Food Biotechnology
Mahdieh Mostafidi; Mohammad Reza Sanjabi; Naheed Mojgani; Sohyel Eskandari; Sepideh Arbabi Bidgoli
Abstract
Introduction The food and water contamination with heavy metals is increasing due to the environmental pollutions. Heavy metals are the elements with the density of more than 5 g/cm3 and have become a serious problem as a result of the urbanization and industrialization. These toxic metals pollute ...
Read More
Introduction The food and water contamination with heavy metals is increasing due to the environmental pollutions. Heavy metals are the elements with the density of more than 5 g/cm3 and have become a serious problem as a result of the urbanization and industrialization. These toxic metals pollute water, soil, plants, and eventually foodstuffs and our bodies. Several methods exist to remediate heavy metal pollution in waters such as membrane filtration, ion exchange mechanisms, or by precipitation. Yet, these techniques are not cost effective, in some cases, and do produce wastes that need to be properly disposed of. Microbial bioremediation could be an alternative. The use of microbes for remediation of heavy metals has been well studied. Some microorganisms, especially soil bacteria, have the ability to tolerate these contaminants. In addition, certain bacterial strains are capable of binding to heavy metals or transforming them into less toxic forms. Low operating costs, usable in foodstuffs, selective removal for specific toxic metals, minimal use of chemicals (resulting in low sludge production) and high efficiencies at very low levels of heavy metals are some of the advantages of biosorption methods. In this regard, the purpose of this study was to investigate the ability of active and passive absorption of heavy metals by a number of Lactic Acid Bacteria (LAB) strains in laboratory environment and food. Materials and Methods Seven LAB isolates including Lacticaseibacillus casei (RTCC 1296-3), Lacticaseibacillus rhamnosus (RTCC 1293-2), Lactiplantibacillus plantarum (RTCC 1290), Limosilactobacillus fermentum (RTCC 1303), Enterococcus faecium (RTCC 2347), Lactobacillus helveticus (RTCC 1304) and Lactobacillus acidophilus (RTCC 1299) were obtained from Razi type culture collection (RTCC), located at Razi vaccine and Serum Research Institute, Iran. All isolates were cultured in MRS (Scharlau, Spain) broth medium, at 37 °C for 24 hours, under anaerobic conditions. Pure cultures were preserved for long term by freezing at -70°C with 20% Glycerol. Heavy metals including Nitrate of Pb (II), Cd (II) and Ni (II) were purchased from Merck (Darmstadt, Germany). All standard solutions were prepared from the stock solutions containing 1000 mgl-1 in distilled water. Other chemicals used in study including Nitric acid (65%) and Hydrogen peroxide (37%), were also purchased from Merck, Germany. This study was conducted in two in- vitro and in-vivo phases; in the in- vitro phase, seven strains of bacteria with probiotic properties (L. casei, L. rhamnosus, L. plantarum, L. fermentum, Ent. facium, L. helveticus and L. acidofilous) were screened and then their ability to bind to cadmium (Cd), Lead (Pb) and nickel (Ni) in aqueous solution was investigated. Then, in the in-vivo stage, three probiotic strains that had the highest biosorption efficiency in the previously stage were selected and their effect with a ratio of 1:1:1 and contact time of 15 and 30 minutes on the removal of these toxic metals in coriander, leek and parsley fresh vegetables was evaluated. The residual concentrations of heavy metals in solution were measured by Inductively Coupled Plasma Mass Spectrometer (ICP-MS; ELAN DRC-e, PerkinElmer SCIEX, Canada) and Morphology of bacteria cell surfaces incubated with metals were monitored by scanning electron microscopy (JEOL JSM 5400 LV, Japan). Results and DiscussionThe results of the in vitro stage showed that the most ability to heavy metals adsorption was related to the Ent. Facium bacterium which were equal to 79.75±0.11, 75.28±0.05 and 83.99±0.10% for Pb, Cd and Ni, respectively. In general, the removal efficiency of heavy metals by LAB bacteria in the inactive and killed state was significantly higher than the active removal efficiency of these bacteria, so that the highest percentage of passive absorption of lead, cadmium and nickel metals by inactive strains of L. casei, L. plantarum and Ent. Facium were 90.01, 81.98 and 86.56%, respectively. Electron microscopy observations and energy dispersive X-ray (EDX) analysis confirmed that the majority of these toxic metals significantly damage the surface of living cells by accumulating and binding on the surface of bacterial cells. A combination of three bacterial strains had a synergistic effect on the binding properties of toxic metals compared to the single state of these bacteria, so that in both active and inactive states, 90-99% of heavy metals from edible leafy vegetables were removed in less than 15 minutes. The results of this research generally showed that the binding capacity of dead biomass is significantly high and it is possible to dispose and reuse biomass in case of biological absorption.
Food Chemistry
Zeinab Soltan Touyeh; Shiva Dehghan Abkenar; Nazanin Khakipour
Abstract
Introduction Rice as a staple food, especially in Asian countries, can be a major source of heavy metals. Heavy metals also enter the soils where crops grow naturally and / or through human activities. Metals are absorbed and accumulated in the edible parts of the plant and enter the food ...
Read More
Introduction Rice as a staple food, especially in Asian countries, can be a major source of heavy metals. Heavy metals also enter the soils where crops grow naturally and / or through human activities. Metals are absorbed and accumulated in the edible parts of the plant and enter the food chain. Toxic metals, which are present in nature due to industrialization, have polluted the environment, including soil, air, water and food, and have adverse effects on human health through food chains. The Codex Organization has set maximum levels for these elements in various cereals to protect trade and health. Nitrate and nitrite are naturally present in soil, water and food. But today, foods have higher levels of nitrate and nitrite. Excessive use of nitrogen fertilizers to achieve higher yields and improper disposal of human and animal wastes may lead to nitrate accumulation in agricultural products. Very few studies have been performed on the measurement of heavy metal and nitrogen indices in replanted rice. The aim of this study was to measure the amounts of heavy metals (lead, cadmium and arsenic) and the amounts of nitrate and nitrite in first harvest rice and re-harvest rice and compare it with the standard values of the World Health Organization. Methods and Materials In this study, a total of 18 rice samples were prepared from three selected farms in the first and second cultivation times and the amount of nitrite, nitrate and heavy metals lead, cadmium, arsenic and mercury were evaluated. Results and Discussion The results showed that in all farms in the second crop the concentration of lead decreased significantly (P<0.05). The concentration of lead in all treatments of the first crop Has been more than allowed and in the second cultivation, the treatment of field number one and two, is more than allowed (P<0.05). The concentration of cadmium in all treatments is within the allowable range and in the second crop compared to the first crop of fields number one and three has a significant decrease and in field number two has increased significantly (P <0.05). The highest amount of cadmium is related to field treatments number three. The highest amount of arsenic was observed in the first crop of farm number one and it is more than the allowable limit and in other treatments the amount of arsenic was less than the allowable level and in all three farms the concentration of arsenic in the second crop was significantly reduced compared to the first crop. Regarding mercury, in fields number one and two, with the change of cultivation, the amount of mercury increased significantly and in field number three, there was a significant decrease (P <0.05). Mercury concentration is less than the allowable limit only in the second culture sample of farm number three. Nitrite and nitrate concentrations were also low in all treatments and were considered zero. Experiments showed the amount of nitrite and nitrate in all samples to be negligible and undetectable. Due to the fact that the detection limit of the method (LOQ) used to measure nitrate and nitrite is 100 ppb, the amount of nitrate and nitrite in all samples can be less than 100 ppb. The permissible level of nitrate in food products and rice grains is set at 50 mg/kg according to national standard 16596. The results of the samples showed that all 18 samples had lower amounts of nitrate than the allowable limit. Therefore, rice samples prepared from the first and second crops, their nitrate content is less than the allowable limit and have a complete degree of health. Conclusion According to the results obtained, all rice cultivated in the first and second crops have some arsenic, cadmium and lead, but the amount measured in some samples is less and in others, more than specified in the national standard of Iran. their consumption may be dangerous for consumers. These results also indicate that due to the stability of the field and plant type, there is a positive and significant relationship between the amount of heavy metals studied in rice and the time of cultivation, and this requires further studies on heavy metal contamination in the region. Take place. Therefore, with the conducted studies, it can be concluded that there are concerns in the consumption of rice cultivated in the city of Mazandaran province, in terms of the possibility of endangering the health of consumers.
Food Technology
Reza Farahmandfar; Sahar Aboutalebzadeh; Hannaneh Moniri; Massoud Kaykhaii
Abstract
Black tea, which is obtained from the leaves of small tree Camellia sinensis, is a popular drink that has been consumed for centuries all around the world. In this study, a sample of Iranian black tea was brewed by two methods of microwave and traditional brewing and their extracts were then assessed ...
Read More
Black tea, which is obtained from the leaves of small tree Camellia sinensis, is a popular drink that has been consumed for centuries all around the world. In this study, a sample of Iranian black tea was brewed by two methods of microwave and traditional brewing and their extracts were then assessed using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing/antioxidant power (FRAP) assays to determine their phenolic and flavonoid contents as well as heavy metal (HM) (copper, nickel, chromium, cadmium and lead) content. It was observed that there is a direct relationship between the antioxidant activity with their phenolic and flavonoid contents. The highest and lowest antioxidant activities were observed for samples brewed by microwave at 360 W for 2.5 min and 900 W for 7.5 min, respectively. As the brewing power and time increased, the antioxidant activity decreased. Brewing tea by microwave and traditional methods caused a significant reduction in the amount of heavy metals, which was lower than the allowable limit according to the Iranian national standards. These results demonstrate the importance of exposure time and radiation power when tea is prepared by microwave.
Food Chemistry
Sedigheh Yazdanpanah; Shadi Jokar; Tahereh Zandilak; Maryam Haghighi
Abstract
Introduction: Coffee is the second most profitable commercial products in the world and in addition to beverage consumption, it is widely used in food industry. Among natural sources, coffee has the highest amount of caffeine. The amount of caffeine in coffee varies depending on the variety of coffee ...
Read More
Introduction: Coffee is the second most profitable commercial products in the world and in addition to beverage consumption, it is widely used in food industry. Among natural sources, coffee has the highest amount of caffeine. The amount of caffeine in coffee varies depending on the variety of coffee and how it is brewed. Coffee beans contain other compounds such as phenol, magnesium, potassium and fiber. Plants are the most important route for the transfer of heavy metals to the human food chain and the natural cycle. Heavy metals in the body can cause everything from biochemical changes in low levels of contamination to effects on the nervous system and even death in high concentrations. They slow down the reaction with enzymes and even stop the body's essential physiological reactions and have the ability to be stored in the bones, which enter the bloodstream after being saturated in the bone. Heavy metals are important because they are non-degradable in the human body. Contamination with mycotoxins in coffee beans such as ochratoxin produced by Aspergillus and Penicillium occurs under the influence of environmental conditions such as temperature, humidity, water activity, transport conditions, storage until consumption. Therefore, the aim of this study was to investigate and compare the physicochemical properties, fungal contamination and metal elements in 4 samples of instant coffee powder Eagle Lux, Good Day, Nestle and Torabika. Materials and Methods: In 4 samples of instant coffee powder fat, moisture, ash, pH, total sugar, caffeine (using HPLC), ochratoxin A contamination (using HPLC) and lead and arsenic metallic elements (using hydride atomic absorption spectroscopy) were determined. The results were reviewed and compared with national and international standards. All experiments were performed in a completely randomized design. Data analysis was performed using SPSS software. The means were compared using Duncan's test at 5% probability level. Results and Discussion: Comparing the results obtained with the permissible limits of national and international WHO standards, all results are within the permitted standard range (pH 5 to 7, maximum moisture 4%, total sugar maximum 72%, ash 4%, fat in cappuccino powder maximum 30%, Caffeine was based on dry matter up to 2.8%, lead 0.5 mg/ kg, arsenic 1 mg/ kg, ochratoxin 10 ppb). The highest pH value (6.83± 0.05) was determined in Good Day sample. The low pH in the Nestle sample may be due to acid rain and low soil pH in the exporting countries. Minimum amount of ash (2.38± 0.05%), moisture (1.41± 0.05%), lead (0.026± 0.000 mg / kg) and arsenic (0.013± 0.000) mg / kg) was observed in Torabika sample. Lead level was similar in Good Day and Torabika samples. The highest amount of caffeine (0.23 ±0.05 wt %) was obtained in Good day sample. Ochratoxin A was not detected in all samples. The lowest amount of total sugar (42.75± 0.05 g /100 g) was observed in Nestle sample. Therefore, it is the most suitable sample for diabetic patients. Torabika sample is recommended as the best sample due to the low amount of lead, arsenic, ash and fat, as well as low moisture content. With increasing moisture and sugar, the possibility of liquid steps forming between particles increases and this causes the degree of cohesion and agglomeration of the powder and the marketability of the powder disappears. Increased mineral consumption causes disease due to inhibition of the mechanism of control of absorption in the small intestine and accumulation in the body. Therefore, as the amount of total ash in coffee increases, its adverse effects on the body intensify. Torabika is the most suitable sample for people with cardiovascular disease due to the lower fat content.
Narges Hadigol; Maryam Fahim danesh; Sepideh Hoseini
Abstract
Introduction: Pomegranate peel is an important source of bioactive compounds which have high potential of alternative source of activated carbon for bleaching and the removal of heavy metal from liquid media. The present study was undertaken to evaluate the feasibility of pomegranate peel carbon for ...
Read More
Introduction: Pomegranate peel is an important source of bioactive compounds which have high potential of alternative source of activated carbon for bleaching and the removal of heavy metal from liquid media. The present study was undertaken to evaluate the feasibility of pomegranate peel carbon for the removal of heavy metal from oil and aqueous solution and then to investigate its activity in the bleaching of sesame oil.
Materials and methods: Response surface methodology and Box-Behnken design were applied to study and optimize the adsorption condition to remove metal ions on prepared pomegranate peel adsorbent. For this purpose, the effects of three independent variable pH(X1), contact time (X2) and adsorbent dose (X3) on metal ions concentration (dependent variable) were studied using a three-level three-factor Box–Behnken design. In addition, different types of adsorbents (pomegranate peel carbon and activated earth) were tested for adsorption of pigment, peroxides and heavy metals of sesame oil.
Results and discussion: Results showed that optimum condition required for maximum adsorption were found to pH= 5.3, equilibrium time 200 min and adsorbent concentration 2.5 g/L. Under the optimal conditions the removal of heavy metals i.e. Fe, Cr, Pb, as and Hg from aqueous solution by activated carbon developed from pomegranate peel are more than 80%. Results of sesame oil bleaching with pomegranate peel carbon showed good bleaching efficiency and oxidative stability. Furthermore, pomegranate peel carbon comparing with bleaching earth showed better ability to decrease heavy metal content of oil.
Ainaz Khodanazary; Sara Golgolipour; Kamal Ghanemi
Abstract
Introduction: Grass carp (Ctenopharyngodonidella, family Cyprinidae) is one of the main fresh water fish species and highly demanded aquaculture species in Iran. Among the cultivated fish, grass carp, also called farmed white fish, has received great attention because of its similarity to Caspian white ...
Read More
Introduction: Grass carp (Ctenopharyngodonidella, family Cyprinidae) is one of the main fresh water fish species and highly demanded aquaculture species in Iran. Among the cultivated fish, grass carp, also called farmed white fish, has received great attention because of its similarity to Caspian white fish in Iran. The muscle of fish contains important levels of nutrients which are beneficial to health. Most research has been done and published on raw flesh. Cooking can lead to a loss of the nutritional value of foods. In this case the preservation of the maximum nutritive value can be ensured by using correct methods of cooking. The aim of this research was the influence of five cooking methods (poaching, boiling, microwave pan- frying and deep- frying) on changes of free fatty acids, thiobarbitoric acid, heavy metal (Ni, Cr, Co, Cd, Pb) and sensory properties of grass carp (Ctenopharyngodonidella)fillets was evaluated.Materials and method: Grass carpsamples were purchased from a local market in Khorramshahr city, Khuzestan province, Iran. The fish were kept alive and transported to thelaboratory. On arrival,tsamples were washed and eviscerated. The samples were filleted and cut into slices (100 g each). The fish samples were cooked using AOAC 976.16 procedure (method for cooking seafood). Five common cooking procedures were selected: poaching in stainless steel pot of boiling water for 30 min and 30 s, steaming in stainless steel steamer for 5 min and 30 s, microwaving in microwave for 40 s, pan-frying (without oil) in frying pan for 6 min at 180 ºC and deep-frying in olive oil in a deep fryer for 5 min at 180 ºC. After the cooking process, the samples were cooled to room temperature and the skin and backbone of the samples were removed. All fish in each lot were homogenized using a kitchen blender and analyzed to determine free fatty acid, thiobarbitoric acid, heavy metal and sensory properties. All sample homogenates were assayed in triplicate.Results and discussion: The results indicated that the cooking methods of pouching, microwave and deep-frying increased thiobarbitoric acid (TBA), while cooking methods of boiling and pan- frying did not change TBA. The free fatty acid (FFA) content of the fillets was significantly reduced by the different cooking methods. The Ni in the cooking methods of boiling, pan- frying and deep- frying was not detected. The Cr in the cooking method of deep-fried samples was significantly decreased. The Co concentrations were below limits of detection in all samples. The Cd was only detected in microwave samples. The Pb content increased during cooking of fillets. The results of sensory properties were showed that the texture, odour, flavor, colour and overall likeness properties improve likeness score to some extent in deep-frying method and there were not significantly different between boiling, poaching and pan-frying.
