Blackberry and avocado residues can be used to manufacture pharmaceutical and cosmetic products because of the vitamins, antioxidants, and minerals that can be found in their skins, seeds and husks.
The residues can be used just as the industry uses organic waste (biomass) to obtain gas or kerosene.
An investigation conducted by the National University of Colombia (UN) Manizales determined that blackberries and avocado fruits were a rich source of compounds with high potential for the biofuels and bioenergy industry, as well as for the production of organic acids (vinegar, ascorbic acid, and salicylic acid, among others).
"We found that blackberry residues contained nearly 126.41 mg/kg of antioxidants and that avocados had up to 17% of oil; which are valuable compounds for the pharmaceutical, food, and cosmetic industries," says Javier Andres Davila Rincon, one of the researchers.
Since Colombia's fruit processing industry generates significant amounts of inedible waste, they can potentially be an important source for the extraction of valuable compounds. Nearly 70% of the fruits and vegetables in Colombia (by weight) become by-products or inedible because of malpractices, issues of associated to the cold distribution chain and improper transportation of the fruit, among other things.
For example, according to Colombia's Ministry of Agriculture, the country produced nearly 3.3 million tons of fruit in 2011. "However, if we take into account the percentage of fruit lost in the processing industry, the country loses nearly 2.31 million tons every year," the young researcher stated.
In this regard, Professor Carlos Ariel Cardona Alzate, the head of the Chemical Process, Catalytic and Biotechnological group in the UN Manizales, said that nearly 65% of the waste was organic and 35% of it was inorganic. "Only 40% of the organic waste is managed adequately, 50% is handled improperly, and only 10% is recovered through recycling," he said.
The main use and application of the biomass generated by organic waste (particularly corn, coffee, rice, prunings, branches, and wood) is to obtain electrical and thermal combustion energy, and, in some cases, to produce biofuels. Thus, researchers started to look for alternatives where they could use the waste in the cosmetic and pharmaceutical industry through a pilot design of a refinery based on fruits.
According to the researchers, some functional compounds (phenolics, carotenoids, flavonoids, vitamins, antioxidants, enzymes, and anthocyanins, among others) could be found in the fruits, both in their edible parts and in their residues.
They residues also have an attractive lignocellulosic content that can be used to obtain value-added products through biochemical, mechanical, and thermochemical processes.
Researchers were able to obtain the raw material required for this research thanks to the link between the institution's Institute of Biotechnology and Agribusiness (IBA) with some companies in the region, such as Frugy. The study was based on hydrolysis processes (decomposition of organic substances by water) and the extraction of valuable compounds with supercritical fluids (any fluid under extreme temperatures) from the skins, seeds and husks of blackberry and avocado.
Researchers determined that the blackberry had a good deal of phenolic compounds and extracts with antioxidant capacity, as well as anthocyanins, which can be used in medicine, specifically in cancer prevention. Furthermore, the fruit's holocellulose content (over 61%) could be used in obtaining C5 and C6 sugars; the lignin (19.22%), composite components, and polymeric materials found could be used for fuel production.
In the case of avocado (Hass variety), researchers used the fruits' shell and seed to extract flavonoids, terpenoids, steroids, tannins and saponins. The residues had a 52.88% holocellullose content (cellulose and hemicellulose) and could be used to manufacture products from C5 and C6 sugars. Both residues would be essential in the production of extracts with antioxidant capacity.
Researchers employed a thermo-mechanical method (which involves using controlled temperature and mechanical stress processes) to extract avocado oil, which could have similar properties and uses than olive oil.
Another value added benefit obtained by researchers, was generating the energy needed by the bio-refinery plant to extract the chemical compounds of blackberries and avocados, by using said residues to obtain electric and thermal energy.
The investigation conducted by Javier Andres Davila has expanded the concept of bio-refinery for processing fruit in Colombia, through an innovative approach that allows full and sustainable use of its components. This could lead to an improvement of the productive chains.
Source: UN / DICYT