts of localized enzymolysis and sonication on physical, techno-functional, and structure attributes of sunflower meal protein (SMP) and its hydrolysate (SMPH) were studied. SMP was subjected to enzymolysis (using alcalase) to prepare SMPH with various degrees of hydrolysis (6-24% DH). Enzymolysis decreased colour lightness, turbidity, and particle size of unsonicated and sonicated SMP, while it increased the absolute values of zeta potential (P < 0.05). Sonication improved oil absorption capacity and dispersibility over unsonicated samples. Contrarily, sonicated preparations showed a decrease in water holding capacity. Intrinsic fluorescence and FTIR spectral analyses suggested that SMPH had more movable/flexible secondary structures than SMP. Moreover, the changes in sulfhydryl clusters and disulfide linkages following sonication demonstrated limited unfolding of SMP and SMPH structure and decrease in intermolecular interactions. SDS-PAGE profile exhibited significant reduction in molecular weight (MW) of sonicated SMP, whereas did not display differences between unsonicated and sonicated SMPH. From further MW analysis, SMPH was categorized with high proportion of small-sized peptides ≤ 3 kDa fractions, which increased from 78.64 to 93.01% (control) and from 82.3 to 93.88% (sonication) with enzymolysis (6-24DH). Localized enzymolysis and sonication can be utilised to modify the physical and conformational attributes of SMP and SMPH, which could enhance their functionalities and broaden the utilisation area in food industry.

中文翻译：

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局部酶解和经超声化学修饰的向日葵蛋白：物理，功能和结构属性。

研究了局部酶解和超声处理对向日葵粕蛋白（SMP）及其水解物（SMPH）的物理，技术功能和结构属性的影响。对SMP进行酶解（使用碱性蛋白酶）以制备具有不同水解度（6-24％DH）的SMPH。酶解降低了未超声处理和超声处理过的SMP的颜色亮度，浊度和粒径，同时增加了Zeta电位的绝对值（P <0.05）。超声处理可提高未超声处理样品的吸油量和分散性。相反，超声处理的制剂显示持水量降低。本征荧光和FTIR光谱分析表明SMPH比SMP具有更多的可移动/灵活二级结构。此外，超声处理后巯基簇和二硫键的变化表明，SMP和SMPH结构的展开有限，并且分子间的相互作用降低。SDS-PAGE谱显示超声SMP的分子量（MW）显着降低，而未超声和超声SMPH之间没有差异。通过进一步的MW分析，SMPH被归类为比例≤3 kDa的小分子肽，通过酶解（6-24DH）从78.64％增加到93.01％（对照），从82.3％增加到93.88％（超声）。可以利用局部酶解和超声处理来修饰SMP和SMPH的物理和构象属性，从而增强其功能并扩大食品工业的应用范围。