Table 1.
Summary of the bioactive composition, antioxidant characteristics, colour analysis, antibacterial activity, and physicochemical properties of a selection of commercially available Australian honeys.
| Highest Ranked Honeys | Lowest Ranked Honeys | |||||
|---|---|---|---|---|---|---|
| Bioactive Composition | ||||||
| TPC (mg GAE)a | Y1 | Z1 | T1 | AB6 | AO3 | A3 |
| 0.663 (0.078) |
0.635 (0.049) |
0.604 (0.124) |
0.309 (0.125) |
0.344 (0.025) |
0.360 (0.019) |
|
| TFC (μg CE)a | Z1 | Y1 | S5 | A3 | B4 | G6 |
| 96.4 (7.37) |
92.5 (12.1) |
84.6 (11.8) |
41.6 (1.48) |
44.9 (2.38) |
47.0 (4.70) |
|
| β-carotene (mg/kg)a | Z1 | Y1 | X1 | A3 | K5 | Q6 |
| 69.6 (4.95) |
69.5 (17.9) |
51.5 (3.68) |
17.1 (4.58) |
17.4 (2.32) |
19.3 (15.6) |
|
| Lycopene (mg/kg)a | R5 | Y1 | Z1 | A3 | K5 | AF3 |
| 24.9 (17.8) |
24.8 (10.0) |
23.5 (3.76) |
7.43 (3.62) |
7.74 (2.60) |
7.98 (1.79) |
|
| Antioxidant Characteristics | ||||||
| DPPH (mmol TE) | Y1 | AN2 | AI4 | AE3 | J4 | H4 |
| 0.713 ± 0.041 |
0.600 ± 0.088 |
0.596 ± 0.046 |
0.207 ± 0.045 |
0.242 ± 0.020 |
0.315 ± 0.021 |
|
| DPPH Inhibition (%) | Y1 | AN2 | AI4 | AE3 | J4 | H4 |
| 69.0 ± 3.97 |
58.1 ± 8.46 |
57.8 ± 4.38 |
20.5 ± 4.32 |
23.9 ± 1.94 |
30.8 ± 2.03 |
|
| CUPRAC (mmol TE)a | Y1 | Z1 | O1 | J4 | AO3 | AJ5 |
| 21.8 (1.36) |
20.8 (0.910) |
19.8 (0.803) |
8.28 (1.31) |
8.51 (0.368) |
10.4 (0.151) |
|
| FRAP (mmol TE) | Y1 | O1 | Z1 | J4 | AE3 | AO3 |
| 3.76 ± 0.158 |
3.08 ± 0.635 |
2.84 ± 0.266 |
0.670 ± 0.390 |
0.841 ± 0.297 |
1.05 ± 0.168 |
|
| Colour Analysis | ||||||
| Colour Intensity (mAU)a | Z1 | Y1 | X1 | G6 | K5 | Q6 |
| 1440 (98.5) |
1196 (42.9) |
905 (77.5) |
241 (5.30) |
261 (4.00) |
303 (6.70) |
|
| L*a | O1 | A3 | B4 | Y1 | Z1 | AP3 |
| 33.6 (0.800) |
25.1 (1.20) |
23.8 (1.90) |
11.7 (0.800) |
12.0 (0.800) |
12.6 (0.850) |
|
| a* | O1 | AA1 | AN2 | G6 | K5 | AO3 |
| 7.90 ± 0.212 |
7.50 ± 0.436 |
7.36 ± 1.78 |
0.980 ± 0.327 |
1.98 ± 0.455 |
2.30 ± 0.596 |
|
| b*a | O1 | A3 | P4 | Y1 | Z1 | L6 |
| 24.7 (0.400) |
18.2 (2.05) |
16.7 (3.10) |
5.30 (0.800) |
6.00 (1.05) |
6.20 (0.900) |
|
| Antibacterial Activity | ||||||
| S. aureus MIC50 (% dilution; w/v) | L6 | P4 | AK2 | Q6 | R5 | AM2 |
| 5.82 |
4.76 |
4.75 |
0.078b |
0.122 |
0.124b |
|
| Physicochemical Properties | ||||||
| pHa | A3 | AI4 | P4 | AF3 | AP3 | AO3 |
| 4.64 (0.160) |
4.60 (0.200) |
4.43 (0.170) |
3.74 (0.020) |
3.81 (0.050) |
3.82 (0.160) |
|
| TSS (°Brix) | H4 | B4 | E4 | AC4 | AB6 | AN2 |
| 60.2 ± 0.001 |
59.3 ± 0.115 |
59.3 ± 0.115 |
55.3 ± 0.115 |
55.8 ± 0.001 |
56.2 ± 0.001 |
|
| Viscosity (Pa s)a | O1 | H4 | A3 | P4 | C2 | AK2 |
| 158.0 (1.32)† |
76.4 (2.14)† |
65.0 (26.1)† |
11.0 (0.275)††† |
12.8 (0.362)††† |
16.8 (0.776)†† |
|
| aw | A3 | B4 | C2 | AO3 | AN2 | AM2 |
| 0.583 | 0.572 | 0.568 | 0.454 | 0.459 | 0.461 | |
Note: The three highest and lowest ranked honeys are presented. MIC50 was calculated from triplicate data; L*, a*, b* measurements were taken in quintuplicates, aw was analysed once for each sample, and all remaining variables were completed in triplicate. Normally distributed variables are presented as mean ± standard deviation, and not normally distributed variables are identified by ‘a’ and reported as median (interquartile range). ND = no data (insufficient sample volume); † = 5 rpm; †† = 10 rpm; ††† = 20 rpm; b = honey samples that recorded Ps. aeruginosa inhibition at 25% dilution concentrations (w/v). Letters represent honey sample ID; superscripts next to the honey identification letter are related to front-label category descriptions of the honey: 1 = Manuka Honey; 2 = Organic Honey; 3 = Generic Brand Honey; 4 = Australian Floral Honey; 5 = Regional Honey; 6 = Pure Honey.