Scaling of Flory-Huggins interaction parameter for polyols with chain length and number of hydroxyl groups

Nanoencapsulation of curcumin and quercetin in zein-chitosan shells for enhanced broad spectrum antimicrobial efficacy and shelf-life extension of strawberries

Strawberries face significant post-harvest microbial spoilage risks due to high water and sugar content as well as low organic acid contents in their flesh. The study aimed to develop and characterize a novel strategy to delay microbiological spoilage in strawberries using single and co-encapsulation of curcumin (Cm) and quercetin (Q), creating stable nanoencapsulates specifically designed to target mold spores, vegetative fungi, and bacteria, with potential applications for both foodservice and consumer use. Using a layer-by-layer antisolvent method, nanoencapsulates of Cm and Q were synthesized, characterized, and assayed against both human and plant pathogenic bacteria and fungi in vitro and in situ. The nanoencapsulates formed stable, spherical emulsion droplets with monodisperse size distribution, high specific surface area, and moderately electro-positive ζ-potentials. Encapsulation efficiencies were 56% (Cm), 65% (Q), and 46.05±4.78% (Cm) and 53.68±4.83% (Q) for CmQ. The nanoencapsulated compounds exhibited strong antimicrobial activity against Pseudomonas aeruginosa, Listeria monocytogenes, Salmonella Montevideo, Saccharomyces cerevisiae, as well as Botrytis cinerea and Aspergillus niger spores in vitro. In strawberries, Cm and Q nanoencapsulates reduced decay incidence by 60% and 80% at 25°C and 4°C, respectively, significantly lowering aerobic bacteria by 3.55 ± 0.20 log CFU/g for Cm and 1.97 ± 0.35 log CFU/g for Q, respectively. Yeast and mold counts were likewise reduced by 2.46 ± 0.02 log CFU/g for Cm and 1.43 ± 0.16 log CFU/g for Q. Strawberry quality parameters (firmness, pH, and color) remained stable (P≥0.05) after five days at 25°C and 15 days at 4°C. This study highlights a sustainable and effective nanoencapsulation approach for extending microbiological shelf life of strawberries offering a promising opportunity in food preservation to mitigate spoilage and reduce post-harvest losses on perishable fruits and vegetables.

Interactions in plasticizer mixtures used for sugar replacement

In our quest for novel ingredients to be used in sugar replacement strategies, we have investigated the thermodynamics of polycarboxylic acids, such as citric acid. We have demonstrated the applicability of the Flory-Huggins (FH) theory to describe the thermodynamics of polycarboxylic acids solutions. Moreover, for citric acid we can describe the complete phase diagram with the theory. It shows that polycarboxylic acids have similar plasticizing and hygroscopic properties as sugars and polyols. Regarding mixtures of polycarboxylic acids and carbohydrates, the FH theory is able to describe a) the water activity of the mixtures, b) the solubility of ternary mixtures of acids and sugars, c) the lowering of the deliquescence point for binary mixtures of crystals, and d) the melting point depression in eutectic mixtures. Unexpectingly, our investigations show there is a strong non-zero FH interaction parameter between carboxylic acids and carbohydrates. In our prior sugar replacement strategy we have assumed zero interactions between plasticizers. Here, we will readdress this assumption. Carefull investigations of solid-liquid equilibrium of eutectic mixtures involving polycarboxylic acids and/or carbohydrates, shows nearly zero interaction in eutectic mixtures consisting only of two carbohydrates or two polycarboxylic acids. We now hold the hypothesis that there is strong non-zero interaction if the mixture contains plasticizers strongly differing in the amount of hydrogen bonding groups. This strong interaction explains why these mixtures, like polycarboxylic acids and carbohydrates, are excellent candidates as deep eutectic solvents. Furthermore, we conclude that polycarboxylic acids are useful additions to the toolbox of sugar replacers, albeit that there are some limitations to their amounts used.

Nanoparticle-Mediated Delivery of Micheliolide Analogs to Eliminate Leukemic Stem Cells in the Bone Marrow

Micheliolide (MCL) is a naturally occurring sesquiterpene lactone that selectively targets leukemic stem cells (LSCs), which persist after conventional chemotherapy for myeloid leukemias, leading to disease relapse. To overcome modest MCL cytotoxicity, analogs with ≈two-threefold greater cytotoxicity against LSCs are synthesized via late-stage chemoenzymatic C-H functionalization. To enhance bone marrow delivery, MCL analogs are entrapped within bone-targeted polymeric nanoparticles (NPs). Robust drug loading capacities of up to 20% (mg drug mg-1 NP) are obtained, with release dominated by analog hydrophobicity. NPs loaded with a hydrolytically stable analog are tested in a leukemic mouse model. Median survival improved by 13% and bone marrow LSCs are decreased 34-fold following NPMCL treatments versus controls. Additionally, selective leukemic cell and LSC cytotoxicity of the treatment versus normal hematopoietic cells is observed. Overall, these studies demonstrate that MCL-based antileukemic agents combined with bone-targeted NPs offer a promising strategy for eradicating LSCs.