Properties of Soy Protein Isolate Antimicrobial Films and Its Application in Preservation of Meat

Abstract

Recently, increasing interest to improve food safety and extend their shelf-life has led to the development and testing of the edible films with antimicrobial properties. The soy protein isolate (SPI) antimicrobial films were made with Nisin (N), sodium lactate (NaL), EDTA (E) and their optical combination (C). The C film showed a significant (p<0.05) antimicrobial effect on three food pathogens, E.coli, Salmonella and Bacillus cereus, which inhibitory zone is 32mm, 33.33mm and 32.33mm, respectively. The addition of N and NaL to SPI film reduced its mechanical properties, that is, the tensile strength (TS) was reduced from 10.8716MPa to 8.1405MPa (N1) and 3.2715MPa (NaL3) and the elongation at break (E) was increased from 3.03% to 4.73% (N3, N4) and 11.21 % (NaL4). While the addition of EDTA and combination increased TS from 10.8716MPa to 17.0600MPa (E4) and reduced E from 3.03% to 2.36% (E1). The water vapor permeability (WVP), oxygen permeability (OP) and total color difference (ΔE) of films had changed with the addition of antimicrobial agents. The FTIR analysis showed no specific interaction between active groups of Nisin with functional group of control film. However, the intensity of peaks in the spectrum of NaL and EDTA increased, indicating interactions between NaL, EDTA and SPI.The application experiments showed the total bacterial count and TVB-N value of sample wrapped by ordinary wraps, SPI film and SPI antimicrobial film were incresed as storage time extended. On the 6th day, the sample wrapped by SPI film has been metamorphism, which total bacterial count and TVB-N value were 8.922 lg cfu/g and 21.340 mg/100g. On the 9th day, the sample wrapped by ordinary wraps has been metamorphism, which total bacterial count and TVB-N value were 7.866 lg cfu/g and 21.150 mg/100g. And the sample wrapped by SPI antimicrobial film had been metamorphism on the 12th day, indicating that the SPI antimicrobial film had a bacteriostatic preservation effect on the meat antibacterial preservation and extend the shelf life to 3-6 days compared with SPI film and ordinary wraps. The SPI antimicrobial film broadens the application of SPI film.

Blending with shellac to improve water resistance of soybean protein isolate film

“…The 10 positions of the film were measured using a hand micrometer (Aice, China) with a sensitivity of 0.001 mm in order to obtain the average thickness of the films (Liu et al, 2017).…”

Crosslinking methods for improving the properties of soy-protein based films for meat packaging: a review

“…The incorporation of essential oils from oregano or thyme into soy-based edible films is effective in retarding oxidative changes in meats and can be used as an antioxidantactive packaging. Proteins are excellent materials used for obtaining edible or non-edible coatings and films, and different vegetable and animal protein sources have been studied for their mechanical properties, thickness, moisture content, water vapor permeability, sensorial properties, and suitability for the environment [15], [23], [65].…”

Surface Modification via Dielectric Barrier Discharge Atmospheric Cold Plasma (DBD–ACP): Improved Functional Properties of Soy Protein Film

“…The moisture permeability of the control and ACP -treated soy protein film was evaluated by water vapor permeation instrument (PERMATRAN -W 1/50, Mocon, Minneapolis, MN, USA) according to the procedure of Wiles et al [31], with minor modifications. The film (100 mm 2 film area) was placed uniformly in a closed container with a relative humid-ity of 50% ± 1% at 25 • C and for 48 h. Water vapor permeability (WVP) was expressed as Equation (2).…”

“…Bio-based materials evoked intensive interests due to ease of processability, abundant resources, and eco-friendliness. Among them, soy protein, a widely distributed vegetable protein, has been undoubtedly considered as the most important material, ascribed to its extremely low price, easy availability, high protein content, and excellent film-forming properties [2]. Hence, films made from soy protein can be applied in edible packaging and food preservation.…”