Ultrasound-assisted extraction and modification of plant-based proteins: Impact on physicochemical,functional, and nutritional properties

Ultrasonication is a green technology that has recently received an enormous research attention for extraction of plant-based proteins and tailoring the functionalities of these ingredients. Ultrasonication is generally used as a pretreatment method in the conventional protein solubilization protocols because it can break the cell matrix to improve the extractability. The rate of protein extraction and increase in the extraction yields depend on operating conditions such as sonic energy density, time of sonication, the substrate to slurry ratio, agitation, and so on. Ultrasonication is also applied to modify the physical, structural, and functional properties of protein-based ingredients, besides simultaneous extraction and modifications. Significant changes that occur in protein physical properties due to sonication include size reduction, rheology, electrical conductivity, and zeta (ζ) potential. These changes are due to cavitation-induced shear leading to changes in secondary and tertiary structures, including protein aggregation and cross-linking due to oxidation. Physical and structural changes affect the resulting ingredient functionality and nutritional quality of protein. Changes in the functional properties, especially hydrophobicity, solubility, emulsion, and foaming, depend on the extent of ultrasound energy applied to the protein. This study aims to review major ultrasound process parameters and conditions for extraction and modification of plant proteins and their impact on protein structural changes and resulting physicochemical, functional, and nutritional properties.     

Enhanced corrosion behavior and mechanical properties of AZ91 magnesium alloy developed by ultrasonic-assisted friction stir processing

In this study, ultrasonic-assisted friction stir processing (UaFSP) and friction stir processing (FSP) were conducted on AZ91 magnesium alloy sheets, and their microstructure, corrosion behavior, and mechanical properties were comparatively investigated. Scanning electron microscopy, open-circuit potential, and potentiodynamic polarization were used to study the corrosion behavior of the material. Electrochemical measurements reveal that employing UaFSP, the corrosion rate of the AZ91 magnesium alloy was significantly reduced where lower corrosion current density for UaFSP specimens was obtained (2.09 µA/cm²) compared with 3.42 µA/cm² for the FSP and 6.82 µA/cm² for the base metal. This is mainly attributed to the alteration of morphology and better distribution of the β-Mg₁₇Al₁₂ phase during UaFSP. By using ultrasonic vibration in FSP, a finer grain structure was obtained, which improved the tensile strength and hardness of the AZ91 Mg alloy.     

Ultrasonic-assisted reductive extraction of matrine from sophorae tonkinesis and its purification by macroporous resin column chromatography

In this work, ultrasonic-assisted reductive extraction of matrine from Sophorae tonkinesis was studied for the first time. During this process, sodium metabisulfite was added as a reducing agent in order to covert maximum amount of oxymatrine, sophocarpine, and oxysophocarpine to matrine. After optimization by response surface methodology, the extraction yield of matrine was found to be 2.03%, much higher than the yield obtained through traditional extraction method. After filtration, H103-macroporous adsorption resin column chromatography, concentration, and recrystallization, matrine with 98.2% purity was obtained.     

超声波辅助提取橡胶籽油的工艺优化研究

为优化超声波辅助提取橡胶籽油的工艺,应用二次正交旋转组合进行试验设计,同时对橡胶籽油的理化、结构和热学性质进行分析.优化得到超声波辅助提取橡胶籽油的工艺条件为:提取温度55℃,提取时间60 min,液料比8.57∶1,超声频率90 kHz.在此工艺条件下,橡胶籽油得率为36.03％.FTIR以及DSC结果表明,橡胶籽油的理化、结构和热学性质与普通植物油相近,可以作为新的油源制备生物柴油.     

大黄中多糖的提取工艺及其抗氧化活性的研究

优化大黄多糖的提取工艺,并对大黄多糖的抗氧化性进行研究。以大黄为原料,采用溶剂回流法提取大黄中的多糖,确定大黄多糖的最佳提取工艺,对提取条件进行优化。再以超声波辅助提取作为对照,对比两种方法对多糖得率的影响。采用溶剂回流提取时,以蒸馏水作为提取剂,在料液比为1：30,提取温度为90℃,提取时间为2h的条件下,大黄多糖的得率最大可达15．7％。而采用超声波辅助提取,多糖得率较溶剂回流的提取方法低,在超声温度为70℃,超声时间为30min,料液比为1：35的条件下,多糖得率最大为7．9％。抗氧化性结果研究表明：大黄多糖对DPPH自由基的清除作用较为明显,随着大黄多糖浓度的上升,清除率显著增加。在浓度增加到0．8mg／mL时大黄多糖与vc对DPPH的清除率开始接近,之前均小于vc。为大黄多糖的综合利用开发提供了理论依据。     

超声波破壁提取葡萄酒酵母泥中多糖的研究

目的 利用超声波法提取葡萄酒酵母泥中多糖。方法 研究了酵母浓度、超声温度、超声时间对葡萄酒酵母泥中多糖得率的影响, 并采用响应面分析法对葡萄酒酵母泥中多糖提取工艺进行优化设计。结果 超声波法提取葡萄酒酵母泥中多糖的最佳条件为: 酵母浓度9.10%, 超声温度为65.42 ℃, 超声时间为132.97 min。最终酵母多糖得率为1.85%, 对最佳工艺条件进行验证, 酵母多糖实际得率为1.86%, 结果重复性较好。结论 超声波辅助提取葡萄酒酵母泥中的多糖, 工艺简便, 多糖得率较高, 具有实际的应用价值。     

猕猴桃根总黄酮的超声提取及抗氧化活性

以湘西"米良猕猴桃"根为原料,采用超声波辅助乙醇提取总黄酮,通过单因素及正交实验优化提取条件,考察总黄酮对羟基自由基清除效果及对油脂氧化的抑制作用,并与常用抗氧化剂作比较。结果表明,以体积分数60%乙醇按照每1 g固体30 mL液体(即料液比1∶30,下同)在60℃水浴中超声提取40 min后,猕猴桃根中总黄酮得率为1.5%。该提取物对羟基自由基清除效果随质量浓度的增大而升高,对食用油脂的氧化有较好的抑制作用。     

响应面法优化超声辅助提取普洱茶中类胡萝卜素工艺研究

研究云南普洱茶中类胡萝卜素的提取工艺。采用超声辅助提取的方法,在研究料液比、提取时间、超声时间及提取温度等单因素实验基础上,采用响应面法分析确定普洱茶中类胡萝卜素的最优提取工艺。结果表明,最优的提取工艺是超声时间为120 s,静置提取时间为32.6 min,提取温度为51.4℃。在此条件下,普洱茶中类胡萝卜素的提取液吸光度可达到理论预测值的98.8%。     

RSD法优化紫葡萄皮花色苷超声辅助萃取工艺研究

紫葡萄皮糖苷是一种水溶性色素,以紫葡萄皮为材料。采用超声工艺提取,以超声功率、超声温度、超声频率、超声时间为主要因素,通过测定花色苷的吸光值,采用pH示差法以确定其含量,应用响应面设计进行优化。试验结果表明,紫葡萄皮糖苷超声提取最优提取条件为：超声功率286 W,超声温度为45.2℃,超声频率为48.8kHz,超声时间为45min。此时花色苷得率为0.235g/100g。