applied food biotechnology
Volume:5 Issue: 1, winter 2018

Minimizing the exposure to nitrate and nitrite and therefore reducing the level of potentially carcinogenic nitrosamines is desired due to the strong public demand and political controversy around this issue in many countries. The present study was designed to investigate antibacterial activity of five different types of essential oils alone or in combination with different concentrations of sodium nitrite.
Material and Five types of essential oils Zataria multiflora Boiss, Satureja bachtiarica Bunge, Rosmarinus officinalis L., Mentha pulegium, and Origanum vulgare L were used in the experiments. NaNO2 in concentrations of 0, 100, and 200 mg kg-1 were used to study the growth inhibition of Clostridium spp. inoculated in vacuum processed beef fillet. Essential oils were analyzed by gas chromatography-mass spectrometry. Antimicrobial activity against vegetative cells of Clostridium perfringens and Clostridium sporogenes were primarily done by disc diffusion method and minimum inhibitory concentration of essential oils against vegetative cells were determined by broth macro dilution. Sensory evaluation of the uninoculated cooked vacuum processed beef fillet samples with three essential oils with higher antibacterial activity against the more resistant Clostridium spp. was done.
Results and Among the examined Essential oils Satureja bachtiarica Bunge showed the most inhibition effect on Clostridium perfringens (4.1 mg ml-1) and Clostridium sporogenes (5.5 mg ml-1) followed by Zataria multiflora Boiss, Origanum vulgare L., Mentha pulegium and Rosmarinus officinalis L. The antimicrobial activity of essential oils against Clostridium spp. was increased in combination with sodium nitrite. It can therefore be assumed that the combination of these two additives could have significant repercussion in the control of Clostridium perfringens and Clostridium sporogenes in vacuum processed beef fillet samples without compromising the organoleptic properties. The best result was achieved by the combination of 100 mg kg-1 sodium nitrite and 1.1 %v w-1 Satureja Bakhtiarica Bunge which could inhibit the growth of Clostridium species. The results of the current study showed that the essential oils of interest have had drastic effects on clostridium inhibition and could be used in the meat industry especially for sausages due to their impact on technological, microbiological and sensory properties.
Conflict of interest: The authors declare no conflict of interest.

Solid State Fermentation is an economic technology to produce value-added products. Also, the use of agricultural by-products, as a waste management strategy, has recently been considered. On the other hand, the new mutants are interesting for the production of enzymes. The aim of this study was to investigate the effect of mutation on the improvement of cellulase quality. Therefore, rice by-products were used under solid state fermentation for production of cellulase. Moreover, the characteristics of the new cellulose produced from the new mutated strain was studied.
Material and Cellulase was produced under solid state fermentation process. Spore suspensions of Trichoderma reesei were subjected to Co60 γ irradiation and mutated. The activities of cellulases (from parent and mutants) were compared. The effects of temperature and pH on cellulase activity and the stability of cellulase in optimum condition were investigated.
Results and Cellulase was successfully produced under solid state fermentation on the mixture of rice by-products as substrate. The results showed that mutation had a significant effect on cellulase activity and Characteristics. Trichoderma reesei B (a mutated strain) had about 30% filter Paperase and 23% Carboxymethyl Cellulase higher than its parent. Cellulase activity of Trichoderma reesei B was 47% higher than its parent at the optimum temperature (50°C). In other temperatures, the activity of cellulase extracted from Trichoderma reesei B was significantly higher than that of the others; for example, at 60°C, the enzyme activity was 120% higher than its parent. It is notable that an 84% increase in the enzyme activity was observed at the optimum pH (4.5) after mutation and cellulase activity increased from 0.72 U g-1 dry solid to 1.31 U g-1 dry solid.
Conflict of interest: The authors declare no conflict of interest.

Microalgae are photosynthetic organisms that are in contact with several reactive oxygen species, and under these conditions microalgae produce a wide variety of antioxidant compounds to protect from highly oxidant growth conditions, these facts can be used to optimize antioxidant production, however, firstly studies of antioxidant production by microalgae should be done. This work was focused to establish differences of antioxidants formation among microalgae species and elucidate some antioxidant properties of phycocyanin.
Material and Superoxide dismutase activity was performed by using a commercial kit and determined by spectrophotometry. Phycocyanin and carotenoids were quantified by spectrophotometry and tocopherols were analysed by high pressure liquid chromatography with a fluorescence detector. Trolox equivalent antioxidant activity was determined by using 2,2´-azinobis (3-ethylbenzothiazoline-6-sulphonic) reagent, scavenging and synergic antioxidant activities were also ascertained.
Results and The microalgae used in this study produces different amounts of superoxide dismutase, carotenoids, α, δ and γ-tocopherols, and phycocyanin. Trolox equivalent antioxidant activity varied according with the amount of antioxidants produced. Phycocyanin scavenge superoxide and hydrogen peroxide radicals work well to produce synergy with α-tocopherol, increasing protection of biomolecules against oxidation. One microalgae specie may be selected to produce one of the antioxidants mentioned above, but more detailed studies on growth phases are required to improve the antioxidant production. Microalgae has the potential to be considered as a natural antioxidants source.
Conflict of interest: The authors declare no conflict of interest.

Acrylamide as a toxic substance for human beings is produced by Maillard reaction at high temperatures. In this research, this reaction can be inhibited based on using aspariganse enzyme, controlling the cooking time and temperature during baking in yeast-leavened bread.
Material and In this study, a response surface methodology 5-level-3-factor central composite design was applied to study the effects of asparaginase (300-900 U Kg-1 of flour), baking temperature (230-280°C) and baking time (13-16 min) on acrylamide formation in yeast-leavened wheat bread.
Results and Added asparaginase showed a reducing effect on acrylamide formation (p≤0.0001). Baking temperature significantly increased the acrylamide content in bread (p≤0.0001). A strong correlation was found between the baking temperature and acrylamide formation. Baking time and its interaction with asparaginase had a low but significant reducing effect on acrylamide content in bread (p≤0.0001). Three parameters of the cooking temperature and time as well as enzyme concentration have been optimized using response surface methodology, their values obtained 245.71°C, 14.55 min and 752.15 U Kg-1, respectively. Enzymatic process could be suggested as a safe and convenient method for preventing acrylamide formation in bread making.
Conflict of interest: The authors declare no conflict of interest.

Bisphenol A is a well-known industrial compound which is widely used in producing plastic throughout the world. Containers made with these plastics may expose people to small amounts of bisphenol A in food and water and cause adverse effects on human health. In this study, the effect of commercial probiotic formulations on reduction of bisphenol A in aqueous solution is investigated.
One dose of six types of commercial mixtures of probiotic strains were added to a certain amount of bisphenol A in saline basal medium at 37°C. During a 24 h treatment with probiotics, samples were taken from the environments at different times and prepared for further analysis with enzyme-linked immunosorbent assay. The experimental framework was set up in a way that compares formulations and determines the most efficient strains for bisphenol A reduction. In addition, the effect of peripheral conditions such as pH and temperature were also studied.
Results and Multi-strain probiotics had an impressively high performance in bio-removal of bisphenol A from aqueous solutions. Up to 80% of bisphenol A concentration was decreased during the first hour of treatment in almost all trials. Among them, the synergy of Lactobacillus acidophilus and Lactobacillus plantarum strains were the most successful. On the other hand, mixture of probiotics had more persistent effect and robust binding ability than single strains. Finally, it can be expected that regular usage of probiotic supplementation with special mixture of strains can suppress the harmful effects of bisphenol A.
Conflict of interest: The authors declare no conflict of interest.