Ladakhi wild apricot kernel protein-based films: effect of protein and plasticizers on the mechanical, moisture interaction and optical properties

Abstract

In the present study, an attempt was made to utilize the de-oiled wild apricot kernels from the Ladakh region of India to produce packaging films. Apricot kernel protein isolate (AKPI) films were developed using the solution casting method and characterized for their properties, which varied depending on the protein concentration and the type and level of plasticizer used. The amino acid profile of AKPI revealed the predominant presence of negatively charged amino acids, particularly glutamic and aspartic acids. A minimum of 8% protein was essential to produce wild apricot kernel protein-based films with good properties. Sorbitol-plasticized films exhibited significantly higher tensile and seal strength (p < 0.05) than glycerol-plasticized films. In contrast, glycerol-plasticized films demonstrated higher elongation at break. Sorbitol-plasticized films also showed significantly lower WVTR values than glycerol-plasticized films. Films with higher protein concentrations exhibited increased L*, a*, and b* values, which signify greater light scattering and enhanced redness and yellowness. Sorbitol-plasticized films typically had lower L* and a* values and higher b* values than glycerol-plasticized films. Principal component analysis (PCA) identified three principal components that collectively explained 94.24% of the data variance, indicating the significant influence of the tensile strength, seal strength, swelling ratio, and moisture content on the properties of AKPI films. Hierarchical cluster analysis (HCA) further grouped the films based on sorbitol or glycerol plasticization, revealing distinct clusters and patterns in the dataset. The study demonstrated the effective utilization of de-oiled apricot kernels for producing potentially biodegradable materials, which could be further explored for food and other packaging applications.