Characterisation of beta‐lactoglobulin/sodium alginate dry films

Abstract

Optimum beta-lactoglobulin/sodium alginate dry films (β-LG/SA(S)) formed from casting solutions containing β-LG 1.25% (w/v) and SA 1% (w/v) showed appropriate characteristics to be easily handled. SEM micrographs showed a less homogeneous microstructure of this films respect to sodium alginate dry films used as control (SA(F)). Tensile strength of 18 MPa and an elongation value of 5% were obtained for β-LG/SA(S). DSC thermograms did not demonstrate changes in thermal properties of SA in presence of β-LG. Studies based on fluorescence quenching by acrylamide did not show variations in the tertiary structure of β-LG when β-LG/SA(S) were dissolved in an aqueous environment. In addition, binding properties of the protein were similar to the native one when an alquilsulfonate compound was used as ligand. The maintenance of native binding properties of β-LG after the films' dissolution would allow the development of new carriers for food bioactive compounds based on β-LG/SA(S) dry films.

Binary Alginate-Whey Protein Hydrogels for Antioxidant Encapsulation

“…Besides the occurrence of charge interactions between alginate and β-lactoglobulin, hydrophobic interactions can also be established. Raman spectroscopy analysis revealed that the interactions between WPI and alginate cause conformational changes in WPI; in particular, the ordered structures of α-helixes and β-sheets of WPI were strengthened at pH 4.0 and 5.0 [ 30 , 31 ]. In a further study, the effect of β-lactoglobulin cross-linking using transglutaminase on the binding with alginate was investigated.…”

“…Whey protein/β-lactoglobuin and alginate mixtures were studied for the production of edible coating and film. Interestingly, the β-lactoglobulin binding properties were maintained in the dry film and after film re-dissolution, which would allow the development of new carriers for food bioactive compounds [ 31 ]. The presence of β-lactoglobulin improved the oxygen barrier properties of the film [ 33 ] but decreased the tensile strength, and hence further studies are required before using these edible films for application in the food industry [ 31 , 33 ].…”

“…Interestingly, the β-lactoglobulin binding properties were maintained in the dry film and after film re-dissolution, which would allow the development of new carriers for food bioactive compounds [ 31 ]. The presence of β-lactoglobulin improved the oxygen barrier properties of the film [ 33 ] but decreased the tensile strength, and hence further studies are required before using these edible films for application in the food industry [ 31 , 33 ]. A variety of gelled structures made of alginate and WPI/β-lactoglobulin can be obtained, which are referred to with different denominations depending on the size and structure, such as beads (or spheres), capsules, microparticles, and nanocomplexes [ 33 ].…”

An efficient method for improving the stability of Monascus pigments using ionic gelation

“…Sodium alginate (SA) is a natural polysaccharide, consisting of ⊎-D-mannuronic acid (M unit) and ⊍-L-guluronic acid (G unit). 18,19 The Na + in SA can exchange with Ca 2+ , and the G unit can also react with Ca 2+ , resulting in formation of an 'egg-box' network structure. 20 SA-based hydrogels are universally studied to encapsulate bioactive ingredients by the ionic gelation method.…”

“…Sodium alginate (SA) is a natural polysaccharide, consisting of β‐ d ‐mannuronic acid (M unit) and α‐ l ‐guluronic acid (G unit) 18,19 . The Na + in SA can exchange with Ca 2+ , and the G unit can also react with Ca 2+ , resulting in formation of an ‘egg‐box’ network structure 20 .…”