Physicochemical properties and antioxidant activities of thermally treated poly-floral honey from Chire woreda, Sidamo regional State, Ethiopia

Figures & data

Figure 1. Study area Map.

Table 1. Thermal processing of honey samples

Treatments	Untreated Honey sample	Treated Honey samples
Heating Temperature	Control	55°C			95°C
Heating Time		0.5 h	1 h	2 h	0.5 h	1 h	2 h

Table 2. Thermal treatment effect on the physicochemical properties of honey

Variables Temperatures Time		Total sugar (%)	Reducing sugar (%)	Sucrose (%)	pH	Free acid value (meq/kg)	Electrical Conductivity (mS/cm)	Moisture content (%)	HMF (mg/Kg)	Diastase number (DN)
Unheated honey		72.48 ± 1.73^a	68.51 ± 1.32^e	3.78 ± 2.88^e	4.54 ± 0.53^a	35.05 ± 0.07^e	0.12 ± 0.03^a	12.5 ± 0.50^b	6.36 ± 1.58^a	13.16 ± 1.1 ^f
55°C	0.5 h	68.51 ± 1.32^b	64.95 ± 1.20^d	3.31 ± 1.00^de	4.40 ± 0.37^a	41.3 ± 2.40^d	0.13 ± 0.04^a	12.4 ± 0.09^b	6.73 ± 1.05^a	8.22 ± 0.30^e
	1 h	64.94 ± 1.19^c	61.73 ± 1.92^c	3.05 ± 1.34^d	4.30 ± 0.24^a	43.80 ± 1.41 ^cd	0.135 ± 0.02^a	12.2 ± 0.03^b	8.98 ± 2.10^a	6.30 ± 0.26^d
	2 h	60.25 ± 1.03^d	57.48 ± 1.80^b	2.63 ± 0.90^c	4.21 ± 0.33^a	48.7 ± 0.85^c	0.145 ± 0.06^a	11.9 ± 0.06^ab	9.73 ± 1.06^a	4.83 ± 0.18^c
95°C	0.5 h	58.55 ± 1.57^d	56.19 ± 2.89^b	2.18 ± 0.20^b	3.98 ± 0.46^a	50.60 ± 0.57^c	0.15 ± 0.04^a	11.8 ± 0.12^ab	11.22 ± 2.1^a	3.65 ± 0.29^b
	1 h	53.77 ± 2.02^e	51.55 ± 1.34^a	2.11 ± 0.50^b	3.74 ± 0.72^a	56.00 ± 2.83^ab	0.185 ± 0.02^a	11.6 ± 0.06^ab	18.33 ± 2.4^b	2.32 ± 0.16^a
	2 h	51.05 ± 1.46 ^f	49.51 ± 1.28^a	1.49 ± 0.66^a	3.61 ± 0.53^a	58.60 ± 1.56^a	0.245 ± 0.05^a	11.5 ± 0.07^a	31.06 ± 1.9^c	1.33 ± 0.28^a

Values are expressed as mean ± SD (n = 3). Different letters across the column indicate a significant difference among honey samples at p < 0.05.

Table 3. Total phenolic and flavonoid contents of thermally treated honey

Variables Temperatures Time		Total phenolic content (mg GAE/100 g)	Total flavonoid content (mg CE/100 g)
Control		45.37 ± 1.75^a	13.61 ± 2.84^a
55°C	0.5 h	48.36 ± 1.46^ab	15.30 ± 0.30^ab
	1 h	50.47 ± 1.76^abc	17.15 ± 0.64^bc
	2 h	52.28 ± 1.09^bc	19.16 ± 0.35^bcd
95°C	0.5 h	56.28 ± 3.20 ^cd	19.82 ± 0.60^cde
	1 h	59.11 ± 1.22^de	20.60 ± 1.41^de
	2 h	64.26 ± 3.17^e	21.70 ± 1.27^e

Values are expressed as mean ± SD (n = 3). Different letters across the column indicate a significant difference among honey samples at p < 0.05.

Figure 2. DPPH radical scavenging power (%) of thermally treated honey and the reference (ascorbic acid). Each value is expressed as mean ± SD.

Table 4. Thermal treatment effect on the DPPH scavenging activity (IC₅₀) and ferric reducing power of honey

Variables Temperatures Time		DPPH scavenging activity (IC50, mg/mL)	Ferric reducing (mg AAE/100g)
Control		92.47 ± 2.52 ^f	100.9 ± 1.76^a
55°C	0.5 h	58.59 ± 2.90^e	118.75 ± 0.35^a
	1 h	45.29 ± 1.78^d	138.25 ± 3.18^b
	2 h	36.67 ± 1.39 ^cd	161.25 ± 1.76^c
95°C	0.5 h	29.22 ± 2.30^c	175.75 ± 3.88^d
	1 h	16.30 ± 1.05^b	190.00 ± 3.53^e
	2 h	9.48 ± 0.53^b	204.25 ± 1.76 ^f
Standard		0.060 ± 0.01^a

Values are expressed as mean ± SD (n = 3). Different letters across the column indicate a significant difference among honey samples at p < 0.05.

Figure 3. The correlation of antioxidant activities and total phenolic and flavonoid contents of thermally treated honey.