Review Article

Plastics are well-established for convenient and safe packaging and distribution of food and feed goods. At present, this special sector of the plastic market displays remarkably increasing quantities of its annual production. Caused by the ongoing limitation and strongly fluctuating prices of fossil feedstocks, classically used for plastic production, there is an evident trend to switch towards so-called “bio-plastics”. Especially for bulk applications such as food packaging, a broad implementation of “bio-plastics” constitutes a future-oriented strategy to restrict the dependence of global industry on fossil feedstocks, and to diminish current problematic environmental issues arising from plastic disposal. However, food packaging demands a great deal of the utilized packaging material. This encompasses tailored mechanical properties such as low brittleness and adequate tensile strength, a sufficient barrier for oxygen, CO2, and aromatic flavors, high UV-resistance, and high water retention-capacity to block the food´s moisture content, or to prevent humidity, respectively. Due to their hydrophobic character and the broad flexibility of their mechanical features, prokaryotic poly(hydroxyalkanoates) (PHAs) are considered as promising materials to compete with petro-plastics on the food-packaging market. Nevertheless, short-comings in particular aspects of their material performance and economics of their biosynthesis and purification constitute stumbling blocks on the long way towards broad implementation of PHAs for food packaging. This article discusses advantages and drawbacks of PHAs as food packaging materials, and demonstrates how desired properties can be improved by the designing of novel composite materials, and also encompassing techniques by applying nanoparticles.

Original Article

Statistical Optimization of Xanthan Gum Production and Influence of Airflow Rates in Lab-scale Fermentor

S. Moshaf, Z. Hamidi-Esfahani, M.H. Azizi, - Applied Food Biotechnology

Applied Food Biotechnology, Vol. 1 No. 1 (2014), 25 September 2014, Page 17-24

The present study was undertaken to investigate and optimize the possibility of xanthan gum production by Xanthomonas campestris PTCC1473 in 500ml shake flasks on the second grade date palm. Using an experimental response surface methodology (RSM) coupled with a central composite design (CCD), three major independent variables (nitrogen source, phosphor source and agitation rate) were evaluated for their individual and interactive effects on biomass and xanthan gum production in submerged fermentation. The optimum conditions selected for gum production were 3.15 g.l-1 for nitrogen source, 5.03 g.l-1 for phosphor source, and 394.8 rpm for agitation rate. Reconfirmation test was conducted, and the experimental value obtained for xanthan production under optimum conditions was about 6.72±0.26 g.l-1, which was close to 6.51 g.l-1 as predicted by the model. A higher yield of biomass production was obtained at 13.74 g.l-1 for nitrogen source, 4.66 g.l-1 for phosphor source, and 387.42 rpm for agitation rate. In the next stage, scale-up from the shake flasks to the 1-L batch fermentors was carried. By using the optimum conditions for xanthan gum, the biomass and xanthan gum concentrations after 72h in three levels of air flow rate (0.5, 1 and 1.5 vvm) were obtained as 3.98, 5.31 and 6.04 g.l-1,and 11.32, 15.16 and 16.84 g.l-1, respectively. Overall, the second grade date palm seemed to exhibit promising properties that can open new pathways for the production of efficient and cost-effective xanthan gum.

Optimization of a Modified GS Medium for a Probiotic Strain (L. acidophilus ATCC4356)

N. Pedram, S.A. Ataei

Applied Food Biotechnology, Vol. 1 No. 1 (2014), 25 September 2014, Page 25-29

Probiotics are defined as living microorganisms with beneficial effects on the host. Probiotics, according to the least negative effect on the body, are considered as a good alternative to chemical drugs. Lactobacillus acidophilus is used as a probiotic that is able to reduce cholesterol level in the blood. The effect of various concentrations of carbon, nitrogen and phosphorus for enhancing the biomass production of Lactobacillus acidophilus was examined. The response surface methodology based on Box–Wilson CCD was applied to explore the optimal medium composition. Glucose, yeast extract, K2HPO4 and KH2PO4 were selected as dependent variables. All experiments were run at 37°C for 31h under stationary conditions. By solving the regression equation and analyzing the response surface carton, optimal concentrations of the components were determined as glucose (5-8.75 g.l-1), yeast extract (36.75-39 g.l-1), K2HPO4 (0.1-0.2125 g.l-1) and KH2PO4 (0.3925-0.7075 g.l-1). Validation experiment confirmed that the optimized medium was comparable to the MRS medium (the most common medium for Lactobacillus acidophilus strain) in biomass production, having the advantages of economy andpracticality.

Studies on Aflatoxin, Prenatal Exposure and Its Toxicosis in Adamawa Sate, North East of Nigeria

N.I. Ibeh, P.I. Oronsaye, U.I. Unuabonah

Applied Food Biotechnology, Vol. 1 No. 1 (2014), 25 September 2014,

Of the known mycotoxins, the most important in relation to direct hazard to human health are the aflatoxins produced by a large number of Aspergillus spp. To determine the level of exposure of aflatoxin from mother to child and its mode of transfer. 70 pregnant women in the labor ward of The Federal Medical Centre Yola were investigated for their aflatoxin content by using the velasco fluorotoxinmeter which comprised of 89 samples of amniotic fluid, 213 of serum from maternal blood and 211 serums from neonatal cord blood; 57 of those were controls. The aflatoxin values of G1, G2, and M2 above 20 ppb were obtained in 66 samples of the amniotic fluid (74.1%); 133 from venous maternal blood (62.4%) and 142 from neonatal cord blood (67.2%). This results is suggestive that aflatoxin present in maternal blood crosses the transplacental barrier and accumulates in the fetus which further explains the high concentration of aflatoxin in the amniotic fluid and the in - utero exposure to these toxins.

The Staphylococcus aureus Exotoxin Recognition Using a Sensor Designed by Nanosilica and SEA genotyping by Multiplex PCR

H. Ahari, B. Akbari-Adreghani, V. Razavilar, A. Motallebi, S. Moradi, A.A. Anvar

Applied Food Biotechnology, Vol. 1 No. 1 (2014), 25 September 2014, Page 37-44

Considering the ever increasing population and industrialization of the developmental trend of human life, we are no longer able to detect the toxins produced in food products using the traditional techniques. This is due to the fact that the isolation time for food products is not cost-effective, and even in most of the cases, the precision of practical techniques like bacterial cultivation and other techniques suffers from operator errors, or the errors of the mixtures used. Hence, with the advent of nanotechnology, the design of selective and smart sensors has turned into one of the greatest industrial revelations of the quality control of food products that, in few minutes time and with a very high precision, can identify the volume and toxicity of the bacteria. In this research, based on the bacterial antibody's connection to nanoparticles, a sensor was used. In this part of the research, as the basis for absorption for the recognition of bacterial toxin, medium sized silica nanoparticles of 10 nm in the form of solid powder were utilized with Notrino brand. Then the suspension produced from the agent-linked nanosilica, which was connected to the bacterial antibody, was positioned near the samples of distilled water, which were contaminated with Staphylococcus aureus bacterial toxin with the density of  10-3 molar, so that in case any toxin exists in the sample, a connection between the toxin antigen and the antibody would be formed. Finally, the light absorption related to the connection of antigen to the particle-attached antibody was measured using spectrophotometry. The 23S rRNA gene that is conserved in all Staphylococcus spp. was used as the control. The accuracy of the test was monitored by using the serial dilution (l0-6) of overnight cell culture of Staphylococcus spp. bacteria (OD600: 0.02 = 107 cell). It showed that the sensitivity of PCR is 10 bacteria per ml of cells within few hours. The results indicated that the sensor detects up to 10-4molar density. Additionally, the sensitivity of the sensor was examined after 60 days; by the 56 day, it had confirmatory results, which started to decrease after this time. Comparison of practical nanobiosensory method with the conventional methods including culture and bio-technology methods (such as polymerase chain reaction) confirmed its accuracy, sensitiveness and uniqueness.  It also reduces the time from hours to 30 minutes.

Inhibitory Effects of Several Essential Oils towards Salmonella typhimurium, Salmonella paratyphi A and Salmonella paratyphi B

S.F. Mazhar, F. Aliakbari, R. Karami-Osboo, D. Morshedi, P. Shariati, D. Farajzadeh

Applied Food Biotechnology, Vol. 1 No. 1 (2014), 25 September 2014, Page 45-54

Plant essential oils are natural products extracted from plants and because of their antimicrobial properties can be used as natural additives in foods. They are also useful for decontamination of food-borne pathogens and can be a safe additive in foods. The antimicrobial activities of essential oils belonging to Saturiea hortensis, Thymus vulgaris, Mentha polegium, Cuminum cyminum, Lavandula officinalis and Mentha viridis L. (spearmint) were investigated at different concentrations (0.1, 0.3, 0.5, 1, 2, 5 and 10%v/v) against Salmonella typhimurium, Salmonella paratyphi A and Salmonella paratyphi B by using the agar well diffusion method. Essential oils showed inhibitory effect on Salmonella spp. in the agar well diffusion assay. In addition, the capability of essential oils for decontamination of minced row beef, ground beef, minced raw chicken and minced raw fish inoculated with Salmonella spp. at 0.1 and 0.5%v/v were assessed. Reduction of the Salmonella spp. population was observed following the inoculation of the cultures with 0.1 and 0.5%v/v essential oils.

This research aimed to investigate the viability of probiotic bacteria (Lactobacillus acidophilus LA-5 and Bifidobacterium lactis BB-12) and yogurt bacteria (Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus) in yogurt during the fermentation, immediately after fermentation and during refrigerated storage (21 d, 4˚C). Also the biochemical characteristics of milk as affected by the commercial 4-strain mixed starter culture were investigated. Storage time affected the viability of all bacterial species. The concentration of lactic acid during the fermentation increased in parallel with the titrable acidity, and the concentration of acetic acid was proportional to the viability of Bifidobacterium lactis. The acetaldehyde level was decreased in the yogurt from day 0 up to the end of the storage. Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus were multiplied considerably during the fermentation. Streptococcus thermophilus could maintain its viability to the highest level, but Lactobacillus delbrueckii ssp. bulgaricus lost its viability rapidly during the cold storage compared to Streptococcus thermophilus. The multiplication and viability of probiotic bacteria were also influenced by the associative strains and species of yogurt organisms. Bifidobacteria counts were satisfactory. The loss of viability for bifidobacteria was gradual and steady during the storage, and they showed good stability during the storage as compared to Lactobacillus acidophilus.