Manufacturing Process Description
Quality Control and Analysis of raw material (fresh avocado)
Wash raw material using alkaline solution (pH 7.7). The alkaline solution is obtained diluting Sodium Carbonate (CAS No. 497-19-8) in water until the value of pH 7.7 for the solution is reached.
Wash raw material with pH 6.0, deionized water. The deionized water is obtained by passing water through the inverse osmosis treatment.
Avocado fruit is washed with high pressure water. The washed fruit is then processed to remove seed, skin and any potential for environmental residues.
Depulping of avocado oil (process where pulp is separated from skin and stone), using pressing/centrifuging processes.
Mixing of pulp with deionized water under regulated and controlled temperatures, always under 45°C. This ensures that the crude oil obtained in step 6 is cold pressed.
Double centrifuge to assist separation of solids and other liquids.
Degumming - It is the first step in refining. It is mainly performed by the hydration of crude oil (hydration is the process where water is added to the oil). Phospholipids, proteins and gums are oil soluble due to their dehydrated structures. However, this solubility is dissipated when they are hydrated. Hydratable phospholipids are removed in this way while non-hydratable phospholipids are removed by acid treatment.
Neutralization (Refining) - The Free Fatty Acids (FFA) contents in crude oils increase depending on various factors, like ripening of the raw materials. For oils to be made available for human consumption, FFA should be removed, to achieve longer shelf life.
Neutralization is saponification of free fatty acids. Doing this, sodium soaps are formed and separated easily from the oil in the form of soap stock.
Bleaching is the treatment with innocuous, inert diatomaceous earth, non- acidified and acidified clays, or any agent that removes color bodies and some odors from the fat or oil. Bleaching involves the mechanical strain of unrefined oils through plate and frame filters and a filter medium of bleaching clays and earth. The bleaching process uses paper or cloth filters which removes suspended compounds and provides more uniform, lighter colored oil.
Color of oil is determined by the lipochroms specific to each oil. The most common natural coloring compounds are alpha and beta carotene, x-anthophylls and chlorophyll in vegetable oil.
The objective of bleaching method is removal of coloring pigments, oxidation products, trace metals, remaining phsphatides and soap by highly activated absorbents called "bleaching earth". Bleaching earths (innocuous and inert diatomaceous earth, non-acidified and acidified clays) also have high surface area. Since bleaching is performed at high temperatures (110-120°C), in order to protect oil from oxidation, this procedure is made under vacuum; in other words oxygen free environment. Finally, bleaching increases oil stability.
After the impurities are removed at the time of degumming, neutralization and bleaching processes, some of the oils still contain compounds and waves that cause haziness and opaqueness that tend to precipitate at low temperatures. However, this appearance reduces attractiveness of the oil.
In the course of winterization, oil is cooled slowly and agitated very gently to very low temperatures. Meanwhile crystals are formed. Winterization is completed with the filtration of the crystals. Avo Plus has developed a special procedure to winterize its oil, called Hydro Press. Hydro Pressing the oil provides it with superior quality than traditional winterization procedures.
Deodorization removes reacted compounds which are decayed by-products in the form of peroxidized fats. The process uses high vacuum temperature, and live steam to remove strong flavors and odors from the oil. Deodorization is the last major processing step in refining of edible oils. It is responsible for the removal of compounds that cause undesirable odour, flavour and colour. Impurities that are separated during deodorization are classified into three groups:
- Saponificable compounds: free fatty acids, partial glycerides, esters, gummy constituents.
- Unsaponificable compounds: parafinic hydrocarbons, olefinic and polyolefinic materials, sterols, triterpenic alcohols,
- Oxidative reaction products, aldehides, ketones, peroxides.
Odoriferous and flavouring impurities present in the oil are bound to the fatty acid chain of triglycerids via weak Vander Waals Forces. Mentioned substances have low vapour pressures at high temperatures. Consequently with the aim of an operating pressure at which these compounds can be distilled readily with respect to their vapour pressure, deodorization is performed at high temperatures and low pressures. The maximum temperature that can be used, however, is limited due to its detrimental effects on oil stability. Additionally, vapor directly injected to oil sweep these compounds and make separation easier. Nevertheless, deodorization is also performed under vacuum to increase steam usage yield, protect hot oil from oxidation and prevent formation of free fatty acids via hydrolysis.