Background Gelatin is a multifunctional ingredient used in the food, pharmaceutical, cosmetic, and photographic industries as a gelling agent, stabilizer, thickener, emulsifier, microencapsulating agent, and film-former. The most abundant sources of gelatin are pig skins, bovine hides, and cattle bones. However, the mammalian gelatins are rejected by some consumers due to either socio-cultural-religious or health-related concerns. An alternative to mammalian gelatins are the aquatic gelatins, which are extracted from the by-products of aquatic food processing, such as the skins, bones, scales and fins of fish. Scope and approach This review focuses on the main qualities of gelatin obtained from different aquatic animals. In addition, the strategies used to improve the properties of aquatic gelatins are discussed. Key findings and conclusions Gelatin has been extracted from various fish species, and the physical and chemical properties of fish gelatin have been further investigated. Aquatic gelatins have very similar properties to mammalian gelatins, making them a potential substitute for pork and beef gelatins in many applications. The main limitation, however, for the use of aquatic gelatins is their weaker rheological properties when compared to mammalian gelatins. However, it is possible to improve the properties of aquatic gelatins using physical, enzymatic and natural cross-linking agents. Hopefully, gelatins derived from aquatic animals will be more widely used in various applications after modification using suitable methods.

An overview of gelatin derived from aquatic animals: Properties and modification

Effects of sugars on the gelation kinetics and texture of duck feet gelatin

Gelling temperatures of gellan solutions with the addition of Na + and K + ranging from 15 to 450 mM or Ca ++ and Mg ++ from 2 to 40 mM were determined by dynamic rheological testing at four polymer concentrations between 0.4 and 2.0% (w/w). Gelling temperatures were much higher for gellan solutions containing divalent cations than for those containing the same amount of monovalent cations. Solutions containing K' gelled at higher temperatures than those containing Na + . Effects of Ca ++ and Mg ++ on gelling temperatures were not significantly different. A general model was developed to predict the gelling temperature of gellan solutions as functions of cation and polymer concentrations.

Gelling Properties of Gellan Solutions Containing Monovalent and Divalent Cations

Topical application of antifungals does not have predictable or well-controlled release characteristics and requires reapplication to achieve therapeutic local concentration in a reasonable time period. In this article, the efficacy of five different US Food and Drug Administration-approved antifungal-loaded (amphotericin B, natamycin, terbinafine, fluconazole, and itraconazole) electrospun gelatin fiber mats were compared. Morphological studies show that incorporation of polyenes resulted in a two-fold increase in fiber diameter and the mats inhibit the growth of yeasts and filamentous fungal pathogens. Terbinafine-loaded mats were effective against three filamentous fungal species. Among the two azole antifungals compared, the itraconazole-loaded mat was potent against Aspergillus strains. However, activity loss was observed for fluconazole-loaded mats against all of the test organisms. The polyene-loaded mats displayed rapid candidacidal activities as well. Biophysical and rheological measurements indicate strong interactions between polyene antifungals and gelatin matrix. As a result, the polyenes stabilized the triple helical conformation of gelatin and the presence of gelatin decreased the hemolytic activity of polyenes. The polyene-loaded fiber mats were noncytotoxic to primary human corneal and sclera fibroblasts. The reduction of toxicity with complete retention of activity of the polyene antifungal-loaded gelatin fiber mats can provide new opportunities in the management of superficial skin infections.

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Interaction of gelatin with polyenes modulates antifungal activity and biocompatibility of electrospun fiber mats

Gelatin and Non-Gelatin Capsule Dosage Forms

The melting temperature of gelatin gel increased with increasing concentrations of polyols and sugars added at any gelatin concentation. The enthalpy of gel melting measured by Eldridge-Ferry plots and calorimetric measurements was decreased by addition of these polyhydric compounds, indicating that the gel stabilization by them is predominantly due to the large decrease in entropy of gel melting. Circular dichroism analysis showed that the helix formation of gelatin molecules was enhanced with increasing concentrations of these additives, but there was no positive correlation between their helix-forming ability and gel-stabilizing ability. The viscosity of gelatin solution was less in these mixed solvents than in water. Based on these results, a possible stabilization mechanism of gelatin gel by polyhydric compounds was discussed, in comparison with that of native collagen, in terms of the thermodynamics of protein-solvent interactions.

Xuan Li

Papers

Effects of Polyols and Sugars on the Sol-Gel Transition of Gelatin