Walnuts are the rounded, single-seeded stone fruits of the walnut tree native to southern Europe, which is a member of Juglandaceae family. The walnut is enclosed in a green, leathery, fleshy husk which is inedible. Removal of the husk reveals the wrinkly walnut shell, which is in two halves, and encloses the kernel, which is likewise in two halves separated by a partition. The seed kernels are enclosed in a brown seed coat which contains antioxidants. The antioxidants protect the oil-rich seed from atmospheric oxygen so preventing rancidity (oxidative rancidity). Due to their high fat content, walnuts have a significant nutritional value. They are of the following composition: water: 5%, protein: 15%, fat: 63%, carbohydrates: 13%, fiber: 2%, minerals: 2%, Oil content: 50 – 65%.
Characteristic indicators of good quality are: large seeds (nuts), thin shell, pleasant flavor (not rancid) and a light shell color. On acceptance, particular attention must be paid to inspecting the cargo for insect infestation. The nut shells may also become unattractive due to tannin which makes black stains on the outer shell in particular. For this reason, walnuts are sulfur-treated and, now, are bleached only with sodium hypochlorite. Walnut contains quinones, oils, tannins; nuts contain essential fatty acids, including cis-linoleic and alfa-linolenic.
Oil prepared from the walnut nut is immensely beneficial for women. Women suffering from menstrual dysfunction or others who are plagued by dry and blistering eczema may take two teaspoons of unprocessed walnut oil every day as an enhancement to their regular diets to derive the best results and get relief from their problems. Walnut oil is a good source of omega-3 fatty acids which are essential to human nutrition.
Walnuts are primarily eaten raw and are also used in trail mixes. Walnuts are also processed into walnut paste for the confectionery and bakery industries. Walnut oil is obtained by pressing fully ripened walnuts; this oil is ideal for salad dressings. Walnut oil is edible and is generally used less than other oils in food preparation, often due to high pricing. It is light-coloured and delicate in flavour and scent, with a nutty quality. Although sometimes used for pan frying, most chefs do not use walnut oil for high temperature cooking, as heating can remove some of the oil’s flavour & nutrition and produce a slight bitterness; instead it is used primarily as an ingredient in cold dishes such as salad dressings, where its flavour more easily comes through. In addition, the antioxidants present in the oil are easily destroyed in cooking. Most walnut oil is produced in France though there are also producers in Australia, New Zealand and California. Walnuts can be used in a variety of sweet and savory recipes including cakes and breads and are especially good with cheeses. They make a decorative garnish and are a reasonable substitute for pecan nuts.