Carrillo Yessica Silva, Ulloa José Armando, Urías Silvas Judith Esmeralda, Ramírez Ramírez José Carmen, Leyva Ranferi Gutiérrez
Programa de Doctorado en Ciencias Biológico Agropecuarias, Universidad Autónoma de Nayarit, Carretera Tepic-Compostela, Km 9, 63780, Xalisco, Nayarit, Mexico.
Centro de Tecnología de Alimentos, Universidad Autónoma de Nayarit, Ciudad de la Cultura Amado Nervo, 63155, Tepic, Nayarit, Mexico.
Heliyon. 2024 May 31;10(11):e32225. doi: 10.1016/j.heliyon.2024.e32225. eCollection 2024 Jun 15.
The impact of high-intensity ultrasound (HIU, 20 kHz) on the physicochemical and functional characteristics of gourd seed protein isolate (GoSPI) was studied. GoSPI was prepared from oil-free gourd seed flour through alkaline extraction (pH 11) and subsequent isoelectric precipitation (pH 4). The crude protein concentration of GoSPI ranged from 91.56 ± 0.17 % to 95.43 ± 0.18 %. Aqueous suspensions of GoSPI (1:3.5 w/v) were ultrasonicated at powers of 200, 400, and 600 W for 15 and 30 min. Glutelins (76.18 ± 0.15 %) were the major protein fraction in GoSPI. HIU decreased the moisture, ash, ether extract, and nitrogen-free extract contents and the hue angle, available water and and color parameters of the GoSPI in some treatments. The L color parameter increased (7.70 %) after ultrasonication. HIU reduced the bulk density (52.63 %) and particle diameter (39.45 %), as confirmed by scanning electron microscopy, indicating that ultrasonication dissociated macromolecular aggregates in GoSPI. These structural changes enhanced the oil retention capacity and foam stability by up to 62.60 and 6.84 %, respectively, while the increases in the solvability, water retention capacity, and emulsifying activity index of GoSPI were 90.10, 19.80, and 43.34 %, respectively. The gelation, foaming capacity, and stability index of the emulsion showed no improvement due to HIU. HIU altered the secondary structure of GoSPI by decreasing the content of α-helices (49.66 %) and increasing the content of β-sheets (52.00 %) and β-turns (65.00 %). The electrophoretic profile of the GoSPI was not changed by HIU. The ultrasonicated GoSPI had greater functional attributes than those of the control GoSPI and could therefore be used as a functional food component.
研究了高强度超声（HIU，20 kHz）对葫芦籽分离蛋白（GoSPI）理化性质和功能特性的影响。通过碱性提取（pH 11）和随后的等电沉淀（pH 4）从无油葫芦籽粉中制备GoSPI。GoSPI的粗蛋白浓度范围为91.56±0.17%至95.43±0.18%。将GoSPI的水悬浮液（1:3.5 w/v）分别在200、400和600 W功率下超声处理15和30分钟。谷蛋白（76.18±0.15%）是GoSPI中的主要蛋白质组分。在某些处理中，HIU降低了GoSPI的水分、灰分、乙醚提取物和无氮提取物含量以及色调角、有效水分和颜色参数。超声处理后，L颜色参数增加（7.70%）。扫描电子显微镜证实，HIU降低了堆积密度（52.63%）和粒径（39.45%），表明超声处理使GoSPI中的大分子聚集体解离。这些结构变化分别使持油能力和泡沫稳定性提高了62.60%和6.84%，而GoSPI的溶解性、保水能力和乳化活性指数分别提高了90.10%、19.80%和43.34%。HIU并未改善乳液的凝胶化、发泡能力和稳定性指数。HIU通过降低α-螺旋含量（49.66%）、增加β-折叠含量（52.00%）和β-转角含量（65.00%）改变了GoSPI的二级结构。HIU未改变GoSPI的电泳图谱。超声处理后的GoSPI比对照GoSPI具有更好的功能特性，因此可作为功能性食品成分使用。
