Functional Properties of Protein Isolates from Caragana korshinskii Kom. Extracted by Three Different Methods

Abstract

Seeking cheap, sustainable protein sources greatly facilitates in alleviating the dependence upon expensive animal-based protein in many developing countries. Caragana korshinskii Kom. offers a good alternative feedstock because of its high-content of protein, low fertilizer and pesticide requirements, excellent stress (high salty and less water) tolerance, wide adaptability, etc. The functional properties of C. korshinskii Kom. protein isolates by three different extraction methods were investigated. The extraction processes greatly influenced the physiological characteristics of protein isolates. C. korshinskii Kom. protein isolate by traditional alkaline extraction (Al-CPI) exhibited good performance on emulsifying activity index, oil and water absorption capacity, and foaming property compared to A-CPI ( C. korshinskii Kom. protein isolate by the acetone precipitation method) and TCA-CPI ( C. korshinskii Kom. protein isolate by trichloroacetic acid-acetone precipitation). The water and oil adsorption capacities of Al-CPI were observed at 4.99 and 3.45 g/g, respectively, even much higher than those of soy protein isolate (SPI) (3.94 and 2.95 g/g, respectively). The highest foaming capacity was observed by Al-CPI at 185.0%, followed by A-CPI (177.5%), TCA-CPI (142.5%), and SPI (141.9%), respectively. It has to be noted that A-CPI showed good solubility at acidic pH and excellent in vitro digestibility. After sequential pepsin-trypsin digestion, the percentage of N release of A-CPI reached up to 83.7%, which was 1.63 times that of Al-CPI (51.2%), 1.19 times that of TCA-CPI (70.1%), and slightly higher than that of the commercial SPI (82.5%). These results indicate that C. korshinskii Kom. holds great potential for application in the animal feed and food additive industry.

Integrating kinetics with thermodynamics to study the alkaline extraction of protein from Caragana korshinskii Kom

“…It is likely that during the slower extraction process, the stronger alkaline solutions are more effective in breaking down the structure of C. korshinskii Kom., thereby freeing more protein in the solvent, as suggested in previous research with distiller's grain (Bals et al, ). Furthermore, our previous study (Zhong et al, ) indicated that an increased alkalinity of the solvent would increase the protein solubility of C. korshinskii Kom. in aqueous solutions, also helping explain the higher protein yield due to increased NaOH concentration.…”

“…exhibited good physiological characteristics. The in‐vitro digestion analysis indicated that they were even comparable with commercial soybean protein isolates (Zhong et al, ). However, valorization of the protein fraction is challenging in a biorefinery.…”

“…Alkaline extraction was carried out using the method of Zhong et al (), with some modifications. Briefly, a mixture of 10 g C. korshinskii Kom.…”

“…Considering its ecological and environmental values, such as conserving soil and water resources, as well as improving soil fertility, it is widely grown for vegetation rehabilitation as well as controlling desertification in the northwest of China (Cheng et al, ). However, the shrub needs to be harvested every 3 years to make it flourish, thereby generating a large amount of biomass with a high content of cellulose, hemicelluloses and lignin, as well as protein (Zhong et al, ). At present, only a small amount of the biomass is used for fiber‐board production, and most of the remainder is burned as firewood or processed as animal feed (Bian et al, ).…”

Effect of maleylation on physicochemical and functional properties of rapeseed protein isolate

“…In-vitro digestibility of protein was determined as described by Groninger and Miller (1979) after incorporating the modification from Zhong et al (2012). Twenty milligram of pepsin was added to 700 mg of protein suspension having pH 1.5-2.0 (adjusted with 1 N HCl) and maintained at 37°C in a water-bath shaker.…”