Dissecting the polysaccharide-rich grape cell wall changes during winemaking using combined high-throughput and...

Area of Science:

• Enology
• Plant Cell Wall Biochemistry
• Food Science

Background:

• Grape cell wall structure and its changes during winemaking are not fully understood.
• Enzymes are used in winemaking to break down cell walls for clarification and pigment extraction.

Purpose of the Study:

• To investigate the polymeric structure and composition of grape cell walls during winemaking.
• To understand how these structures change throughout the fermentation process.

Main Methods:

• Applied monosaccharide composition analysis (GC-MS), infra-red (IR) spectroscopy, and comprehensive microarray polymer profiling (CoMPP).
• Utilized chemical and enzymatic fractionation techniques to deconstruct grape berry tissues.
• Analyzed soluble wine polysaccharides and fractionated pomace.

Main Results:

• Identified soluble wine polysaccharides rich in rhamnogalacturonan I (RGI), homogalacturonan (HG), and arabinogalactan proteins (AGPs).
• Fractionated grape tissues into pectin-rich (HG, RGI, AGPs) and xyloglucan-rich fractions, revealing highly methyl-esterified pectin networks coating skin cells.
• Demonstrated enzyme-resistant pectin polymers associated with inner skin cells.

Conclusions:

• Grape cell wall composition undergoes significant changes during winemaking.
• Complex interactions between grape matrix and enzymes are crucial for releasing desirable compounds.
• This study provides a framework for improving wine quality through better understanding of grape cell wall deconstruction.