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.     

超声辅助提取兔皮胶原蛋白及其理化特性

以兔皮为原料,研究超声波在酶法提取胶原蛋白中的应用。结果表明,超声辅助制得的胶原蛋白的提取率为(83.69±0.51)%,与传统酶法相比提高了25%。聚丙烯酰氨凝胶电泳结果表明,超声处理制得的兔皮胶原蛋白主要由α1,α2和β亚基组成,并未造成亚基的降解;紫外光谱表明,超声处理后的胶原蛋白的特征吸收波长为217nm,说明其较好地保持了I型胶原蛋白的特征;傅立叶变换红外光谱表明,经过超声处理后的胶原蛋白分子中的氢键遭到部分破坏,但其三螺旋结构仍保持完整;差示扫描量热仪结果表明,超声法制得的兔皮胶原蛋白的热变性温度和热焓值均略低于传统兔皮胶原,相对而言仍具有较高的热稳定性。     

大豆品种对SPI制取过程中蛋白提取率影响的研究

以十三个不同的大豆品种为原料制取大豆分离蛋白(SPI),并对碱提与酸沉两步工序中影响蛋白提取率的三个重要因素:豆粕NSI值、碱溶提取率、乳清蛋白进行了相关分析。      

离子特性及贮藏条件对强酸性电生功能水理化性质的影响

在相同条件下对离子配比不同以及阳离子不同的电解液分别电解,测定生成水样的理化指标。研究发现,当氯离子浓度不变时,钠离子浓度成倍数增加会导致强酸性电生功能水（AEW）中有效氯浓度成倍数增加;当同时电解Cl-为35mmol/L的溶液时,KCl、MgCl2、NaCl和CaCl2四种电解质产生水样的有效氯浓度分别为90.1、74.8、56.8和48.2mg/L。另外,本文还将有效氯浓度为50mg/L左右的强酸性电生功能水在不同条件下贮藏了21d,定期测定有效氯浓度（ACC）、pH、氧化还原电位（ORP）、电导率（EC）以及溶解氧浓度（DO）在贮藏过程中的变化。结果表明,大容量器、玻璃容器和低温贮藏有利于酸性电生功能水有效氯和溶解氧的保存,密闭有利于氧化还原电位值的保持;酸性电生功能水贮藏不宜超过1周,最好在5d以内;不同电解质制备水样的贮藏稳定性由高到低依次为MgCl2、CaCl2、NaCl和KCl。      

Effect of extracting time and temperature on yield of gelatin from different fish offal

The aim of the study was to determine the optimal conditions for preparing gelatin from different kinds of fish offal: heads and backbones of Baltic cod, skins of fresh and cold-smoked salmon, and skins of salted and marinated herrings. The yield of gelatin extraction at 45 °C was 71–75% for fresh salmon skins or cod backbones, and 86%, for smoked salmon skins. When heating marinated herring skins for 15 min or salted herring skins for 45 min, about 100% of collagen was converted to gelatin. For fish skins, 45 °C and 15–60 min extraction time, depending on the kind of skins, were established as optimal conditions for preparing gelatin. The yield of gelatin extraction from the cod heads did not exceed 70%, even when a three stages process was used. In the case of backbones, 100% of collagen in the form of gelatin was isolated using this procedure. SDS-PAGE analysis showed that gelatin from fish skins was much less degraded than gelatin from pigskins.     

Bovidae-based gelatin: Extractions method,physicochemical and functional properties,applications, and future trends

Gelatin is one of the most important multifunctional biopolymers and is widely used as an essential ingredient in food, pharmaceutical, and cosmetics. Porcine gelatin is regarded as the leading source of gelatin globally then followed by bovine gelatin. Porcine sources are favored over other sources since they are less expensive. However, porcine gelatin is religiously prohibited to be consumed by Muslims and the Jewish community. It is predicted that the global demand for gelatin will increase significantly in the future. Therefore, a sustainable source of gelatin with efficient production and free of disease transmission must be developed. The highest quality of Bovidae-based gelatin (BG) was acquired through alkaline pretreatment, which displayed excellent physicochemical and rheological properties. The utilization of mammalian- and plant-based enzyme significantly increased the gelatin yield. The emulsifying and foaming properties of BG also showed good stability when incorporated into food and pharmaceutical products. Manipulation of extraction conditions has enabled the development of custom-made gelatin with desired properties. This review highlighted the various modifications of extraction and processing methods to improve the physicochemical and functional properties of Bovidae-based gelatin. An in-depth analysis of the crucial stage of collagen breakdown is also discussed, which involved acid, alkaline, and enzyme pretreatment, respectively. In addition, the unique characteristics and primary qualities of BG including protein content, amphoteric property, gel strength, emulsifying and viscosity properties, and foaming ability were presented. Finally, the applications and prospects of BG as the preferred gelatin source globally were outlined.     

Comparative study on characteristics of gelatin from the skins of brownbanded bamboo shark and blacktip shark as affected by extraction conditions

Gelatins from the skins of brownbanded bamboo shark (BBS; Chiloscyllium punctatum) and blacktip shark (BTS; Carcharhinus limbatus) were extracted using the distilled water at different temperatures (45, 60 and 75 °C) and times (6 and 12 h). Yields of gelatin from the skins of BBS and BTS were 19.06–22.81% and 21.17–24.76% (based on wet weight), respectively. Gelatins from both species extracted at 45 °C for 6 h exhibited the highest bloom strength (206–214 g), which was higher than that of commercial bovine bone gelatin (197 g) (p < 0.05). Gelatin gels from BBS skin could set at room temperature (25–26 °C) within 24 min. However, gelatin gels from BTS skin was not able to set within 3 h at the same temperature. Scanning electron microscopic study showed that gelatin gel from BBS skin presented the thicker strand than those from BTS skin and bovine bone. Cross-linked components (β- and γ-chains) and α-chains were more degraded with increasing extraction temperatures, especially at 75 °C. Gelatin from BTS skin was more susceptible to hydrolysis than that from BBS skin. Fourier transform infrared (FTIR) study revealed that the major absorption bands of gelatin from the skins of both sharks shifted to a higher wavenumber, compared with their corresponding acid soluble collagen (ASC). Therefore, gelatins from the skin of BBS has a potential to replace mammalian for gelatin, due to its similarity in bloom strength and setting behavior to the commercial bovine bone gelatin.     

Original article: Optimisation of extraction conditions and characteristics of skin gelatin from Nile tilapia (Oreochromis niloticus)

Response surface methodology was used to optimise gelatin extraction conditions from the skin of Nile tilapia (Oreochromis niloticus), and characteristics of the gelatin were determined. Concentration of NaOH (%, X₁), alkaline treatment time (h, X₂), concentration of HCl (‰, X₃) and acid treatment time (min, X₄) were chosen for independent variables. Dependent variable was yield of gelatin (%, Y). Optimal conditions were X₁ = 3.2 (%), X₂ = 2.3 (h), X₃ = 0.7 (‰) and X₄ = 84 (min), and predicted value of response optimal conditions was Y = 20.4%. Actual value was 19.3% by verification experiments under optimal conditions. Crude protein content of the tilapia skin gelatin was 88.5%. The content of imino acids including proline and hydroxyproline in the gelatin was 185 residues per 1000 total amino acid residues. Its gel strength was 260 g. The gelling and melting points were 18.0 and 22.4 °C, respectively.     

鱼鳔的功效因子及其开发利用研究进展

鱼鳔是药食两用的滋补珍品。文章综述了鱼鳔的化学成分、传统药用价值、临床功效、功能因子研究和开发利用现状,以期为其进一步开发利用提供参考。     

Improved extraction of carrageenan from red seaweed (Chondracantus canaliculatus) using ultrasound-assisted methods and evaluation of the yield,physicochemical properties and functional groups

Food Science and Biotechnology - Red seaweed Chondracanthus canaliculatus, an underexploited algae species, was used as a potential source for the obtaining of carrageenan. Seaweed was treated...     

黄皮果果胶的提取工艺优化及理化性质分析

以纯果胶得率为评价指标,在超声（功率为250 W）预处理30 min后,分别考察提取溶剂、初始pH值、料液比、提取温度及时间等因素对纯果胶得率的影响。在此基础上,采用正交试验优化黄皮果胶的制备工艺,并分析以黄皮果胶理化性质。结果表明,制备黄皮果胶的最佳工艺条件为以盐酸（0.01 mol/L）为提取溶剂,提取温度90 ℃、液料比为20∶1（mL∶g）、初始pH值为2.0,提取时间120 min。该优化提取工艺条件下,黄皮果胶得率为6.84%,半乳糖醛酸含量为76.51%,且各项理化指标均达到国家标准GB 25533—2010《食品添加剂果胶》要求。     

Structural characteristics of camel-bone gelatin by demineralization and extraction

Camel bone was demineralized through HCl acidulation process at different concentrations (0.0%, 1.5%, 3.0%, and 6.0%) over 1–5 days. The level of demineralization was acid concentration and soaking time dependent. Highest demineralization (62.0%) was recorded in bone sample treated with 6.0% dilute acid for 5 days. Energy dispersive X-ray spectroscopy (EDX) elemental analysis revealed reduction in Ca and increase in N and H, while O remains unaffected. Particulate characteristics by scanning electron microscope showed an increased surface roughness of bone after demineralization. Fourier transform infrared (FT-IR) analysis of ossein depicted the presence of functional group similar to that of bone protein (collagen). Statistical optimization by central composite design (CCD) revealed a significant quadratic model for optimum values of extraction temperature, pH, and extraction time. The highest gelatin yield from camel bone was 23.66% at optimum extraction condition (71.87°C, pH 5.26, and 2.58 h) and the bloom was 205.74 g. Camel bone is suitable for production of gelatin with good potentials in food and nonfood applications.     

Effect of batch extraction conditions on yield of soluble solids from rooibos tea

Extraction of soluble solids from rooibos tea (Aspalathus linearis) was investigated by single stage batch extraction. The effect of extraction temperature, extract: tea mass ratio and flow rate of water on extract concentration and yield of soluble solids was determined. Extract concentration and yield increased linearly with increase in temperature from 23 to 90°C.
Increasing the mass ratio from 5:1 to 10:1 decreased extract concentration, but increased yield. Both extract concentration and yield decreased with an increase in flow rate from 0.1 to 0.2 m³/hr. The water-soluble solid content of rooibos tea leaf was 21.74%, 75.1% of which was extracted at 90°C, mass ratio 10:1 and flow rate 0.1 m³/hr.     

八月瓜果皮果胶提取工艺优化及其理化特性研究

以八月瓜果皮为原料,优化酸提醇沉法提取其果胶的工艺,并对果胶酯化度、半乳糖醛酸含量进行测定。首先采用单因素实验探讨了料液比、p H、提取时间、提取温度等因素对果胶得率的影响,再通过正交实验优化提取工艺,最后对果胶的酯化度、半乳糖醛酸进行分析。结果表明,酸提醇沉法提取八月瓜果胶的最佳工艺条件为液料比1∶20（g/m L）、p H1.5、提取时间120 min、提取温度90℃,此条件下得率达12.15%;八月瓜果皮果胶的酯化度为81.94%,属于高酯果胶,其半乳糖醛酸含量为83.17%,符合GB 25533-2010对果胶半乳糖醛酸含量的要求。