Classification of Southern Tunisian honeys based on their physicochemical and textural properties

Figures & data

Table 1. Honey samples and botanical origins from different regions of Tunisia.

Honey	Origins	Amount (Number of regions)	Honey type	Pollen In (%)
Heather	Medenine	72	Erica sp; Eucalyptus sp; Thymus capitatus;Rhamnus	55.70 ± 4.89
Alfaalfa	Gabes	50	Castanea sativa;Rhamnus;retama raetam;phoenix dactylifera	54.20 ± 6.89
Caraway	Kairouan	32	Carum carvi;Foeniculum vulgare; lavandula stoechas;cucurbita maxima	54.40 ± 6.70
Pricklypear	Kairouan	46	Opuntia ficus-indica; Eucalyptus sp; Rosmarinus sp	61.64 ± 8.45
Jujuba	Djerba	66	Rhamnus;Echium plantagineum; Eucalyptus sp	58.70 ± 5.87
Carob	Kairouan	71	Ceratonia siliqua; Eucalyptus sp; prunus dulcis;thymus capitatus	63.40 ± 6.10
Thistle	Gabes	64	Carduus rutans: Rosemarinus sp; Mentha pulegium L	60.02 ± 7.04
Almond	Sfax	54	Prunus dulcis; sorghum bicolor; opuntia ficus-indica	59.30 ± 8.90
Sulla	Tozeur	81	Sulla coronaria; Rhamnus; Eucalyptus sp	59.02 ± 5.79

Table 2. Physicochemical parameters of the monofloral honey samples of Tunisian origin.

Honey type	Water content (%)	Protein (%)	Total soluble Solids (°Brix)	pH	Acidity (meq/kg)	Water activity	Electrical conductivity (mS cm^−1)	Activity of invertase (Unit/kg)	HMF (mg/kg)	Vitamin C (mg/Kg)	Lycopene (mg/kg)	Anthocyanins (ug/kg)
Heather	12.39 ± 0.65^a	0.09 ± 0.01^ab	82 ± 0.005^e	3.89 ± 0.02^c	13.37 ± 0.14^a	0.62 ± 0.005^bc	0.42 ± 0.015^b	62.58 ± 0.05^a	25.55 ± 0.86^e	80.81 ± 2.65^a	4.24 ± 0.22^e	15.45 ± 0.15^d
Alfalfa	15.88 ± 0.08^cde	0.095 ± 0.005^ab	80.75 ± 0.25^cd	3.45 ± 0.045^a	17.25 ± 0.25^d	0.59 ± 0.01^abc	0.59 ± 0.01^d	72.8 ± 1.00^b	22.36 ± 1 .76^de	91.33 ± 2.55^f	2.095 ± 0.035^b	24.86 ± 0.86^f
Caraway	16.42 ± 0.53^de	0.12 ± 0.01^bcd	80.63 ± 0.125^c	3.67 ± 0.01^b	19.18 ± 0.055^e	0.62 ± 0.01^c	0.50 ± 0.01^c	76.49 ± 1.09^bc	21.38 ± 0.78^d	53.29 ± 2.94^c	1.075 ± 0.075^a	18.37 ± 0.35^e
Prickly pear	15.91 ± 0.045^cde	0.13 ± 0.01^cd	79.97 ± 0.025^b	3.49 ± 0.055^a	15.22 ± 0.015^c	0.60 ± 0.01^bc	0.39 ± 0.01^b	105.92 ± 0.63^e	11.48 ± 0.92^a	129.38 ± 4.19^h	6.095 ± 0.16^g	23.52 ± 1.12^f
Jujube	17.23 ± 0.27^e	0.15 ± 0.01^d	79.45 ± 0.15^a	3.68 ± 0.02^b	17.20 ± 0.030^d	0.61 ± 0.01^bc	0.42 ± 0.005^b	110.24 ± 1.14^e	13.28 ± 1.28^ab	103.31 ± 2.95^g	5.045 ± 0.065^f	11.73 ± 0.77^bc
Carob	15.12 ± 0.75^bcd	0.11 ± 0.01^bc	80.5 ± 0.00^c	3.66 ± 0.01^b	20.17 ± 0.035^f	0.61 ± 0.01^bc	0.32 ± 0.015^a	145.37 ± 0.32^f	17.28 ± 0.72^c	43.74 ± 2.51^b	6.17 ± 0.065^g	9.87 ± 0.76^ab
Thistle	16.62 ± 1.26^de	0.075 ± 0.005^a	79.93 ± 0.175^b	3.46 ± 0.02^a	14.22 ± 0.04^b	0.59 ± 0.005^ab	0.34 ± 0.015^a	94.36 ± 0.90^d	12.43 ± 0.83^ab	62.13 ± 1.9^d	4.41 ± 0.025^e	12.83 ± 0.41^c
Almond	13.60 ± 0.39^ab	0.10 ± 0.01^abc	81.14 ± 0.055^d	4.63 ± 0.02^d	19.23 ± 0.025^e	0.57 ± 0.01^a	0.41 ± 0.015^b	69.78 ± 1.22^ab	17.69 ± 0.89^c	30.71 ± 2.55^a	3.20 ± 0.03^c	12.49 ± 1.07^c
Sulla	13.90 ± 0.41^abc	0.11 ± 0.01^bc	81.15 ± 0.15^d	3.66 ± 0.01^b	20.21 ± 0.01^f	0.57 ± 0.005^a	0.31 ± 0.005^a	81.78 ± 1.08^c	15.00 ± 0.20^bc	72.56 ± 1.44^e	3.84 ± 0.055^d	8.38 ± 0.18a

The results are determined as mean ± standard error. The mean values, in the same column with different letters, are considered to be significantly different (P < 0.05).

Figure 1. Principal component analysis (PCA) of the physicochemical properties of southern Tunisian honeys.

Figure 2. Cluster analysis of the physicochemical properties of southern Tunisian honeys.

Table 3. Color parameters (L *.a * andb *) of the monofloral honeys samples of Tunisian origin.

		Color Parameters
Honey	L*	a*	b*
Heather	30.64 ± 0.07^c	2.71 ± 0.14^a	17.99 ± 0.025^ab
Alfalfa	25.42 ± 0.145^a	10.71 ± 0.29^e	19.47 ± 0.145^bc
Caraway	28.32 ± 0.105^b	10.52 ± 0.055^e	24.33 ± 0.195^f
Prickly pear	31.06 ± 0.53^c	5.31 ± 0.015^b	21.98 ± 0.675^de
Jujube	27.08 ± 0.28^b	7.74 ± 0.22^d	16.29 ± 0.185^a
Carob	27.16 ± 0.01^b	5.91 ± 0.055^c	23.73 ± 0.74^ef
Thistle	25.58 ± 0.17^a	10.75 ± 0.12^e	20.91 ± 1.18^cd
Almond	63.19 ± 0.95^d	6.39 ± 0.31^c	42.97 ± 0.23^h
Sulla	30.46 ± 0.37^c	8.13 ± 0.05^d	27.25 ± 0.86^g

The same letters in the same column indicate that the difference is not significant at (P > 0.05).

Table 4. Composition in sugar of the monofloral honey samples of Tunisian origin.

		Composition (%)
Honey type	Fructose	Glucose	Sucrose	Maltose	F/G	Glucose+ Fructose
Heather	35.95 ± 0.45^bc	31.15 ± 0.05^ab	3.00 ± 0.20^b	2.31 ± 0.055^g	1.15	67 .1
Afalfa	36.75 ± 0.25^cd	30.78 ± 0.025^ab	2.30 ± 0.1^a	1.85 ± 0.045^e	1.19	67.53
Caraway	36.19 ± 0.69^bc	32.39 ± 0.17^d	2.6 ± 0.1^ab	3.99 ± 0.035^c	1.12	68.58
prickly pear	38.00 ± 0.40^de	32.02 ± 0.57^cd	3.45 ± 0.15^c	0.01 ± 0.00^a	1.19	70.02
Jujube	35.57 ± 0.57^abc	31.31 ± 0.19^bc	4.48 ± 0.175^d	3.16 ± 0.045^h	1.14	66.88
Carob	37.96 ± 0.40^de	33.32 ± 0.16^e	2.98 ± 0.08^b	1.49 ± 0.075^d	1.14	71.28
Thistle	38.18 ± 0.055^e	35.51 ± 0.25^f	3.41 ± 0.09^c	2.11 ± 0.085^f	1.075	73.69
Almond	34.33 ± 0.07^a	30.38 ± 0.15^a	2.28 ± 0.08^a	1.11 ± 0.045^c	1.13	64.71
Sulla	35.19 ± 0.07^ab	31.25 ± 0.10^bc	2.7.± 0.05^ab	0.36 ± 0.04^b	1.13	66.44

The same letters in the same column indicate that the difference is not significant at (P > 0.05).

Figure 3. Principal component analysis (PCA) of color parameters and sugars of southern Tunisian honeys.

Figure 4. Cluster analysis of color parameters and sugar of southern Tunisian honeys.

Figure 5. Analysis of the main components of the textural parameters and the activation energy of honeys of Tunisian origin (heather, alfalfa, caraway, almond, thistle, jujube, carob, sulla and prickly pear) .

Figure 6. Cluster analysis of the textural parameters and the activation energy of southern Tunisian honeys.

Figure 7. Flow curve: shear stress as a function of shear rate of monofloral honeys of Tunisian origin at 25 ° C.

Table 5. Arrhenius law parameters of the monofloral honey samples of Tunisian origin.

Honey type	Activation energy Ea (kJ/mol)	Viscosity constant A (Pa.s)	R^2
Heather	50.02 ± 0,02^b	3.05.10^−7	0.991
Alfalfa	43.41 ± 0,02^e	1.88.10^−6	0.975
Caraway	41.13 ± 0,03^f	4.20 × 10^−6	0.984
prickly pear	39.27 ± 0,001^g	6.65.10^−6	0.988
Jujube	31.75 ± 0,05^i	11.24 × 10^−5	0.948
Carob	45.93 ± 0,03^c	6.94 × 10^−7	0.996
Thistle	37.86 ± 0,06^h	9.73 × 10^−6	0.99
Almond	70.99 ± 0,005^a	8.92 × 10^−6	0.982
Sulla	45.34 ± 0,07^d	1.18 × 10^−6	0.915

The same letters in the same column indicate that the difference is not significant at (p > 0,05).

Table 6. Textural parameters of the different types of monofloral honeys of Tunisian origin.

Honey type	Extrusion Force (g)	Extrusion work (g.s)	Resilience	Cohesiveness (g.s)
Heather	123.5 ± 1.5^bc	755.63 ± 24.38^ab	0.5 ± 0.00^d	0.63
Afalfa	125 ± 2^bc	828.75 ± 16.25^bc	0.02 ± 0.00^a	0.70
Caraway	131 ± 4^c	869.06 ± 25.31^c	0.01 ± 0.00^a	0.72
prickly pear	120.5 ± 1.50^ab	780.04 ± 6.33^ab	0.10 ± 0.00^b	0.65
Jujube	113.5 ± 1.5^a	695.63 ± 35.63^a	0.15 ± 0.05^bc	0.58
Carob	122 ± 2^b	765.31 ± 30.94^ab	0.06 ± 0.00^a	0.64
Thistle	121 ± 0^ab	786.92 ± 5.94^ab	0.2 ± 0.00^c	0.54
Almond	124.5 ± 1.02^bc	750 ± 5.67^ab	n.d	0.61
Sulla	124 ± 3.5^bc	750.5 ± 30.5^ab	0.04 ± 0.00^a	0.63

The same letters in the same column denote the difference is not significant at (P > 0.05).