School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China; Jiangsu Key Laboratory of Marine Bioresources and Environment, Jiangsu Ocean University, Lianyungang 222005, China; Institute of Food Physical Processing, Jiangsu University, Zhenjiang 212013, China.
School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China.
Ultrason Sonochem. 2022 Aug;88:106080. doi: 10.1016/j.ultsonch.2022.106080. Epub 2022 Jun 22.
Diversiform okra dry powders were prepared and controlled-temperature ultrasonic-assisted extraction (CTUAE) was then utilized to obtain okra pectin (OP) from the preparative powders. During processing of hybrid techniques, 6 types of dry powders were prepared through different drying technologies (hot air drying, HD; freeze-drying, FD) and meshes (60, 80, 120 meshes) at first. Next, the extraction yield, physicochemical and function characteristics, and molecular structure of OP were analyzed with or without CTUAE technique. Meanwhile, the time-frequency domains of acoustic fields during extraction process of OP were monitored to analyze the effects of ultrasonic fields. Results showed that OP main chains with less cracking by FD than that by HD; the yield, GalA, esterification degree (DE), M and viscosity of OP increased, but its particle size decreased. Water holding capacity (WHC) and oil holding capacity (OHC) of OP by HD were more prominent. Secondly, HD OP had dendritic rigid chains, while FD OP had flexible chains with multiple branches. For HD OP, as meshes of okra dry powders decreased, GalA, viscosity and emulsification ability decreased; while gel strength and thermal stability increased. For FD OP, the reduction of meshes improved thermal stability. Above all, CTUAE technique increased the yield and GalA, and decreased DE, M and particle size of OP. In terms of functional characteristics, the technique also improved gel strength, resilience and viscoelasticity, enhanced emulsifying stability, WHC and thermal stability, and reduced viscosity. Finally, the correlation between functional and structural characteristics of OP was quantified, and some suggestions were made for its application in food areas.
制备了不同形态的秋葵干粉末，然后采用控温和超声辅助提取（CTUAE）技术从制备的粉末中提取秋葵果胶（OP）。在混合技术处理过程中，首先通过不同的干燥技术（热风干燥，HD；冷冻干燥，FD）和目数（60、80、120 目）制备了 6 种干粉末。然后，分析了有无 CTUAE 技术时 OP 的提取产率、理化和功能特性以及分子结构。同时，监测了提取 OP 过程中声场的时频域，以分析超声场的影响。结果表明，FD 比 HD 对 OP 主链的破坏较小；OP 的产率、半乳糖醛酸（GalA）、酯化度（DE）、分子量（M）和黏度增加，而粒径减小。HD OP 的持水能力（WHC）和持油能力（OHC）更为突出。其次，HD OP 具有树枝状刚性链，而 FD OP 具有带有多个分支的柔性链。对于 HD OP，随着秋葵干粉末目数的减小，GalA、黏度和乳化能力降低；而凝胶强度和热稳定性增加。对于 FD OP，减小目数可提高热稳定性。总之，CTUAE 技术提高了 OP 的产率和 GalA，降低了 DE、M 和粒径。就功能特性而言，该技术还提高了凝胶强度、回弹性和粘弹性，增强了乳化稳定性、WHC 和热稳定性，降低了黏度。最后，对 OP 的功能和结构特性之间的相关性进行了量化，并对其在食品领域的应用提出了一些建议。
