STUDIES ON THE PHYSICOCHEMICAL CHARACTERISTICS, MICROBIAL LOAD AND STORAGE STABILITY OF OIL FROM INDIAN ALMOND NUT (TERMINALIA CATAPPA L.)

Abstract

Oils constitute one of the essential components of balanced diet as good source of energy, as well as complementing the energy needs of the society in the form of biodiesel. The chemical and physical properties of oils are amongst the most important properties that determine the quality and help to describe the present condition of oils. The physicochemical characteristics, microbial load and storage stability of Indian almond (Terminalia catappa) seed oil collected in Cape Coast, Ghana were investigated and compared with that of frytol vegetable oil manufactured by a leading manufacturing industry in Ghana. The seed recorded a good yield of 52.11% oil. The mean physicochemical parameters of the almond nut oil were:- specific gravity (0.923), refractive index (1.465), moisture content (0.550%), insoluble impurities (0.133%), free fatty acid (0.38%), and peroxide, iodine, acid and saponification values were (4.073 meq/kg), (121.19 wijs), (0.78 mgKOH/g), (168.27 mgKOH/g) respectively. All the physicochemical parameters determined were significantly (p<0.05) higher than those determined for frytol. Storage stability of both oils under room temperature showed faster deterioration of oils when exposed to daylight than when stored in darkness. The mean free fatty acid values (oleic acid) obtained for both oils when exposed to light and darkness respectively throughout the period of study (2 months) were 0.585% and 0.490% for almond and 0.585% and 0.260% for frytol. Similarly, the mean peroxide values were 25.670 and 19.15meq/Kg for almond and 15.115 and 12.95meq/Kg. There were no detections for Salmonella in both oil samples. However, there were detections for fungi in both oils with mean counts of 1.4 x 10³cfu/ml for almond and 1.3 x 10³cfu/ml for frytol. The mean mesophilic counts for almond and frytol were 4.0 x 10³cfu/ml and 4.8 x 10³cfu/ml respectively. The physicochemical properties of the almond seed oil indicated that it is edible, drying and suggested its suitability for industrial purposes as well as the nutritional potentials of the nut, which could serve as an alternative food ingredient for unsaturated vegetable oil.

Keywords: Physicochemical parameters, almond nut oil, frytol, shelf life, microbial load