Effect of heat treatment on antimycotic activity of Sahara honey

Objective:To evaluate the influence of the temperature on honey colour,polyphenol contents and antimycotic capacity and to evaluate the correlation between these parameters.Methods:Sahara honey were heated up to 25,50,75 and 100℃for 15,30 and 60 min,and their colour intensity,polyphenol contents and antimycotic capacity.The Folin-Ciocalteu test was used to determine the total polyphenol contents(TPC).The antimycotic activity was evaluated both by agar diffusion method and micro wells dilution method against the Candida albicans(C.albicans)and Candida glabrata(C.glabrata).Results:Initial values for TPC in Sahara honey ranged from 0.55 to 1.14 mg of gallic acid per kg of honey,with the average value of 0.78 mg of gallic acid per kg of honey.The TPC values after heat-treatment were 0.54 to 1.54 with the average value of 1.49 mg.The minimal inhibitory concentrations before heat-treatment of Sahara honey against C.albicans and C.glabrata ranged from 3.06%-12.5%and 50%respectively.After heat-treatment the minimal inhibitory concentrations between 12.5%and 50%for C.albicans and C.glabrata,respectively.The diameters of inhibition zones of Sahara honey with 50%concentration varied from(12.67-15.00)mm by C.albicans to(14.33-15.67)mm by C.glabrata.The diameters of inhibition zones after heat-treatment at 25 and 50°C for 15.30 and 60 min ranged from(2.00-18.67)mm by C.albicans to(8.00-16.67)mm by C.glabrata.Statistically significant relations between the TPC and the colour intensity of Sahara honey(r=0.99,P<0.05).Furthermore,the results showed that the TPC and colour is not correlated with the antimycotic capacity.Conclusions:To our knowledge this is the first report on the antimycotic capacity of Sahara honey.