Extraction and characterization of a functional protein from Millettia speciosa Champ. leaf

Abstract

Natural plant-derived protein with excellent bioactivities has attracted much attention so a functional protein with molecular weight of 15.2 kDa was extracted from Millettia speciosa Champ. leaf for the first time. Under the pH of 12.0, solid-liquid ratio of 1:40 (w/v), extraction time of 2.0 h, and extraction temperature of 50 °C, the highest extracting efficiency (79.25 ± 0.78%) of the Millettia speciosa Champ. leaf protein (MLP) was achieved. The main structure of MLP contained β-fold and β-corner by Fourier transform infrared spectroscopy (FTIR) and Circular dichroism (CD) spectra analysis. Additionally, MLP was predominant with glutamic acid, aspartic acid, and leucine, which could be considered as a high quality natural protein. MLP showed great water holding capacity (WHC), oil absorption capacity (OAC), as well as emulsifying and foaming properties. Simultaneously, MLP exhibited considerable antioxidant activity. These results suggested that MLP could be utilised as a promising ingredient of functional foods.

Graphical Abstract

Keywords:

• Millettia speciosa Champ.
• leaf protein
• physicochemical properties
• functional properties
• antioxidant activity

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China under Grant [number 21676104, 21878105, 21908070]; National Key R&D Plan under Grant [number 2018YFC1603400, 2018YFC1602100]; the Key Research and Development Program of Guangdong Province under Grant [number 2019B020213001]; the Science and Technology Program of Guangzhou under Grant [number 201904010360]; China Postdoctoral Science Foundation under Grant [number BX20180102, 2019M652902]; and the Fundamental Research Funds for the Central Universities under Grant [number 2019PY15, 2019MS100].