Comparative Study of the Physicochemical Properties and Antimicrobial Properties of Shea and Cocoa Butters
This study is aimed to determine the following:
- Physic-chemical properties of the Shea and Cocoa butter
- Anti-microbial properties of the Shea and Cocoa butter
Shea Tree (Vitellariaparadoxa)
Vitellariaparadoxa (formerly Butyrospermumparkii), commonly known as shea tree, shi tree, or vitellaria, is a tree of the family Sapotaceae. It is the only species in the genus Vitellaria, (Anonymous, 2011) and is indigenous to Africa. The shea fruit consists of a thin, tart, nutritious pulp that surrounds a relatively large, oil-rich seed from which Shea butter is extracted. It is a deciduous tree usually 7–15 m (23-49 ft.) tall, but has reached 25 m (82 ft.) and a trunk diameter of 2 m (6.5 ft) (Masters et al., 2010).
The Shea tree is a traditional African food plant. It has been claimed to have potential to improve nutrition, boost food supply in the “annual hungry season”, (Master et al.,2010) foster rural development, and support sustainable land care (NRC, 2006).
The tree starts bearing its first fruit when it is 10 to 15 years old; full production is attained when the tree is about 20 to 30 years old. It then produces nuts for up to 200 years. The fruits resemble large plums and take 4 to 6 months to ripen. The average yield is 15 to 20 kilograms (33-44 lbs.) of fresh fruit per tree, with optimum yields up to 45 kilograms (99 lbs.). Each kilogram of fruit gives approximately 400 grams (14 oz.) of dry seeds ( NRC, 2006).
Shea butter fatty acid profiles
Shea butter is composed of five principal fatty acids: palmitic, stearic, oleic, linoleic, and arachidic (see table below). About 85 to 90% of the fatty acid composition is stearic and oleic acids. The relative proportion of these two fatty acids affects shea butter consistency. The stearic acid gives it a solid consistency, while the oleic acid influences how soft or hard the shea butter is, depending on ambient temperature.
The proportions of stearic and oleic acids in the shea kernels and butter differ across the distribution range of the species. Ugandan shea butter has consistently high oleic acid content, and is liquid at warm ambient temperatures. It fractionizes into liquid and solid phases, and is the source of liquid shea oil. The fatty acid proportion of West African shea butter is much more variable than Ugandan shea butter, with an oleic content of 37 to 55%. Variability can be high even locally, and a tree that produces hard butter can grow with one that produces soft butter.
Nuts are gathered from a wide area for local production, so shea butter consistency is determined by the average fatty acid profile of the population. Within West Africa, shea butter from the Mossi Plateau region of Burkina Faso has a higher average stearic acid content, and so is usually harder than shea butter from other West African regions (Maranzet al., 2004).
MATERIALS AND METHODS
The samples and materials used for this study were raw Shea nuts and raw cocoa nibs. The dried cocoa beans were obtained from Cocoa ware house in Owo Local Government Area in Ondo State, while the dried Shea nuts were obtained from the main market in Owo Town, in Owo Local Government Area of Ondo State; both states are located in Nigeria. The samples obtained were sun-dried, cleaned thoroughly to remove extraneous materials (stones, pebbles and twigs) and then separated into two portions. One portion was roasted in the oven at 120°C for 2 hours, while the other portion was used in its raw state. The raw and roasted cocoa beans were shelled to obtain the cocoa nibs. The different samples were pounded separately with a pestle in a clean wooden mortar and thereafter ground with a laboratory Warring blender to obtain suitable particle sizes for laboratory analysis. The ground samples were stored in an air-tight plastic container and kept in the refrigerator, prior to analysis.
RESULTS AND DISCUSSION
Table 4.1: Physicochemical Properties of Shea butter and Cocoa butter
CONCLUSION AND RECOMMENDATIONS
This research work compared the physicochemical and antimicrobial properties of Shea and Cocoa butter. The physico-chemical properties of composition of Shea nut butter can compare favorably with Cocoa butter excluding the saponification value and flash point of Cocoa butter which was found to be far greater than that of Shea butter with a value of 340oC (flash point) and 673.2mg/g (S.V). Both samples (Shea butter and Cocoa butter) also show some considerable antimicrobial properties against Klebsiella pneumonia, Yeast and Staphylococcus aureus. Therefore, it can be concluded that both Shea butter and Cocoa butter can be suitable substitute for other oils in any industrial application.
Based on the results observed from this research work, it is therefore recommended that further research is needed to see the effects of environments over a period of time on the physicochemical and chemical properties of Shea butter and Cocoa butter.
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