Van Rooyen B, De Wit M, Osthoff G, Van Niekerk J, Hugo A. Effect of pH on the Mechanical Properties of Single-Biopolymer Mucilage (
Opuntia ficus-indica), Pectin and Alginate Films: Development and Mechanical Characterisation.
Polymers (Basel) 2023;
15:4640. [PMID:
38139892 PMCID:
PMC10747180 DOI:
10.3390/polym15244640]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 11/28/2023] [Accepted: 12/05/2023] [Indexed: 12/24/2023] Open
Abstract
Pectin and alginate are well-established biopolymers used in natural film development. Single-polymer mucilage films were developed from freeze-dried native mucilage powder of two cultivars, 'Algerian' and 'Morado', and the films' mechanical properties were compared to single-polymer pectin and alginate films developed from commercially available pectin and alginate powders. The casting method prepared films forming solutions at 2.5%, 5%, and 7.5% (w/w) for each polymer. Considerable variations were observed in the films' strength and elasticity between the various films at different polymer concentrations. Although mucilage films could be produced at 5% (w/w), both cultivars could not produce films with a tensile strength (TS) greater than 1 MPa. Mucilage films, however, displayed > 20% elongation at break (%E) values, being noticeably more elastic than the pectin and alginate films. The mechanical properties of the various films were further modified by varying the pH of the film-forming solution. The various films showed increased TS and puncture force (PF) values, although these increases were more noticeable for pectin and alginate than mucilage films. Although single-polymer mucilage films exhibit the potential to be used in developing natural packaging, pectin and alginate films possess more suitable mechanical attributes.
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