School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang, Jiangsu 212013, People's Republic of China.
Faculty of Applied Sciences and Technology, Sunyani Technical University, P. O. Box 206, Sunyani, Ghana.
J Food Biochem. 2019 Aug;43(8):e12948. doi: 10.1111/jfbc.12948. Epub 2019 Jun 19.
To improve the utility of walnut meal protein, influences of ultrasonication on the kinetic and thermodynamic constraints of enzyme (trypsin) hydrolysis were assessed using a multi-frequency counter current S-type ultrasound machine. Results revealed that both the ultrasonication treatment and control hydrolysis obeyed the first-order kinetics within the study constraints. After 90 min hydrolysis time, the uppermost percentage conversion rate (57.5%) of substrate to product and the percentage increase (25.42%) in hydrolyzed protein concentration were obtained at 323 K and 10% substrate concentration, respectively. The Michaelis constant (K ) in ultrasonic enzymolysis declined by 58.66% over the control. The reaction rate coefficient (k) for the proteolysis improved by 84.75%, 52.43%, 48.25%, and 37.79% at 219, 303, 313, and 323 K, correspondingly. Generally, the bond energy (E ), enthalpy change (ΔH), entropy change (ΔS), and Gibbs free energy (ΔG) were reduced by the ultrasound pretreatment with 36.61%, 28.05%, 18.22%, and 5.24%, respectively. PRACTICAL APPLICATIONS: Walnut meal protein has a well-balanced amino acid profile and its economic utilization could be increased practicably as a food ingredient via production of hydrolysates/peptides for the production of improved food ingredients instead of being cast off as animal feed. This study demonstrated a positive bearing of ultrasonication-assisted alkaline pretreatment on proteolytic reaction characteristics and its energy efficiency for walnut meal protein, which makes this technique applicable to the enhancement of plant proteins for inclusion in food products, especially tree nut and oil seed waste products from the oil industry.
为了提高核桃粕蛋白的实用性，采用多频逆流 S 型超声仪评估了超声对酶（胰蛋白酶）水解动力学和热力学限制的影响。结果表明，在研究限制范围内，超声处理和对照水解都遵循一级动力学。在 90 分钟的水解时间后，在 323 K 和 10%底物浓度下，底物到产物的最高转化率（57.5%）和水解蛋白浓度的百分比增加（25.42%）分别获得。超声酶解的米氏常数（K ）比对照降低了 58.66%。蛋白水解的反应速率系数（k）分别提高了 84.75%、52.43%、48.25%和 37.79%，对应的温度分别为 219、303、313 和 323 K。一般来说，键能（E ）、焓变（ΔH）、熵变（ΔS）和吉布斯自由能（ΔG）分别通过超声预处理降低了 36.61%、28.05%、18.22%和 5.24%。
核桃粕蛋白具有均衡的氨基酸组成，通过生产水解物/肽作为改良食品成分的原料，而不是作为动物饲料丢弃，其经济利用可以实际增加。本研究表明，超声辅助碱性预处理对核桃粕蛋白的蛋白水解反应特性及其能量效率具有积极的影响，这使得该技术适用于增强植物蛋白以纳入食品产品，特别是来自油行业的树坚果和油籽废物。
