Carbohydrate Polymers 133 (2015) 567–577 Contents lists available at ScienceDirect Carbohydrate Polymers j ourna l ho me page: www.elsevier.com/locate/carbpol Dissecting the polysaccharide-rich grape cell wall changes during winemaking using combined high-throughput and fractionation methods Yu Gao a , Jonatan U. Fangel b , William G.T. Willats b , Melané A. Vivier a , John P. Moore a,∗ a Institute for Wine Biotechnology, Department of Viticulture and Oenology, Faculty of AgriSciences, Stellenbosch University, Matieland 7602, South Africa b Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, DK-1001, Denmark a r t i c l e i n f o Article history: Received 29 April 2015 Received in revised form 3 July 2015 Accepted 9 July 2015 Available online 22 July 2015 Keywords: Cell wall Fractionation Grape pomace Profiling Pectin Xyloglucan Winemaking a b s t r a c t Limited information is available on grape wall-derived polymeric structure/composition and how this changes during fermentation. Commercial winemaking operations use enzymes that target the polysaccharide-rich polymers of the cell walls of grape tissues to clarify musts and extract pigments dur- ing the fermentations. In this study, we have assessed changes in polysaccharide composition/turnover throughout the winemaking process by applying recently developed cell wall profiling approaches for monosaccharide composition (GC–MS), infra-red (IR) spectroscopy and comprehensive microarray poly- mer profiling (CoMPP). CoMPP performed on the concentrated soluble wine polysaccharides showed a fraction rich in rhamnogalacturonan I (RGI), homogalacturonan (HG) and arabinogalactan proteins (AGPs). We also used chemical and enzymatic fractionation techniques in addition to CoMPP to under- stand the berry deconstruction process more in-depth. CoMPP and gravimetric analysis of the fractionated pomace used aqueous buffers and CDTA solutions to obtain a pectin-rich fraction (pulp tightly-bound to skins) containing HG, RGI and AGPs; and then alkali (sodium carbonate and potassium hydroxide), lib- erating a xyloglucan-rich fraction (mainly skins). Interestingly this fraction was found to include pectins consisting of tightly associated and highly methyl-esterified HG and RGI networks. This was supported by enzymatic fractionation targeting pectin and xyloglucan polymers. A unique aspect is datasets suggesting that enzyme-resistant pectin polymers ‘coat’ the inner xyloglucan-rich skin cells. This data has important implications for developing effective strategies for efficient release of favorable compounds (pigments, tannins, aromatics, etc.) from the berry tissues during winemaking. This study provides a framework to understand the complex interactions between the grape matrix and carbohydrate-active enzymes to produce wine of desired quality and consistency. © 2015 Elsevier Ltd. All rights reserved. 1. Introduction Grape berry composition has a direct influence on final wine quality (Hernández-Hierro et al., 2014). The physical breaking of the grape berries during the crush and the subsequent degrada- tion of berry tissues through chemical and enzymatic reactions form the must (grape juice), the cap (mostly skins and pulp, Abbreviations: AIR, alcohol insoluble residue; AGP, arabinogalactan pro- tein; CoMPP, comprehensive microarray polymer profiling; CBM, carbohy- drate binding module; CDTA, cyclohexanediamine-tetra-acetic acid; EPG, endo- polygalacturonase; FT-IR, Fourier transform-infrared spectroscopy; GC, gas chromatography; HG, homogalacturonan; mAb, monoclonal antibody; PME, pectin methyl esterase; RG, rhamnogalacturonan. ∗ Corresponding author. E-mail address: moorejp@sun.ac.za (J.P. Moore). which we define as de-seeded pomace) and sediment (mostly pulp and seeds) (González-Neves et al., 2010), which provides the fermentation matrix for wine production. The release of grape- derived compounds (particularly from the skins) contributes to the specific wine-style and the perceived quality of the wine (Busse-Valverde, Gómez-Plaza, López-Roca, Gil-Mu ˜ noz, & Bautista- Ortín, 2011). Wine industries apply commercial enzyme blends (mainly crude enzyme mixtures from fungi such as Aspergillus spp.) during alcoholic fermentation to aid the winemaking pro- cess and enhance quality parameters. For example, in red wine fermentations, enzyme mixes are included to support macera- tion (e.g. leaching of phenolic compounds from berry skin into must) (Canal-Llauberes, 1993). Enzymes are added to both red and white wine fermentations for the purpose of clarifying the wine, decreasing viscous polymers and improving free-run juice/wine volumes (Canal-Llauberes, 1993). http://dx.doi.org/10.1016/j.carbpol.2015.07.026 0144-8617/© 2015 Elsevier Ltd. All rights reserved.