ISSN: 2345-5357

Vol. 4 No. 4 (2017)

Review Article


Genetically Modified Foods: Promises, Challenges and Safety Assessments

Manouchehr Dadgarnejad, Shahzad Kouser, Masoumeh Moslemi

Applied Food Biotechnology, Vol. 4 No. 4 (2017), 23 September 2017 , Page 193-202
https://doi.org/10.22037/afb.v4i4.17244

Background and Objective: Application of genetically modified organisms in the agriculture sector and food industry began since last years of 20th century. Since then this technology has become a central part of the broader public controversy about the advantages and safety of these products. This article has tried to review aspects of these types of organisms and foods.

Results and Conclusion: Genetically modified technology has potential to overcome agricultural problems, such as biotic and abiotic issues by enhancing pests and herbicides resistance, drought tolerance, fast ripening, and finally enhancing yield and nutritional quality. Besides these revolutionary advantages, during the last decades some potential human, animal and environmental risks have been taken in account for these organisms or foods. However, no scientific evidence exists adequately about their harmful human or animal effects, and also, some new scientific and management methodologies (new technologies and regulations) have been developed to mitigate the environmental risks. Some challenges such as pest adaptation are being solved by refuge technology, gene pyramiding and insertion of best-coupled primers through the known conditions reducing unintended outcomes including silencing, activation or rearrangement of non-target genome pieces. However, it does not mean that no harmful effect will happen in the future. Therefore, it is required that before release of any genetically modified crop, all requested risk assessments be performed, and then post release monitoring be done to follow the possible gene flow and prevent any potential disastrous contaminations to the food chain. Finally, it could be concluded that the safe usage of this technology, by considering all nationally and internationally accepted environmental and health safety assessment protocols, can help us to use advantages of this technology in agriculture, medicine and industry. However, more safety evaluations are being done frequently.

Conflict of interest: There is no conflict of interests to declare.

Original Article


Transesterification of Waste Cooking Sunflower Oil by Porcine Pancreas Lipase Using Response Surface Methodology for Biodiesel Production

Soraya Ebrahimi, Ghasem Darzi Najafpour, Fatemeh Ardestani

Applied Food Biotechnology, Vol. 4 No. 4 (2017), 23 September 2017 , Page 203-210
https://doi.org/10.22037/afb.v4i4.16904


Background and Objective: Biodiesel production from recycled vegetable oils is considered as an economically acceptable alternative for fossil fuels in the recent years. In this work, porcine pancreas lipase as an active catalyst in transesterification reaction of waste cooking sunflower oil with methanol for biodiesel production was used.

Material and Methods: In order to define optimum process parameters and predict the best results, response surface methodology and the central composite design was performed. The effects of methanol to oil molar ratio, lipase concentration and reaction temperature on transesterification were investigated. Biodiesel production was carried out in 25 ml shake flasks at 180 rpm for 72 h.

Results and Conclusion: Under optimal conditions, the biodiesel yield was 75% which was nearly consistent with the predicted yield of 76%. At optimal conditions the molar ratio of methanol to oil, reaction temperature, and lipase percent were determined as 3:1, 44°C and 4.4%, respectively. Due to relatively high obtained yield, biodiesel production from waste cooking sunflower oil has provided a sound environmental and commercial process.

Conflict of interest: The authors declare no conflict of interest.

Acidophilus Milk Shelf-life Prolongation by the Use of Cold Sensitive Mutants of Lactobacillus acidophilus MDC 9626

Alireza Goodarzi, Hrachya Hovhannisyan, Gohar Grigoryan, Andranik Barseghyan

Applied Food Biotechnology, Vol. 4 No. 4 (2017), 23 September 2017 , Page 211-218
https://doi.org/10.22037/afb.v4i4.17116

 

Background and Objective: The shelf-life of Acidophilus milk fermented by probiotic culture Lactobacillus acidophilus is limited due to acidification caused by continued organic acid formation at low temperatures. Increasing of titrable acidity in turn causes reducing of the total viable count of probiotic bacteria. To overcome acidification we suggested to use coldsensitive mutants of Lactobacillus acidophilus, with limited metabolism at low temperatures. In order to facilitate the selection of cold sensitive mutants, it was decided to use Rifampicin and Streotomycin mutations affecting thermostability of the key molecules of cell metabolism the RNA polymerase and ribosome, respectively.

Material and Methods: Ultra violet mutagenesis was used to enhance the yield and diversity of rifampicin and streptomycin resistant mutants of Lactobacillus acidophilus. To perform negative selection of cold sensitive mutants, antibiotic resistant colonies replica plated and incubated at 23ºC. The growth rate, milk fermenting rate, titratable acidity were measured.

Results and Conclusion: Among tested resistant to either rifampicin or streptomycin clones with frequency mean of 1.0 %, ten mutants were isolated which have lost the ability to grow at minimal temperature. Fermented with cold-sensitive mutants of Lactobacillus acidophilus milks, during storage in the refrigerator, almost twice as long retained high amount of probiotic bacteria and low titratable acidity as compared to the parent strain. Thus, direct relationship between temperature sensitivity of the starter and shelf life of acidophilic milk was confirmed. Rifampicin and Streptomycin resistant mutations are powerful tools for selection of cold-sensitive dairy starters for preparing dairy fermented products with long shelf-life.

Conflict of interest: The authors declare no conflict of interest.


Background and Objective: The use of antifungal lactic acid bacteria as starter for bread making could be a good alternative to improve the stability of bread shelf life.

Material and Methods: In this study, a total of 57 lactic acid bacteria were isolated from spontaneously fermented wheat sourdoughs collected in Chahar-Mahalo Bakhryari province of Iran. The isolates were screened for in vitro antifungal activity (towards Aspergilus niger or Penicillium roqueforti); and the selected isolates (six isolates) were applied in flat bread making. The freshly baked breads were nebulized with a suspension of either molds, containing 104 spores ml-1, and the fungal growth on breads was monitored over a 7-day storage period.

Results and Conclusion: Bread produced with either isolates AN3 and MB1 (both were identified as Enterococcus faecium) restrained the growth of Aspergillus niger for up to 5 days. Even though none of the isolates were strong enough to inhibit the growth of Penicillium roquforti on bread, the surface area of breads contaminated by this fungus was significantly lower than the control samples. To our knowledge, it was the first report indicating the anti-mold activity of Enterococcus faecium strains isolated from sourdough. These isolates seem to be promising for further analysis and their application in bread industry for prolonging the shelf life.

Conflict of interest: The authors declare that there is no conflict of interest.

Polyphenol and Microbial Profile of On-farm Cocoa Beans Fermented with Selected Microbial Consortia

Tochukwu Vincent Balogu, Azuonye R. Onyeagba

Applied Food Biotechnology, Vol. 4 No. 4 (2017), 23 September 2017 , Page 229-240
https://doi.org/10.22037/afb.v4i4.16845

Background and Objective: Quality and preference of cocoa as raw material for various mcocoa products primarily depend on fermentation techniques that modulate the resultant flavour and the phytochemical properties. This study investigated the combined effect of selected microbial consortia and bioreactors on phytochemical profiles of fermented cocoa beans.

Material and Methods: Three microbial consortia labeled as Treatments (T-1, T-2, T-3) were used as starter culture (≈105cells ml-1) for on-farm cocoa fermentation on three chambers (basket, woodbox, and plastic) for 7 days. These novel consortia were T-1, Staphylococcus spp + Pseudomonas spp+ Bacillus spp, T-2, Staphylococcus spp + Pseudomonas spp +L. lactis, and T-3, Bacillus spp+ Lactobacillus spp + Saccharomyces spp+ Torulopsis spp.

Results and Conclusion: The microbial profile were significantly (P≤0.05) altered by all treatments (T-1, T-2, T-3) and microbial frequency was enhanced by 5 -22.5%. T-3 and T-1 significantly altered phenolic content in basket chamber. Tannin was significantly (p≤0.05) varied by T-1(basket, plastic, wood box) and T-2(plastic). Tannin: polyphenol conversion ratio adopted as fermented cocoa bean quality benchmark was significantly enhanced by T-1 (basket, woodbox) and T-2 (plastic), but was significantly suppressed by T-3 (basket). This study evidently concluded that the appropriate synergy of microbial flora and fermenting chambers could achieve good cocoa quality with low polyphenol content (best for cocoa beverages) or high polyphenol content (best for pharmaceutical, confectionery and nutraceutical industries). These findings would avail an economic alternative to the expensive polyphenol reconstitution of cocoa butter used for various industrial products, thereby maximizing economic benefits for both cocoa farmers and industrialists.

Conflict of interest: The authors declare no conflict of interest.

Antibiofilm Effects of Lactobacilli against Ciprofloxacin-Resistant Uropathogenic Escherichia coli strains in Pasteurized Milk

Mahsa Yeganeh, Hedayat Hosseini, Sedigheh Mehrabian, Elham Siasi Torbati, Seyed Morteza Zamir

Applied Food Biotechnology, Vol. 4 No. 4 (2017), 23 September 2017 , Page 241-250
https://doi.org/10.22037/afb.v4i4.17783

Background and Objective: Uropathogenic Escherichia coli-induced urinary tract infections are the most common uropathogenic Escherichia coli etiological agent. In addition, most of biofilms created by these bacteria can be regarded as a serious problem in the food industry. Foodborne diseases have always been considered an emerging public health concern throughout the world. Many outbreaks have been found to be associated with biofilms. Thus, the aim of the present study is to investigate the anti-adhesive effects of lactic acid bacteria against strains of Ciprofloxacin-Resistant Uropathogenic Escherichia coli using microbial techniques in pasteurized milk.

Material and Methods: In this study, strains of Lactobacillus plantarumLactobacillus casei and Lactobacillus acidophilus were provided from Pasteur Institute of Iran. Twenty strains of Uropathogenic Escherichia coli-Induced Urinary Tract Infections were isolated from patients with urinary tract infection in Shahid Labbafinejad hospital of Iran. Eight strains with ability of biofilm formation were selected for microbial tests. All of these eight strains were resistant to ciprofloxacin. Disk diffusion method was used to assess the susceptibility of all isolates to the ten common antibiotics. Eight samples of Uropathogenic Escherichia coli were inoculated in pasteurized milk. The microtitre plate 100 method was used to detect anti-adhesive activity of lactobacilli supernatant.

Results and Conclusion: Results showed that the eight human isolates were resistant to antibiotics. Isolate of number 4 was the most susceptible strains to antibiofilm effects of lactobacilli in the pasteurized milk. The anti-adhesive effects of lactobacilli on Uropathogenic were confirmed in all microbial tests. In this study, Lactobacillus plantarum revealed the highest inhibitory activity against Uropathogenic Escherichia coli 4 strain with inhibition zones of 42 mm. This strain was reported as a proper probiotic bacterium. According to the results, these lactobacilli have had spectacular effects on biofilm formation and pathogenicity of Uropathogenic strains to prevent the adhesion.

Conflict of interest: The authors declare no conflict of interest.