Moisture sorption behaviors, water activity-temperature relationships, and physical stability traits of spices, herbs, and seasoning blends containing crystalline and amorphous ingredients

Multiscale dynamics and molecular mobility in cellulose-rich materials

Cellulose, an abundant biopolymer in nature as a structural component of plant cell walls, has a native semi-crystalline structure in which the arrangement of amorphous-crystalline domains governs its key properties such as mechanical and physico-chemical properties. The performance of the material in different situations is shaped by molecular mobility, which affects attributes such as mechanical properties, chemical reactivity, and water absorption. Nevertheless, it is difficult to investigate experimentally the structural and dynamic properties of cellulose-rich materials. This is especially the case for the glass transition, which impacts its quality and properties. This experimental challenge is notably evidenced by the considerable variability in data across the literature. The purpose of this study is to offer a comprehensive multi-scale exploration of dynamics within cellulose-rich materials, emphasizing literature data on cellulose glass transition and molecular relaxations, and providing insights into methods for characterizing their physical state and underscoring the impact of water-cellulose interactions on molecular mobility in these systems. The promising results obtained using multiple approaches bring out the importance of combining methods to achieve a more accurate and detailed understanding of the complex thermal transition in cellulose materials, particularly when considering the influence of water on their thermal dynamics and properties.

Natural Food Resource Valorization by Microwave Technology: Purslane Stabilization by Dielectric Heating

The application of microwave-assisted drying is a promising technique due to the features of process sustainability that are usable for responsible productions. It is largely applied for the stabilization of food products, especially in the agro-food sector. In this study, the weed Portulaca oleracea L. (purslane), with its richness in antioxidant components in addition to its recognized pharmacological properties, has been considered due to its potential to be a natural, well-accepted future food. Attention was focused on the role of the heat and mass transfer rates involved in the drying processes on the nutritional profile of the dried products. For this purpose, different drying protocols (convective, microwave irradiation, microwave-vacuum irradiation) were applied to different parts of purslane herb (apical, twigs, entire structures) and chemical characterizations were performed by a GC/MS analysis of the extracts of the dried products. The results show that microwave treatments can assure a better preservation of fatty acids such as SFAs, MUFAs, and PUFAs (which constitute over 90% of the total components in the apical part, 65% in twigs, and 85% in microwave-vacuum-dried entire purslane samples) and phytosterols (their highest preservation was found in microwave-dried twigs) compared with convective treatments. The chemical composition variability as well as treatment times depend on the drying rates (in microwave treatments, the times are on a minute scale and the rates are up to three orders of magnitude greater than convective ones), which in turn depend on the heating transport phenomena. This variability can lead towards products that are diversified by properties that transform a weed into a valorized food source.

Moisture and caking resistant Tremella fuciformis polysaccharides microcapsules with hypoglycemic activity

Tremella fuciformis polysaccharides (TPs) have attracted extensive attention as functional food constituents due to their bioactivity. However, β-D-glucan obtained from TPs is readily degraded by oxidation and easy to absorb water and agglomerate. The purpose of this study was to reduce moisture adsorption and caking strength through spray drying by using maltodextrin as wall materials and explore the hypoglycemic effect and molecular mechanism of TPs microcapsules. It was observed that dextrose equivalent (DE) value and concentration of maltodextrin (MD) affect the morphology, encapsulation efficiency, loading capacity, water adsorption and caking strength of TPs microcapsules powder. The administration of TPs microcapsules powder prevented body weight and serum insulin loss, and significantly decreased the blood glucose level, serum triglycerides, as well as total cholesterol levels, which seemed to be related to increasing the glycogen synthesis and facilitating the glucose transportation by regulating the PI3K/Akt pathway.