title: How Does Alkali Aid Protein Extraction in Green Tea Leaf Residue: A Basis for Integrated Biorefinery of Leaves.
abstract: Leaf protein can be obtained cost-efficiently by alkaline extraction, but overuse of chemicals and low quality of (denatured) protein limits its application. The research objective was to investigate how alkali aids protein extraction of green tea leaf residue, and use these results for further improvements in alkaline protein biorefinery. Protein extraction yield was studied for correlation to morphology of leaf tissue structure, protein solubility and hydrolysis degree, and yields of non-protein components obtained at various conditions. Alkaline protein extraction was not facilitated by increased solubility or hydrolysis of protein, but positively correlated to leaf tissue disruption. HG pectin, RGII pectin, and organic acids were extracted before protein extraction, which was followed by the extraction of cellulose and hemi-cellulose. RGI pectin and lignin were both linear to protein yield. The yields of these two components were 80% and 25% respectively when 95% protein was extracted, which indicated that RGI pectin is more likely to be the key limitation to leaf protein extraction. An integrated biorefinery was designed based on these results.
authors.affiliation: Biobased Chemistry and Technology Group, AFSG, Bornse Weilanden 9, 6708WG Wageningen, Wageningen UR, the Netherlands.
authors.forename: Chen
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Biobased Chemistry and Technology Group, AFSG, Bornse Weilanden 9, 6708WG Wageningen, Wageningen UR, the Netherlands; Food and Biobased Research Institute, Bornse Weilanden 9, 6708WG Wageningen, Wageningen UR, the Netherlands.
authors.forename: Johan P M
authors.initials: JP
authors.lastname: Sanders
authors.affiliation: Department of Plant Sciences, Laboratory of Molecular Biology, Droevendaalsesteeg 1, 6708 PB, Wageningen, Wageningen UR, the Netherlands.
authors.forename: Ting T
authors.initials: TT
authors.lastname: Xiao
authors.affiliation: Biobased Chemistry and Technology Group, AFSG, Bornse Weilanden 9, 6708WG Wageningen, Wageningen UR, the Netherlands; Food and Biobased Research Institute, Bornse Weilanden 9, 6708WG Wageningen, Wageningen UR, the Netherlands.
authors.forename: Marieke E
authors.initials: ME
authors.lastname: Bruins
mesh_terms: D000468:Alkalies / Q000302:isolation & purification*; D001709:Biotechnology / Q000379:methods; D006863:Hydrogen-Ion Concentration; D008031:Lignin / Q000302:isolation & purification; D010368:Pectins / Q000302:isolation & purification; D018515:Plant Leaves / Q000737:chemistry / Q000378:metabolism; D010940:Plant Proteins / Q000302:isolation & purification*; D013662:Tea / Q000737:chemistry / Q000378:metabolism*
chemical_list: D000468:Alkalies; D010940:Plant Proteins; D013662:Tea; D010368:Pectins; D008031:Lignin