Insights into biomacromolecule-based alcogels: A review on their synthesis, characteristics and applications

Linear and non-linear rheological properties of water–ethanol hybrid pectin gels for aroma enhancement

“…In practice, intense agitation in the mixing process of ethanol and pectin solutions was demonstrated to be crucial to the prevention of pre-gel formation associated with the deterioration of solvent properties and resultant localized irreversible aggregation ( Zhang, Song, Tian, Zhao, & Zhou, 2022 ). Despite a more efficient mixing of ethanol and water, intense agitation could prohibit locally preferential competitive hydration between the pectin molecule and ethanol, which might alter the thermodynamics and of the given system, resulting in marked changes in the sol–gel equilibria ( Shimizu & Matubayasi, 2014 ).…”

“…As a result, aggregation into super strands makes up a stiff but irregular network structure. However, from a theoretical point of view, there is not much fundamental work being carried out to explain the non-linear rheological behaviors based on sophisticated network characterizations and to establish a quantitative structure-ethanol concentration relationship for WEPGs ( Zhang, Song, Tian, Zhao, & Zhou, 2022 ).…”

“…Owing to the presence of the polar hydroxyl group, alcohols are more water-soluble than simple hydrocarbons and can be used as anti-solvents, which directly initiate the rapid precipitation of the water-soluble polymers and modulate the sol–gel equilibria ( Jiang et al, 2021 , Tong et al, 2022 ). Besides the exclusion of cosolvent from polymer surfaces, the enhancement of water structure around the polymers induced by cosolvent can easily alter the gel structure and its rheological properties ( Shimizu and Matubayasi, 2014 , Zhang et al, 2022 ). Taking advantage of such a hybrid solvent system, we have tuned the overall rheological responses of gels by changing the alcohol concentration and regulated the distribution of small molecules as well ( Zhou et al, 2020 ).…”

“…Another advantage of WEPGs is to overcome the challenge of enhancing the smell of pectin gels, because most volatile aroma compounds are hardly incorporated and retained in highly hydrophilic hydrogels, but can be easily dissolved in alcohols ( Zhang, Song, Tian, Zhao, & Zhou, 2022 ) and synchronously trapped in WEPGs. As desired, the aroma-enhanced WEPGs should retain those aroma compounds when subject to food processing, such as extrusion, mixing and stirring, where large stress or strain are applied, and efficiently release them when undergoing situations like chewing and swallowing.…”

Aggregation of konjac glucomannan by ethanol under low-alkali treatment

“…, methanol, ethanol and glycerin) have manifested themselves as gelation promoters in various studies with underlying mechanism being explained by either the excluded volume effect which render those gelling polymers shrinking at low hydration levels or affecting the structural interactions: water molecules tend to be more restrained around those small molecules, promoting polymer–polymer interactions rather than polymer–solvent interactions. The gel of which the dispersing medium consists predominantly of an alcohol or a combination of alcohols and other solvent molecules is known as alcogel ( Zhang, Song, Tian, Zhao, Zhou, 2022 ).…”