An enhanced fat extraction from Pycnanthus angolensis (African nutmeg) seeds using cellulase from Aspergillus niger strain BC23

Abstract

A promising extraction method for obtaining fat from Pycnanthus angolensis seeds through Aspergillus niger strain BC23 enzyme pretreatment and particle size reduction is presented in this work. The employed A. niger enzyme was produced from corn bagasse waste material, which served as the only source of carbon. P. angolensis seeds were dried, pulverized and subsequently sieved into two different particle sizes of 1.0 mm and 1.4 mm. This was followed by enzyme pretreatment prior to fat extraction. Results demonstrated that while the peak enzyme activity (121.036 U/mL) occurred on day 4 of fermentation, the maximum cellulase activity could be achieved at 60% saturation of ammonium sulfate purification. Compared with the results of water-treated and untreated seed samples, the fat yield, free fatty acid and iodine values of the enzyme-treated seed samples were considerably higher (P < 0.05). As peroxide value was less in the enzyme-assisted extracted fat, which pointed to a good-quality oil, the decreased refractive index suggested peak unsaturation. Despite considerable differences (P < 0.05) in refractive indices, fat’s specific gravity matched (P > 0.05) when enzyme-treated, water-treated and untreated samples were compared. On the whole, size reduction of P. angolensis seeds pretreated with A. niger cellulase enzyme to improve both fat quality and yield implied it as a useful inventory for confectionary as well as cosmetic industries.