New sources of genipin-rich substances for crosslinking future manufactured bio-based materials

Genipap (Genipa americana L.), also known as caruto, is a fruit native to Central and South America and presents a novel source of a crosslinking substance containing genipin for biopolymers in various applications. In this study, the fruit's core was used to extract the genipin-rich genipap oil, and a complete characterization of the oil as an inexpensive replacement for commercial genipin powder is included. The extracted genipap oil shows a high phenolic content and remarkable non-hemolytic, antioxidant, and antimicrobial activity. The potential of genipap oil is further demonstrated by its advantage over commercial genipin powder, which did not show antioxidant activity. The crosslinking capacity of the genipap oil was tested with chitosan films and hot-pressed sheets of protein blends from agro-industrial biomass, including zein, wheat gluten, and potato protein. The results indicated that incorporating genipap oil in these blends allowed for manufacturing homogenous structures and improved their mechanical performance compared to the non-crosslinked blends. The use of the oil represents an advantage from a material engineering perspective as it allows for better distribution of genipin during the thermal processing of the materials compared with the commercial genipin. Further, commercial genipin requires solvents and extensive purification processes, which hinders its upscalability. These results support the use of the extracted fruit oil as a green, inexpensive, efficient crosslinking agent, opening new avenues for several applications.