Full Research Paper
Food Technology
Farinaz Saremnejad; Mohebbat Mohebbi; Arash Koocheki
Abstract
Introduction: Increasing diet-linked diseases and following that the consumers ongoing desire for healthier foods makes reduced-fat products of outstanding importance in the food industry. This study aims to reduce the fat content of sauces as a traditional condiment through the incorporation ...
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Introduction: Increasing diet-linked diseases and following that the consumers ongoing desire for healthier foods makes reduced-fat products of outstanding importance in the food industry. This study aims to reduce the fat content of sauces as a traditional condiment through the incorporation of air bubbles in the oil phase. Response surface methodology (RSM) was used for identifying the effect of aeration process variables on foam properties. However, the main challenge of reduced-fat foods is to ensure their acceptability. Recently fat taste has been introduced as a sixth basic taste. Fatty acids have been considered as the stimulus for this taste. So, linoleic acid as the stimulus for fat perception was added to the formulation to develop a product that tastes almost like full-fat versions but contains less fat. The advantages of aerated foods over conventional products are clear. Nonetheless, the determination of quality and sensory parameters during storage, marketing, and consuming is necessary. For this purpose, produced aerated sauces, along with commercial full- and reduced-fat sauces, were compared by measuring the acidity, pH, oxidative stability, and sensory properties. Materials and Methods: Required amounts of mono- and diglyceride (MDG) and oil were mixed. Then nonaqueous foams were generated by whipping the MDG-oil mixtures. In the optimization study, the effect of MDG concentrations (2, 6, and 10 wt. %), whipping speed (1100, 3250, and 5400 rpm) and time (5, 15, and 25 min) on foam properties (overrun and drainage) was analyzed using RSM. The foam obtained from the optimum process condition was used to produce an aerated reduced-fat sauce. Sauce preparation was performed according to a usual recipe with the difference that the fat content was replaced by nonaqueous foam. Furthermore, 3.00 mM of linoleic acid as a fat taste stimulus was added to the formulation. First, an aqueous phase containing ingredients was prepared. Then nonaqueous foam was progressively incorporated in the aqueous phase. For the purposes of comparison, aerated sauces (0 and 3.00 mM stimulus), along with commercial sauces (zero, low, and full-fat), were analyzed by measuring the pH, acidity, oxidative stability, and sensory properties. Results and Discussion: According to the results of the optimization study, the desired foam (overrun ≥ 60 %) achieved by oil containing 10 wt. % MDG at 3400 rpm for 10 min. Overrun increased progressively with MDG concentration but decreased slightly above 10 wt. % due to the difficulty of dispersing air bubbles in such a viscous gel. Considering the effect of whipping speed, and time, it was observed that mixtures reached their maximum volumes within 25 min. With a further increase in the whipping rate, the time required to achieve the maximum amount of foam was decreased. However, at high whipping speed (5400 rpm), foam volume decreased rapidly with time, and almost a lot of foam collapsed. The lowest and highest pH was related to zero and full-fat commercial sauces, respectively. There was no difference (p>0.05) between the pH of the control and the linoleic acid containing aerated, as well as low-fat sauces. Over time, as the pH decreases, the acidity of the aerated sauces increased and making the products with appropriate microbial stability. Due to the significant reduction of fat amount, oxidation of the aerated sauces was much slower than the full-fat one (p<0.05). Appearance, taste, and texture characteristics of aerated sauces provided a sensory profile similar to the full-fat sauce. The aerated sauce containing linoleic acid had higher sensory scores, indicating its general acceptance. Conclusions: In this study, nonaqueous foam as a new approach for fat replacement in emulsion-based foods such as sauces was practically applied. The optimum aeration process conditions were determined by the help of experimental design. Two types of aerated sauces were prepared based on the linoleic acid concentration, and their physicochemical and sensory characteristics were compared with commercial sauces. The acidity and pH of the sauces were in the standard range, and also their oxidative stability was acceptable during storage time. Generally, the aerated sauce containing linoleic acid had relatively similar sensory profiles to the full-fat sauce. Therefore, it seems that nonaqueous foam could be used successfully to develop reduced-fat alternative foods, which could also be meet the consumers' and marketing requirements.Materials and Methods: Required amounts of mono- and diglyceride (MDG) and oil were mixed. Then nonaqueous foams were obtained by whipping the MDG-oil mixtures. In the optimization study, the effect of MDG concentration (2, 6, and 10 wt. %), whipping speed (1100, 3250, and 5400 rpm) and time (5, 15, and 25 min) on foam properties (overrun and drainage) were analyzed using RSM. The foam obtained from the optimum process condition was used to produce an aerated reduced-fat sauce. Sauce preparation was performed according to a usual recipe with the difference that the fat content was replaced by nonaqueous foam. Furthermore, 3.00 mM of linoleic acid as a fat taste stimulus was added to the formulation. First, an aqueous phase containing ingredients was prepared. Then nonaqueous foam was progressively incorporated in the aqueous phase. For purposes of comparison, aerated sauces (0 and 3.00 mM stimulus), along with commercial sauces (zero and full-fat), were analyzed by measuring the pH, acidity, oxidative stability, and sensory properties. Results and Discussion: According to the results of the optimization study, the desired foam (overrun ≥ 60 %) achieved by oil containing 10 wt. % MDG at 3200 rpm for 10 min. Overrun increased progressively with MDG concentration but decreased slightly above 10 wt. % due to the difficulty of dispersing air bubbles in such a viscous gel. Considering the effect of whipping speed, and time, it was observed that mixtures reached their maximum volumes within 25 min. With a further increase in the whipping rate, the time required to achieve the maximum amount of foam was decreased. However, at high whipping speed (5400 rpm), foam volume decreased rapidly with time, and almost a lot of foam collapsed. The lowest and highest pH was related to zero and full-fat commercial sauces, respectively. There was no difference between the pH of the control and the linoleic acid containing aerated sauces. Over time, as the pH decreases, the acidity of the aerated sauces increased and making them products with appropriate microbial stability. Due to the significant reduction of fat amount, oxidation of the aerated sauces was much slower than the commercial ones. Appearance, taste, and texture characteristics of aerated sauces provided a sensory profile similar to the full-fat sauce. The aerated sauce containing linoleic acid had higher sensory scores, indicating its general acceptance. Conclusions: In this study, nonaqueous foam as a new approach for fat replacement in emulsion-based foods such as sauces was practically applied. The optimum aeration process conditions were determined by the help of experimental design. Two types of aerated sauces were prepared based on the linoleic acid concentration, and their physicochemical and sensory characteristics were compared with commercial sauces. The acidity and pH of the sauces were in the standard range, and also their oxidative stability was acceptable during storage time. Generally, the aerated sauce containing linoleic acid had relatively similar sensory profiles to the full-fat sauce. Therefore, it seems that nonaqueous foam could be used successfully to create reduced-fat alternative foods, which could also be meet consumers' and marketing requirements.
Full Research Paper
Food Engineering
Samaneh Monajem; Ali Ganjloo; Mandana Bimakr
Abstract
Conclusion: Based on the findings of the current study, the 75% v/v A. vera gel coating could be a promising natural coating agent for preservation of bioactive compounds of cherry tomatoes during the postharvest life especially at storage temperature of 5 ºC.
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Conclusion: Based on the findings of the current study, the 75% v/v A. vera gel coating could be a promising natural coating agent for preservation of bioactive compounds of cherry tomatoes during the postharvest life especially at storage temperature of 5 ºC.
Full Research Paper
Food Technology
Reza Jaberi; Ahmad Pedram Nia; Sara Naji-Tabasi; Amir Hossein Elhami Rad; Masoud Shafafi
Abstract
Introduction: Fats are widely used in food formulations to improve nutrients and quality of food products. In recent years, consumer awareness of the relationship between diet and health has increased, which results in increasing concerns about fats in products, in terms of high levels of saturated fatty ...
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Introduction: Fats are widely used in food formulations to improve nutrients and quality of food products. In recent years, consumer awareness of the relationship between diet and health has increased, which results in increasing concerns about fats in products, in terms of high levels of saturated fatty acids. Therefore, various attempts have been conducted to find appropriate method to produce solid fats with unsaturated fatty acid content. The production of low-fat cake is of special nutritional importance due to the effects of fats and the incidence of various diseases such as hypercholesterolemia and cardiovascular. In cake making, oil is very important, first of all, it has an effect on keeping the air in the cake dough. It causes porosity and increases the volume of the cake. The conversion of liquid oils to gel-like structures that have the properties of a solid fat (rheological properties, viscoelasticity, dispersibility, and softness) without using large amounts of saturated fats is an important development in the food industry, and structures produced by oleogelation are called oleogels. Therefore, the main purpose of this study was to produce low-calorie muffins by removing fat and replacing it with an oleogel system prepared from a soluble complex of xanthan gum and egg white by indirect foam molding. Materials and Methods: First, aerogels were produced indirectly using egg white protein complex and xanthan gum, and then oleogel was produced by adsorption of oil. In this method, first, water suspensions containing 0.5 wt% of xanthan and 5 wt% of egg white protein were prepared. In the next step, the oleogel was used to produce muffin with reduced oil in three levels of 10, 30 and 50%. In this study, texture characteristics, color, porosity, water activity, moisture, specific volume of muffin samples were investigated. In the control sample, cake dough contained 100% wheat flour, 50% sugar powder, 30% liquid vegetable oil, 2% baking powder, 0.2% vanilla, 36% eggs and 12% invert syrup. To prepare samples containing oleogels, oil was removed and different concentrations of oil reduction at the level of 50, 30 and 10% in the formulation were added to each treatment. Results and Discussion: Muffin with 10% reduced oil had the highest volume and density and had similar texture characteristics to the control sample. By reducing the amount of fat to 50% of the initial amount in muffin, the volume decreased and the firmness of the texture increased significantly (p <0.05). The reduction of the percentage of porosity confirmed that the texture stiffness in higher values of substitution. The sensory evaluation showed that the 10% reduced oil sample had the highest consumer acceptance. According to the results of this study, it can be suggested that preparing muffins with oleogels can reduce the problems caused by fats, while improved sensory and qualitative properties and be produced as a functional food.
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Food Engineering
Mohsen Zandi; Ali Ganjloo; Mandana Bimakr; Abolfazl Gharebaghi
Abstract
Introduction: Grape is a non-climacteric fruit with a low rate of physiological activity but is subject to serious physiological and parasitic disorders after harvest and during long term storage (Ciccarese et al., 2013). Currently, Edible coatings have been studied as potential substitutes for conventional ...
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Introduction: Grape is a non-climacteric fruit with a low rate of physiological activity but is subject to serious physiological and parasitic disorders after harvest and during long term storage (Ciccarese et al., 2013). Currently, Edible coatings have been studied as potential substitutes for conventional plastics in food packaging. Edible coating is a thin layer of edible material formed as a coating on a food product. Edible coating can offer several advantages to the fresh fruit and vegetable industry such as improvement in the retention of color, acids, sugar and flavor components, the maintenance of quality during shipping and storage, the reduction of storage disorders and improved consumer appeal (Antoniou et al., 2015; Cazon et al., 2017; Fakhouri et al., 2015; Galus & Kadzińska, 2015). Farsi gum as a novel source of polysaccharides has drawn much attention in a wide range of various fields such as pharmaceutics, food and cosmetics industries. Functional properties of Farsi gum are influenced by its structure and molecular weight (Hadian et al., 2016; Joukar et al., 2017). By inclusion of bioactive compounds in the Farsi gum network the aforementioned impairments could be overcome and moreover, new protective and functional valences could be added. The inclusion of lipid-based component in Farsi gum gives it excellent light and moisture barrier properties. The benefic impact on human health of hemp seed oil is worldwide recognized. A recent study demonstrated the antimicrobial properties of hemp seed oil. Due to their abundance in biologically active compounds, hemp seed oil is promising natural alternatives that may extend the shelf-life, microbiological safety and nutritional values of food (Cozmuta et al., 2015; Leizer et al., 2000; Salarnia et al., 2018). Growing awareness of the quality of fruit has necessitated increasing effort to develop rapid and non-destructive methods for evaluating fruit quality (Bhargava & Bansal, 2020; Rachmawati et al., 2017; Tao & Zhou, 2017; Wu & Sun, 2013). The aim of this study was the consideration of image processing application for grape sorting based on visual surface characterize. Materials and Methods: Coating emulsion was prepared using (Farsi gum (0%, 1.5% and 3%), hemp seed oil (0%, 0.075% and 0.15%) and glyceride (0.3%)). grape fruit were coated by immersion in coating dispersion for 5 min. Samples were then allowed to loss the excess coating dispersion. Coatings were developed at room temperature during an hour. Samples were refrigerated at 4± 1°C for 28 days and analyses were performed at days 0 and 28. Defect identification and maturity detection of grape fruits are challenging task for the computer vision to achieve near human levels of recognition. The image acquisition was performed in a homogenously controlled lighting condition. Considering the camera lens’s focal length, the samples were placed 25 cm under the camera’s lens to be under camera’s field of view. The images of grape were segmented from the background using thresholding of the high contrast images via MATLAB software (R2019a, image processing toolbox). The optimum threshold value was obtained to be 0.35, 0.45 and 0.30 for R, G and B channel, respectively. Results and Discussion: The proposed techniques can separate between the defected and the healthy grape fruits, and then detect and classify the actual defected area. Classification is performed in two manners which in the first one, an input grape is classified with two different algorithms (RGB and binary). The Result showed that the accuracies for detecting the surface defects on grape were 97.73% and 96.30% using RGB and binary algorithms, respectively. Proposed method can be used to detect the visible defects of coated grape, and to grade the grape in high speed and precision. Conclusions: The results of this research and similar ones can provide helpful recommendations in grading fruits for fresh consumption. The simplicity and the efficiency of the proposed techniques make them appropriate for designing a low-cost hardware kit that can be used for real applications.
Full Research Paper
Food Engineering
Morteza Kashaninejad; Seyed Mohammad Ali Razavi; Mohammad Reza Salahi
Abstract
Introduction: One of the products that its production has not been investigated well and is an imported product is cream powder. Foam mat drying is a widespread technique to dehydrate liquid or semi-liquid foods with high viscosity, adhesion and high sugar content, which are usually difficult to dry. ...
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Introduction: One of the products that its production has not been investigated well and is an imported product is cream powder. Foam mat drying is a widespread technique to dehydrate liquid or semi-liquid foods with high viscosity, adhesion and high sugar content, which are usually difficult to dry. Evaluating moisture content over time is the first indication of how the drying process is performed and can be used as a tool to compare the drying behavior of food. The rate of drying, which is expressed as a function of time or moisture content, is also a very important parameter that helps to understand drying properties of a material. Color can also indicate chemical changes in food during the thermal process such as browning and caramelization. Therefore, since in the drying industry, process time, product quality, optimization and equipment design are directly affected by the rate of drying of food, hence, in this study, in the process of drying the camel milk cream by the foam mat drying method, drying operation at temperatures of 45, 60 ,and 75 °C and thicknesses of 1, 3 and 5 mm was performed in a non-continuous cabinet dryer to evaluate the kinetics of drying , structure and color of the dried foam. Materials and Methods: Camel milk cream was mixed with carboxymethyl cellulose (0.1%), cress seed gum (0.1%) and 80% whey protein concentrate (5%) at 25 ° C. After pasteurization, the samples were stirred with a mixer at a maximum speed of 1500 rpm (5 minutes) for proper aeration. The foam samples were poured into a plate in a thin layer with thicknesses of 1, 3 and 5 mm and then dried in a dryer at temperatures of 45, 60 and 75 ° C until a constant moisture was reached. The process treatments were performed in a completely randomized central composite design (CCD) (5 replications at the center point) for 2 variables at three levels. The effective diffusion coefficient was calculated based on the second Fick's law of diffusion. Then, using Arrhenius equation, which shows the relationship between temperature and effective diffusion coefficient, activation energy was also calculated. After the drying stage, in order to investigate the changes in moisture during the drying, by determining MR, we have used some experimental models that were previously used for drying agricultural products, to fit the experimental data using the statistical software MATLAB 2016. Results and Discussion: The results showed that increasing the temperature from 45 to 75° C reduced the drying time of the samples by almost 50%. Reducing the thickness from 3 to 1 mm led to an 80% reduction in drying time of the samples. The overall effective diffusion coefficient of the tested samples varied between 7.09×10-10 and 8.11× 10-9 m2/s. The increase in the temperature led to an increase in the effective diffusion coefficient of the samples. The activation energy of the samples varied between 25.59 and 38.22 kJ /mol, and comparison of the means showed that the activation energy of the samples was also increased by increasing the foam thickness. Totally, 17 models were evaluated to investigate the drying kinetics of the samlses and in all cases of foam drying , page and Midilli models with R2 values above than 0.99 and the lowest values of RMSE indicate the best fit with the experimental data among the 17 fitted model. Examining the digital images of the samples also showed that at low temperatures, the structure of the dried foams was smooth and it became more uneven and porous as a result of increasing the temperature. Also, the trend of changes in the parameters of the gray level co-occurrence matrix (GLCM) (energy, correlation, and homogeneity) of the samples was almost the same with the changes in temperature and thickness so that, the increase in the drying temperature and a decrease in the thickness of the samples led to a decrease in these parameters. Increasing the foam thickness at high temperatures led to a decrease in the browning index and at low temperatures, led to an increase in the browning index of the samples.
Full Research Paper
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 ...
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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.
Full Research Paper
Food Chemistry
Farideh Mojrian; Marzieh Moeenfard; Reza Farhoosh; Hadi Mahdavian Mehr
Abstract
Introduction: Date seeds (also known as pits and kernel) are among the most important wastes which are generated during direct consumption or from the date processing industries. Despite the presence of several nutrients and bioactive compounds and their subsequent beneficial health effects, these by-products ...
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Introduction: Date seeds (also known as pits and kernel) are among the most important wastes which are generated during direct consumption or from the date processing industries. Despite the presence of several nutrients and bioactive compounds and their subsequent beneficial health effects, these by-products are frequently discarded to use as soil fertilizer or as feed for livestock. Roasting opens a cost-effective way to include date seed in the human diet. The aqueous extract of roasted date seed represented a coffee-like beverage. Date seed coffee has a relatively low acceptance among consumers and is usually supplemented with a variety of additives to improve the taste. Therefore, due to rising the global coffee price, in the present studywe aimed to substitute Arabica beans with roasted date seeds in order to make a coffee beverage similar to Coffea Arabica boiled coffee brew. Results and Discussion: Substitution with roasted date seed resulted in lower lipids, protein and caffeine of coffee brews as the values were decreased from 330.67, 956.75, 76.51 mg/100 mL in Coffea Arabica (100%) to 192.61, 149.00, 45.59 mg/100 in date seed coffee (100%), respectively. Higher amounts of date seed also resulted in lower pH and acrylamide content. Accordingly, pH was decreased from 5.7 in D100 to 4.4 in A100. Acrylamide content was attenuated from 5.06 µg/100 mL in A100 to 1.71 µg/100 mL in D100. Reduction in viscosity was also observed from 0.93 (A100) to 0.86 mPa.s (D100). The mean value of the color parameter including L*, a* and b* in the 100% Coffea Arabica brew was more than the 100% date seed coffee, which indicated that the coffees brewed from date seeds in different proportions were brighter and had higher red and yellow color parameters. Substitution with date seed had less effect on the total phenol content as TPC of coffees ranged from 28 to 42 mg/100 mL for 100% date seeds brew and Coffea Arabica brew, respectively. On the other hand, the flavonoid content (TFC) of coffees was significantly affected by the amount of date seeds (5 to75 mg/100 mL for 100% date seeds and Coffea Arabica brew, respectively). All brews have high antioxidant activity. For DPPH the highest results (88/9 %) were obtained in the coffee brewed from 100% date seeds, while the FRAP value it was vice versa. The results of sensory evaluation indicated a high similarity among A100 and D10 coffees as parameters such as aroma, color and texture (concentration) of coffee were evaluated appropriate. The results also showed that substituting Coffea Arabica up to 35% with roasted date seeds can improve the overall acceptance of the coffee brews by reducing bitterness.Conclusion: In general, the ability to replace Coffea Arabica with date seeds up to 10 and 35% was reported acceptable in terms of sensory characteristics, as the color and aroma were similar to 100% Coffea Arabica. Besides that due to reduced bitterness, the overall acceptance were almost high.
Full Research Paper
Food Technology
Rahmatollah Pourata; Hamid Jahangir-Esfahani; Iman Shahabi-Ghahfarrokhi
Abstract
Introduction: Among the bio-based materials which used in the food packaging, starch is interested as an ecofriendly material. This interest is mainly due to its acceptable film forming properties, easy access, renewability and low cost. Nevertheless, high hydrophilic and weak mechanical properties have ...
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Introduction: Among the bio-based materials which used in the food packaging, starch is interested as an ecofriendly material. This interest is mainly due to its acceptable film forming properties, easy access, renewability and low cost. Nevertheless, high hydrophilic and weak mechanical properties have been limited its utilization as a commercial packaging material. Many researches have been done to reduce hydrophilic properties of starch using chemical modification, irradiation, and composition with nanoparticles and other biopolymers. Most of the methods are based on blocking the hydroxyl groups of starch chains with hydrophobic agents, formation of emulsions and blocking of the pores. Fatty acids, such as oleic acid (OA) are lipid derivatives that can potentially improve the moisture barrier properties of hydrophilic films. OA is a yellow liquid at room temperature and miscible with biopolymer without further heating treatment. Due to the polar nature of biopolymers, OA needs to surfactant to get homogenous distribution in the matrix of biopolymers. On the other hand, OA is not very sensitive to oxidation which increases its safety in food packaging applications. Titanium dioxide (TiO2) is an inert, cheap and nontoxic material with broad application as a food pigment and potential activity against a wide variety of microorganism due to its photocatalytic activity.TiO2 is the most commonly used semiconductor, photocatalyst which activated by UV ray. The main purpose of the current study was modification of starch hydrophilicity using OA, nano-titanium dioxide and UV ray. In this study OA and TiO2 added at the optimized condition and the solution was irradiated by UV ray. Materials and Methods: A starch solution 5 (wt. %) in distilled water was prepared. This solution was mixed and heated (85 ˚C for 15 min) until the starch gelatinized. Thus, plasticizer (glycerol, 40 wt. % of dry base) was incorporated into the solution to achieve more-flexible films. OA 1(wt. % of dry base) mixed with Tween 80 as emulsifier (10 wt. % of the OA). This solution was mixed and heated (50 ˚C for 10 min). Then, 10 ml of distilled water was added to the solution, and homogenized by ultrasonic homogenizer (Dr. Hielscher, Teltow, Germany) for 7 min. The suspension of TiO2 nanoparticles in water was prepared so that the final TiO2 content in film specimens was 2 (wt % of dry base). The suspensions were stirred for 10 min, and homogenized by ultrasonic homogenizer for 60 min. The TiO2 suspension was added to starch solution gradually and mixed for 10 min. Afterward, OA- Tween 80 solution was added to starch solution gradually and mixed for 10 min.The starch solution containing TiO2 and OA was homogenized by ultrasonic homogenizer for 7 min. Film forming solution placed under three UV-C lamps (8w, Phillips, Holland) at a distance of 5 cm. The solutions were stirred simultaneously with UV irradiation. After 0, 30, 60 and 90 min of UV exposure, the air bubbles were removed and the solutions were casted into flat, leveled, non-stick disposable 15 cm-Petri dishes. Each of the dishes were contain 43 g which dried for 48 hours at room temperature. All the film specimens were conditioned at 50-55% relative humidity and room temperature for 48 hours before subjected to further analysis.Moisture content (MC), moisture absorption (MA), solubility in water (SW), water vapor permeability (WVP), surface properties, visual properties and mechanical properties of the film specimens were measured. The chemical structure of the films was investigated by FTIR spectroscopy.Results and Discussion: The results shown that water contact angle of the starch film was increased by adding OA and TiO2. But it was decreased after UV exposure of the starch-OA-TiO2 solution. WVP of the starch based films was decreased by its composition with OA and TiO2. But no change was observed after UV exposure of the starch-OA-TiO2 compositions. MC of the starch-OA-TiO2 film had no change, simultaneously. However, the tensile strength and Young’s modulus were decreased by adding OA-TiO2. Elongation at break and tensile energy to break were increased, simultaneously. However, the mechanical properties of the starch-OA-TiO2 nanocomposites were changed by UV exposure but these changes did not follow a specific trend.Although, whiteness index (WI) and total color difference (ΔE) were not changed by OA-TiO2 composition. But yellowness index (YI) was changed, simultaneously. After UV irradiation ΔE and YI were increased and WI was decreased. The results, demonstrated that the virgin starch-OA-TiO2 composition was the best modification method to decrease the sensibility of starch based films to moisture as a packaging material. UV irradiation at short time (30 min) was the optimum condition to modify sensibility of the films to moisture and mechanical properties among the UV cured films.
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Food Engineering
Ali Saeidan; Mehdi Khojastehpour; Mahmood Reza Golzarian; Marzieh Moeenfard
Abstract
Introduction: Due to the fact that the presence of high doses of aflatoxin in agricultural products such as cocoa beans is unacceptable in terms of national and international standards, appropriate quality control tests should prevent such products to entering in the process of processing cocoa beans. ...
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Introduction: Due to the fact that the presence of high doses of aflatoxin in agricultural products such as cocoa beans is unacceptable in terms of national and international standards, appropriate quality control tests should prevent such products to entering in the process of processing cocoa beans. Conventional methods of detecting aflatoxins such as ELISA and HPLC are very time consuming, expensive and require expertise, so replacing these tests with non-destructive and rapid methods such as near-infrared spectroscopy can increase the detection efficiency. Brado et al. (Berardo et al., 2005) used infrared spectroscopy to evaluate and diagnose Fusarium verticillium, which produces fumonicin toxin in maize. Manvar et al. (Mohammadi Manvar, 2015) used transmission and reflection Infrared spectroscopy to detect aflatoxin levels in Iranian pistachios. Singh et al. (2012) used hyperspectral imaging in the range of 700-1100 nm to detect fungal contamination of Penicillium SPP, Aspergillus Glaucus, and Aspergillus Niger in wheat. Kandpal et al. (Kandpal et al., 2015) in a research work using hyperspectral imaging in the range of 700-1100nm classified grains of maize contaminated with aflatoxin toxin using PLS-DA into five groups. In current study, an attempt was made to detect the amount of aflatoxin in cocoa beans using infrared spectroscopy and to classify healthy and infected beans into groups. Materials and Methods: In this research, 180 cocoa beans, each weighing 1 gram, were selected to do analyses. One mg of aflatoxin B1 powder (A. flavus, A 6636, Sigma-Aldrich, St. Louis, Mo USA) was prepared from Sigma Aldrich representative in Iran and by dissolving this powder in absolute ethanol and concentrations of 20µg/kg, 500µg/kg was obtained as mentioned. For cocoa bean spectroscopy, a near infrared spectrometer in Shiraz University Central Laboratory (NIRS XDS Rapid Content Analysis) was used, which has the ability to spectroscopy in the range of 400-2500 nm. PLS-DA method was used to classify aflatoxin-infected samples from healthy samples. All 180 experimental samples were divided into two groups of training (120 samples) and test (60 samples) and the constructed model was first calibrated with training values and then evaluated with test data. Due to the fact that some noise is always stored in the spectral data and in order to remove this noise, a series of mathematical pretreatment, including: first and second derivatives was used (Chen et al., 2013; Nicolai et al., 2007). Results and Discussion: Comparing the average amount of infrared reflection spectrum, it is revealed that healthy grains have less reflection intensity than infected grains. Also, there are a number of local maximums and minimums where the difference in reflective intensity is more pronounced than elsewhere, and this phenomenon is due to the different concentrations of toxins in cocoa beans. After applying the second Savitzie Golay derivative pretreatment and performing PLS-DA classification using two latent variables, the distinction between classes can be clearly seen. The separation rate of the samples on the second LV is more specific, however, the second and first class samples in this LV have a closer score to each other. The peaks observed at 1440 nm and 1482 nm according to the first Everton O-H bond can be related to fungal contamination (Berardo et al., 2005; Sirisomboon et al., 2013). Also, the peak at 1838 nm is related to the tensile C-H bond, which can be related to the CH2 groups. According to the results obtained from the calibration, cross-validation and testing sections, it is determined that the degree of calibration error (ER) and the degree of error-free calibration (NER) in the pretreatment mode with the second-order derivative of Savitz Golay are the lowest and highest values, respectively. Also, in this pretreatment for the calibration model and testing, the specificity index for the first-, second- and third-class samples are equal to 1.00, which means that all classes are correctly classified. In the cross-validation model, the value of the specificity index for the third class (samples with 500 ppb contamination) is equal to 97%. This indicates that 97% of infected seeds are correctly classified in the third group and only 3% in the other groups are incorrectly classified. Conclusion: The present study demonstrates the feasibility of near-infrared spectroscopy to identify and classify cocoa beans contaminated with aflatoxin. The results showed that the coefficients of independent variables (spectral wavelengths including 1440, 1482 and 1838 nm) decreased according to increasing in the concentration of toxin. Finally, it can be said that the method of detecting aflatoxin contamination using infrared spectroscopy is an efficient, non-destructive and fast method.
Full Research Paper
Food Technology
Soheyl Reyhani Poul; Sakineh Yeganeh
Abstract
Introduction: Shrimps are highly sensitive to oxidation at refrigerator temperature. On the other hand, storage of shrimp in freezing conditions leads to a decrease in product quality after thawing. It should be noted that shrimp oxidation also occurs in freezing conditions, but the oxidation rate in ...
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Introduction: Shrimps are highly sensitive to oxidation at refrigerator temperature. On the other hand, storage of shrimp in freezing conditions leads to a decrease in product quality after thawing. It should be noted that shrimp oxidation also occurs in freezing conditions, but the oxidation rate in these conditions is much slower than storage in refrigerated conditions. Therefore, it seems necessary to use a method that can control the oxidation of shrimp in both freezing and refrigerating conditions. The aim of this study was to evaluate the feasibility of controlling shrimp oxidation (at refrigerator temperature) using whey protein coating containing ascorbic acid or α-tocopherol, and to compare the efficacy of these antioxidants (in combination with whey protein). Materials and Methods: In order to advance the purpose of the research, shrimp fillets were stored in four treatments, including treatments No. 1 (control), 2 (shrimp fillet coated by whey protein), 3 (shrimp fillet coated by whey protein + ascorbic acid) and 4 (shrimp fillet coated by whey protein+ α-tocopherol) at refrigerator temperature for 9 days. In order to evaluate the oxidation intensity and also the stability of the treatments against oxidative damage, peroxide indices, free fatty acids, anisidine and thiobarbituric acid of the treatments were determined on days 0, 3, 6 and 9. This study was implemented in form of completely randomized design and data were analyzed by one-way ANOVA. Significant differences among means were tested by Duncan's test at 95 confidence level. Results and Discussion: The results showed that whey protein alone (treatment 2) as shrimp coating can partially control the oxidation process of fillet fats compared to control. But when whey protein was combined with ascorbic acid (treatment 3) and α-tocopherol (treatment 4), the coatings' strength against oxidative deterioration significantly increased (p<0.05). According to our findings, during the storage period, the lowest amount of peroxide, free fatty acids, anisidine and thiobarbituric acid indices were related to treatment 3 (p<0.05). During the storage period, all the mentioned indicators (in all treatments) had an increasing trend, but the slope of this trend was different and the lowest slope was related to treatment 3. Comparison of fresh shrimp fillet fatty acid profile with fatty acid profile of treatments at day 9 showed that the whey protein coating combined with ascorbic acid (treatment 3) had the most protective effect on the structure of fatty acids. Overall, according to the results of the present study, it can be claimed that whey protein- ascorbic acid coating is more effective than whey protein-α-tocopherol coating to increase the oxidative stability of shrimp fillet. Therefore, the ascorbic acid is more efficacious than α -tocopherol (in combination with whey protein) in controlling the oxidation of shrimp fillets.
Full Research Paper
Food Biotechnology
Zohreh Sosani Gharibvand; Behrooz Alizadeh Behbahani; Mohammad Noshad; Hossein Jooyandeh
Abstract
Introduction: Nowadays, production and utilization of Nano materials have increased due to their unique and interesting properties. So far, different physical and chemical methods have been used to synthesize silver nanoparticles. Chemical synthesis is not compatible due to the hazardous chemicals residues ...
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Introduction: Nowadays, production and utilization of Nano materials have increased due to their unique and interesting properties. So far, different physical and chemical methods have been used to synthesize silver nanoparticles. Chemical synthesis is not compatible due to the hazardous chemicals residues on the surface of the nanoparticles (NP) as well as production of by products with high impact on the environment. Physical routes for synthesis of NPs have some drawbacks, too. These methods require high energy and space, and are expensive. Therefore, biological methods for the synthesis of silver nanoparticles are considered emerging technologies as economic choices in the green chemistry field. Among these methods, plant-mediated synthesis of AgNPs is a rapid, simple, non-toxic and eco-friendly technique. Silver nanoparticles exhibit high bactericidal activity at their utilized concentrations with no toxic effect on human cells, and they also strongly enhance the antibacterial activity of conventional antibiotics even against multi-resistant bacteria through their synergistic effects. Callistemon citrinus belongs to the family Myrtaceae and includes more than 30 species. The plant is widespread in wet tropics, notably Australia, South America and tropical Asia, but presently can be found all over the world. Callistemon citrinus is a potential medicinal plant used to treat gastrointestinal distress, pain, and infectious diseases caused by bacteria, fungi, viruses, and parasites. In this study Callistemon citrinus aqueous extract was used to reduce silver ions in silver nitrate solution. In the following, the antimicrobial activity of nanoparticles synthesized by various qualitative and quantitative methods on Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella typhi and Listeria innocua was investigated. Materials and Methods: For the synthesis of silver nanoparticles, 25 mL of silver nitrate solution was added to 5 mL of leaf extract with a concentration of 100 mg/mL and maintained for 24 h at 20 °C. Change the color of the solution to Red represents the production of silver nanoparticles in the solution. To stabilize the presence of silver nanoparticles, the absorption spectrum of silver nanoparticles produced by spectrophotometer was prepared. Antimicrobial activity of silver nanoparticles synthesized using Callistemon citrinus leaf aqueous extract was examined by disc diffusion agar, well diffusion agar, minimum inhibitory concentration (microdilution broth) and minimum bactericidal concentration on Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella typhi and Listeria innocua. Results and Discussion: The results showed that in disc diffusion agar method, the diameter inhibition zone increased with increasing the concentration of silver nanoparticles. The maximum effect of silver nanoparticles synthesized using Callistemon citrinus leaf aqueous extract at a concentration of 150 mg / ml was observed for Pseudomonas aeruginosa. An inhibition zone was observed for all examined pathogenic microorganisms at all concentrations. The results showed that in the well diffusion agar method, nanosilver particles at a concentration of 18.75 mg/ml did not show any inhibitory effect on all the pathogenic microorganisms. The results of statistical analysis showed that there was no significant difference between all the concentrations of silver nanoparticles synthesized for Escherichia coli, Salmonella typhi and Staphylococcus aureus (P˂ 0.05(. The MIC for Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella typhimurium and Listeria innocua was 128, 256, 256, 256 and 512 mg/mm, respectively. The MBC for all the pathogenic strains was 512 mg/mm. The results of this study showed that the Callistemon citrinus leaf extract has a good ability to synthesize silver nanoparticles. Nanoparticles synthesized from Callistemon citrinus leaf extract had good antimicrobial activity against examined pathogenic bacteria, especially Gram-negative bacteria. Green-synthesized nanoparticles can be used as antimicrobial agent to fight infectious diseases caused by various microbial strains, although more research is needed in vitro, animal models and in vivo.
Short Article
Food Technology
Narjes Babaei; Mohammad Goli
Abstract
Introduction: Diabetes recognized as one of the most important health problems and the most common metabolic disease in the world. The prevalence of diabetes is increasing worldwide, including in Iran (Forouhi & Wareham, 2010). Celiac is a disease in which the mucous membrane of the small intestine ...
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Introduction: Diabetes recognized as one of the most important health problems and the most common metabolic disease in the world. The prevalence of diabetes is increasing worldwide, including in Iran (Forouhi & Wareham, 2010). Celiac is a disease in which the mucous membrane of the small intestine of a person with wheat gluten intolerance damaged by gluten and causes intestinal inflammation (Hopper et al., 2007). Stevia rebaudiana bertoni belongs to the Astrasse family, a perennial natural, calorie-free sweetener that has a sweetening power of 100 to 400 times greater than sucrose (Agarwal et al., 2009). Isomalt, a polyol, used as sugars substitute (sucrose, high fructose corn syrup, glucose syrup, etc.) (Schiweck and Munir, 1992). This study aimed at producing dietary Sohan-Pilaki for diabetic and celiac patients using replacement of sucrose with Stevia-Isomalt and the complete replacement of wheat flour with rice-corn flour. Rice and corn flour used to improve the textural and nutritional properties. Material and Methods: For production of dietary Sohan-Polaki, the raw materials (white sugar 40.03%, sorbitol liquid 16.01%, vegetable oil 32.03%) transferred to the kettle for melting over a gentle flame followed by adding the rest materials such as rice and corn flour (8.1%), egg yolk (3.2%) and cardamom (0.72%). The final dough then poured into the tray container after splicing and finishing the production operation and after being chilled and formed to the required dimensions by the forming machine. For the preparation of dietary Sohan-Polaki, independent variables were included, replacement of Stevia-Isomalt with surface (0 to 100%), rice to corn flour ratio (0 to 100%) and cooking temperature (160 to 180°C). All other compounds considered constant. Isomalt is a substitute for sugar as a filler. To obtain optimal points, 34 experiments proposed by Design Expert software, central composite design response surface methodology, double in the other points, six central points with alpha 2. Test responses included density (replacement of rapeseed, Naghipour et al., 2013), textural properties, i.e., hardness (TPA, Khazaiy Pool et al., 2015), color changes assessment (Lab, Image J, Aslanzadeh et al., 2014). Results and Discussion: Isomalt causes increasing the rigidity and led to a decrease in porosity and ultimately a decrease in density (Bagherpoor and Khosroshahi Asl, 2016). The quality of the sweets eaten directly related to their texture characteristics. Among the various textural parameters, hardness considered to be an important characteristic, which refers to the maximum force curve height at the first pressure and represents the maximum force applied during the biting operation (Cheng and Bhat, 2016). The amount of moisture, dry matter, amount and type of protein and fat also have some effect on hardness. In addition, at high levels of replacement wheat with corn flour, hardness increased with increasing Stevia-Isomalt content. Increasing the sucrose concentration due to its effect on the corn starch chains of the amorphous region, causes granulation of the starch and stabilization of the gel, leading to harder gel formation (Sun et al., 2014).Discoloration caused by caramelization and non-enzymatic browning reactions due to rising temperatures. As the temperature increases, the oxidation of the fats becomes more intense, which in turn has a significant effect on the color of the dyes studied (Ghandehari Yazdi et al., 2018). Since non-sucrose sweeteners play an important role in lightness changes, they are also associated with caramelization and the Millard reaction (non-enzymatic browning) between reducing sugars and amino acids. Sucrose (non-reducing sugar) at high temperatures converted to glucose and fructose (reducing sugars). Thus, if the amount of sucrose reduced, the color intensification is weaker due to the lower formation of the products from the reaction of Millard (Gonzalez-Mateo et al., 2009).Overall, according to the type of flour consumed in the Sohan-Polaki formulation, the two final optimal formulas, i.e., optimal formula 1, including sucrose replacement with Stevia-Isomalt 24%, the ratio of rice to corn flour 0.99 and cooking temperature of 166°C ( With a density of 1.37 g/cm3, the hardness of 1.85 N and color changes compared to the control 3.66) and optimal formula 2, including sucrose replacement with Stevia-Isomalt 24%, the ratio of rice to corn flour 0.02, and cooking temperature of 180°C (with a density of 1.23 g / cm3, the hardness of 2.07 N and color changes compared to the control of 10.16) were introduced as the best treatments.
