Although in non-cashew producing countries there is a tendency to believe that only the cashew nut exists, in reality this represents only a small part of the entire fruit complex. The apple constitutes 75% by weight, the actual walnut just 10%. Of this remaining 90% nothing is thrown away.
Ripe cashew apples can be eaten fresh, cooked in curry, or fermented in vinegar, citric acid, or an alcoholic beverage. It is also used to prepare preserves, chutneys, jams and is used to flavor drinks, both alcoholic and non-alcoholic. Cashews are more widely marketed than cashew apples, because the fruit, unlike the nut, bruises easily and has a very limited shelf life. It has a slightly astringent taste and are usually used in the preparation of a variety of products, including cashew juice (CAJ), jams, jellies, ice creams and other laboratory-prepared products such as burgers, pastries, cakes, granola bars, etc.
The cashew kernel is enclosed in a reddish-brown membrane called the husk, which represents approximately 5% of the total nut. In the outer skin of the cashew there is approximately 25% tannins (it is a chemical substance present in plant extracts), which has properties similar to those of the wattle bark used in the leather industry. The foam is waste, but the tannin content makes it a high-value product for the development of thermostable environmentally friendly compounds. Cashew husk is used in emerging industrial applications, such as adsorbents, composites, biopolymers, dyes and enzyme synthesis. In recent years the head has also been added as an alternative food to wheat bran in the diet of pregnant sows.
Cashew bagasse is rich in organic compounds and could be a valuable source of materials suitable for the production of bioethanol (a liquid fuel obtained from the fermentation process of agricultural products with high sugar content) and other microbial products through biological processes.
Cashew shell oil, also known as CNSL, is a caustic liquid rich in non-isoprenoid phenolic lipids and makes up 15 to 30 percent of the cashew shell. It is a viscous liquid of a greenish-yellow or reddish-brown color is obtained from the walnut shell. Recent studies highlight its enormous application potential in the pharmaceutical field, in the formulation of resins, coating and lining materials, laminates, adhesives, biofuel derivatives and insecticides. It can in fact completely or partially replace some currently very polluting "ingredients" used in the development of the products listed above.
The same nut can be used to produce cashew oil, which is a dark yellow oil derived from pressing cashews and is used for cooking or as a salad dressing. The oil is considered of the highest quality and is produced by a single cold pressing.
