Using the sun to process the much sought after Aloe sap paste produces a higher quality end product and in half the time used in conventional processing methods like using firewood a recent study by ICIPE says, a discovery that could now open doors to commercial exploitation of the sap and increase Kenya's export volumes in the $110 million aloe vera global market.
Aloe secundiflora, a succulent perennial herb that is one of about 450 species of the Aloe family grows predominantly in the arid and semi arid areas of Kenya like Baringo, Laikipia, Samburu and Mombasa. It is much sought after for its yellow bitter sap paste, which is used in the manufacture of pharmaceutical and cosmetic products and in alcoholic beverages. The plant is a major source of livelihood for marginalised communities.
Kenya produces some 11 tonnes of A. secundiflora paste annually. While this is good news especially for the lucrative export market where a kilo goes for between $5 and $8,, the process used to extract the paste from the plant has been the subject of many debates especially due to the amount of fuelwood used fanning deforestation.
Local communities extracting the sap cut the leaves of the plant at the base and drain the sap, which they then sell to dealers who process it into a rock-hard dark green paste, primarily for export.
“The sap from the leaves of A. secundiflora has a high percentage of water, which has to be removed to form a stable paste. Local dealers process the sap into paste by heating it in drums mounted on traditional three-stone fuelwood cooking stoves. The icipe-led study found that this processing method utilises approximately 4.1 tonnes (4,100 kilogrammes) of fuelwood to process one tonne of paste,” said Dr Wilber Lwande a scientist from ICIPE.
With Kenya producing some 11 tonnes of Aloe paste every year, the processing use approximately 45 tonnes of fuelwood, which is sourced from the meager vegetation resources in the semi-arid areas. The wanton felling of trees to cater for the processing not only contribute to deforestation and loss of biodiversity but also to carbon dioxide green house gas emissions, whose long term effects include environmental and land degradation and climate change respectively according to Dr Lwande.
The scientists now say temperature range of 90 to 100 degree celsius which is required in the processing can be achieved by solar energy which is readily available in areas where the plant grows. This they say is the ultimate answer to the deforestation menace now threatening these already dilapidated areas and also ensuring higher quality of the sap compared to that processed using fuel wood.
The researchers also established that the paste obtained from A. secundiflora sap using solar concentrating technology was more stable and of higher quality and value. For instance, the paste had a higher content of Aloin A, compared to that produced using either electricity or fuelwood. Aloin A is a bitter, yellow-brown coloured compound found in the sap of Aloe species. The compound is used as a stimulant laxative in treating constipation and as a bittering agent in commercial alcoholic beverages. Aloin content is generally used as a standard measure of the quality of Aloe extracts.
“The variations in Aloin content in A. secundiflora paste produced using solar, electricity and fuelwood energy could be attributed to possible changes in thermo-chemical reactions in the sap. For instance, the use of fuelwood could result in overheating, while solar energy provides a more gentle heating process. We also found solar energy to be more efficient in reducing the water content of A. secundiflora leaf sap as compared to electricity and fuelwood energy, thereby providing a more stable paste,” said Dr. Wilber Lwande.
The scientists now say tapping solar would ensure even more processing of the sap within lesser time, protect the ecosystem and increase the volume for export. This they say would encourage more people to go into its processing, creating jobs and increasing incomes.
USA is the major producer of the plant, followed by South Africa and Kenya. The Main importers are China and Saudi Arabia.
Written by Bob Koigi for African Laughter