Cocoa butter, also called theobroma oil, is a pale-yellow, edible vegetable fat extracted from the cocoa bean. It is used to make chocolate, as well as some ointments, toiletries, and pharmaceuticals.
Cocoa butter has a cocoa flavour and aroma. Its melting point is just below human body temperature. Cocoa contains about 54 percent of it, therefore, if something is wrong with the cocoa butter then it raises a serious quality concern with the cocoa.
One quality parametre that can easily be underestimated but can render your cocoa unwholesome is Free Fatty Acid (FFA).
It is the quality parametre that can tell you how long your cocoa can stay healthy without undergoing rancid to produce off flavours in your cocoa mass.
Semi-finished cocoa product manufacturers and finished product manufacturers are so concerned about this parameter because they store their cocoa beans or their cocoa mass for a very long time before usage. The higher the value of free fatty acid, the shorter it can be stored before going rancid.
Free Fatty Acids (FFA) in Cocoa
Free Fatty Acid, most commonly referred to as FFA are carboxylic acids released from Triglycerides (Selamatet al., 1996) through the effects of lipase (E.C 22.214.171.124) or an oxidation reaction.
Cocoa beans or butter contains low amounts of unsaturated fatty acids (Whitefield, 2005) hence lower amounts of free fatty acids relatively, with high amounts of polyphenols and natural anti-oxidants therefore, exposed to the negligible risk of oxidation (Nickless, 1996).
It has been detected that plant lipase activity is usually high during seed germination (Wanasundara et al., 2001) and cocoa beans may not be an exception as in the overripe pods. Overripe pods may contain some amount of black and rotten beans due to senescence.
Wood and Lass (1985), Pontillon (1998), Fowler (1999) Hiol (1999) and Afoakwa et al., 2011 suggested that FFA may occur in stored cocoa beans due to the activity of microflora, particularly moulds and their associated lipases activity under humid condition.
In the trade and industry of cocoa, the maximum allowed limit of percentage free fatty acid content is 1.75 Wood and Lass (1985).
The quality of raw cocoa beans depends widely on their free fatty acids (FFA) content. High FFA content is a serious quality defect and reduces the technical and economic value of the cocoa beans.
The work investigates the influence of cocoa processing technologies on FFA formation during storage of raw cocoa beans. Different samples of ferment dried cocoa beans purchased from Cote d’Ivoire were stored and analyzed for FFA content.
Very low FFA contents were found in whole healthy cocoa beans generally complied with UE standards (1.75% oleic acid equivalent) throughout storage while high FFA content was found in poor quality and broken healthy beans. The formation of FFA did not depend on the genotype or on cocoa post-harvest processing technologies.
However, high and increasing FFA contents were observed in defective cocoa beans and could be attributed probably to the activity of microflora which in turn were associated with initial quality and loss of physical integrity of the cocoa beans.
Cocoa beans are the seed from the fruit of Theobroma cacao tree. Cocoa butter, the natural fat, contained in cocoa beans is the only continuous phase of chocolate.
It is responsible for the dispersion of the other constituents of chocolate properties during storage, handling and tasting (Nickless, 1996).
Cocoa butter is reported to be the main vegetable fat used in the chocolate manufacture because of its rheological, textural and chemical characteristics such as triglycerides fatty acids composition, (Awua, 2002; Lipp and Anklam, 1998; Whithefield, 2005).
Its hardness depends on the saturated and unsaturated fatty acid contents bound in triglycerides, and on free fatty acids (FFA) content.
The general opinion is that higher FFA content leads to a decrease in hardness of cocoa butter (Pontillon, 1998) and must be considered as a raw cocoa commercial value reducing factor both for producers and chocolate manufacturers.
For reasons of quality, therefore, the directive 73/241/EEC (EEC, 1973) limits the maximum FFA content to 1.75% oleic acid equivalent in cocoa butter.
Yet, for several years, from 15 to 20% of annual Ivorian cocoa production is considered to have excessive FFA contents (exporters' statistics) recurrently and seasonally, notably at the end of the main season.
Effect of Fermentation on Free Fatty Acids in Dried Cocoa Beans
Although the fermentation process plays an important role in achieving good chocolate flavor, the duration of fermentation can also affect the quality of beans.
Several works have shown different fermentation periods. A study by Kirchhoff et al., (1989); Lopez and Dimick, (1995) and Dand, (1997), shows that three to six days period of fermentation with 48-hourly turnings for aeration under favourable conditions are essential for best results.
The duration of the fermentation process has been observed to be for 96 hours for the tray method and 120 hours generally for Forasteros with about 48 hours less for Criollo types.
Simplice et al., (2008) revealed that cocoa beans fermentation duration seemed to have a critical effect of increasing the chances for FFA formation. He recorded slight increases in FFA in cocoa beans with varying increases in the duration of fermentation.
The initial and final FFA contents in cocoa beans fermented over 3 days were found to be higher than those in cocoa beans fermented below 3 days (Guehi et al., 2008).
It is not advisable to extend fermentation beyond recommended periods for a particular method, due to the fact that off flavours may begin to develop due to increase in activity of fungal mold in the nib that may increase amounts of Free Fatty Acids breaking from the fat molecules through oxidation and the introduction of mycotoxins (Lagunes-Galvez et al., 2007).
Effects of Storage on Free Fatty Acid
In an experiment that I did in my lab on free fatty acid in 2017 when we were looking for a suitable condition for cocoa butter storage confirmed the researches by others, that:
1. Cocoa and cocoa butter should be stored in lower humidities (below 75% RH) else there will be mycotoxin syntheses [Dr Terry Mabbett, pest control Magazine, March/April,2013 edition, volume 55Issue2]
2. Increasing pod storage time increases the free fatty acid content in the cocoa butter [Afoakwa et al,2014]. Therefore, the cocoa pod should be stored between 3 and 7 days and not beyond.