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A Study on the Mechanical Properties of Pea Protein Isolate Films
Author(s) -
Kowalczyk Dariusz,
Gustaw Waldemar,
Świeca Michał,
Baraniak Barbara
Publication year - 2014
Publication title -
journal of food processing and preservation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.511
H-Index - 48
eISSN - 1745-4549
pISSN - 0145-8892
DOI - 10.1111/jfpp.12135
Subject(s) - plasticizer , ultimate tensile strength , elongation , sorbitol , glycerol , materials science , pea protein , food packaging , food science , chemical engineering , chemistry , composite material , organic chemistry , engineering
Effects of glycerol ( G ly) (3–7% w/w) and sorbitol ( S or) (4–8% w/w) concentration, pH (7.0, 9.0, 11.0) and heating (90C, 20 min) of film‐forming solutions ( FFS ) on the tensile strength (σ max ), elongation at break (ε b ), elastic modulus ( EM ) and puncture strength ( PS ) of pea protein isolate ( PPI ) films were investigated in this study. The films plasticized with S or exhibited significantly higher σ max , EM , PS and lower ε b , in comparison with G ly‐plasticized films. Incorporation of higher G ly and S or amounts in the films led to decreases in σ max , EM and PS but did not affect ε b . An increase of pH value from 7.0 to 11.0 resulted in improved σ max of G ly‐plasticized films, while for films with S or, this effect was not observed. In turn, ε b and PS of the films were significantly increased by alkalization of FFS , regardless of the plasticizer type. Generally, an improvement in mechanical strength of PPI films produced from heated FFS was observed. X ‐ray diffraction analyses of G ly‐ and S or‐plasticized PPI films did not show any differences in their internal structure. Practical Applications Edible films may be used as selective barriers to gasses, carriers of antimicrobial agents or agents improving appearance and handling of many different food groups. Most studies suggest their application as edible coatings that may prolong the shelf life of unprocessed plant and animal products. Other possible uses include wraps and separation layers; pouches, bags, food casings, and labels; drug coatings, capsules and microcapsules; paper coatings. The S or‐plasticized PPI films can be promising materials for the applications, e.g., in the fields of fruit and vegetables quality preservation. Because of S or recrystallization, these films are not suitable for low‐water activity food, especially if stored for a long duration at ambient conditions.