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What Determines The Color Of The Walnut Kernel? How To Prevent The Kernel From Darkening?

May. 21, 2021

What Determines The Color Of The Walnut Kernel? How To Prevent The Kernel From Darkening?

According to classification, light walnut kernels have higher value and higher market value. Many recyclers encountered or noticed a dark kernel during the recycling process. This raises some questions: what determines the color of the walnut kernel, how to avoid the darkening of the walnut kernel, and how to make the walnut kernel white.

To a large extent, the color of the kernel depends on the type of nut, but there are also external factors.

The green walnut peel paint is dark on the hands, and it will be difficult to wash in the future. In those areas where nuts are everywhere, people have known the existence of nuts since childhood. These dyes (iodine and walnut) can penetrate the nuts and make the inner core a darker color. Therefore, in order to prevent the kernels from turning black, mature nuts must be cleared of the green peel as soon as possible. It is especially important to take out the nuts that have fallen on the ground. In large orchards, when they first mature, nuts are harvested and sent for cleaning. There, the peel is removed and the remaining iodine, walnuts and dust are also washed away.

The color of the kernel also depends on the quality of storage. Nuts in shell should be stored in a dry, well-ventilated place, away from direct sunlight, the temperature is from -5 to +10, and the humidity does not exceed 50%. You can pack walnuts in cardboard or wooden boxes, in mesh bags, and weigh up to 20 kg. Peeled walnuts are small in size and should be stored in the refrigerator or freezer. On an industrial scale, kernels are stored in vacuum packaging.

There are different opinions on the effect of the sun on the color of kernel. The peel and kernel of walnut contain tannins, such as gallic acid and tannins. Under the influence of sunlight and oxygen, they oxidize and turn brown. Therefore, it is best not to expose the nuts to the sun. If there is no way to hide the nut in a dark place, you at least need to move it to a cool place.

There is no natural way to bleach walnut kernels. Chemically bleaching the kernels is not safe and will affect the quality of kernels. Bleached kernel will no longer be considered environmentally friendly, and the manufacturers of such a kernel are unlikely to eat it themselves. Only by preventing the darkening of the core, can we get the lightest core possible. Some manufacturers use the method of blanching, that is, peeling the walnuts. This method is suitable when the nuts appear to be "beaten" or will be used in confectionery after all stages of processing.

If you plan to grow your own nuts, it is important to pay attention to the variety you choose, as there are varieties with lighter kernels.

A common cause of black kernels is late harvest. The longer the mature nut is in the peel, the more dye will penetrate into it.

Proper storage not only affects the color of the kernel, but also affects its quality and long-term storage without losing its useful properties.

By protecting the walnut from sunlight (after harvest), you can protect it from oxidation, so the inner core will darken. By following these rules, you will get a light, high-quality kernel that will be well and long-term stored and can be sold for profit.

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