Idrogel
Food Hydrocolloids. 2010. DOI:10.1016/j.foodhyd.2009.11.016.
Tabletted soy protein cold-set hydrogels as carriers of nutraceutical substances.
Maltais A, Remondetto GE, Subirade M
ABSTRACT
The swelling of soy protein filamentous hydrogels and tablets thereof and the release of riboflavin from these drug delivery devices were investigated under simulated gastrointestinal conditions in the presence or absence of digestive proteases. Microscopic examination showed riboflavin arranged into crystals dispersed randomly throughout the hydrogel and the tablet powder. Swelling experiments showed a comparable behavior of water uptake for hydrogel and tablet at pH 1.2 as well as tablet at pH 7.5, featuring a low swelling rate. Hydrogel at intestinal pH began to shrink after 1 h, which coincided with a loss its structure. Riboflavin release was faster at pH 7.5 than at pH 1.2 for both devices. Swelling was the principal mechanism of riboflavin release from tablets at pH 7.5, while drug-polymer interactions slowed this release at pH 1.2. In the presence of pepsin at pH 1.2, both devices showed slow zero-order release of riboflavin for 6 h, while both were digested completely in the presence of pancreatin at pH 7.5. These results suggest that these tabletted hydrogels and the hydrogels themselves might both be useful for transporting bioactive molecules through the gastrointestinal tract and delivering them in the small intestine. Considering their non-synthetic nature, they should be of great interest for the development of innovative functional foods.
Commento
Gli idrogel sono materiali liquidi o semisolidi formati da molecole a lunga catena cross-lincate una all’altra che formano numerose cavità molto piccole che posso assorbire acqua o altri liquidi come spugne. Se all’interno degli spazi sono assorbite molecole bioattive, queste vengono rilasciate molto lentamente e in modo controllato. I tecnologi stanno studiando numerose applicazioni, comprese quelle nel settore nutraceutico. In questo lavoro isolati proteici di soia sono stati utilizzati per preparare degli idrogel usando un processo di gelificazione a freddo per incapsulare ingredienti bioattivi. Scegliendo tra questi la vitamina B, è stato osservato che, in condizioni che simulano l’ambiente gastrointestinale (presenza o assenza di proteasi), questa viene rilasciata solo a livello dell’intestino tenue (in presenza della pancreatina). Avendo una origine naturale, questi materiali hanno eccellenti possibilità di applicazione nel settore nutraceutico.