American Journal of Agricultural and Biological Sciences 3 (2): 502-510, 2008 ISSN 1557-4989 © 2008 Science Publications
Processing of Aloe Vera Leaf Gel: A Review
C.T. Ramachandra and P. Srinivasa Rao Department of Agricultural and Food Engineering, Indian Institute of Technology, Kharagpur-721302, India Abstract: Proper scientific investigations on Aloe vera have gained more attention over the last decade due to its reputable, medicinal, pharmaceutical and food properties. Some publications have appeared in reputable scientific journals that have made appreciable contributions to the discovery of the functions and utilizations of Aloe vera lacking processing of leaf gel. Present processing techniques aims at producing best quality aloe products but end aloe products contain very little or virtually no active ingredients. Hence, appropriate processing techniques should be employed during processing in order to extend the use of aloe vera gel. Further research needs to be done to unravel the myth surrounding the biological activity and the exploitation of aloe constituents. Key words: Cold process, Qmatrix process, whole leaf process, desiccant air dehydration, time temperature, sanitation process INTRODUCTION Aloe vera (Aloe barbadensis Miller) is a perennial plant of liliacea family with turgid green leaves joined at the stem in a rosette pattern. Aloe vera leaves are formed by a thick epidermis (skin) covered with cuticle surrounding the mesophyll, which can be differentiated into chlorenchyma cells and thinner walled cells forming the parenchyma (fillet). The parenchyma cells contain a transparent mucilaginous jelly which is referred to as Aloe vera gel. Potential use of aloe products often involves some type of processing, e.g. heating, dehydration and grinding. Processing may cause irreversible modifications to the polysaccharides, affecting their original structure which may promote important changes in the proposed physiological and pharmaceutical properties of these constituents. Processing of Aloe vera gel derived from the leaf pulp of the plant, has become a big industry worldwide due to the application in the food industry. It has been utilized as a resource of functional food, especially for the preparation of health drinks which contain Aloe vera gel and which have no laxative effects. It is also used in other food products, for example, milk, ice cream confectionery and so on. However, Aloe vera gel juice was not very popular due to their laxative effect and majority of them contained absolutely no active mucilaginous polysaccharides or acemannan. Although colour changes have little relation to the therapeutic effectiveness of stabilized gel, they are rarely acceptable psychologically to the user. The color change is totally unacceptable in some products. It therefore becomes imperative that a simple but efficient processing technique needs to be developed, especially in the aloe beverage industry, to improve product quality, to preserve and maintain almost all of the bioactive chemical entities naturally present in the plant during processing. The production process of aloe products involve crushing, grinding or pressing of the entire leaf of the Aloe vera plant to produce an Aloe vera juice, followed by various steps of filtration and stabilization of the juice. The resulting solution is then incorporated in or mixed with other solutions or agents to produce a pharmaceutical, cosmetic or food product. In the food industry, Aloe vera has been utilized as a resource of functional food, especially for the preparation of health food drinks and other beverages, including tea. The amount of Aloe vera that finds its application in the pharmaceutical industry in not negligible as far as the manufacturing of topical ointments, gel preparations, tablets and capsules are concerned. Aloe vera gel also finds its application in the cosmetic and toiletry industries, where it is used as a base for the preparation of...
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