Encapsulation and release kinetics of ethylene into pre-formed V-type starch and granular cold-water-soluble starch

Ethylene gas was loaded into pre-formed V-type starch (V-6, V-7 and V-8) by molecular encapsulation, and granular cold-water-soluble starch (GCWSS) was chosen as a control. The formation, structural characteristics and morphological properties of inclusion complexes (ICs) were investigated using X-ray diffraction, scanning electron microscopy, and C-13 solid-state nuclear magnetic resonance spectroscopy. The V-6a-type starch represented the most effective structure in encapsulating ethylene gas among different pre-formed V-type starches. The Avrami equation was used to describe the release kinetic properties of ethylene gas from ICs under various conditions of temperatures and relative humidities (RHs). The release of ethylene from ICs conformed to diffusion-limited release mechanisms (temperature) and first-order kinetics (RH). This could be caused by the differences in starch structure and association mechanisms between ethylene and starch single helices. Accelerated ripening experiments showed that ethylene-starch ICs could ripen bananas within 5 days, suggesting that this molecular encapsulation technology can provide precise control and targeted application of ethylene gas in the ripening of vegetables and fruits.

Automated summary

In this study, ethylene gas was loaded into different pre-formed V-type starches using molecular encapsulation technique. The V-6a starch showed the most effective structure in encapsulating ethylene gas. The formation, structural characteristics, and morphological properties of the inclusion complexes (ICs) were investigated, along with the release kinetic properties of ethylene gas. The results demonstrated that this molecular encapsulation technology can provide precise control and targeted application of ethylene gas in the ripening process of vegetables and fruits.