Food Biotechnology
Soheyl Reyhani Poul; Sakineh Yeganeh; Zeynab Raftani Amiri
Abstract
Introduction Since heat treatments and special standards are not used in the production of traditional (homemade) tomato paste, fungal and bacterial spoilage in the product occurs extensively during storage in the refrigerator (4°C). Astaxanthin extracted from aquatics has antimicrobial activity ...
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Introduction Since heat treatments and special standards are not used in the production of traditional (homemade) tomato paste, fungal and bacterial spoilage in the product occurs extensively during storage in the refrigerator (4°C). Astaxanthin extracted from aquatics has antimicrobial activity and color similar to tomato and can probably be effective in preventing spoilage of tomato paste. In addition, astaxanthin has other properties in the field of preventing and controlling diseases and maintaining human health, which justifies its use in food formulations as an enrichment. Since heat, enzyme, acid, etc. treatments are practiced during the production of tomato paste, these factors may change the structure and thus the function of astaxanthin. For this reason, astaxanthin nanoencapsulation is necessary for its use in tomato paste formulation. Materials and Methods In this research, first, astaxanthin was extracted from Haematococcus pluvialis microalgae using the acid-acetone combined method. Then, this pigment was nanoencapsulated using maltodextrin-sodium caseinate coating and the resulting nanocapsules were used together with the pure form of astaxanthin in the formulation of tomato paste. The research treatments were control, tomato pastes containing 3 and 6% astaxanthin (A and B, respectively) and also 3, 6 and 9% nanocapsules carrying the pigment (C, D and E, respectively). These treatments were kept at refrigerator for 28 days and were evaluated (on days 0, 7, 14, 21 and 28) in terms of the total number of fungi, Howard's number (HMC), pH, fungal flora, total bacteria count, amount of lactic acid bacteria and sensory properties. This research was conducted in a completely randomized design. Data were analyzed by One-way Anova and the difference between the means was evaluated by Duncan's test at 95% confidence level. Results and Discussion The results showed that the fungi proliferation, total count and lactic acid bacteria were slower than the control during the storage period in the treatments containing astaxanthin and its carrying nanocapsules, and the minimum number of the mentioned microorganisms and Howard's number were related to treatments D and E (p>0.05). Treatments C, B and A were ranked next in this respect (p<0.05). The number of fungi in two treatments D and E from day 0 to 28 varied from 128 to 332 cfu/gr. Also, the Howard number of these treatments was recorded from 18 to 34% in the mentioned time period. However, these two indices in the control ranged from 121 to 792 cfu/gr and 18 to 91%, respectively, during the storage period. The count of total bacteria and the amount of lactic acid bacteria in the control on day 28 were equal to 8.9 cfu/gr and 311 mg/kg, respectively, but these two values were recorded in the E and D treatments on the same day, about 4.8 cfu/gr and 110 mg/kg, respectively. Counting the total number of fungi, bacterias and also Howard's number in control and other treatments showed that the effect of nanocapsules carrying astaxanthin on microbial growth and proliferation is significantly greater than pure astaxanthin (p<0.05). The pH of the treatments varied from 3.9 to 5.8 during the storage period and the most standardized pH (3.9-4.4) was recorded in C, D and E (p>0.05) treatments (p<0.05). The pH of two treatments A and B (p>0.05) was higher than the three mentioned treatments and lower than the control (p<0.05). This finding showed that nanocapsules carrying astaxanthin have a greater effect on controlling the pH of tomato paste than pure astaxanthin during storage at refrigerator (p<0.05). The identification of the fungal flora of the treatments on the 28th day confirmed that two genus of Penicillium and Aspergillus form the main flora of the product. The results of the sensory evaluation of the treatments on day 0 showed that adding astaxanthin and its carrier nanocapsules does not change the color, aroma, taste and texture indicators (subsequently the general acceptance) of tomato paste (p>0.05). On the 28th day, the mentioned sensory indices only in the two treatments D and E were not significantly different from the 0 day, but they changed negatively in the other treatments (p<0.05). Conclusion According to the findings of the present research, astaxanthin extracted from Haematococcus pluvialis microalgae has the ability to inhibit fungal and bacterial spoilage and stabilize the sensory properties of tomato paste stored at refrigerator. This properties were improved by adding nanoencapsulated pigment using maltodextrin-sodium caseinate combined coating. Since there were no significant differences between the two treatments containing 6% and 9% of nanocapsules carrying astaxanthin (D and E) in terms of quality indices and microbial spoilage, therefore, the treatment containing 6% nanocapsules is introduced as the optimal treatment.
Azam Sattari; Jafar Mohammadzadeh Milani; Zeynab Raftani Amiri; Ali Pakdin Parizi
Abstract
Introduction: Oat establishes a healthy basis for food products. It has gained relevance in human nutrition because it is one of the few cereals with a high content of soluble fiber namely β -glucan, and is a good source of proteins, vitamins, and minerals (Butt et al., 2008). β-glucan is one ...
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Introduction: Oat establishes a healthy basis for food products. It has gained relevance in human nutrition because it is one of the few cereals with a high content of soluble fiber namely β -glucan, and is a good source of proteins, vitamins, and minerals (Butt et al., 2008). β-glucan is one such polysaccharide that has received much attention from the past few years due to its several health beneficial properties, including the ability to remove free radicals in a way identical to antioxidants (Gardiner, 2000). β-glucan is an unbranched polysaccharide consisting of β-D-glucopyranose units linked through (1→4) and (1→3) glycosidic bonds in cereals and (1→6) glycosidic bonds in fungal sources (Ahmad et al., 2016). β-glucan from different sources vary in their molecular structure, chain conformation, solubility, number of β- (1→3)- or β-(1→6)-linkage, and thus different biological activities (Descroix et al., 2006). β-glucan is regarded as an important functional ingredient to lower serum cholesterol, promote weight management, reduce glycemic response, enhance immune system, besides having a prebiotic effect (Zhu et al., 2016; Shah et al., 2016). β–glucan from barley and oat at a 3 g/day dosage as recommended by FDA would reduce cardiovascular disease risk including a reduction in blood glucose and also has satiety effects. Therefore, in order to meet the demands of people related to diets that have a low glycemic index and antioxidant property, non-starch polysaccharides like β-glucan can be used as an ingredient in the products to develop new functional foods (Lee et al., 2016). Oat grain’s fat content is more than that of wheat and it is full of lipase, lipoxygenase, and other hydrolytic enzymes. Over time, enzymes lead to the hydrolysis of the fats present in the oat that make the rancidity taste. Due to the effect of enzyme activity on the stability of oat flakes, these enzymes need to be deactivated during oat processing. One of the methods for disabling enzymes is a hydrothermal process (Doehlert et al., 2010). In this study, the effect of the hydrothermal process using autoclave on the physical and rheological properties of oat β-glucans at different times and temperatures has been investigated. Materials and methods: In this study, beta-glucan was extracted from oats using the hot water extraction method. Hulled oat grains, it put into the autoclave for hydrothermal processing, at three different temperatures of 110, 120 and 130°Ϲ in two different times (10 and 20 minutes) intervals, to measure the effect of time and temperature on physicochemical and functional and rheological properties of β-glucan. After extraction, the physiochemical and functional properties of extracted β-glucan such as solubility, foaming, foaming stability and rheological properties were tested. In order to measure the moisture, ash and protein content, the standard methods (AOAC, 2005) were used. The fat content of the flour was measured by the standard AACC method 25-30. The starch was determined by polarimetry method. For solubility measurement, according to Betancur-Anoka (2003) method, after preparing 90 ml of 1% w / v solution from each sample β-glucan, it was divided into 3 equal parts. Then each of them was placed in a warm bath of 25, 50 and 75 °C for 30 minutes. After centrifuging for 15 minutes at about 8000 g, 10 ml of the upper clear solution was transferred to an oven at 125 °C to reach a constant weight. Finally, solubility percentage at different temperatures was calculated.The foaming capacity and foam stability were studied using the temelli method (1997). For this purpose, 2.5 g, β-glucans was dissolved in 100 mL distilled water. The resulting solution was mixed vigorously for 2 min using a hand held food mixer at high speed in a stainless steel bowl with straight sides and volumes were recorded before and after whipping. To determine foaming capacity, foams were slowly transferred to a 1000 mL graduated cylinder and the volume of foam that remained after staying at 25 ± 2°C for 2 h was expressed as a percentage of the initial foam volume (Temelli et al. 1997; Ashraf Khan et al., 2016). β -Glucan gum solutions were prepared in duplicate in the desired concentration (1.0% of gum, w/w) using distilled water. The rheological properties of the samples were studied by an Anton Paar Physica Rheometer (Physica, MCR 301, Anton Paar GmbH, Germany), with a parallel plate geometry. Results and discussion: β-glucan obtained from hydrothermal process on oat flour at 120°C for 10 minutes had the highest solubility at 25°C and the lowest solubility at 50°C, and 130°C treatment for 10 minutes had the highest solubility at 75°C from hydrothermal process on oat flour at 120°C for 10 minutes had the highest solubility at 25°C, and the treatment of 110°C for 10 minutes and also the treatment of 120°C for 20 minutes had the highest solubility at 50°C and 75°C. The amount of foam in treatment at 130°C for 10 minutes were lower than other treatments and the treatment at 110°C for 10 minutes had the highest foaming stability. In the study of rheological properties, the effect of shear rate on viscosity showed by increasing the shear rate, viscosity decreased in all samples. β-glucan from hydrothermal process on oat flour at 120°C for 10 minutes, had the highest amount of viscosity. In the temperature sweep the parameters included G′ modulus and G″ modulus, the amount of G′ and G″ in β -glucan sample that extracted from hydrothermal process on oat flour were decreased in all samples. Also, G′ and G″ of extracted β-Glucan from hydrothermal process on oat flour at 120°C for 10 minutes was higher than other treatments. In the frequency sweep, at a lower frequency, the amount of G″ was more than G′, and both of them were increased by an increasing frequency and the amount of G′, G″ and η* at 120°C for 10 minutes was higher than other treatments in the frequency of 1 and 10 (Hz). The results showed that the hydrothermal process had a significant effect on the properties and functional properties of β -glucan. Extracted β -glucan sample at 120°C for 10 minutes had the highest solubility at 25°C, and the sample had the lowest solubility at 50°C. The sample treated at 120°C for 20 minutes had the highest solubility at 75°C. The foaming capacity of the sample at 130°C for 10 minutes was lower than other treatments and the treatment at 110°C for 10 minutes had the highest foaming stability. In the study of rheological properties, the effect of shear rate on viscosity decreased in all samples and the treatment of 120°C for 10 minutes had the highest amount of viscosity. In temperature sweep measurement, the amount of G′ and G″ were decreased in all samples and at 120°C for 10 minutes it had the highest amount of G′ and G″. In the frequency sweep, at a lower frequency, the amount of G″ was more than G′, and both of them were increased by an increasing frequency and the amount of G′, G″ and η* at 120°C for 10 minutes was higher than other treatments in the frequency of 1 and 10 (Hz).
Fereshteh Hosseini; Zeynab Raftani Amiri
Abstract
In this study, the effect of stevia (0-0.04 g/100g) as a sucrose replacer, milk protein concentrate (mpc) (0-4 g/100g), and modified waxy corn starch (0-3 g/100g) as fat replacers on the physico-chemical and sensory characteristics of 15% fat cream were analyzed using a central composite rotatable design. ...
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In this study, the effect of stevia (0-0.04 g/100g) as a sucrose replacer, milk protein concentrate (mpc) (0-4 g/100g), and modified waxy corn starch (0-3 g/100g) as fat replacers on the physico-chemical and sensory characteristics of 15% fat cream were analyzed using a central composite rotatable design. Response surface methodology was used for optimization of low calorie cream formulation. Results showed that an increase in sucrose substitution with stevia and mpc concentration was followed by an increase in cream acidity, while pH decreased. Increasing sucrose substitution with stevia in cream decreased firmness, apparent viscosity and consistency, whereas increasing concentration of milk protein concentrate and modified starch increased the cream firmness, apparent viscosity and consistency. However, according to multiple response optimization, the optimum levels of 0.034 g/100g stevia, 1.64 g/100g mpc and 2.30 g/100g modified starch predicted acidity 0.15% acid lactic, pH 6.5, firmness 1.4 N, apparent viscosity 28730.3 mPa.s and consistency 0.52 cm/30 s. The calorie value of formulated cream was 46.44% less than the control sample (cream with 30% fat and 12% sucrose), and no significant difference in total acceptance between them was found, while formulated cream had higher score for taste and creamy state.
Zeynab Raftani Amiri; Mohammad Ezazi
Abstract
Introduction: Nowadays, use of by products in formulation of functional foods in order to improve their nutritional value and also avoid environmental pollution in food industry is increasing. Whey, a by product of dairy industry is one of such compounds. The acid whey resulted from concentration of ...
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Introduction: Nowadays, use of by products in formulation of functional foods in order to improve their nutritional value and also avoid environmental pollution in food industry is increasing. Whey, a by product of dairy industry is one of such compounds. The acid whey resulted from concentration of yoghurt, as a by-product, can be applied in whey based fruit beverages due to its minerals and beneficial residual proteins. It represents about 85–95% of the milk volume and contains nutrients, such as lactose as a most content, soluble proteins, lipids, minerals, vitamins, and organic acids. Acid whey has a pH of approximately 4.5 due to the conversion of lactose into lactic acid by lactic acid bacteria during the process of yoghurt production. Lactose is the main ingredient of whey, which comprises 90 percent of whey dry matter. According to FAO, the worldwide production of cheese was estimated to be 19,000 kilo tones (kt) in 2010, thus resulting in approximately 177,000 kt whey as a by product. The annual growth arises to production of approximately 211,000 kt whey in 2020. Therefore, the research for new lucrative whey utilization beside whey protein recovery is an ongoing challenge for the dairy industry. More than 70% of the world’s population suffer from lactose intolerance, which limits consumption of lactose containing dairy products. Lactose intolerant individuals, who consume milk or other dairy products like as acid whey, even at small quantities, facing gastroenterological complications related to the uptake of calcium and certain other nutrients. Thus it is important to reduce the lactose content of mild and dairy by products before using them in new foods formulation. In this study production of low lactose whey by enzyme was investigated. Beta-D-Galactosidases, EC (3.2.1.23), is a hydrolase enzyme that converts lactose into glucose and galactose and increases the sweet taste in products. It is commonly known as lactase, which is one of the most important enzymes in food, dairy and fermentation industries. Mixing of the low lactose whey with fruit compound or concentrates and sweetener agents make delicious and functional new beverage.
Materials and methods: The acid whey resulted from concentration of Greek yoghurt, as a by-product, was applied in whey based fruit beverages. The lactase enzyme (Sapherra FMP) was prepared from Novozyme Company. Pineapple compound prepared by Orana Company from Denmark. The quantity of sugar (Shadianeh) in each sample has been investigated based on the equivalent sweetness recognition by panelists in lactase treated samples in comparison with non treated samples. Premixed sugar and stabilizer in precise amount for each treatment was added to water and agitated in stainless steel agitating mix. After that whey and pineapple compound, and then 1000 ppm enzyme were added to samples and kept at 4 degree Celsius for 3 hours and finally pasteurized. All samples homogenized by 150 bar in 60 degree Celsius. Packaging of samples was done in 250 gram tetra pack container at aseptic condition. The effect of lactase enzyme on sugar quantity and taste improvement of acid whey based beverage produced by 5 percent of pineapple compound, has been investigated by lactase enzyme (0 and 0.1 percent), acid whey (30 and 40 percent), storage temperature (ambient and refrigerator) and time storage (0, 4, 8, 10 and 12 weeks after production) on a factorial experiment in a completely randomized design.
Results and discussion: The results of sensory evaluation in 12 weeks at two different storing temperatures (refrigerator and ambient), showed that addition of lactase enzyme before pasteurization of whey based pineapple flavored compound could kept not only the pH on constant, and reduced the sugar quantity to achieve constant sweetness in all samples, but also improved the sensory specification of beverage, significantly (p
Sarvenaz Osia; Zeynab Raftani Amiri
Abstract
Introduction: The Phaseolus Vulgaris on a global scale of cultivation has been categorized in the first rank and considered as the seventh staple food in the world. Proteins are usually classified into 3 groups including flours with 50 to 65 percent protein, concentrate with 65 percent protein and isolates ...
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Introduction: The Phaseolus Vulgaris on a global scale of cultivation has been categorized in the first rank and considered as the seventh staple food in the world. Proteins are usually classified into 3 groups including flours with 50 to 65 percent protein, concentrate with 65 percent protein and isolates with over 90 percent protein. Protein concentrate is produced by defatted flour through removal of soluble sugars, soluble fiber and minor compounds by alcohol, water or diluted acid with pH around 4-4.8. Protein isolate is affected by further refining processes compared to protein concentrate. In addition to the importance of the nutritional properties, crop proteins have a key role as a functional agent in the formulation of food products. Solubility, water binding capacity, oil absorption capacity, emulsifying and foaming abilities are noticed as the main functional properties. One of the specific and unique varieties of beans is Phaseolus Vulgaris var (aroos bean). The aim of this study was to determine the chemical composition of flour and bean protein isolate. In addition, some of the functional properties such as emulsification properties, foaming and stability as well as the effect of pH and ionic strength on above-mentioned characteristics were investigated.
Materials and Methods: The seed of Phaseolus Vulgaris and refined soybean oil (0ila) were purchased from Sari local supermarket. Phaseolus Vulgaris protein isolate was extracted and obtained powder was kept in impervious polyethylene plastic bags against moisture and air and placed at -18 ° C until analysis. The efficiency was calculated based on the sediment. Also, chemical composition and purity of the isolates were determined. Some functional properties, including emulsifying properties and foaming capacity at pH 4, 7, 8 and 10 were tested; and impact of the ionic strength of NaCl in concentrations of 0, 0.5 and 1 molar were examined. The results of all treatments were expressed based on the average of triplicate. Means were subjected to analysis of variances (one way-ANOVA) using (SPSS Statistics version 16) software program. Differences among the mean values of the various treatments were determined by Duncan test and the significance was defined at p < 0.05. The graphs were drawn using Excel software.
Results and Discussion: Phaseolus Vulgaris had 9% protein isolate efficiency and purity of 89.06%. The amount of protein in Phaseolus Vulgaris flour was less than the amount of protein that has been reported for other crops. While in terms of purity, protein isolate was similar to legumes in other studies. Foaming ability and emulsifying properties of Phaseolus Vulgaris protein isolate at 7 = pH were 42% and 65%, respectively. The value of this parameter using exposure to alkaline region and keeping far from the isoelectric point at pH = 10 were risen to the highest amount of 70.23% and 77.33%, respectively. During 90 minutes, stability of emulsions and foams were gradually decreased. With increasing of NaCl concentrations, foaming capacity and emulsifying properties were significantly reduced. Considering the efficient functional of Phaseolus Vulgaris protein isolate, further investigation required in order to be used in the formulation of meat products, cakes, cookies, crackers, sauces and soups.
Elahe Maghsoudlou; Reza Esmaeilzadeh kenari; Zeynab Raftani Amiri
Abstract
Introduction: Lipid oxidation is a complex series of reactions that occurs during processing, storage and final preparation of foods containing lipids (Bera et al., 2006). Among the various methods of protection against oxidation, specific additives are used which are antioxidants (Pokorny et al., 2006).Polyphenols ...
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Introduction: Lipid oxidation is a complex series of reactions that occurs during processing, storage and final preparation of foods containing lipids (Bera et al., 2006). Among the various methods of protection against oxidation, specific additives are used which are antioxidants (Pokorny et al., 2006).Polyphenols are natural antioxidants that possess characteristic properties, such as free-radical scavenging and inhibition of oxidizing processes in the body. For using of phenolic compound, they must be extracted from plant material. Traditional methods of extraction are labor-intensive, time consuming, and require large volumes of solvent (Wang and Weller, 2006(. In recent years, ultrasound-assisted extraction (UAE) has become an effective method for edible oils and fats from natural product extraction. UAE is an inexpensive, simple and efficient alternative to conventional extraction techniques (Chen et al., 2010). The mechanism of UAE is attributed to mechanical and cavitation efficacies which can result in disruption of cell wall, particle size reduction, and enhanced mass transfer across cell membrane (Wang, Wu, Chen, Yue, Liang, & Wu, 2013). Figs are an excellent source of phenolic compounds and some studies have described the presence of several phenolic compounds in this species (Solomon et al., 2006; Teixeira et al., 2006; Vaya and Mahmood, 2006). However, according to our knowledge, there are no studies about the detailed investigation of different parts of the fig and evaluation of its oxidative stability. Therefore, the objective of this study was to evaluate antioxidant activity of pulp and skin of two varieties of fig (Siyah and Sabz) and its application as natural antioxidant in canola oil.
Material and methods: Fig fruit (F. carica L.) from two selected commercial varieties: Siyah and Sabz wwere collected from Gorgan, Iran in September 2014. Canola oil was purchased from Alia Golestan Company (Kordkooy, Iran). All other chemicals used in this study were of analytical grade and were purchased from chemical suppliers such as Merck and Sigma-Aldrich Chemical Companies.
The figs were weighed and immediately peeled. The pulp was cut and made into flat sheets. Thereafter, the pulp and skin of each fruit were shade-dried for 5 days followed by drying at 60 ℃ in an oven for 24 hours to ensure complete drying (Memmert 100-800, Germany). The samples were then milled and sieved. Samples obtained were kept in polyethylene bags.
Dried fig powders were mixed with ethanol (1:10), then placed in ultrasonic bath, and then sonicated at 37 kHz for 20 min at 40°C by Elma Transsonic ultrasonic bath model 690/H (Cottbus, Germany). The extract was filtered and subsequently evaporated at 40 ℃ in an oven. The concentrated extracts were stored at -18 C until further analyses (EsmaeilzadehKenari et al., 2014).Extracts were used in concentrations of 0.5, 1, 1.5, 2, 2.5 and 3 mg/ml.
Phenolic compounds and flavonoids were measured by Folincio-calteu and aluminum chloride, respectively. The antioxidant activity of the extracts was evaluated using DPPH and reducing power tests. Then we assessed the efficiency of extract of skin fig of Siyah variety at 1 mg/ml the oxidative stability using Peroxide, thiobarbituric acid, conjugate di en, acid value, Oxidativestabilityindexand colorindex in canola oil during thermal conditions (180 ℃, 24 hours) compared with Synthetic antioxidants of TBHQ.
Results and discussion: The fig extracts contained different antioxidative fractions which were able to inhibit lipid oxidation effectively, by different mechanisms of action. Antioxidant activity of Siyah variety extract was higher than that of Sabz variety extract; furthermore, skin extracts were found to render higher antioxidant activity than pulp extracts. The stabilization effect of Siyah fig skin extract on canola oil (using peroxide, thiobarbituric acid, conjugate di en, acid values, oxidative stability index and color index) was comparable with the synthetic antioxidant (TBHQ).Therefore, skin of Siyah fig can be used as a potent source of natural antioxidant in food system.
Forough Gillani; Zeynab Raftani Amiri; Reza Esmailzadeh Kenari
Abstract
Introduction: Cornelian cherry (Cornus mas L.), which belongs to the family Cornaceae, grows in Iran, in areas such as Qazvin and Arasbaran. The fruit possesses anti-inflammatory and antioxidant properties and it is used as an herbal remedy in medicine. Separation of natural antioxidant compounds from ...
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Introduction: Cornelian cherry (Cornus mas L.), which belongs to the family Cornaceae, grows in Iran, in areas such as Qazvin and Arasbaran. The fruit possesses anti-inflammatory and antioxidant properties and it is used as an herbal remedy in medicine. Separation of natural antioxidant compounds from plant sources requires an appropriate method of extraction, which is effective factor to achieve the higher efficiency of these valuable compounds. In this study, the effect of extraction methods (immersion and ultrasound) and different solvents (ethanol 100%, ethanol – water (50:50 V/V) and water) on amount of phenolic compounds and antioxidant properties of cornelian cherry fruit extract were investigated.
Materials and Methods: Qazvin cornelian cherry was purchased from the local market of Amol city, Mazandaran province, Iran. All solvents and chemicals used in this study were of analytical reagent grade and were prepared from Merck (Darmstadt, Germany) and Sigma–Aldrich (St. Louis, MO). Cornelian cherry was washed, core separated, dried in front of the sun for 5 days and then powdered with kitchen miller. Powdered cornelian cherry fruit was extracted using immersion extraction techniques, ultrasound and different solvents (ethanol 100%, ethanol –water (50:50 V/V) and water). In the immersion method, powdered cornelian cherry fruit were mixed with each solvent in the ratio of 1:10, individually. Then, the mixtures were shaken overnight at room temperature. After 24 hrs, the extracts were filtered through Whatman No. 42 filter paper and the solvents were evaporated in an oven at 55°C. In the ultrasound technique, the mixture of powdered samples with any solvent (1:10) was sonicated in an ultrasonic bath for 45 min at 35°C. The extracts were then filtered and the solvents were evaporated using an oven at 55°C. Finally, the extracts obtained from extraction methods were kept in a freezer for furthere experiments. The total phenolic content of the extracts was determined with the Folin-ciocalteau method, briefly, 0.5 mL of cornelian cherry fruit extracts with concentration of 1mg/mL were mixed with 2.5 mL of Folin–Ciocalteu reagent (previously diluted 10-fold with distilled water) and 2 mL of 7.5% sodium carbonate solution, then the samples were kept for 30 min at room temperature in the dark and at the end the absorbance of the solutions was read at 760 nm. The ability of the extracts to scavenge 2, 2-diphenyl-1-picrylhydrazyl radical (DPPH) was determined. 0.3 mL of each extract with a different concentration (500-3000μg/mL) was mixed with 2.7 mL of methanolic solution of DPPH (6 × 10 -5 mole/L), then the mixture was shaken vigorously and was placed in the dark for 60 min. Absorbance was recorded at 517 nm. The percentage of the DPPH radical scavenging was calculated according to the following equation:
% inhibition of DPPH radical= [(ADPPH – AS) / ADPPH] ×100
AS and ADPPH are the absorbance of the solution the absorbance of the DPPH solution, respectively. Reducing power of extracts on iron ion was measured. 1mL of each extract with a different concentration (500-3000μg/mL) was mixed with 2.5 ml of phosphate buffer (0.2 M, pH= 6.6) and 2.5 ml potassium ferricyanide [K3Fe(CN)6] (1%), then the mixture was incubated at 50° C for 30 min. After that, 2.5 ml of 10% trichloroacetic acid were added to the mixture, then, was centrifuged at 1000g for 10 min. Subsequently, 2.5 ml of the upper layer solution was mixed with 2.5 ml of distilled water and 0.5 ml of 0.1% FeCl3. Finally, the absorbance values of the solutions were read at 700 nm.
Results and discussion: The result of this study showed that the type of solvent and extraction method has been effective on amount of phenolic compounds of extracts, and also concentration dependent of phenolic compounds with antioxidant activity was observed in all extracts. The highest amount of phenolic compounds with 142.72 mg/g (based on Galic acid) was observed in sample extract obtained from solvent of water- ethanol (50:50 V/V) employing ultrasound method. Also, this extract with the lowest IC50 value with the amount of 0.955 mg/ml in the DPPH free radical scavenging method and the highest absorption with the amount of 0.601 in the reducing power of Iron III test, the highest antioxidant performance is shown. A negative correlation was observed between the total phenolic content and the IC50 value in the methods of measuring the antioxidant activity (DPPH and reducing power), which revealed the higher total phenolic content will give the lower IC50, that means the higher antioxidant activity. The results of present research showed that cornelian cherry fruit is a natural source of phenolic compounds and have considerable antioxidant activity.
Mohammad Dolatabadi; Zeynab Raftani Amiri; Reza Esmaeilzadeh kenari
Abstract
Introduction: In recent years, much attention has been focused on agricultural wastes especially those containing phenolic compounds with natural antioxidant properties. One of these sources is the green husks of walnuts. The contents of phenolic compounds of plants are influenced under various factors ...
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Introduction: In recent years, much attention has been focused on agricultural wastes especially those containing phenolic compounds with natural antioxidant properties. One of these sources is the green husks of walnuts. The contents of phenolic compounds of plants are influenced under various factors including genetic factors, agricultural varieties and the species, climate and extraction procedures. Extraction is the first step for researchers who work on plants. Traditional extraction techniques with solvent such as water have disadvantages such as time consuming process, solvent consumption and high labor work. So the need to develop and use new extraction techniques, including combination of ultrasound bath and microwave devices, has provided valuable results. This method increases the mass transfer rate of the cell wall and intracellular compounds more rapidly transported out of the cell. In the ultrasound method to create cavitation in the extraction process and with collapse of bubbles and mechanical effects on the cell wall and most influential into the cell solvent improves the mass transfer. Extraction process performed by ultrasound process was used to facilitate the release of the intracellular content. These two methods can increase extraction efficiency within a shorter time and using less solvent, increasing the amount of extracted compounds are less damaging to the environment. Three different weather conditions for walnut production in northern Iran and different methods for extraction and measurement of phenolic compounds were adapted to find the best area and the most efficient extraction method.
Materials and methods: Three areas were selected from north parts of Iran including Bandar Gaz with mild climate, Shahrood with semi-arid climate and Hezarjerib region with mountainous climate located in the Alborz Mountain chains in which walnut is one of their major products. Walnuts randomly were picked by hand without any damage to their husks from a few walnut trees in a random garden in each region. The selected walnut trees were almost similar and were about 35 to 40 years old. In the selected areas, it is not conventional to use pesticides or chemicals and toppings for walnut trees. Walnuts collected were transported to the lab in cold conditions (8 to 10° C) and after cleaning the walnuts, green husks were separated and kept at -18 °C. Solvent extraction of phenolic compounds was carried out by choosing ethanol - water in a ratio of (1-1) by soaking, ultrasound and microwave methods at different times. The amount of phenolic compounds was measured using a spectrophotometer device with the aid of using the Folin Ciocalteau reagent, and antioxidant properties were measured using DPPH free radical scavenging and regenerative power of Iron III.
Results and discussion: This research was carried out on a factorial design (334) with three replications with Duncan's test for comparison of averages at the 95% confidence level. Comparing the extraction methods (soaking, microwave and ultrasound) showed that the most efficient method was ultrasound method at 30 minutes and the highest phenolic compounds in walnut green husk was for Hezarjerib area. In addition to the savings in time of extraction and safety in this method, the extraction of phenolic compounds is preferred to the other two methods. The results showed that the antioxidant properties were increased with increase in the amount of phenolic compounds. The results of this study also revealed that the walnuts green husks from Hezarjerib had the highest antioxidant properties followed by temperate region (Bandargaz) and semi-arid region (Shahrood).
Atefeh Rezai Zadeh; Zeynab Raftani Amiri
Abstract
Introduction: Today, the demand for low calorie food based on fruits and easy production and keeping primary features including texture and taste is increasing. Jelly is one of low calorie products which is produced from fruits and other components, and its usage is increasing for human health. Chemical ...
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Introduction: Today, the demand for low calorie food based on fruits and easy production and keeping primary features including texture and taste is increasing. Jelly is one of low calorie products which is produced from fruits and other components, and its usage is increasing for human health. Chemical ingredients and natural features of fruits decrease the cancer. In addition to nutrition and medical values, rheological and texture features affect the general quality of fruit jelly. Gelatin is a protein which is obtained by thermal hydrolysis of collagen and is the main protein of bone, cartilage and skin. The source, animal age and the type of collagen are influential factors on gelatin characteristics. Different gelatins have different thermal and rheological characteristics such as transformation temperature to jelly and melting temperature. The melting temperature of gelatin is lower than human body temperature. In food industry, gelatin is used as an alternative for fat, to improve elasticity and transparency of fruit juices and also is used in production of jelly, chocolate, edible films, and so on. Gelatin quality and its application in industry are mainly because of its rheological features. Global demand for gelatin during recent years increases due to its low cost and solubility in biologic environments.
Materials and methods: In this study, the gelatin from chicken feet was extracted by acidic method using hydrochloric acid 0.5% normal with the rate of 1: 3.22 weight / volume. pH was adjusted to 7 by the use of sodium hydroxyl 1 normal and was dried in an incubator at 450 c for 28 hours. Different tests such as pH, protein, ash, moisture, fat, viscosity, jelly strength, color and rheology were done in gelatin molecule to measure of storage modules (G') and loss modules (G''). Then, the effect of extracted jelly in concentrations of 0 to 1.5 % on the physico-chemical (Brix, humidity, acidity, color, texture) and organoleptic properties of cantaloupe jelly (odor, sweetness, color, appearance, jelly status, transparency, adhesion) were investigated using five point Hedonic scale ranked. Experiments related to cantaloupe jelly were conducted in terms of a completely random design. A one-way analysis of variance and Duncan test (P≤ 0.05), in three replications were used to establish the significance of differences in experimental data’s. The result was performed using the SPSS version 16.0 windows program, and charts were plotted with Excel 2010.
Results and Discussion: The results showed that the average yield of gelatin based on the wet weight was 4.80%, pH value before drying is 3.7, the total amount of protein is 83.95%, the total amount of ash is 0.89%, moisture is 9.66%, fat is 0%, viscosity is 216 centipoise. The strength of jelly is 487g that in compare with other alternatives such as gelatin from chicken skin is 355±48.1 gr, cow gelatin is 299±71.1 gr, fish gelatin including 181 to 263 gr for tilapia, 280 gr for horse mackerel fish, 125 and 177 gram for Sin croaker and Shortfin scad, respectively. The main reason for low level of gelatin in fish skin is the low amount of hydroxyl proline. Thus, it can be claimed that the high gel strength in chicken feet gelatin might be due to lower extraction temperature, strong hydrogen bond and more probably hydroxyl proline. Hydrocolloid solutions are usually viscoelastic; therefore, the level of storage modules (G') and loss modules (G'') is measurable for them. Gelatin from chicken feet exhibited G' greater than the G'' in a wide range of frequencies of the oscillatory test, which have indicated the gel network is high stable. By increasing the amount of gelatin in the cantaloupe juice, transparency and firmness of cantaloupe jelly increased. In the sensory analysis, jellies had not significant differences in the intensity of sweetness. In terms of overall acceptability, the sample containing 1.25 and 1.5 percent of gelatin gained maximum score.
Elahe Maghsoudlou; Reza Esmaeilzadeh kenari; Zeynab Raftani Amiri
Abstract
Recently, Subcritical Water Extraction (SWE) has been well known as a green technology for extraction of bioactive compounds from plants. In this study, Subcritical water extraction, ultrasound assisted extraction (UAE) and shaker solvent extraction (SSE) were compared for extraction of phenolic compounds ...
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Recently, Subcritical Water Extraction (SWE) has been well known as a green technology for extraction of bioactive compounds from plants. In this study, Subcritical water extraction, ultrasound assisted extraction (UAE) and shaker solvent extraction (SSE) were compared for extraction of phenolic compounds from fig (Ficuscarica) pulp and skin. Antioxidant activity of the extracts was evaluated using DPPH radical scavenging, reducing power and rancimat tests. Subcritical waterhad the highest ability for extraction of total phenolic content (65.89±0.21 and 80.79±0.09 mg of gallic acid equivalents per gram of extract respectively) and flavonoid compounds (7.51±0.33 and 10.1±1.02 mg of quercetinequivalents per gram of extract, respectively)from both pulp and skin.The lowest IC50 in DPPH radical scavenging and reducing power tests were related to SWE of skin extract of fig. Furthermore, in extraction of total phenol and flavonoid compounds, subcritical water extraction showed to be a more suitable method than other solvent extraction methods, both in pulp and skin.
Zeynab Raftani Amiri; Hengameh Darzi Arbabi
Abstract
Thermal conductivity is an important property of juices in the prediction of heat- and mass-transfer coefficients and in the design of heat- and mass-transfer equipment for the fruit juice industry. An artificial neural network (ANN) was developed to predict thermal conductivity of pear juice. Temperature ...
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Thermal conductivity is an important property of juices in the prediction of heat- and mass-transfer coefficients and in the design of heat- and mass-transfer equipment for the fruit juice industry. An artificial neural network (ANN) was developed to predict thermal conductivity of pear juice. Temperature and concentration were input variables. Thermal conductivity of juices was outputs. The optimal ANN model consisted 2 hidden layers with 5 neurons in first hidden layer and the second one has only one neuron. The ANN model was able to predict thermal conductivity values which closely matched the experimental values by providing lowest mean square error (R2=0.999) compared to conventional and multivariable regression models. However this method also improves the problem of determining the hidden structure of the neural network layer by trial and error. It can be incorporated in heat transfer calculations during juices processing where temperature and concentration dependent thermal conductivity values are required.
Sepideh Haghighat Kharazi; Reza Esmaeilzadeh kenari; Zeynab Raftani Amiri
Abstract
The present study attempts to investigate the effect of thermal treatment at 180 °C for 8 hours on chemical changes, quality indexes and oxidative stability of three Iranian common virgin olive oils (Zard, Mari and Phishomi). Oil samples were taken every 2h of heating treatment and assessed for fatty ...
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The present study attempts to investigate the effect of thermal treatment at 180 °C for 8 hours on chemical changes, quality indexes and oxidative stability of three Iranian common virgin olive oils (Zard, Mari and Phishomi). Oil samples were taken every 2h of heating treatment and assessed for fatty acid composition, conjugated diene value, carbonyl value, color index and oxidative stability index. Prior to the treatment, the total amount of phenolic compounds was also measured. Mari oil showed the highest amount of phenolic compounds (P
