Release Characteristics of Fenugreek Polysaccharide-Lemon Essential Oil Inclusion Compound and Its Application in Cigarette Flavouring

Embedding is an effective method to overcome the poor thermal stability and release properties of lemon essential oil (LEO). This research focused on the fabrication of inclusion complexes through co-precipitation and response surface optimization, employing Fenugreek polysaccharide (FP15) as the wall material. The complexes were assessed through thermal analysis and in vitro slow-release investigations. XRD, FTIR and SEM analysis proved that LEO formed supramolecular structure with FP15 through hydrogen bonding and van der Waals force, and was successfully embedded with packaging efficiency of 57.33%. Thermal behaviour analysis showed that FP15 as a wall material significantly improved the thermal stability of LEO. The analysis based on the KAS and Coats-Redfern methods showed that the apparent activation energy of inclusion compounds increased with the increase of conversion rate, and the secondary reaction model (F2) could better describe the pyrolysis reaction mechanism of inclusion compounds. In vitro release experiments showed that the release of LEO from the inclusion at 37°C (human body temperature) and 65°C (food processing temperature) followed a first-order kinetic model, with LEO being released from the carrier by non-Fickian diffusion. The analysis of pyrolysis products showed that the inclusion compound pyrolyzed at 300°C, 600°C and 900°C to produce a large number of aldehydes, esters and non-/semi-volatile organic acids. The production of these flavour substances improves the quality, concentration of aroma, rich-ness and harmony of the cigarette during smoking. In summary, FP15 as a wall material slowed down the release of LEO, enhanced its stability and improved the sensory quality of cigarettes.