Abstract:
Honey is the natural sweet substance produced by honey bees open to intentional adulteration, or
it may be contaminated during production and storage. The objective of this research work was to
profile certain physicochemical parameters to study about the honey nature and its
chemotaxonomy. For these, 47 fresh honey samples were collected at the local apiarists from seven
administrative zones in the Amhara Region. The collected honey samples were analyzed for the
contents of various parameters using internationally accepted standard methods and its
chemotaxonomy work were done.
The average values of the studied physicochemical parameters at each administrative zone were
in the range of 16.06 - 18.51, 0.26 - 0.60, 61.45 - 74.01, and 2.96 - 4.73 in g/100 g of honey for
moisture content, ash content, total reducing sugar and apparent sucrose content, respectively. In
addition, pH (3.85 - 4.23), free acidity (26.39 - 37.80 meq/kg), electrical conductivity (33.37 -
63.43 μS/cm) and HMF (3.88 - 8.50 mg/kg) were obtained in the studied samples. In the principal
component analysis (PCA) model using these physicochemical data’s, the first three principal
components explained a total variation of 69.1% and the linear discriminant analysis (LDA) model
had an average of 80.85% discrimination power that classify the honey samples into three
administrative provinces.
The mean values of total polyphenol content (TPC) based on gallic acid equivalent (GAE) were
17.03 - 42.04 mg GAE; the entire flavonoid content using catechin equivalent (CE) was 3.20 - 7.40
mg CE, and on using quercetin equivalent (QE), it was 1.67 - 5.08 mg QE per 100 g of honey. The
ascorbic acid equivalent antioxidant content (AEAC) of the honey samples were 16.23 to- 26.59
mg AEAC per 100 g of the honey. The percent antioxidant activities (% AA) of the honey samples
were 23.74 - 40.11%. In the PCA model using these data’s, the top three principal components
described 96.63% of the total variations. The overall discrimination power of these LDA model
was 70.2% which classify the honey sample in to three geographical origins.
The content of the major elements was in the range of 24.8 - 1996.3 mg/kg of the honey sample in
the order of K > Ca > Na > Mg. The minimum and maximum values for the trace metals were
2.35 mg/kg and 162.75 mg/kg, respectively in the order of Fe > Cr > Zn > Ni > Mn > Cu > Co.
Furthermore, the content of the toxic heavy metals was 0.57 – 6.21 mg/kg in the order of AS > Cd
> pb. In the PCA model of these metallic data, the first four principal components explained
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80.16% of the total variation. By these metallic data, the region's honey was best classified into
five major clusters using LDA with an average discrimination power of 89.91%.
In conclusion, based on the physicochemical values the region’s honey was of a good quality that
meets the national and international standard limits; and on the obtained phenolic and antioxidant
data, it has a very good therapeutic nature. From the data of the major and trace metals it has its
own nutritional contribution while the level of the toxic metal is above the maximum permissible
limit given by European Commission regulation indicating that pollution of the environment is at
an alarming rate. By selecting 16 higher loading parameters that have relatively very high
discrimination potentials from each part of the analysis it was possible to classify the regions
honey in to their 7 respective administrative zones effectively using the LDA model.