Hoda Ghayomi; Mohammad Ali Najafi; Naser Soltani Tehrani; Mohammad Rahnama
Abstract
Biodegradable films containing lactic acid bacteria (LAB) are considered as new tools for advanced methods of food storage. In this study, Lactobacillus casei ATCC 39392 (L. casei 39392) was directly incorporated into a film formation solution of sodium caseinate (NaCas) and methyl cellulose (MC). The ...
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Biodegradable films containing lactic acid bacteria (LAB) are considered as new tools for advanced methods of food storage. In this study, Lactobacillus casei ATCC 39392 (L. casei 39392) was directly incorporated into a film formation solution of sodium caseinate (NaCas) and methyl cellulose (MC). The bioactive films were prepared in a manner to contain 106CFU/cm2 L. casei 39392. The moisture content, solubility in water, water vapor permeability (WVP), color, opacity, tensile strength, percentage of elongation at break, and the elastic modulus of the films were studied. The survival rate of L. casei 39392 was examined during 30 days of storage (5 °C, RH 75%) and the films inhibitory effect on the growth of Pseudomonas aeruginosa PTCC 10832 was also studied at 5 °C for 12 days. The presence of L. casei 39392 increased the film’s opacity and its WVP compared to the control (p ˂ 0.05). The survival rate of L. casei 39392 was higher in NaCas films than in methylcellulose films (p < 0.05). A higher inhibitory effect on the growth of P. aeruginosa 10832 (85.3%) was observed in the MC bioactive film, and this inhibitory effect became noticeable from the fourth day of storage onwards (p ˂ 0.05). Our results showed that the bioactive films containing L. casei 39392 could be used and recognized as biofilms containing natural preservatives.
Somayeh Niknia; Seyed Mohammad Ali Razavi; Mehdi Varidi
Abstract
In this study, sodium caseinate was hydrolyzed with Withania coagulans extract and the response surface methodology (RSM) was applied to optimize the effects of hydrolysis conditions including hydrolysis temperature, enzyme concentration and hydrolysis time on the degree of hydrolysis, solubility, and ...
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In this study, sodium caseinate was hydrolyzed with Withania coagulans extract and the response surface methodology (RSM) was applied to optimize the effects of hydrolysis conditions including hydrolysis temperature, enzyme concentration and hydrolysis time on the degree of hydrolysis, solubility, and foaming properties. The analysis of variance in RSM showed that the linear effects of enzyme level and hydrolysis time and quadratic effects of hydrolysis temperature were important factors affecting the hydrolysis process remarkably (P<0.0001). Results were indicative of the fact that the increase in responses was obtained by an increase in hydrolysis time and enzyme level. The generated quadratic model showed that the optimum conditions for maximizing the responses were when enzyme concentration of 1.75 (%w/w), temperature of 55.43°C and hydrolysis time of 490 min.
Hashem Razavi Setoti; Seyed Ali Mortazavi; Monirosadat Shakeri; Shahram Beiraghi-Toosi; Elham Asadolahi
Abstract
In this study, antimicrobial effects of Zataria Multiflora boiss added to sodium caseinate film on four bacterial species: Staphylococcus aurous, Escherichia coli, Bacillus subtilis and Salmonella intertidis was investigated. Disk diffusion method was used to study the antimicrobial activity of Zataria ...
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In this study, antimicrobial effects of Zataria Multiflora boiss added to sodium caseinate film on four bacterial species: Staphylococcus aurous, Escherichia coli, Bacillus subtilis and Salmonella intertidis was investigated. Disk diffusion method was used to study the antimicrobial activity of Zataria multiflora Boiss in sodium caseinate film. 9 mm disks were prepared from produced films with different concentrations of Zataria multiflora Boiss. with 1, 2, 3 and 4%. Surface culture was done under sterile condition using 0.1 ml of broth culture of each bacterial (106 -107 cfu/ml) on BHI agar. Then the disks were placed. Diameter of inhibition zone was considered as an index of antimicrobial activity of the film. Statistical analyses were done by means of SigmaSDAT software and mean comparison was carried out by LSD test. Results showed that disks containing essential oils of Zataria multiflora Boiss. in each concentration inhibited growth of E.coli, Sa.interitidis and B.cereus. Since there was no significant differences between 3% and 4% concentrations for these bacteria (p>0/05), concentration of 3% is the most appropriate and cost-effective concentration with the highest antimicrobial effect. Only the film containing 1% of essential oil of Zataria multiflora Boiss. Made no inhibition zone on S.aurous, in the other word had no inhibitory effect in this concentration. But inhibition zones created by 2, 3 and 4% for S.aurous were significantly different (p
