Rheological Properties of Alginate–Essential Oil Nanodispersions

Abstract

Due to its favorable structural properties and biocompatibility, alginate is recognized as a suitable versatile biopolymer for use in a broad range of applications ranging from drug delivery, wound healing, tissue engineering, and food formulations such as nanodispersions. Rheological analysis plays a crucial role in the design of suitable nanoemulsion based coatings. Different essential oil and alginate nanodispersion compositions stabilized by Tween 80 were analyzed for rheological and conductometric properties. The results confirmed that the nanoformulations shared a pseudoplastic non-Newtonian behavior that was more evident with higher alginate concentrations (2%). Nanodispersions made of alginate and essential oil exhibited a slight thixotropic behavior, demonstrating the aptitude to instantaneously recover from the applied stress or strain. Oscillatory frequency sweep tests showed a similar fluid-like behavior for 1% and 2% alginate nanodispersions. Finally, it was demonstrated that advantages coming with the use of the essential oil are added to the positive aspects of alginate with no dramatic modification on the flow behavior.

Quality Control of Fresh-Cut Apples after Coating Application

“…With the aim of further expanding the exploration of the applicability of LEO/alginate-based nanodispersions in routine coating experiments, we considered two type of nanodispersion that differ with respect to LEO content [12]. The two nanoformulations were characterized through DLS and rheology before coating application.…”

“…The enrichment of alginate-based coatings with EOs has been recently studied [12] for applications on fish and meat products and on fresh-cut fruit. Heydari et al in 2015 [13] studied the combined effect of sodium alginate coating and horsemint EO on the quality of refrigerated bighead carp fillets and they observed reduced spoilage of the fillets and extended shelf-life.…”

Alginate Films Encapsulating Lemongrass Essential Oil as Affected by Spray Calcium Application

“…Primary emulsions were obtained, according to previous studies [7,9], by mixing LEO (0.5-2.5% w/w) as lipidic phase and Tween 80 (1.5% w/w) as surface active agent in an aqueous suspension of sodium alginate (1% w/w) with a laboratory T25 digital Ultra-Turrax rotor-stator homogenizer (S25-N25 -IKA, Staufen, Germany) at 20,000 rpm for 4 min. The obtained dispersions were then subjected to ultrasonic treatment (Vibra Cell, Sonics & Materials, Inc. USA) for 20 min at 40% amplitude with pulses of 1 s. A suspension containing only Tween 80 (1.5% w/w) and alginate (1% w/w) was prepared in order to evaluate the influence of the surfactant on the studied properties.…”

“…It is isolated from different species of brown seaweeds and is a linear polysaccharide where guluronic (G) and mannuronic (M) acids are the constituting monomers, present in different ratios. Anionic, water-soluble, biocompatible, food-grade and low cost, alginate meets the requisites of application in several fields, also exhibiting interesting rheological properties [7,8]. Alginate is also used as a thickening or gelling agent in food formulations, demonstrating its ability to react with divalent cations (like calcium) to form a strong network [9].…”

Rheological Characterization of Hydrogels from Alginate-Based Nanodispersion

“…In light of the current increasing interest in composite hydrogels, here we present a study on the rheological characterization of hydrogels prepared from nanodispersions made of an essential oil stabilized in alginate aqueous suspensions by a nonionic surfactant: Tween 80. The rheological characterization of the starting nanodispersions has been recently published [ 26 ]. Here, we consider the in situ gelation of the alginate-based nanodispersions and the difference in the mechanical response, along with the variation of oil, alginate, and calcium content.…”