Development of highly reusable, mechanically stablecorn starch-based aerogel using glycerol for potential application in the storage of fresh spinach leaves

Impact of glycerol on the physico-functional, morphological, mechanical, and rehydration properties ofcorn starch-based aerogel has been investigated. The aerogel was prepared from hydrogel (sol-gel method) using solvent exchange and supercritical CO₂ drying. Glycerol-infused aerogel had a more connected, denser structure (0.38-0.45 g/cm³), enhanced hygroscopic behavior, and was reusable up to eight times in terms of its capacity to absorb water after being drawn from the soaked sample. However, the inclusion of glycerol reduced the aerogel's porosity (75.89-69.91 %) and water absorption rate (WAR; 118.53-84.64 %) but enhanced its percentage shrinkage (75.03-77.99 %) and compressive strength (26.01-295.06 N). The most effective models for describing the rehydration behavior of aerogel were determined to be the Page, Weibull, and Modified Peleg models. Glycerol addition improved the internal strength of the aerogel so could be recycled without significant change in the physical characteristics of the aerogel. By effectively eliminating the condensed moisture that was developed inside the packing owing to the transpiration of fresh spinach leaves, the aerogel extended the storage life of the leaves by up to eight days. The glycerol-based aerogel has the potential to be employed as a carrier matrix for various chemicals and a moisture scavenger.

Improved stability of β-carotene by encapsulation in SHMP-corn starch aerogels

This study aimed to prepare a starch-based aerogel with microporous network structure, and to investigate its physicochemical properties after β-carotene encapsulation. Corn starch aerogels (CSA) prepared with sodium hexametaphosphate (SHMP) as a cross-linking agent and β-carotene encapsulation were evaluated in terms of morphology, long- and short-range molecular order, bioavailability, and stability. After encapsulating β-carotene, the morphology of SHMP-CSA showed that the aerogels presented agglomeration, and the relative crystallinity increased from 17.2% to 22.2%. The characteristic bands of β-carotene were not found in the FT-IR pattern, and the short-range molecular order of aerogel was decreased, proving that β-carotene was well embedded in the aerogel. During the simulated in vitro release process, β-carotene was almost completely released. After ultraviolet or light irradiation, the retention rate of β-carotene was much higher than that in the control group. These results demonstrated that SHMP-CSA encapsulation could effectively improve the stability of β-carotene.