Food Technology
Vahid Hakimzadeh; Fatemeh Ghorbanpour; Hassan Rashidi
Abstract
Introduction: One of the relatively new dairy products is cheese sauce, which can increase the consumption of cheese per capita and replace unhealthy sauces. Functionality process by adding useful compounds to food while maintaining its appearance improves properties of foods. Nowadays, due to the importance ...
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Introduction: One of the relatively new dairy products is cheese sauce, which can increase the consumption of cheese per capita and replace unhealthy sauces. Functionality process by adding useful compounds to food while maintaining its appearance improves properties of foods. Nowadays, due to the importance of compounds such as essential fatty acids, antioxidants and fiber, the demand for consuming products containing these compounds in the diet is very high. Date seed extract contains fiber, antioxidants, lignans and essential fatty acids. On the other hand, whey also has many nutritional properties. The purpose of this research is to prepare cheese sauce using such compounds so that while preparing a useful product, it is possible to prevent the wastage of valuable by-products. Material and Methods: In this research, the effect of Date kernel extract in amounts of zero (control), 5 and 15% to cheese sauce formula in the presence (15%) and absence of whey on the physicochemical characteristics of cheese sauce powder samples was investigated. The organoleptic properties of samples, also were studied in 5-hedonic form. All experiments were done based on completely randomized block design and in three replications. Duncan's test was used to compare the average dataResults and Discussion: The results showed that the addition of whey and date kernel extract to the cheese sauce significantly increased the characteristics such as dry matter percentage, powder solubility, phenolic compounds, antioxidant property and viscosity compared to the control sample. But on the other hand, the increase of Date kernel extract and whey in amounts of 15% decreased the amount of protein in cheese sauce. The results of the sensory properties of the samples also showed that the highest acceptability was related to the sample with 5% of seed date extract in the presence of whey.
Food Technology
S. Mostafa Sadeghi; Mandana Tayefe; Leili Fadayi Eshkiki; Kambiz Ghiasvand
Abstract
IntroductionBakery products such as cakes are consumed in a relatively large amount all over the world due to their ready to eat format. Among different foods, bakery products provide a great opportunity to use edible portions of seeds, vegetables or other unconventional food sources. On the other hand, ...
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IntroductionBakery products such as cakes are consumed in a relatively large amount all over the world due to their ready to eat format. Among different foods, bakery products provide a great opportunity to use edible portions of seeds, vegetables or other unconventional food sources. On the other hand, cakes are susceptible to oxidation due to high amounts of fat and consequently reduce shelf life. Therefore, due to the high nutritional value of cake, improving its characteristics seems necessary. Wheat germ is the richest known source of vitamin E of plant origin. Consumption of wheat germ can prevent artery- clogging and also helps fight against free radical damage and procrastination are effective in the aging process of cells and preventing coronary disease. Despite the beneficial properties of wheat germ, it is difficult to keep it raw in the formulation of crops due to the presence of high unsaturated fatty acids and lipase enzymes. However, by performing thermal processes such as steam, fluidized substrate or thermal dryer, enzymes such as lipase and lipoxygenase can be deactivated. In this study, the effect of adding wheat germ as a rich source of fiber, tocopherols and essential fatty acids as well as ascorbyl palmitate as antioxidant compound on the qualitative and structural properties of cake was investigated. Materials and MethodsIn this study, five treatments of oil cake including control, ascorbyl palmitate (100 ppm), wheat germ (5, 10 and 15%), were prepared and physic-chemical properties including the moisture, firmness and volume of cake at the beginning of storage period, peroxide number and acidity during 14-day storage period were investigated. In order to evaluate the texture of the cake, texture analyzer was performed with dimensions of 25 mm and penetration of 50% in the sample at a speed of 2 mm/s and a 30-second stop between the first and second compressions. The specific volume of the produced samples and moisture of the middle part of the samples were measured 3 hours after baking. Results and DiscussionThe results showed that addition of L-ascorbyl palmitate had no significant effect on moisture content, hardness and cake volume. However, wheat germ increased hardness (in amounts more than 5%), decreased moisture content and specific volume of cake. Also, with increasing the amount of wheat germ, a significant decrease in peroxide and acidity of the samples were observed during the storage period. However, the values of the mentioned indices in the sample containing palmitate ascorbyl were lower than those containing wheat germ. According to the results, it seems that the sample containing 5% processed wheat germ can be recommended as a suitable formulation for cake enrichment. ConclusionConsidering that oxidation of cakes and reduction shelf life in different type of cakes are probable due to the presence of considerable amounts of fatty acids, in this study the effect of adding L-ascorbyl palmitate as a common antioxidant and processed wheat germ due to its antioxidant behavior on the moisture content, hardness, specific volume, texture and shelf-life characteristics of the oil cake was investigated. The overall results show that by adding L-ascorbyl palmitate, there was no significant effect on moisture content, hardness and specific volume. However, processed wheat germ increased hardness (in amounts more than 5%), decreased moisture content and specific volume of cake. Also, with increasing the amount of wheat germ, a significant decrease in peroxide value and acidity of the cake was observed during the storage period. However, the values of moisture content, hardness and specific volume in the sample containing palmitate ascorbyl were lower than samples containing wheat germ. According to the results, it seems that sample containing 5% processed wheat germ can be recommended as a suitable formulation for cake enrichment and artificial antioxidant replacement.
Food Technology
Reza Farahmandfar; Sahar Aboutalebzadeh; Hannaneh Moniri; Massoud Kaykhaii
Abstract
Black tea, which is obtained from the leaves of small tree Camellia sinensis, is a popular drink that has been consumed for centuries all around the world. In this study, a sample of Iranian black tea was brewed by two methods of microwave and traditional brewing and their extracts were then assessed ...
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Black tea, which is obtained from the leaves of small tree Camellia sinensis, is a popular drink that has been consumed for centuries all around the world. In this study, a sample of Iranian black tea was brewed by two methods of microwave and traditional brewing and their extracts were then assessed using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing/antioxidant power (FRAP) assays to determine their phenolic and flavonoid contents as well as heavy metal (HM) (copper, nickel, chromium, cadmium and lead) content. It was observed that there is a direct relationship between the antioxidant activity with their phenolic and flavonoid contents. The highest and lowest antioxidant activities were observed for samples brewed by microwave at 360 W for 2.5 min and 900 W for 7.5 min, respectively. As the brewing power and time increased, the antioxidant activity decreased. Brewing tea by microwave and traditional methods caused a significant reduction in the amount of heavy metals, which was lower than the allowable limit according to the Iranian national standards. These results demonstrate the importance of exposure time and radiation power when tea is prepared by microwave.
Maryam Mandegari; Abdol Majid Mirzaalian Dastjerdi; Laleh Mosharaf; Maryam Tatari
Abstract
Introduction: Pomegranate (Punica granatum L.) is an important horticultural fruit that is generally very well adapted to the Mediterranean climate. Arils are the edible part of this fruit, being rich in anthocyanins and bioactive compounds such as phenolic compounds and flavonoids which act as antioxidants ...
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Introduction: Pomegranate (Punica granatum L.) is an important horticultural fruit that is generally very well adapted to the Mediterranean climate. Arils are the edible part of this fruit, being rich in anthocyanins and bioactive compounds such as phenolic compounds and flavonoids which act as antioxidants and free radical scavengers. Susceptibility to chilling injury in pomegranate fruits is a major limiting factor in storing fruits at low temperatures. Below 5 °C, pomegranate fruits show symptoms such as surface pitting, browning, discoloration, and decay. The control of temperature is an effective tool for extending the shelf life of fresh horticultural products. Oxidative stress, as caused by an excess of reactive oxygen species (ROS), is usually associated with chilling injury in fruits. Nitric oxide (NO) is an important gas molecule, the involvement of which in many physiological processes can protect plant cells against oxidative stress by reducing the accumulation of ROS. Postharvest studies have shown that the application of NO gas can extend the storage life of a range of horticultural produce by delaying ripening or senescence. Due to the high number of pomegranate cultivars in Iran, limited amounts of information exist on how the qualitative characteristics of arils in the Malas pomegranate can be affected by nitric oxide and different temperatures during storage. The Malas cultivar comprises a large share of pomegranate exports from Iran. In this research, the positive effects of nitric oxide were examined on reducing the chilling injury and maintaining the fruit quality of pomegranate. The application of this treatment at different concentrations and different storage temperatures led to variable effects on the qualitative characteristics of arils in the Malas pomegranate. Materials and methods: Malas pomegranate fruits were harvested commercially from Isfahan Province and were transferred to the Food Industry Laboratory of Isfahan Natural Resources Research. The fresh arils were separated from fruit tissues and were immersed in solutions of nitric oxide (0, 5 and 10 μM/L) for 5 min. After draining, the arils were placed in packaging films of polyethylene and were immediately stored at 2, 4 and 8 °C for 21 days. Several parameters were measured every 7 days during the storage time. These were the weight loss, total soluble solids, titratable acidity, TSS/TA, acid ascorbic, total phenol, total anthocyanin content, antioxidant activity, MA, ion leakage, POD, PPO activity and sensory evaluation. The current study was carried out as a factorial assay and was based on a completely randomized design with three replications. Data were processed by ANOVA using the SAS software version 9.4. Significant differences were identified using Duncan’s test at 1% probability level. Results and discussion: Results showed that the total anthocyanin content, total phenol, antioxidant activity, and titratable acidity decreased during storage time. The control group and the treatment with low temperatures significantly reduced the qualitative characteristics of arils during storage. The water content of arils treated with 5 and 10 μM nitric oxide was maintained considerably for 21 days during storage. According to these results, unlike titratable acidity and ascorbic acid which decreased in both treated and untreated fruits, there was an increase in the total soluble solids and POD activity of arils during storage. However, nitric oxide reduced the rate of these changes, whether it be the decrease or increase in the measured parameters. During the experiment, the control samples showed lower values of quality regarding all parameters. The use of nitric oxide in fruits reduced lipid peroxidation and ion leakage significantly, whereas the antioxidant activity increased. The decrease in ion leakage was observed most notably in fruits that were treated with 10 μM nitric oxide. Furthermore, low temperatures managed to disrupt the metabolic balance of reactive oxygen species, leading to the accumulation and destruction of antioxidant enzymes. In the present study, exogenous treatments with nitric oxide at 5 and 10 μM significantly reduced the lipid peroxidation content and electrolyte leakage of arils being stored at cold temperatures, compared to untreated arils. Nitric oxide suppressed the activity of polyphenol oxidase (PPO) and preserved the physical appearance and the internal quality of pomegranate arils. The decrease in phenolic compounds (29.32%) and antioxidant activity (39.91%), besides the increase in lipid peroxidation (38.37%) and ion leakage (36.98%), caused deteriorations in the appearance and organoleptic properties of the control samples. To alleviate these problems, nitric oxide has beneficial effects on maintaining the anthocyanin content of pomegranate arils by partially inhibiting PPO enzyme activity during storage. It prolongs the postharvest life, helps to preserve the quality of pomegranate arils, suppresses the formation of ethylene, reduces the respiratory rate and controls weight loss, in addition to maintaining the firmness of fruits. Delaying the changes in peel color and TSS are also considered as useful effects of nitric oxide on pomegranate arils. Nitric oxide impeded the process of senescence by slowing down PPO-related activities, thereby maintaining the total phenolic content of pomegranate arils.In conclusion, the application of nitric oxide was observed to reduce ion leakage and PPO activity in pomegranate arils, while also maintaining the quality of arils. Ultimately, the use of 10 µM nitric oxide at 8 °C can be suggested as the most optimum treatment herein.
Fahimeh Tooryan; Maryam Azizkhani
Abstract
Introduction: Nowadays, consumers are applicant to usage of natural replacements causing to side effects of synthetic preservatives such as carcinogenicity and teratogenicity. The tendency to use natural preservatives and replacing them with chemical preservatives has led to various studies of natural ...
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Introduction: Nowadays, consumers are applicant to usage of natural replacements causing to side effects of synthetic preservatives such as carcinogenicity and teratogenicity. The tendency to use natural preservatives and replacing them with chemical preservatives has led to various studies of natural compounds with antioxidant properties such as essential oils. Considering the environmental problems raised from current plastic packaging, edible and biodegradable coating could be developed and also be effective in controlling the chemical and microbial properties of food; especially if their effect be strengthened by adding natural antioxidant and antimicrobial agents like herbal essential oils. Various herbal compounds such as black pepper essential oils with antioxidant properties can be effective in combining with natural biodegradable coatings such as chitosan in oxidation control and enhance the effects or prevent or delay the chemical spoil. Safety and shelf-life of foods can be improved by using this technologies such as using natural preservatives. Adding essential oil, as a suitable source of antioxidant, for improvement the quality of the fish is the main purpose. Many fruits, especially orange, are rich in polyphenols. These materials are the most commonly existing phytochemicals in most fruits. Orange juice concentrate can be a good source of antioxidant and can be employed as a preservative in food products. Omega-3 fatty acid is used in daily healthy diet and plays an important role in prevention of disease. Being a considerably main source of Omega-3 fatty acid groups, fish preservation against oil oxidation and any other similar causatives seems quite necessary. In the present study, the effects of orange juice concentrate and chitosan coating enriched with black pepper essential oil on the chemical degradation of rainbow trout fillet stored in a refrigerator investigated.
Materials and methods: The chemical composition of black pepper essential oils were determined using a gas chromatography equipped with mass spectroscopy (GC/MS). GC-MS analysis of the essential oil was performed using Agilent-Technologies 6890N Network gas chromatographic (GC) system, equipped with Agilent Technologies 5975 inert XL Mass selective detector and Agilent-Technologies 7683 B series auto injector (Agilent-Technologies, Little Falls, CA, USA). Samples were stored at 4 ± 1 C° up to 12 days and evaluated periodically ( on days 0, 4, 8 and 12) for chemical and sensory characteristics. The samples were divided into 8 groups and assessed for PH-values, total volatile nitrogen (TVN), thiobarbituric acid (TBA), peroxide value (PV), free fatty acids (FFA) and sensory evaluation .The samples were also evaluated for antioxidant activity by measuring their scavenging abilities to DPPH radical (2,2 diphenyl-1-picril hydrazyl) and RP (Reducing power). Statistical analysis was performed using SPSS 20 software.
Results & Discussion: Results showed that More than 21 compounds were identified in oil, representing 97.75% of the total oil. The major constituents of essential oils obtained from the black pepper were β-caryophyllene (25.56%), Limonene (15.19%), Sabinene(12.2) , α-copaene(8.5) and beta –bisabolene (7.81) respectively. Results revealed that in comparison to the other treatments the control showed a significant increase in the trend of oxidative and sensory indexes and In the coated samples, the sample of fish coated with orange juice concentrate ,chitosan, and black pepper essential oil was the least amount of indexes than the rest (p<0/05) and showed lower indexes during the storage time .The radical scavenging DPPH, orange juice concentrate with a Brix 1/39 (66/9 %)and pepper essential oil 2% (64/1%) have more ability and had a greater antioxidant activity. In investigating corruption oxidation and sensory evaluation in all samples,chitosan coating with pepper essential oil and orange juice concentrate was higher(score:7/2) than other treatments and there were significant differences between treatment and control (p<0/05). Final peroxide value (meq O2/Kg oil) and tiobarbituric acid (m gr/kg oil MD) number using chitosan coating with pepper essential oil and orange juice concentrate in sample was 0.14 and 0.015, respectively. This significant deference was also observed when comparing to control sample (p<0.05)Minimum oxidative changes were observed in samples treated with orange juice concentrate,chitosan, and black pepper essential oil and had the best conditions in reduction of oxidative rancidity. The results obtained in this study showed that the chitosan coating enriched with black pepper essential oil with orange juice concentrate has a good potential to being employed as an active packaging to preserve food products. Overall, this study demonstrated that using concentrated juice incorporated with chitosan coating with pepper essential oil has a good effect on the quality of rainbow trout fillets and can keep on the sensorial attributes acceptably during 12 days storage time and present a good potential for their application in the food industry.
Reza Farahmandfar; Reza Safari; Fahimeh Ahmadi Vavsari; Tahmineh Bakhshandeh
Abstract
In this study, effect of Thyme (Thymus vulgaris) ultrasonic extract on the quality of Hypophthalmichthys molitrix surimi was evaluated. For this purpose, the leaves of Thymus vulgaris were dried, grinded and soaked in methanol (1:10 w/v) for 30 min at 45˚C and sonicated at 30 kHz for 15 min at 40˚C. ...
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In this study, effect of Thyme (Thymus vulgaris) ultrasonic extract on the quality of Hypophthalmichthys molitrix surimi was evaluated. For this purpose, the leaves of Thymus vulgaris were dried, grinded and soaked in methanol (1:10 w/v) for 30 min at 45˚C and sonicated at 30 kHz for 15 min at 40˚C. The extract was suspended by Dimethyl sulphoxide and mixed with surimi (0.4 and 0.8% w/w). Then, the analysis of chemical (free fatty acid, peroxide value, Thiobarbituric acid and total volatile base nitrogen) and microbial (mesophilic and psychrotrophic viable count) properties of the samples were done at specific intervals after zero, 4, 8, 12 and 16 days of storage at 2 ºC. Results of chemical and microbial analysis showed that 0.8% concentration of T. vulgaris could increase the shelf life of Hypophthalmichthys molitrix surimi and there is significant difference between control and treated samples. Moreover, the results could be claimed that the T. vulgaris due to marvelous antioxidant and antimicrobial component such as thymol (52.17%), ρ-cymene (14.42%), carvacrol (9.11%) and γ- terpinene (4.45%) has significant effect on preventing the Hypophthalmichthys molitrix surimi oxidation and microbial growth. The results also showed ultrasound was the effective way to extract the Thymus vulgaris beneficial compounds.
Maryam Farahmand; Mohammad Taghi Golmakani; Asgar Farahnaki; Gholam Reza Mesbahi
Abstract
Introduction: The pomegranate (Punica granatum L.) belongs to the family Punicaceae, which is planted around the world in different microclimatic areas. The pomegranate production has grown uninterruptedly, which is presumably due to the increasing consumer awareness of the benefits attributed to pomegranate ...
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Introduction: The pomegranate (Punica granatum L.) belongs to the family Punicaceae, which is planted around the world in different microclimatic areas. The pomegranate production has grown uninterruptedly, which is presumably due to the increasing consumer awareness of the benefits attributed to pomegranate and its polyphenols. Pomegranate fruit has valuable compounds with functional and medicinal effects like antioxidant, anticancer, and anti-atherosclerotic effects. Storage of juice concentrate can have a dramatic impact on physicochemical quality. The bioactive compounds and antioxidant activity in fruit juice products are influenced by many external factors like different storage temperatures. Knowledge of the rheological behaviour of juice products is essential for product development, design and evaluation of process equipment like pumps and piping. Pomegranate concentrate is so susceptible to the condition of storage, which results in a reduction in consumer acceptability and quality losses. Accordingly, the industrial concentrate stores frozen (-20 °C) which has a lot of costs to the producer. The objectives of this study were to evaluate the degradation visual color, the rheological characteristics of pomegranate juice concentrates, the stability of phytochemicals, the antioxidant activity, and the haze formation of reconstituted pomegranate juice concentrate during storage at different temperatures to determine the best storage conditions to reduce the quality losses and solving the problem about high cost of storage.
Materials and methods: The concentrated pomegranate (Punica granatum (L.) cv. Rabab) juice used in this study supplied from Narni (Green farm, Neyriz, Iran) factory. The pomegranate juice concentrate was poured into falcons for measuring physicochemical attributes, and micro tubes for determination of antioxidant activities. Then the samples were divided into four parts and stored equally in four different temperatures (-20, 4, 20, and 35 °C). The control samples were stored at -80 °C as fresh sample for the storage period (140 days). Folin-Ciocalteu reagent and 2,2-diphenyl-1-picrylhydrazyl radical (DPPHº) were supplied from Sigma-Aldrich Company (St. Louis, MO, USA). All other chemicals were of analytical grade and purchased from Merck Company (Darmstadt, Germany). The total soluble solid (TSS) was determined with a digital refractometer (Carl Zeiss, Germany). Total insoluble solid was measured by centrifugation at (5,000 × g) according to the IFFJP method 60, using a high speed centrifuge (Ibarz et al., 2011). The haze formation of reconstituted juice was determined by “settling” in a glass tube for 3 hour at room temperature. Color measurements of the juice samples were carried out using a HunterLab (CHROMA METER CR-400/410, KONICA MINOLTA, Japan) after dilution. The rheological characteristics of the pomegranate juice concentrate stored in different temperatures were studied by using a computer controlled rotational viscometer. Sample compartment was monitored at a constant temperature (25°C) using a water bath/circulator, while TSS was 65 °Brix. The viscosity measurements, was carried out According to the methods described by Cárdenas et al., (1997), using a Brookfield cone and plate viscometer (DVII pro Brook field, USA) between the shear rate of 0.5–200 (1/s). Total phenolic content of samples was measured according to the Folin-Ciocalteu colorimetric method (Sun et al., 2007). Total flavonoid content in juices was determined via a spectrophotometer according to the method of Chang et al. (2002). Radical scavenging activities of the samples were measured by using DPPHº as described by Mazidi et al., (2012). The ferrous ion reducing antioxidant power (FRAP) of the samples was measured calorimetrically according to the method by Fawole and Opara (2013). All analyses were performed by the Statistical Analysis System (SAS) software V 9.1 (SAS Institute, Inc., Cary, NC, USA). By using the analysis of variance (ANOVA), the differences among means were determined for significance at P< 0.05.
Results and discussion: The industrial pomegranate juice concentrate stored at (-20, 4, 20, and 35 °C) for 20 weeks, and some physicochemical properties like the second turbidity, CIE Lab color parameters, the rheological properties, the bioactive component (total phenolic and flavonoid contents), and antioxidant properties (FRAP and DPPH) investigated in order to determine the best condition of storage. The second turbidity was obvious among the samples stored at 35 °C in the last fourth weeks. Although there were no significant differences among L* value of the samples stored at -20, 4, and 20 °C, a* and b* value of the samples stored at -20 and 4 °C had the same reduction trend for 14 weeks. Even though the control samples had shear thinning behavior, the samples showed a dilatant behaviour after storage. Antioxidant activities measured via DPPH and FRAP sowed reduction with increasing time and temperature. Flavonoid content increased by increasing time and temperature. In conclusion, storage at 4 °C for 14 weeks was the best storage condition to keep the quality and reduce the costs.
Orang Khademi; Younes Nemati
Abstract
Introduction: There are two types of Japanese persimmon (Diospyros kaki Thunb.), astringent and non-astringent, based on the degree of astringent taste at maturity state. Fruits of either type are strongly astringent when small and immature, but non-astringent type loses its astringency during development ...
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Introduction: There are two types of Japanese persimmon (Diospyros kaki Thunb.), astringent and non-astringent, based on the degree of astringent taste at maturity state. Fruits of either type are strongly astringent when small and immature, but non-astringent type loses its astringency during development on the tree, still with firm flesh. However, the astringent type keeps its astringency and is inedible even when fully colored. It loses its astringency when becomes over-ripe with extremely soft flesh. At this stage, the fruits are usually over ripe with poor quality. Astringency in persimmon is caused by soluble tannins present in the fruit flesh. One mechanism useful in artificial removal of astringency from persimmon fruit is condensation or polymerization of soluble tannins into insoluble non-astringent forms, by acetaldehyde, which is being produced in the fruit flesh during different treatments. Acetaldehyde accumulates in the fruit flesh during its exposure to ethanol vapor or high level of carbon dioxide (CO2) gas, Hence, constant temperature and short duration (CTSD) is the preferred method of CO2 treatment used to remove astringency of persimmon fruit. It involves holding the fruits in ≥95% carbon dioxide atmosphere for a short duration at constant temperature of 20-30°C then transferring to normal atmosphere. However using CO2 treatment as gas form is expensive and needs special equipment. However, solid CO2 (dry ice) is easily available in Iran with low price. It release CO2 gas and can be used for removing astringency in persimmon fruit. The response of persimmon to de-astringent treatment depends on the cultivar. In this study two persimmon cultivars namely: ”Karaj” and ”Japanese” were harvested at maturity (full coloring) stage and treated with dry ice and ethanol vapor to remove astringency and the quality of treated fruits were evaluated.Materials and methods: Astringent persimmon fruits cvs ‘Karaj’ and ‘Japanese’ were harvested at maturity stage and transported immediately to the Department of Horticulture Science, University of Shahed and treated with either ethanol or dry ice. Both ethanol and dry ice treatmenttreatments were applied in low-density polyethylene bags with 0.05 mm thickness and polyethylene container with 3 mm thickness. In the polyethylene container, dry ice was applied at amounts of 3, 5 and 7% per kilograms of fruit and in the polyethylene bags dry ice was applied at amount of 0.16, 0.25 and 0.33 per kilogerams of fruits. For ethanol treatment, in both polyethylene bag and polyethylene container, 10 ml of 36% ethanol per kilogram of fruit was sprayed. Thereafter, bags and containers were sealed completely and kept for 48 hours at 25°C and 80% RH. After removing from the closed bags and containers, fruits were held in air at 25°C, 80% RH for completing astringency removing. After astringency removal treatmenttreatments, soluble tannin contents, astringent taste degree, fruit firmness, total soluble solid and ascorbic acid content were measured. The content of soluble tannin was determined by Folin-Denis method and the degree of astringency was determined by panel test. The experiments were conducted in a completely randomized design (CRD) and analysis of variance (ANOVA) was performed and the means were compared using LSD Test.Results and discussion: After performing the astringency removal treatment, fruits containing less than 1000 ppm of soluble tannin on a fresh weight basis showed no astringency. Results presented here showed that, dry ice treatment, especially at higher concentrations such as 7% in both cultivars, causes removal of astringency and decreases soluble tannin contents below the threshold of 1000 ppm, but ethanol treatment was effective only in Karaj persimmon for the removal of astringency. Similarly, it was indicated that CO2 treatment removed the astringency more easily in some Chinese cultivars than the ethanol treatment. The response of persimmon cv. Karaj was similar to a leading cultivar Hiratanenashi in Japan, for astringency removal by both CO2 and ethanol treatments, while, according to this results, Japanese cultivar had not shown suitable response to ethanol, while it successfully responded to dry ice treatment.Treatments to remove astringency of persimmon fruit often cause fruit softening. Astringency removal treatment induced ethylene production in persimmon which causes to the fruits softening. In this study, the firmness of both cultivars decreased significantly after treatments, however, the average of flesh firmness was significantly higher after dry ice than after ethanol treatments.Total soluble solid contents under the astringency removal treatments in both cultivars reduced significantly. This reduction is due to the removing of soluble tannins responsible for fruit astringency, since they are included in SSC measurements when not polymerized. Moreover, the results showed that ascorbic acid content is not affected by astringency removal treatments.Conclusions: The results presented here showed that removing astringency from persimmon cvs. Karaj and Japanese were achieved by postharvest application of dry ice in the poly ethylene container. Results also showed that dry ice was more effective than ethanol in astringency removal and retained higher quality of fruit. Dry ice is available treatment in Iran and it can be commercially used for removing astringency of Iranian persimmon.
Najmeh Molaahmadibahraseman; Reza Farhoosh; Ali Sharif
Abstract
Introduction: Medical benefits of Omega 3 fatty acids have appealeda lot of research to be done on of fish oil. Among marine fish, kilka has the most industrial application. Kilka oil contains significant amount of omega-3 fatty acids. In this study, physiochemical properties, fatty acid composition ...
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Introduction: Medical benefits of Omega 3 fatty acids have appealeda lot of research to be done on of fish oil. Among marine fish, kilka has the most industrial application. Kilka oil contains significant amount of omega-3 fatty acids. In this study, physiochemical properties, fatty acid composition and stabilization of kilka oil were investigated. p- hydroxy benzoic asid, its methyl ester and alpha-tocopherol as control were compared to each other.Materials and Methods: Crude Kilka fish oil was supplied by Khazarcompany (Babolsar, Iran). All chemicals and solvents used in this study were of analytical reagent grade and purchased from Merck (Darmstadt, Germany) and Sigma–Aldrich (St. Louis, MO). 200 ppm of the mentioned antioxidants was added to the purified oil and kinetic regime of oxidation at temperatures of 35, 45 and 55°C was prepared. After monitoring theoxidation over time using peroxide test, graph of peroxide changes over time was plotted and induction period and kinetic parameters (F, ORR and A) were calculated. In order to compare the performance of antioxidants in oil and water, 10% emulsion of Kilka oil-in-water was prepared and 200 ppm of antioxidant was added to it and its oxidation process was monitored at 55°C.Results and Discussion: Results showed that the fatty acid composition of this oil contains a variety of unsaturated fatty acids, saturated and polyunsaturated (mainly linoleic, eicosapentaenoic and docosahexaenoic acids). Temperature had significant effect on oxidation. p-hydroxymethylbenzoate, a little more than p-hydroxybenzoic asid, could increase oxidative stability of oil. Alpha-tocopherol had better performance as compared with other antioxidants. Performance of methylp-hydroxybenzoatewas better in emulsion than oil. In general, the emulsifier and emulsion preparation as compared with antioxidant had a more prominent role in the oxidative stability of Kilka oil.
Ali Taheri; Abdolmohammad Abedian Kenari; Ali Motamedzadegan; Mehran Habibi Rezaie
Abstract
Protein hydro-lysate was prepared from Gold striped sardine (Sardinella gibossa) by Papain. Hydrolysis conditions (time, temperature, and enzyme activity) were optimized by response surface methodology (RSM) using a factorial design and anti-oxidative activity was the dependent variable. Results of the ...
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Protein hydro-lysate was prepared from Gold striped sardine (Sardinella gibossa) by Papain. Hydrolysis conditions (time, temperature, and enzyme activity) were optimized by response surface methodology (RSM) using a factorial design and anti-oxidative activity was the dependent variable. Results of the total determination coefficient, adjusted R2 and predicted R2 indicating the validity of prediction model and the experiment error was very small. An enzyme activity to substrate ratio (X1), 2%; time (X2), 30 minute, and temperature (X3), 45 °C were found to be the optimum conditions for a higher DPPH free radical scavenging activity (64.5%), using Papain. According to amino acid analysis results and chemical score, methionine and Isoleucine were the limiting amino acids in the hydro-lysate. The protein hydro-lysate tends to be a functional additive in food industries.
