Aloe vera grows best in dry chalky soil or in a sandy loam. While the plant needs warm semi-tropical conditions, overexposure to sun results in stunted plants with low gel yield. Therefore, Aloe vera is commonly interplanted with other crops, such as fruit trees. The quality of Aloe vera plant products varies considerably due to differences in growing, harvesting, processing, and storage techniques, and may also depend on the regulatory regime under which the product is sold. Mexico, followed by the rest of Latin America, China, Thailand, and the USA were described as main producing countries. Aloe vera has become an important plant crop in Arizona and in the Rio Grande valley of southern Texas .The production processes for Aloe vera products include various steps such as crushing, grinding or pressing, filtration, decolorization, stabilization, heat processing, and may be followed by addition of preservatives and stabilizers.
Harvesting of the leaves of the Aloe vera plant is generally performed by hand, with the leaves cut from the base of the plant. Individual leaves are wrapped, crated, and transported to processing plants. Ideally, the leaves are processed within a few hours after harvesting, as temperature, light, air, and humidity can affect the stability of the plant components. At the processing step, the leaves may be cleaned with water and a mild chlorine solution .Aloe vera gel from the fillet of the inner leaf pulp is obtained either by manual removal of the outer layers of the leaf with a knife or by machine. Either method can be flawed and has the potential to contaminate the gel with latex .This process yields crude Aloe vera gel. High quality gel appears opaque, slightly off-white in colour, and is viscous .Aloe vera whole leaf extract is obtained by grinding the whole fresh leaves, without removal of the rind. Extraneous material and lignified fibres are then removed by homogenizing and filtering the crude gel or whole leaf extracts. Since various amounts of latex and rind may be present in the whole leaf extracts, the extracts may appear yellow to yellow-green in colour. Activated carbon adsorption to produce Aloe vera decolorized whole leaf extract is the first processing step where an extract is intentionally subjected to chemical alteration. Aloe vera decolorized whole leaf has lower rheological values than the gel and has a lower content of complex carbohydrates than either gel or whole leaf extracts .The processed extracts are difficult to keep stable, a problem that may cause differences in product potency; therefore, the gel or whole leaf extracts can undergo a stabilization process before being bottled. This process may involve pasteurization, ultraviolet stabilization, chemical oxidation with hydrogen peroxide, addition of chemical preservatives and additives, or concentration, and/or drying .
(b) Production volume
In the cosmetic industry, Aloe vera ingredients hold a prominent position at the top of the list showing the relative frequency of use of plant ingredients within formulations filed with the United States Food and Drug Administration (FDA) .
According to the 2012 Nutrition Business Journal Annual Report, Aloe vera was 20th among best-selling dietary supplements in the USA. There has been a general upward trend in sales from US$ 31 million in 2000 to US$ 72 million in 2011.In 2006, the industry size for Aloe species raw material was estimated to be about US$ 125 million worldwide, while the industry for finished products containing Aloe vera was around US$ 110 billion .
Global sales of Aloe species products in 2012 totalled US$ 351 million, according to IMS Health MIDAS data. Most products were reported as derived from Aloe vera (90%). Substantial sales as a dietary supplement were reported in Brazil (US$ 74 million), Indonesia (US$ 50 million), India (US$ 34 million), USA (US$ 29 million), the Russian Federation (US$ 19 million), Japan (US$ 15 million), and Mexico (US$ 12 million) (IMS Health, 2012).