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Although the temperature in the last week has been low and snow had settled on him, BERTIE is not showing any ill effects. After mild frosts some older beet leaves may die, but younger heart leaves usually survive. The result of this is that less sunlight is intercepted, so the plant growth rate (and photosynthesis) reduces. In addition, as the nights get longer, the amount of sugar used to keep the plant alive (respiration) during the night increases.
The total effect of the lower temperatures, longer nights and less sunlight is that the growth rate of the beet plant slows down, so that the sugar content in the root remains fairly constant from now on.
The beet is left in the ground until it is required for delivery to the factory, unless severe frosts are forecast. Beet freeze when their temperature falls to -3ºC. When frozen beet thaw the ruptured cells start to leak. This encourages the rapid growth of bacteria, which break down sucrose (the product extracted in the factory) into gums and invert sugar (glucose and fructose). Invert sugars are unstable in the factory process and can give rise to acid compounds whose presence causes still more sucrose to be split into invert. Also invert sugars result in the production of off-white sucrose crystals. To prevent freezing, beet is stored in clamps (shaped piles of beet), which are insulated and protected from frosts using straw bales and polypropylene/polyfelt sheets. |
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