Caffeine, invertase enzyme and triangle test sensory panel used to differentiate Coffea arabica and Vernonia amygdalina honey

Honey is a highly consumed natural product, not only for the taste, but also for biofunctional benefit. Due to the strong demand and special merit, the honey industry is under frequent deception worldwide, and the scarce branded honey replaced by the cheapest type of honey. The replacement of branded honey with inferior quality honey is a global concern. Accordingly, identification and setting of a chemical marker for a specific type of honey is essential. In this study, Coffea arabica and Vernonia amygdalina honey investigated. Melissopalynology found that Coffea arabica (54.4–94.2%) and Vernonia amygdalina (47–68.8%) were dominant honey samples. Coffea arabica honey had 96.11 ± 20.02 mg/kg caffeine, 7.64 ± 0.84◦Schade diastase, 14.12 ± 2.25 invertase number (IN); and Vernonia amygdalina honey had 17.02 ± 0.29 mg/kg caffeine, 12.5 ± 0.55◦Schade diastase, 10.09 ± 0.08IN. There was a significant difference (p < 0.05) between Coffea arabica and Vernonia amygdalina honey in caffeine. The association between Coffea arabica pollen count and the amount of caffeine had a positive regression model (Caffeine = 1.3318₍Pₒₗₗₑₙ cₒᵤₙₜ ₒfCₒffₑₐₐᵣₐbᵢcₐ₍%₎₎–3.9392), at r² = 0.8746. In addition, the invertase number was also regressed with a pollen count of Coffea arabica (%), (Invertase number = 0.081₍Pₒₗₗₑₙ cₒᵤₙₜ ₒfCₒffₑₐₐᵣₐbᵢcₐ₍%₎₎–8.6636) at r² = 0.7399. Coffea arabica honey had 16.99 ± 1.01g/100g moisture, 5.6 ± 2.52 mg/kg hydroxymethylfurfural, and −9.91 ± 3.09 [α]ᴰ₂₀ specific rotation. Vernonia amygdalina honey had 19.02 ± 0.05g/100g moisture, 0.43 ± 0.01 mg/kg hydroxymethylfurfural, and −5.98 ± 0.07 [α]ᴰ₂₀ specific rotation. Fructose, glucose, sucrose, turanose, and maltose for Coffea arabica honey were 36.26 ± 1.35, 31.24 ± 2.09, 0.93 ± 0.67, 0.08 ± 0.004, and 0.87 ± 0.79g/100g, respectively; and Vernonia amygdalina honey had 37.54 ± 0.82, 30.12 ± 0.87, 0.1 ± 0.01, 0.07 ± 0.002, 0.78 ± 0.09g/100g, respectively. Based on the triangle test, 94.44% of the panelist identified the bitter taste immediately after swallowing for Vernonia amygdalina honey. Thus, the level of caffeine and triangle test panel used to differentiate Coffea arabica honey and Vernonia amygdalina honey. The amount of caffeine present in honey depends on the dominant level of coffee nectar, which can be used as an indicator of Coffea arabica honey.