| Food sciences |
|
|
|
|
| Optimization on alkaline and enzymatic extraction of tea flower protein and its functional properties |
| HOU Ling, SHEN Xian, CHEN Lin, KIM Eunhye, WU Yuanyuan*, TU Youying* |
| (International Tea Flower Research Center, Department of Tea Sciences, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, China) |
|
|
|
Abstract Tea flower is a new food resource with high protein and low fat, but there are few reports on the total protein extraction of tea flower so far.
In this work, the tea flower protein was classified by Osboren method, and alkaline and enzymatic extractions were used for obtaining the total protein of the tea flower, and the functional properties of the protein were further analyzed. The single factor design of alkaline extraction was four levels of NaOH concentration (0.01, 0.05, 0.10 and 0.30 mol/L), five levels of time (0.5, 1.0, 2.0, 3.0 and 4.0 h), four levels of temperature (40, 60, 80 and 90 ℃) and five levels of liquid solid ratio (8∶1, 15∶1, 20∶1, 30∶1 and 60∶1). Screening test result showed that the alkaline protease was the most suitable enzyme for enzymatic extraction, and the single factor design of enzymatic extraction was four levels of the amount of alkaline protease (0.1%, 1.0%, 4.0% and 8.0%), four levels of liquidsolid ratio (10∶1, 20∶1, 30∶1 and 40∶1), four levels of time (0.5, 1.0, 2.0 and 3.0 h) and three levels of temperature (30, 50 and 70 ℃).
The results of Osboren experiment showed that the tea flower proteins were mainly composed of albumin, accounting for 53.86%, which was suitable for alkaline extraction. Based on the results of single factor test and orthogonal array design, the optimal conditions of alkaline extraction were 0.15 mol/L NaOH, 2.5 h, 75 ℃ and liquidsolid ratio of 30∶1, and the highest protein extraction rate and purity were 91.45% and 90%, respectively. The optimal condition of enzymatic extraction were 5% alkaline protease, liquidsolid ratio of 50∶1, 2 h and 60 ℃, and the highest protein extraction rate and purity were 79.12% and 55%, respectively.
The functional properties of the tea flower protein from alkaline and enzymatic extractions were different. The purity, water retention capacity, emulsion stability and foamability from alkaline extraction were 90%, 4.00 mL/g, 85.18% and 100.00%, which were higher than those (55%, 3.60 mL/g, 30.76% and 80.00%) of enzymatic extraction. The emulsibility, oil absorption capacity, foam stability and solubility of the tea flower protein from enzymatic extraction were 83.87%, 4.40 mL/g, 72.92% and 89.00%, which were higher than those (77.14%, 4.00 mL/g, 40.00% and 60.60%) of alkaline extraction. Besides, the protein from alkaline and enzymatic extractions had good abilities on scavenging 1,1-dipheny-2-picryhydrazyl (DPPH) free radical with the rate of 50.79% and 56.04% respectively, suggesting anti-oxidative function of the tea flower protein.
In sum, the present work provides optimization methods on the extraction of tea flower protein. The good functional properties with water retention capacity, oil absorption capacity, emulsibility, foamability and anti-oxidative ability and so on of the protein will expand the application of tea flower in the field of food and cosmetics.
|
|
Published: 20 July 2016
|
|
|
茶树花蛋白质碱提和酶提工艺优化及其功能性质
采用Osboren蛋白质分类法对茶树花蛋白质进行分类，通过正交试验研究茶树花蛋白质碱法和酶法提取的最佳工艺，并对用这2种方法所提蛋白质的功能特性进行比较研究。结果表明：茶树花蛋白质组成以清蛋白为主，适合用碱法提取。碱提法最佳组合为NaOH浓度0.15 mol/L，提取时间2.5 h，提取温度75 ℃，液固比30∶1，在此条件下的蛋白质提取率达到91.45%，蛋白质纯度达到90%。酶法提取工艺的最佳条件为碱性蛋白酶添加量5%，液固比50∶1，提取时间2 h，提取温度60 ℃，提取率为79.12%，蛋白质纯度为55%。碱法提取的茶树花蛋白质纯度、持水性、乳化稳定性和起泡性优于酶法提取，而酶法提取的茶树花蛋白质的乳化性、吸油性、泡沫稳定性、溶解性优于碱法提取。此外，茶树花碱提和酶提蛋白质对1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picryhydrazyl，DPPH）自由基的清除率分别达到50.79%和56.04%，具有一定的抗氧化功能。
|
Viewed |
|
|
|
Full text
|
|
|
|
|
Abstract
|
|
|
|
|
Cited |
|
|
|
|
| |
Shared |
|
|
|
|
| |
Discussed |
|
|
|
|
