Improvement of soy protein isolate-Alyssum homolocarpum seed gum blend film through intermolecular bonds induced by the mixture of plant extracts

• Published in: Journal of food measurement & characterization Vol. 16; no. 4; pp. 2639 - 2648
• Main Authors: Hajirostamloo, Bahareh, Mortazavi, Seyyed Ali, Molaveisi, Mohammad, Dehnad, Danial
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.08.2022; Springer Nature B.V
• Subjects: Alyssum; Bonding; Chemistry; Chemistry and Materials Science; Chemistry/Food Science; Contact angle; Crystal structure; Diffraction patterns; Elongation; Engineering; Food Science; Hydrogen bonding; Hydrogen bonds; Mechanical properties; Mixtures; Moisture content; Moisture effects; Original Paper; Permeability; Physical properties; Plant extracts; Proteins; Scanning electron microscopy; Tensile strength; Water content; Water vapor; X-ray diffraction; Composite film; Sustainable packaging; Pomegranate peel extract; Structure of edible films; Carrot seed extract
• ISSN: 2193-4126; 2193-4134
• DOI: 10.1007/s11694-022-01359-5

We hypothesized that incorporation of carrot seed extract (CSE) and pomegranate peel extract (PPE) might prompt some intermolecular bonds which improve physical and mechanical characteristics of our base films including soy protein isolate (SPI) and Alyssum homolocarpum seed gum (AHSG). To test this hypothesis, composite films based on SPI and AHSG were enriched with various levels (1%, 5%, 10%, and 20% w/w) of CSE/PPE mixture (50 to 50 ratio) and were characterized through physical, mechanical as well as structural experiments. Results showed that with enhancing the concentration of the extracts, thickness, density, contact angle, flexibility and tensile strength of the films increased, but their water solubility, moisture content as well as water vapor permeability (WVP) decreased, resulting in impeccable films. FTIR analyses showed that hydrogen bonds were formed in the structure of SPI/AHSG films after incorporation of the extracts. According to the scanning electron microscope (SEM) images, the addition of the extract changed the structure of the films. X-ray diffraction patterns show that the addition of the extract altered the crystal structure of SPI/AHSG. Results showed that the WVP of the films was decreased (2.01 g mm m −2  d −1  kPa −1 for the control film) with increasing the concentration of the extracts (0.61 g mm m −2  d −1  kPa −1 for the films containing 20% of extract) while tensile strength and elongation at break increased from 4.85 MPa and 84.72% for control film to 7.21 MPa and 176.31% for the films containing 20% extract. It is concluded that the blend film having 10% mixture of plant extracts results in the best film considering all physical and mechanical properties.