Food Biotechnology
Shohreh Nikkhah; Fakhri Shahidi; Mohebbat Mohebbi; Farideh Tabatabaei Yazdi
Abstract
IntroductionCucumber is an economically important crop, containing vitamins, minerals, antioxidants, and flavonoids. However, due to loss of weight and firmness, microbial contamination, mechanical damage, and yellowing, the storage duration of cucumber is limited to 3–5 days at room temperature. ...
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IntroductionCucumber is an economically important crop, containing vitamins, minerals, antioxidants, and flavonoids. However, due to loss of weight and firmness, microbial contamination, mechanical damage, and yellowing, the storage duration of cucumber is limited to 3–5 days at room temperature. Therefore, pretreatments are crucial for prolonging its shelf life. Chitosan is a cationic polysaccharide and can interact electrostatically with anionic, partially demethylated pectin. Besides, chitosan has inhibitory effects on fungal rot and prevents weight loss in fruits. Pectin can form excellent films. Because of increasing demand to reduce synthetic chemicals as antimicrobial agents, substances derived from plants, such as essential oils, can play a significant role in the future. Several essential oils and essential oil components have shown antimicrobial activity against spoilage and pathogenic microorganisms during fruit and vegetable storage. Essential oils of thyme and cinnamon contained phenolic groups have been found to be most consistently effective against microorganisms, however, essential oils are volatile and irritant. Therefore, forming an inclusion complex using b-cyclodextrin can improve solubility, control volatile, and induce off-flavors and unpleasant odor of the essential oils. The objectives of this study were to develop the microencapsulated thymol (thyme) and trans-cinnamaldehyde (cinnamon) essential oils to produce antimicrobial agents and subsequently evaluate the effectiveness of edible coating made of chitosan and pectin containing microencapsulated trans-cinnamaldehyde or thymol essential oils to improve qualitative and quantitative characteristics and shelf life of cucumber.Materials and MethodsThe inclusion complexes of trans-cinnamaldehyde and thymol in beta-cyclodextrin (CD) were prepared separately by freeze-drying. Each essential oil was dispersed in 1000 ml of beta-cyclodextrin aqueous solution (16 mmol/L, 18.15 g) in molecular ratio 1:1 (2.4 gr thymol, 2.11 gr trans-cinnamaldehyde) and mixed in a laboratory stirrer for 24 hour at room temperature , then frozen (-70 ºc) and freeze-dried (<20Pa, 48 h). Lyophilized samples were stored inside a freezer (-20 ºc) until further use. Cucumbers cv. Nagene with uniform size, appearance, ripeness and without mechanical damage or fungal contamination were selected. Then They were then sanitized by immersion in chlorine solution (150 mg/kg) for 1 min and air dried. Edible coatings were prepared as three immersion solutions of chitosan, pectin, and calcium chloride (CaCl2). The fruits were coated with pectin (1%) and chitosan (0-0.5%-1%) containing beta-cyclodextrin microencapsulated trans-Cinnamaldehyde or thymol each (0-0.25%-0.5%). After coating by chitosan, the fruits were immersed in 1% Calcium chloride solution to induce crosslinking reaction. After dipping step, fruits dried for 8 minutes at room temperature to remove the excess solution attached to the surface .Uncoated fruits served as control. Then fruits were preserved in cold storage (temperature: 10ºc; relative humidity: 90-95%) for 15 days. chemical (total soluble solids, titratable acidity) and physical (total color difference, Hardness, and weight loss) Characterization of fruits were measured immediately after harvest and after 5, 10 and15 days. Microbial tests (total count, mold, and yeast) were done at the end of preservation time. Analytical data were subjected to analysis of variance and factorial adopted completely randomized design and a Duncan comparison test was used. Results and DiscussionThe results showed that weight loss, total soluble solids, and the total color difference increased and hardness and titratable acidity decreased gradually in all samples during cold storage (<0.05). Chitosan and essential oils slowed down this rising or decreasing trends. Interactive effects of chitosan, essential oil type, essential oil concentration, and storage time had positive effects on these quality attributes. The fruits coated with the highest concentration of chitosan (1%) and thymol (0.5%) essential oils showed the least weight loss, loss of hardness, and color change throughout 15 days of storage. Besides thymol in comparison with trans-Cinnamaldehyde was more efficient to prevent yeasts and molds on the surface of cucumber. By increasing chitosan and essential oil amounts, the ability of inhibiting microbial growth by coating is enhanced. ConclusionThe results of chemical, physical and microbial tests, showed that multi-layer coating solution containing chitosan 1% with thymol 0.5% was effective in extending the shelf life of cucumber. The combined usage of microencapsulated thymol essential oil and chitosan-based coating on cucumber could be considered a healthy and effective treatment that reduces microbial spoilage and preserves quality and color characteristics in cucumber and represents an innovative method for commercial application. Therefore, this coating can be used as an alternative to chemical fungicides to prevent fungal rot of cucumber and other fruits, however, it is suggested that more studies should be done in this field.
Seyed Hamidreza Ziaolhagh
Abstract
In this study, some preservative solutions were used as an alternative to sulphur fumigation. For this purpose, sodium metabisulfite, calcium chloride, sodium acetate, and sodium carbonate solutions at concentrations of 0.5, 1 and 2 percent were applied. Grapes (Sorkh-e-Fakhri var.) were dipped in different ...
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In this study, some preservative solutions were used as an alternative to sulphur fumigation. For this purpose, sodium metabisulfite, calcium chloride, sodium acetate, and sodium carbonate solutions at concentrations of 0.5, 1 and 2 percent were applied. Grapes (Sorkh-e-Fakhri var.) were dipped in different concentrations of each solution for 2 minutes. After dipping, the surface water of grapes was dried by natural air blowing and then, put in conventional baskets and stored at 0.5-1°C at 85-95% RH for 6 months. The percentage of moldiness, soluble solids, reducing sugar, acidity, and pH of the samples were determined after 2, 4, and 6 months of storage. The results of this study showed that the effect of type of preservative used and the storage time, on the percentage of moldiness and pH and acidity of all samples were significant at 1% level. Sodium metabisulfite had the highest inhibitory effect on mold growth. Calcium chloride had the greatest effect on moisture retention. In addition, the highest pH was observed in samples immersed in sodium carbonate solution. In the case of interactions, the effect of type of preservative and storage time on moldiness, moisture content, brix, sugar content, and acidity, and also the type of preservative and its concentration on moldiness and acidity of samples were significant. According to the obtained results, it was shown that the grapes could be stored for 6 months by dipping them in 0.5% sodium metabisulfite for 2 minutes before cold storage.
Kowsar Kakaei; Mohammad Noshad; Behzad Nasehi; Mohammad Hojjati; Shahram Beiraghi-Toosi
Abstract
Introduction: In the past years, snack consuming in all age groups, special children have increased due to their low cost and eating readiness. Generally, these products have high starch content, but low nutrients such as vitamins, minerals, amino acids and fiber. In fact, most of the snacks are known ...
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Introduction: In the past years, snack consuming in all age groups, special children have increased due to their low cost and eating readiness. Generally, these products have high starch content, but low nutrients such as vitamins, minerals, amino acids and fiber. In fact, most of the snacks are known as foods with high energy content and glycemic index, but low nutritional value. Adding fruits processing by-products to extruded snacks improves the nutritional value of snacks due to their high content of dietary fiber, bioactive compounds and minerals. Pomegranate (Punica granatum L.) is a perennial plant and is generally cultivated in tropical and subtropical regions the pomegranate seed is one of the pomegranate processing by-products including approximately 15-20% of total fruit. Pomegranate seed contains 36.5-42.4% fiber, 13.5-16.9% lipid, 8.5-11.3% protein and 24.09-33.41% carbohydrates. Therefore, pomegranate by-products rich in bioactive compounds and dietary fiber can be used as a functional ingredient. Since no research have been performed on using the pomegranate seed powder in making snacks yet, this research aimed to investigate the effect of pomegranate powders as a fiber supplement on the extruded physicochemical properties.
Material and Methods: The fruit of pomegranate were purchased from Khuzestan province in Iran. After peeling of pomegranate fruits, arils were pressed. The remaining pomaces were dried at 50 C for 48h. Dried pomace was powdered using a mixer grinder. The corn grits (Golden Corn Company, Iran) were prepared. The moisture and chemical component of raw materials were analyzed. The two screw extruders (model DS56, Jinan Saxin Company) was used to formulate and prepare snacks. First, response surface methodology (RSM) was used to optimize the amount of pomegranate powder to be added to the snacks. For this purpose, the influence of adding the pomegranate seed powder (0-20 %), extruder temperature (120-160 °C) and screw rotation speed (120-180 rpm) on the physicochemical properties of extruded samples were considered. For this reason, the moisture level of the input food was adjusted to 15 % and the feeding speed was 40 (kg/hr). The obtained results from optimization of the snacks formulation and process conditions shows that the optimum amount of factors are fallowing addition of fiber supplementary 11.8 %, the temperature of the extruder 160 °C, the screw speed of 147.1 rpm. After preparing optimal and control samples (without adding pomegranate powder), in order to evaluate the addition of pomegranate powder to the physicochemical properties of snacks, for this purpose, the effect of adding pomegranate powder on fat and protein content, total phenolic compounds, antioxidant activity, density, hardness, water and oil absorbance index, solubility index, soluble and in soluble fiber content, moisture content and microstructure of the produced snacks during 60 days of storage were investigated.
Results and discussion: By adding the pomegranate seed powder, the product moisture content decreased, which is probably due to high insoluble fiber content of pomegranate seed powder like apple residue. Moreover, by adding the pomegranate seed powder, the oil absorption index increased, which is probably due to presence of non-polar amino acids in the pomegranate seed powder. Existence of greater quantities of non-polar amino acids and presence of non-polar side chains in the extruded products may absorb oil hydrocarbon chains, leading to increase oil absorption index. Based on results, adding the pomegranate seed powder increases the hardness of the samples, which is probably due to the high amounts of oil and protein in the pomegranate seed powder. Researchers have reported that the use of food ingredients with high fat, protein, and fiber content increase the product tissue hardness. Also, the addition of pomegranate powder reduced water absorption of samples, which is probably due to the presence of insoluble water compounds such as fat and insoluble fibers in pomegranate powder and the reduction in the starch content of the samples due to the replacement of pomegranate powder. According to the results, addition of pomegranate powder increased the total phenol content and antioxidant properties of samples. While increasing the storage time, the total phenol content in the samples was reduced, which is probably due to the oxidation reactions that occur during storage. The results of this study showed that the addition of pomegranate powder increased the density, a * value, and nutritional value (such as iron, zinc, soluble and insoluble fiber, protein and fat content) in samples. While L* and b* values and water activity of the samples was reduced. Also, the addition of pomegranate powder decreased porosity and created heterogeneous and irregular cavities in the texture of snacks.
Mahshid Shamloofar; Zahra Ghiasvand; Elham Payandan
Abstract
Introduction: Free radicals may cause lots of diseases in humans and oxidative degradation of lipids is a major factor limiting the shelf life of foods. The free radical reaction of lipid peroxidation is generally responsible for the deterioration of lipid-containing foods. Use of antioxidants during ...
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Introduction: Free radicals may cause lots of diseases in humans and oxidative degradation of lipids is a major factor limiting the shelf life of foods. The free radical reaction of lipid peroxidation is generally responsible for the deterioration of lipid-containing foods. Use of antioxidants during the manufacturing process can minimize the extent of lipid peroxidation. Phenolic antioxidant compounds can prevent the destructive effect of free radicals and their resulting mutation. Sunflower oil is widely used in nutrition as a source of essential linoleic (9-cis, 12-cis-octadecadienoic) acid. The present study explored the chemical constitution and antioxidant activity of Fleawort (Plantago ovate) extract and the effect of these natural antioxidants on sunflower oil. It is well known that edible oils used as cooking medium at high temperatures in the presence of oxygen are subject to therm-oxidation, polymerization, and hydrolysis, and the resulting decomposition products not only produce undesirable off-flavors, but can also decrease the nutritional quality of the fried product.
Material and methods: The present study was carried out in refined sunflower oil, free of additives, supplemented by pure concentration levels of normal and encapsulated extract of Fleawort (i.e., 200, 500, 700 and 1000 ppm) and one level of BHT (200) ppm .The doses of Fleawort extract were chosen in agreement with previous studies that have proved that the inhibitory effect on lipid oxidation increased with the antioxidant concentration In this research the phenolic content of the ethanol extract of Fleawort was determined by Folin–Ciocalteu method. The antioxidant activity of this extract was evaluated using DPPH• and ABTS methods. Furthermore, the oven tests including peroxide and thiobarbituric acid values were done at 65º C in sunflower oil.
Results and discussion: The results showed that different concentrations of this extract were effective in retarding the oil oxidation at 65ºC. Among the treatments, the 1000 ppm Concentration of encapsulated extract has higher antioxidant activity than other treatments during storage time. Based on the evaluation results of phenolic compounds in Plantago ovata extract, the amount of phenolic compounds of this extract will be increased according to the concentration of the extract. Although this index was the highest in treatment of EN 1000, there was no significant difference between the ordinary and encapsulated treatments (p>0/05). According to DPPH Evaluation Test for determining the antioxidant capacity of the samples, the highest amount of DPPH was seen in treatment of EN 1000 (p0/05). Also, based on the Restoration Power Test, treatment of EN 1000 had the most meaningful restoration power and in all concentrations of the extract and treatment showed the most meaningful restoration power (p< 0/05) . Treatments with concentration of 1000 ml/l had the maximum total antioxidant capacity and this treatment showed higher total antioxidant capacity compared to BHT treatment and numerically the total antioxidant capacity of all treatments of BHT was allocated to the treatments with concentration of 200 to 500 ml/l of fleawort extract. Peroxide value was used as indicators for the primary oxidation of sunflower oil. Hydroperoxides are the primary products of lipid oxidation. They are odorless and colorless, but are labile species that can undergo both enzymatic and non-enzymatic degradation to produce a complex array of secondary products. Determination of peroxides can be used as oxidation index for the early stages of lipid oxidation During the test time, both normal and encapsulated 1000 treatments had lower peroxide value through incubation time compared to all other treatments and 1000 EN treatment showed the lowest meaningful level of peroxide value (p
Zahra Sheikholeslami; Mahdi Karimi; Toktam Hejrani; Mehdi GhiafeDavoodi; Hamed Fatemian
Abstract
Introductıon: Hydrocolloids have been employed for reduction of moisture migration from the crumb to crust, added to the formulation, improved texture, prevent ice Crystallization and delay staling (Ba´rcenas et al 2003, 2004, Hager, and Arendt, 2013). However, given the importance of their role still ...
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Introductıon: Hydrocolloids have been employed for reduction of moisture migration from the crumb to crust, added to the formulation, improved texture, prevent ice Crystallization and delay staling (Ba´rcenas et al 2003, 2004, Hager, and Arendt, 2013). However, given the importance of their role still trying to find new resources will continue to create the best quality. Today, researchers introduced new technologies such as modified atmosphere packaging, frozen technology and using different additives to produce bread with higher quality, longer shelf life and high nutritional value. Production of the part baked frozen bread is a method which interrupted baking process, the first stage is the crumb formation and the crust color is not developed. The aim of this study was to evaluate the effect of Ocimum Bacilicum and tragacanth at 3 levels (0, 0.3 and 0.5%) (W/W flour basis) on the quality of part-baked Barbari bread after frozen storage and re-baking.
Materials and methods: The Ocimum Bacilicum seeds were cleaned, then were firstly soaked in distilled water to obtain a water to seed ratio of 37:1 at 40˚C and pH 7. Separation of the hydrocolloid from the swollen seeds was achieved by passing the seeds through an extractor equipped with a rotating plate that scraped the gum layer on the seed surface. The extracted solution was then filtered and dried in an air forced oven at 60˚C and finally the powder was milled, sieved using a mesh 18 sifter, packed and kept at cool and dry condition (Karazhiyan et al., 2010, Sahraiyan et al., 2013). Tragacanth purchased from the local market as a tape shape after milling and sieve (70 mesh) were used. Bread prepared as part baked, freezing in -18°C and storage for 15 days, after this time samples were thawing and full baked. The test includes moisture content, specific volume, porosity, firmness, image analysis and sensory properties was measured. For Data Analysis used SPSS software and Duncan test, for mean comparisons.
Results and discusions: The results obtained from volume, texture, moisture content and sensory properties showed Tragacanth gum at 0.5 concentrations and Ocimum Bacilicum gum at 0.5 levels improved moisture content. Using tragacanth at 0.3% and Ocimum Bacilicum gums at 0.5 % concentration improved the specific volume, porosity, firmness, and sensory properties. The hydrocolloids are highly hydrophilic nature, it made hydrogen link between the water available in the system, prevent the movement of water from crumb and improved the firmness and improved the quality of bread (Manadala et al., 2008). The hydrocolloids capable to strengthen the gluten matrix surrounded cell gas as result maintenance them during part baked and frozen storage. Hydrocolloid, coalescence of gas cells as a result of expansion during the proofing step and increase the volume and porosity of bread (Shillini & Laxemi, 2007).
Conclusion: Addition of Ocimum Bacilicum and tragacanth to bread recipe improved the crumb texture of the bread that obtained from part-baking, frozen storage and re-baking. In addition, the presence of gums improved the specific volume, texture and the overall quality of the product during frozen storage, removing the negative effects of that process conditions. The Ocimum Bacilicum in comparison of tragacanth had the greater concentration effect on PBF Barbari bread on improved the quality. The interaction of tragacanth and Ocimum Bacilicum (0.3 and 0.5 %) respectively had the best result to improving the all parameters that investigated in part baked and freezing storage of Barbari bread. This study provides insights into the complexity of interactions between tragacanth and Ocimum Bacilicum as a new source of hydrocolloids and their combined influence on bread characteristics, thereby serving as a guide for future research on the other bread
Nasser Sedaghat; Sara Khoshnoudi
Abstract
Introduction : Pistachio (Pistaciavera L.) is a tasty nut and a good source of nutrients. Ithas a high content of numerous beneficial nutritive and bioactive compounds such as proteins, carbohydrate, moisture, vitamins, minerals, fiber and other micronutrients compounds, but the most exceptional components ...
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Introduction : Pistachio (Pistaciavera L.) is a tasty nut and a good source of nutrients. Ithas a high content of numerous beneficial nutritive and bioactive compounds such as proteins, carbohydrate, moisture, vitamins, minerals, fiber and other micronutrients compounds, but the most exceptional components are the amount of fats and especially unsaturated fatty acids. Therefore, this nut is highly susceptible to rancidity, especially after roasting. Despite the high quality, raw pistachio and pistachio processing industry at Iran, export of roasted and packaged pistachio, due to low shelf life and drastic changes intaste, is not very successfull. An effort was made to investigate the efficacy of gelatin in comparison with carboxymethyl cellulose (CMC) as edible coating to retard fat oxidation in roasted pistachio.Materials and methods:Five coating formulations were investigated in this study as follow: A) Gelatin (4% w/v) + ascorbic acid (1% w/v): TGA, B) CMC (1% w/v)+ ascorbic acid (1% w/v): “TCA”, C) ascorbic acid (1% w/v): “TA”, D) Gelatin (4% w/v) + CMC (1% w/v) + ascorbic acid (1% w/v): “TCGA” and 5) control sample (uncoated sample): “TCO”.Roasted pistachio nuts were coated by dipping the nuts in the coating solutions. For each treatment, 100 gram of pistachio nuts were packaged (BOPP/Al/CPP, 80 micron plastic bags) in triplicate. The physicochemical analysis included measurement of free fatty acid (FFA), peroxide value (meq.O2 kg-1),hardness (N), moisture (%) and the sensory evaluation (texture, rancidity, taste and overall acceptability) were performed on coated and uncoated pistachio nuts stored at 35 and 50 °C. The nuts were sampled on the 0th, 1st, 2nd and 3rd month of storage. Data was analyzed using Minitab 16. Analysis of variance (ANOVA) and general linear models (GLM) procedure wereused to compare the mean values of each treatment and Significant differences between the means of parameters were determined based on the results of the Tukey’s multiple range test (p0.05).FFA content of TCGA sample was significantly lower than other samples.The highest protection, according to these criterions, was provided by gelatin-CMC coating containing ascorbic acid.The control samples exhibited more bitterness and off flavor than the coated samples, seemingly on account of chemical reaction and second products of oxidation content. Instrumental and sensory hardness of pistachio nuts which were coated with gelatin and/ or CMC (TCA, TGA and TCGA) were significantly (p
Nasser Sedaghat; Ghodsieh Moradi; Sara Khoshnoudi; Arash Koocheki
Abstract
Introduction:Pistachio (Pistaciavera L.) is a tasty nuts and a good source of nutrients. During the last decade, the worldwide trades of pistachio have increasing trend, likely reflecting on the increase in consumers demand for this nuts. The high oil and essential fatty acid contents of the pistachio ...
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Introduction:Pistachio (Pistaciavera L.) is a tasty nuts and a good source of nutrients. During the last decade, the worldwide trades of pistachio have increasing trend, likely reflecting on the increase in consumers demand for this nuts. The high oil and essential fatty acid contents of the pistachio kernel is important from a nutritional point of view. However, high unsaturated fatty acids content makes pistachio nuts susceptible to oxidation and consequently off-flavors and off-aromas during storage.Mold growth and the production of aflatoxins is another food-safety concern about pistachio nuts. Lipid oxidation and fungal growth can be controlledby using an appropriateatmosphere in packaging.Therefore, the main objectives of this study were to determine the effect of Modified Atmosphere(MA) compared with Vacuum and Air condition packaging on physicochemical, microbialandsensory properties of raw dried Pistachio nuts (ohadi variety) in an accelerated storage conditions at 30±2°C and 50°C for 12 weeks. Material and methods: The pistachio nuts were treated with 3 different system packaging, these treatment includes modified atmosphere packaging (MAP at 88% N2; 10% CO2 and 2% O2), vacuum packaging and air condition packaging. The pistachio nuts were packed in five-layerpouches (2 PE+ 2 PA+1 glue :80 microns)and stored in triplicate at 30°C and 50°C for12 weeksand they were sampled every four weeks. Oil from pistachio kernels for peroxide, and fatty acid assay were extracted by cold extraction and n-hexane was used as extraction solvent. Peroxide value (Meq.kg-1) of the extracted oil was determined by spectroscopic absorbance reading at 500 nm. Free fatty acids (%), as oleic acid percentages in oil samples, were determined using the titration method. Moisture content (%) was determined by drying 5 g of ground kernels at 103±2 °C until constant weight. The mouldcontent (log CFU/g) of pistachios were performed according to the Iran standard method. The textural analysis of the pistachio nuts were performed using cylinderprobe (diameter: 20 mm) at test speed 50 mm/min and deformation of 4 mm for samples. Fracture force (N) and hardness (N) parameters were measured to evaluate textural properties ofpistachio nuts samples.Sensory evaluation was carried out by a 20 member trained panel (10 females and 10 males). Sensory attributes evaluated included color, firmness, rancidity and overall acceptability on 5 point hedonic scale, whit 5 for excellent and 1 for very dislike. Analysis of variance (ANOVA) was carried out using the least significance difference(LSD) test (p
