The areca nut is one of the most important cash crops in the tropics and has substantial economic value. However, the research information about the edible quality of different areca nuts is still insufficient. This study compared the composition, texture characteristics and flavor release behaviors of four different areca nuts (AN1, AN2, AN3 and AN4) and two commercially dried areca nuts (CAN1 and CAN2). Results showed that AN1 had higher soluble fiber and lower lignin, which was the basis of its lower hardness. Meanwhile, the total soluble solid (TSS) of AN1 was the highest, which indicated that AN1 had a moister and more succulent mouthfeel. After the drying process, the lignification degree of AN1 was the lowest. Through textural analyses, the hardness of AN1 was relatively low compared to the other dried areca nuts. AN1, CAN1 and CAN2 had higher alkaline pectin content and viscosity, and better flavor retention, which indicated better edible quality. The present study revealed the differences of various areca nuts and provided vital information to further advance the study of areca nuts.

To reduce the adverse physical effects on the oral mucosa caused by excessive hardness of betel nut fibres, steam explosion was used to soften betel nuts. The effect of 3 operating parameters (pressure holding time, explosion pressure and initial moisture content) on the morphology, texture and chemical composition of the betel nuts was investigated. The fibre hardness and Shore hardness decreased by 56.17%-89.28% and 7.03%-34.29%, respectively, and the transverse tensile strength and fibre tensile strength also decreased by up to 60.72% and 24.62%, respectively. Moreover, the coefficient of friction and moisture content increased. After steam explosion, the betel nut increased in transverse diameter, became darker and more yellow‒red in colour, and showed a damaged microstructure. The contents of lignin, hemicellulose, free phenol, bound phenol and alkaloids decreased after steam treatment, with total phenols and alkaloids decreasing from 44.07 mg(GAE)/g and 7.84 mg/g to 30.61 mg(GAE)/g and 6.50 mg/g, respectively, after the A-50 s treatment condition. A slight increase in cellulose was observed when steam explosion conditions exceeded 80 s or 0.75 MPa. The steam explosion increased the quantity of phenols, alkaloids and soluble solids released from the betel nut under the same simulated release conditions. The research also showed that the explosion efficiency was positively correlated with the pressure holding time and explosion pressure, while the initial moisture content was reduced the explosion efficiency. Therefore, steam explosion is an effective pretreatment approach to soften betel nut and facilitate healthy development of the betel nut industry.