Cornflower Honey as a Model for Authentication of Unifloral Honey Using Classical Methods Combined with Plant-Based Marker Substances Such as Lumichrome

Abstract

According to legislation, unifloral honeys are characterized by their organoleptic, physicochemical, and microscopic properties. Melissopalynology is the established method for identifying the pollen taken up with the floral nectar by forager bees and is used for authentication of the nectar sources in honey. For cornflower honey (Centaurea cyanus), the pollen input does not correlate with the nectar input, because the nectar is produced both in floral and in extrafloral nectaries. The well-known cornflower marker lumichrome has now also been detected in the extrafloral nectar. Therefore, lumichrome is a suitable marker substance for cornflower honey. Four different methods for the sole analysis of lumichrome in honey were validated and compared. Studies over nine years have shown that unifloral cornflower honey should contain approximately 35 mg/kg lumichrome. For a further differentiated cornflower honey specific verification, other nonvolatile compounds like 7-carboxylumichrome and volatiles, such as 3,4-dihydro-3-oxoedulan I and 3,4-dihydro-3-oxoedulan II, should be analyzed. This enables a more specific accuracy for the classification of unifloral cornflower honey.

Characteristic Components and Authenticity Evaluation of Chinese Honeys from Three Different Botanical Sources

“…In previous studies, riboflavin and lumichrome are sporadically observed in honeys such as sage honey, cornflower honey, yellow sweet clover honey, and kanuka honey. − This study shows that riboflavin, lumiflavin, and lumichrome are also present in safflower, Chinese sumac, and bauhinia honey; most notably, this is the first study to our knowledge to report the simultaneous presence of riboflavin, lumichrome, and lumiflavin in honeys. Moreover, the average content of lumichrome was much higher than those in thistle and sage honeys, , but similar to that in cornflower honey. , The higher average content of riboflavin in safflower honey is similar to that in thistle honey . We speculate that riboflavin, lumiflavin, and lumichrome may be responsible for the bright-yellow color of honeys.…”

“…Moreover, the average content of lumichrome was much higher than those in thistle and sage honeys, 28,32 but similar to that in cornflower honey. 29,33 The higher average content of riboflavin in safflower honey is similar to that in thistle honey. 32 We speculate that riboflavin, lumiflavin, and lumichrome may be responsible for the brightyellow color of honeys.…”

3α-Hydroxylup-20(29)-ene-23,28-dioic Acid as a Phytogenic Chemical Marker for Authenticating Schefflera octophylla (Lour.) Harms Monofloral Honey

“…As the main functional components in honey, metabolites crucially contribute to the effects of health benefits of honey . Besides, establishing honey authenticity identification methods based on characteristic phytogenic components has become the object of multiple studies. , Thus, UHPLC-Q-TOF-MS/MS-based metabolomic analysis was conducted to screen characteristic phytogenic components that can discriminate between MH- Sco and other honeys. The methanol extracts from honey were subjected to UHPLC-Q-TOF-MS/MS after filtering, which is a more rapid and simpler sample pretreatment method compared with previous studies in determining metabolites …”