Bringing food chemistry to life

“The amazing structural properties of plants” – “Via “ScienceWise“  at the Australian National University.

I came across this when I was searching for the strategies used by other people and institutions regarding efforts to expand the public awareness of science. It’s a little old, from February 2008, but I thought it of interest.

Plant cell walls are incredibly important in all sorts of places in foods: from the texture of fruits and vegetables, and how texture softens during ripening, often due to concerted action by enzymes like pectinases, to the efficacy of extraction techniques where plant cell walls that need to be degraded for access to the internal contents e.g. wine grape crushing. Plant cell walls also soften under the impact of enzymes produced by post-harvest microbial growth. Any one who has experienced the effects of Erwinia carotovora soft rot on potatoes or carrots has seen first hand what the concerted effects of pectinases, cellulases, and xylanases can do to the integrity of the plant tissue. Cell walls  are important in cereal processing as well. Depending on their solubility arabinoxylans (AX) in wheat can be beneficial or detrimental to baking properties of flour, and AX create a second elastic polymer network in cookies that can limit their spread. Soluble beta-glucans [closely related to cellulose] are a benefit as soluble fiber in oats and barley, but can be a nightmare  for brewers trying to drain a mash tank.

Daniel J. Cosgrove, of the Department of Biology at Penn State University, got it right when he wrote;

“Without cell walls, plants would be pliant piles of PROTOPLASM, more like slime moulds than the stately trees and other greenery that grace our planet“.

(Cosgrove DJ. 2005. Growth of the plant cell wall. Nature Reviews Molecular Cell Biology 6, 850-861 | doi:10.1038/nrm1746)

Anyone who has mistakenly grabbed a Erwinia rotted potato has experienced what the whole plant kingdom would feel like, and what its TEXTURE would be, without the cell walls – YEECH!

One problem about plant cell walls is their complexity. It has been hard to model their fine structure, and even harder to define the sequence of events in their synthesis.

In the article “Mixing cell biology with mechanical engineering” Shankar Kalyanasundaram, Hung Kha and Richard Williamson, biologist and engineers team up to model primary cell wall structure.

Williamson is quoted…

“The mechanical properties of any material always reflect its underlying structure” of course for food scientists the mechanical properties are also the properties we perceive as texture when we eat the material.

Dr Kalyanasundaram reported; “… biologists might be able to test the individual components that make up the structure of the cell wall, but they don’t have the expertise to model the various components as a system.. How the structure of a cell wall gives rise to its mechanical properties is an important research area, and we need this understanding if we are to better understand cell expansion and the role it plays in plant growth“.

This is entirely aligned in its strategy with  the systems approach to understanding plant cell walls published by  Chris Somerville and colleagues from Stanford in 2004

(Somerville et al. 2004. Toward a Systems Approach to Understanding Plant Cell Walls.  Science 24: Vol. 306. no. 5705, pp. 2206 – 2211. DOI: 10.1126/science.1102765)

The abstract of Kha et al can be found here -  –  –  –  Kha H, Tuble S, Kalyanasundaram S, Williamson RE. (2008) Finite element analysis of plant cell wall materials. Advanced Materials Research 32: 197-201.