The nuts of all the species are edible, but the walnuts commonly available in shops are from the Persian Walnut, the only species which has a large nut and thin shell. A horticultural form selected for thin nut shells and hardiness in temperate zones is sometimes known as the 'Carpathian' walnut. The nuts are rich in oil, and are widely eaten both fresh and in cookery. Walnut oil is expensive and consequently is used sparingly; most often in salad dressing. Walnuts are also an excellent source of omega-3 fatty acids, and have been shown as helpful in lowering cholesterol. They need to be kept dry and refrigerated to store well; in warm conditions they become rancid in a few weeks, particularly after shelling.
In some countries immature nuts in their husks are preserved in vinegar. In England these are called "pickled walnuts" and this is one of the major uses for fresh nuts from the small scale plantings. In Armenian cuisine, walnuts are preserved in sugar and eaten whole. In Italy, liqueurs called Nocino and Nocello are flavoured with walnuts. In Georgia, walnuts are ground along with other ingredients to make walnut sauce.
Walnuts are heavily used in India. In Jammu, India it is used widely as a prasad (offering) to Mother Goddess Vaisnav Devi and, generally, as a dry food in the season of festivals such as Diwali.
How much does one cup of walnuts weigh?
Estimated US cup to weight equivalents:
|Walnuts||shelled - halved||
|100 grams||4 ounces|
|Walnuts||shelled - chopped||
|125 grams||< 5 ounces|
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