title: Multivariate analysis of variance of designed chromatographic data. A case study involving fermentation of rooibos tea.
abstract: An ultimate goal of investigations of rooibos plant material subjected to different stages of fermentation is to identify the chemical changes taking place in the phenolic composition, using an untargeted approach and chromatographic fingerprints. Realization of this goal requires, among others, identification of the main components of the plant material involved in chemical reactions during the fermentation process. Quantitative chromatographic data for the compounds for extracts of green, semi-fermented and fermented rooibos form the basis of preliminary study following a targeted approach. The aim is to estimate whether treatment has a significant effect based on all quantified compounds and to identify the compounds, which contribute significantly to it. Analysis of variance is performed using modern multivariate methods such as ANOVA-Simultaneous Component Analysis, ANOVA - Target Projection and regularized MANOVA. This study is the first one in which all three approaches are compared and evaluated. For the data studied, all tree methods reveal the same significance of the fermentation effect on the extract compositions, but they lead to its different interpretation.
authors.affiliation: Department of Chemistry, University of Rome "La Sapienza", P.le Aldo Moro 5, I-00185 Rome, Italy.
authors.forename: Federico
authors.initials: F
authors.lastname: Marini
authors.affiliation: Post-Harvest and Wine Technology Division, Agricultural Research Council (ARC), Infruitec-Nietvoorbij, Private Bag X5026, 7599 Stellenbosch, South Africa; Department of Food Science, Stellenbosch University, Private Bag X1, Matieland, Stellenbosch, South Africa.
authors.forename: Dalene
authors.initials: D
authors.lastname: de Beer
authors.affiliation: Post-Harvest and Wine Technology Division, Agricultural Research Council (ARC), Infruitec-Nietvoorbij, Private Bag X5026, 7599 Stellenbosch, South Africa; Department of Food Science, Stellenbosch University, Private Bag X1, Matieland, Stellenbosch, South Africa.
authors.forename: Nico A
authors.initials: NA
authors.lastname: Walters
authors.affiliation: Department of Chemistry and Polymer Science, Stellenbosch University, Private Bag X1, Matieland, Stellenbosch, South Africa.
authors.forename: André
authors.initials: A
authors.lastname: de Villiers
authors.affiliation: Post-Harvest and Wine Technology Division, Agricultural Research Council (ARC), Infruitec-Nietvoorbij, Private Bag X5026, 7599 Stellenbosch, South Africa; Department of Food Science, Stellenbosch University, Private Bag X1, Matieland, Stellenbosch, South Africa.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Joubert
authors.affiliation: University of Silesia, Institute of Chemistry, Szkolna 9, 400-006 Katowice, Poland. Electronic address: beata.walczak@us.edu.pl.
authors.forename: Beata
authors.initials: B
authors.lastname: Walczak
mesh_terms: D036903:Aspalathus / Q000737:chemistry*; D002845:Chromatography / Q000379:methods*; D005285:Fermentation; D015999:Multivariate Analysis; D010636:Phenols / Q000737:chemistry; D010936:Plant Extracts / Q000737:chemistry / Q000378:metabolism; D013662:Tea / Q000737:chemistry*
chemical_list: D010636:Phenols; D010936:Plant Extracts; D013662:Tea
keywords: ANOVA simultaneous component analysis (ASCA); ANOVA-target projection (ANOVA-TP); Regularized MANOVA (rMANOVA); Rooibos tea