Investigating of Physiochemical Properties and Volatile Organic Compounds of Honey Varity Produced in Bonga, Ethiopia

Abstract

In this thesis, physiochemical properties and volatile organic compounds (VOCs) of honey varieties from Bonga, Ethiopia were investigated. Three flora-origin honey sample including Schefflera abssinica, Croton macrostachyus and unknown flora honeys were collected from Bonga area. Different physiochemical parameters including moisture, ash contents, pH, free acidity, hydroxymethylfurfural (HMF), and honey colors were studied. The volatile organic compounds (VOC) were extracted by sequential liquid extraction using n-hexane and then, identified by gas chromatography-mass spectrometry (GC-MS). The obtained results showed that physicochemical parameters of all the three flora origin honeys fall within the acceptable ranges set in the national and international guidelines. However, their statistical tests by ANOVA (p<0.05) demonstrated as the physicochemical parameters of the three studied samples were significantly different. Several VOCs were identified from each honey type. From C. macrostachyus, S. abssinica, and unknown flora honeys, 16, 17 and 18 VOCs were, identified, respectively. From these VOCs, six of them were detected in the three honey samples. Particularly, two VOCs, namely, (3-isopropyloxiran-2-yl) methanol, C6H12O2 and 1, 2, 4-trimethyl benzene, C9H12 were take the share of 32.62, 29.88 and 29.98% as well as 24.06, 24.09 and 23.38%) in C. macrostachyus, S. abssinica and unknown flora honey samples, respectively. Some VOCs were detected in two of the honey samples but not in the third. Several VOCs, nearly 50% of the detected compounds from one flora honey were not detected in others. Generally, the obtained results showed that the VOCs of honeys are varied with their floral. However, further study is recommend to identify different flora origin honey markers of the Bonga area or other area honey as the method is promising to easily identify honey based on its flora-origin.