Thursday, December 1, 2016

Parts of the Grape Berry

I started off reading an article called "Phenolics and Ripening in Grape Berries"1 and decided that I needed to take one step back. In reading this article, I found that nomenclature can be a hindrance to understanding what part of the grape berry is being referenced, so I did a little research to learn about the various names that can stand for the same part of the grape berry. This understanding of the grape berry, I found is a necessary prelude to understanding where the various flavor components are located.
The following illustration has been modified from the original2 to refer to the grape berry parts:
In simplistic terms, the grape berry can be divided into the outer skin, pulp and the seeds which is obvious to the unaided eye. However the grape berry is comprised of distinct morphological and anatomically divisions.
Parts of the Grape Berry:3
  • Epidermis: cuticle covering
  • Hypodermis: just under the epidermis comprising several cell layers
  • Mesocarp: contains larger vacuoles and comprising 85–87% of the berry’s spherical volume
  • Endocarp: consists of crystal-containing cells (druses) and an inner epidermis
  • Seeds: contained in locules and composed of an outer seed coat, the endosperm, and the embryo
Not shown in the diagram is the berry vascular system composed of xylem and phloem vessels. With this groundwork laid, I hope to continue in the next blogpost with the chemical constituents that can be found in the various parts of the grape berry.
References:
1. Douglas O. Adams, "Phenolics and Ripening in Grape Berries", Am. J. Enol. Vitic., 57:3 (2006).
2. Dunsford, P.A. and Sneyd, T.N., "Pressing for quality", Proceedings of the Seventh Australian Wine Industry Technical Conference.
3. Fernanda Cosme, Berta Gonçalves, António Inês, António M. Jordão and Alice Vilela, "Grape and Wine Metabolites: Biotechnological Approaches to Improve Wine Quality"

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