Apples and pears: which rots first and why? Scientists now know!

by William Atkins

Monday, 14 July 2008

Page 1 of 2 ! Belgian researchers used the world’s largest x-ray machine to look inside apples and pears to see which fruit carries air better inside its cells and, thus, rots the slower. Guess what they found out? Air needs to circulate inside the structure of fruit—its pores and channels—so that the cells deep within each piece of fruit, after they are picked, are provided with oxygen for respiration. If air cannot move within the fruit, then the cells don’t get this needed oxygen and they eventually die, causing brown fruit and rot. However, if the fruit cells receive the necessary amount of oxygen, then they generate sugars and energy and produce healthy and delicious fruit. Dr. Pieter Verboven, the lead researcher in the study, explains, “But also in pears, no-one knew what the structure of those air voids was. It is still unclear how airways in the fruit develop, and why apples have cavity structures and pears micro-channel networks. The micro-channels are so small that oxygen supply to the fruit core is very limited and cells are quickly 'out of breath' when oxygen levels fall below the safety threshold.” [BBC News: “Apples beat pears on crunch issue”] To find out which fruit—the apple or the pear—does a better job at getting oxygen inside all of its cells, Verboven and his team of researchers performed a scientific study. They used the most powerful x-ray machine ever built on Earth—the European Synchrotron Radiation Facility (ESRF) in Grenoble, France—to show the structure of pears and apples. Verboven's group put apples and pears inside the ESRF, which is able to discern features of apples and pears (actually, just about any type of material) down to below one thousandth of a millimeter. The ESRF, the most powerful synchrotron radiation source in Europe, produces a high-energy light that can penetrate inside most materials, revealing their interior physical structure. With such data, it then produces a high-definition, three-dimensional view of the material for scientists to analyze. Verboven stated, "We already knew that different apple varieties have a different density which means they have a different fraction of air spaces; but we didn't know the structures. We also knew that pears have a much lower amount of void spaces inside because pears sink to the bottom if you drop them in water whereas apples float, which indicates that one has more air than the other one.” [BBC News] Why did they perform the study and what were its results? Please read on. << First page <   1 2 Next page > Last page - Post your comment >>

 

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