Food Engineering
Sajad Jafarzadeh; Mohsen Azadbakht; Faryal Varasteh; Mohammad Vahedi Torshizi
Abstract
Since persimmon is a pressure-sensitive fruit and it is difficult to store this fruit in warehouses, in this research, an attempt has been made to examine the parameters affecting the reduction of changes in its physical properties. The samples were loaded at 150 and 250 N, three types of foam container ...
Read More
Since persimmon is a pressure-sensitive fruit and it is difficult to store this fruit in warehouses, in this research, an attempt has been made to examine the parameters affecting the reduction of changes in its physical properties. The samples were loaded at 150 and 250 N, three types of foam container packaging with polyolefin film, polyethylene-terephthalate, and ordinary box, and four types of polyamine putrescine coating with concentrations of 1 and 2 mM, distilled water and uncoated. Properties such as Physiological Weight Loss, volume, and the density of persimmon fruit, as well as the firmness of this fruit in the prepost-storage stage were examined. The results showed, the highest firmness was obtained in the treatment of putrescine at a concentration of 1 mM and a foam container with polyethylene film with a value of 6.5 N, which was almost three times the firmness of uncoated fruits. The lowest Physiological Weight Loss, volume, and density were obtained in the same type of coating and packaging. The values of these parameters were 2.458%, 1.82, and 0.833%, respectively, compared to the first day of storage. Overall, the use of polyamine treatment showed a significant effect on changes in the physical properties of persimmon fruit, and foam containers with polyolefin film emerged as the optimal packaging option, resulting in the least amount of change among the different types of packaging used.
Food Technology
Maryam Alsadat Nazemi; Sara Ansari
Abstract
Introduction: Roasting is one of the most important thermal processing to improve the physicochemical and organoleptic properties of nuts. Wild almond, especially roasted wild almond is very sensitive to oxidation due to its high content of unsaturated fatty acids. Lipid oxidation can be inhibited by ...
Read More
Introduction: Roasting is one of the most important thermal processing to improve the physicochemical and organoleptic properties of nuts. Wild almond, especially roasted wild almond is very sensitive to oxidation due to its high content of unsaturated fatty acids. Lipid oxidation can be inhibited by using a suitable packaging material and modifying the atmosphere of the packaging. In this research, the effects of roasting degree (light roasting at 50°C/60 min, medium roasting at 100°C/45 min and dark roasting at 200°C/ 30 min), as well as the presence/ absence of nitrogen gas in two types of pouches including polyethylene (PE) and oriented polypropylene/ cast polypropylene (OPP/CPP) were investigated. The effects of above mentioned treatments were examined using Completely Randomized Design on the moisture, total fat, firmness, peroxide value and conjugated trienes, fatty acid profile and sensory properties during two months storage at 37°C. Materials and Methods: The wild almonds used in this research were collected randomly from the Dasht-e-Arjan region in Fars province (Iran). The debittering process of almonds was done by soaking in 4- 6 % (w/v) of NaCl solution for 12 hours at three consecutive days. A certain amount of debittered wild almonds with a uniform size were roasted at 50°C for 60 minutes (light- roasting), 100°C for 45 minutes (medium- roasting) and 200°C for 30 minutes (dark- roasting) in a laboratory toaster (SSN-2004x, Iran). After cooling at room temperature, samples of 100 g were packed using gas flushing packing machine (90SM4, Shadmehr Co., Iran) in three different conditions: a) air atmosphere (in transparent PE pouches, 70- 75 mm thickness), b) modified atmosphere flushed with N2 gas (in transparent PE pouches, 70- 75 mm thickness), c) modified atmosphere flushed with N2 gas (in two-layer transparent OPP-CPP pouches, 25 and 50 mm thickness of the first and second layer). The samples were stored for two months at 37°C and 7-8% R.H. At definite time intervals, the samples were analyzed for the moisture content by oven drying, total oil content by the soxhlet method, protein content by the Kjeldahl method, and fiber content through chemical gravimetric method. Extraction of oil from the nut samples was carried out using hexane, as described by Kornsteiner et al. (2009). Peroxide value (PV) was determined by the iodometric assay according to IUPAC standard method 2.501. Conjugated trienes were calculated according to IUPAC Official Method 2.205 based on measuring absorbance of a solution containing 0.01-0.03 g of oil in 25 ml of isooctane. The fatty acid composition of wild almond oils was determined by gas chromatography equipped with flame ionization detection. Hardness of the wild almond was evaluated using a Texture Analyzer (CT3-Brookfield, USA). Sensory evaluation of samples was carried out by 30 trained panelists using a five point hedonic scale. Statistical analysis of completely randomized design with three replications and means comparison in 95% confidence level was employed using the SPSS-19 software. Results and Discussion: Analysis of variance indicated that the independent effects of roasting conditions, packaging and storage time and the interaction of roasting conditions and storage time on the mentioned parameters were significant (p<0.01). With roasting at higher temperatures, the moisture content and hardness decreased significantly while the oil, protein and fiber content of wild almond kernels and the peroxide value (PV) and conjugated trienes (CT) of their oils increased significantly. However, the increase in protein and CT for medium and low roasting conditions and the increase in fiber for medium and high roasting conditions were not significant (p>0.05). Moreover, increasing the roasting temperature of wild almond led to a significant increase of palmitic acid and a significant decrease of stearic acid whereas other fatty acids did not change significantly. There was a remarkable increase and then a rapid decrease in the fiber, fat and protein content of all roasted samples during the first and second months of storage, respectively. Whereas the PV and CT of oils increased and the moisture content and hardness decreased significantly during the two- months storage. For each roasting temperature, wild almonds packaged in pouches under N2 had lower PV and CT of oils and the OPP/CPP pouches under N2 had better performance in this regard and retaining moisture, fat, protein, fiber content and texture. At the end of storage with PV of 24.6 (meqO2/kg oil) and K268 of 1.92 the dark-roasted almond sample packaged with PE/air atmosphere was the least stable, and the light-roasted sample packaged with OPP/CPP under N2 with PV of 5.3 (meqO2/kg oil) and K268 of 1.57 was the most stable form against oxidation. According to the results of sensory analysis, the highest overall acceptability score was attributed to the samples roasted at 100°C for 45 minutes.
Somayeh Rastegar; Azam Shojaee; Behjat Tajeddin
Abstract
Introduction: Persian walnut (Juglans regia) from Juglandaceae family is one of the most important fruits in the world that has an important role in human health. It contains a notable list of plant nutrients that has been found to have disease preventing and health promoting properties. Walnut is a ...
Read More
Introduction: Persian walnut (Juglans regia) from Juglandaceae family is one of the most important fruits in the world that has an important role in human health. It contains a notable list of plant nutrients that has been found to have disease preventing and health promoting properties. Walnut is a source of bioactive compounds such as phenolic and flavonoid complexes where they act as antioxidants and free radical scavengers. It also contains pleasant flavor and high concentration of minerals and fatty acids. Extending shelf-life of this perishable fruit has been accomplished due to its high oil level and oxidation of oil (Tajeddin, 2004). Rate of loss in walnut kernel quality and quantity between harvest and consumption affects its productivity. Control of temperature is the most effective tool for extending the shelf life of fresh horticultural products. However, to reduce high losses and keeping product’s quality, packaging method is very important as well as low temperature. Therefore, in this study, the effect of temperature (4 and 25 oC) and packaging methods (vacuum and air packaging) on the changes of walnut kernel compounds was evaluated to improve quality of its storability during six month cold storage.
Materials and methods: Walnut harvested from a commercial garden at the mountain regional of Raber, Kerman province. All chemical materials for different tests obtained from Merck Company, Germany. Immediately after walnuts harvesting, they were dehulled and dried in expose of sun shade with the circulation of natural air. The walnuts were then transferred to the laboratory and their wooden shells were removed. Subsequently, about 25 g of walnut kernel was packaged in the polyethylene films with 87μm (0.087 mm) thickness, under a vacuum machine and stored at 4°C and 25°C to be later assessed for further analyses intended for six months. Phenol, flavonoid, carbohydrate, protein, water percent, color parameters (C, h, WI), organoleptic characteristics, and peroxide value of kernels were measured every month during storage time. The control samples of packaged walnuts under environmental conditions were also stored. The current study carried out as a factorial assay on the basis of a completely randomized design with three replications at Hormozgan University. Data were subjected to ANOVA using SAS software version 9.4. Verification of significant differences was done using Duncan's Test at 1% probability level.
Results and discussion: Results showed that carbohydrate and proteins decreased during storage time. Both of vacuum package and low temperature contorted the reduction of different characteristics of kernel such as bioactive compounds during storage significantly. Sensory properties were also reduced during storage, especially at the end of period, in all conditions except for treatment at 4°C and vacuum packing. Control samples (temperature 25°C and air-containing packags) during the experiment showed a lower quality for all factors. Samples that stored in low temperature and vacuum package had better brightness (higher chroma, Hugh, lightness (L) and white index values (Wi)) than other treatments. The treatments had a significant role in the preventing of increasing peroxide value. The peroxide value in treated samples was increased from 0.023 to 0.68 meq/g, while in vacuum packages it was changed from 0.023 to 0.37 meq/g. Increasing of peroxide value was observed from 0.023 to 0.68 and from 0.023 to 0.25 meq/g in room temperature and cold temperature, respectively. After six months, the average peroxide value in all samples was less than one milliequivalent per oil kilogram. Decreasing of phenolic compounds (30%) and flavonoids (35%) and increasing the peroxide index simultaneously led to the reduction of the appearance and organoleptic properties of the control samples. Generally, vacuum package and low temperature condition that using in this study showed the best effect on the nutritional compounds quality of walnut kernel such as bioactive components during six months storage. Shelf life enhancement of walnut by vacuum packaging in the different polymers has been already reported by Tajeddin, 2004.
Jafar Nabati; Farshad Izadi; Reza Abbasi; Farshid Hassani
Abstract
Introduction: Potato (Solanum tuberosum) belongs to Solanaceae family and is a perennial plant which is herbaceous in nature. Potato is the world’s number one non-grain food commodity and 75% of the total production are being harvested in densely populated developing countries such as China and India, ...
Read More
Introduction: Potato (Solanum tuberosum) belongs to Solanaceae family and is a perennial plant which is herbaceous in nature. Potato is the world’s number one non-grain food commodity and 75% of the total production are being harvested in densely populated developing countries such as China and India, and thus alleviates the food crisis in third world countries. Potato is the most imperative and widely cultivated vegetable crop in Iran, per capita consumption in the country is more than 35 kg. Potatoes are the World’s most widely grown tubural crop and the fourth largest crop in terms of fresh produce after rice, wheat and maize. According to the National Policy on Potato Industry, the potato is an important food and cash crop that plays a major role in food security and is only second to maize in terms of utilization. Potato production is increasing due to the economic decline of competing cash crops such as maize, pyrethrum, and barley, and increasing demand from consumers and processors. Potato tuber undergoes physiological dormancy period during the postharvest storage. The length of the dormancy period is dependent on the varietal genetic profile, environmental factors and storage conditions. Commercial potato cultivars grown for the processing industry has shorter dormancy periods and associated with different storage disorders like sweetening, greening, toxicants, etc.; therefore it is vitally important to employ suitable storage conditions to ensure their continuous supply. Potato is semi perishable crop, however placed under low temperature storage to prevent them from sprouting and to ensure their regular supply whenever required. Low temperature potato storage is however, associated with low temperature sweetening and is specifically undesirable in processing potato varieties. The phenomenon is primarily associated with the potato storage under low temperature and as a result of which the insoluble starch is enzymatically hydrolyzed into soluble glucose, fructose and sucrose. Tuber sweetening deteriorates the tuber commercial quality and causes the fried products to turn brown and bitter in taste due to subsequent acrylamide formation. Packaging is an essential component of post harvest supply chain management in horticultural crops. In Iran and other developing countries, potatoes stored in polyethylene bags with a capacity of 40 to 80 kg that causes many problems during storage. Therefore, this study was conducted to evaluate the different potato packing methods for industry uses.
Material and Methods: Study was conducted in 2015-2016 at cold storage Ravand, in the Toos Industrial Zone, Mashhad, Iran in a completely randomized design with triplicate. Treatments including cold storage of potatoes, storage in a wooden box, kept in mesh bags, storage in polyethylene bags, and storage in punched polyethylene bags and kept in split polyethylene bags. Potato cultivar used in this study was Agria Picked up in the second half of October. Box weight was measured before storing tubers. Tuber store below six degrees Celsius and relative humidity between 85% and 90% were considered for all treatments. The amount of carbon dioxide during storage was set between 700 and 1000 ppm. Storage period took six months. After storage period, the number of healthy, sprouting and rotting tubers were counted and the sugar content, total phenol content and quality of chips, starch content, dry matter and tuber specific gravity were measured.
Results &Discussion: The results showed that the highest and the lowest loss percentage observed in mesh bags and polyethylene bags respectively. The difference between the two treatments was 2.4 percent. Tuber maintenance in polyethylene bags and polyethylene bag split showed the highest and lowest percentage of decay. Most sprouting tuber was observed in polyethylene bags and punched polyethylene bags, and the lowest sprouting tuber observed in a mesh bag and wooden box. The difference between the highest and lowest percentage of sprouting tuber in punched polyethylene bags and mesh bag was 16 percent. There were no significant differences observed in reducing sugars and total phenol component at different storage methods. The highest percentage of starch obtained in split polyethylene bags and mesh bag and the least amount of starch in punched polyethylene bags. Packing tubers in mesh bag showed the maximum and in split polyethylene bags showed the minimum brown color in chips. The difference between the highest and lowest specific gravity was two percent, however, in all treatments specific gravity was more than one. The highest of dry matter percentage observed in a mesh bag and split polyethylene bags with 24 percent and the lowest of dry matter percentage was observed in punched polyethylene bags. Tuber loss weight in polyethylene bags was lower than other treatments, but rotten tubers percentage was higher than the other treatments. In contrast, tuber weight loss in split polyethylene and punched bag's was equal to storage in wooden boxes and tuber decay in split polyethylene bags was lower than other treatments. Chips quality in split polyethylene bags was more than other treatments and equal to wooden boxes. Generally, wooden boxes, split polyethylene bags and punching bags are found suitable to reduce the percentage of rot and sprouting potato tubers and as effective way to store potatoes in storage room.
Salah Fahiminia; Lotfali Naseri
Abstract
In order to maintain the quality and increase the shelf life of fruits, many studies have been carried out in terms of the packaging specially applications of the nano-composite packages in the packaging. Because of the low storage ability of the plum fruit, in this study, the effects of the four nano-composite ...
Read More
In order to maintain the quality and increase the shelf life of fruits, many studies have been carried out in terms of the packaging specially applications of the nano-composite packages in the packaging. Because of the low storage ability of the plum fruit, in this study, the effects of the four nano-composite packages and common polyethylene (as a control) were analyzed on maintaining quality and increasing of the plum fruit, in a factorial experiment based on a completely randomized design at two levels of the storage. So, the containers including plum fruits were kept at temperature of 1±1 ºC and relative humidity of 90±5 % during 45 days. After 22 and 45 days, the fruit different quality properties such as total antioxidant activity, ascorbic acid (vitamin C) content, total soluble solids, acidity, titratable acidity, firmness, fruit weight loss percentage and decay were measured. The results showed that the application of the nano packages as compared with common polyethylene could maintain the fruit quality at level of (P≤0.01) after 45 days of storage, and increase the post harvest shelf life of the plum fruit as the highest total antioxidant activity, vitamin C, acidity, titratable acidity, firmness and the lowest fruit weight loss percentage and content of the decay were observed in nano-composite packages. According to these results, using the nano-silver packages was effective on increasing the plum fruit quality maintenance during the storage.
Soudabeh Einafshar
Abstract
Sour cherry is one of the most important horticultural products in Iran that consumes as fresh and dried fruit. In this research the effect of osmotic pretreatment on Physicochemical, antioxiative and microbial characteristics of 4 cultivars of sour cherry: Early Jibilium, Butermo, Sigany and Local were ...
Read More
Sour cherry is one of the most important horticultural products in Iran that consumes as fresh and dried fruit. In this research the effect of osmotic pretreatment on Physicochemical, antioxiative and microbial characteristics of 4 cultivars of sour cherry: Early Jibilium, Butermo, Sigany and Local were investigated. The samples were placed in different osmotic solution, dried and vacuum packed in Polyamide pouches The physicochemical tests (pH, Bx, titrable acidity, moisture content, color, anthocyanin and phenolc compounds and antioxidative activities) and microbial tests were carried out after 6 and 12 months. The results showed that sour cherry Butermo var. had the most Bx, pH, acidity. Local and Early Jibelium var. had the least Bx and ph. The amount of moisture of Early Jibelium and Local var. were the most and the least, respectively. The chroma of Local var. was the most and had the more red purity than other varieties. Butermo and Local var. with 28.8 and 23.35 mg Cyanidin 3 Glychoside had the most and the least anthocyanins respectively. The amount of total phenolic compounds in Butermo Var. was significantly more than other varieties. The reducing power of Early Jibelium var. was the more significantly than other varieties. Osmosis process had no effect on the moicrobial growth, anthocyanins and phenolic compounds and antioxidative activities. One year storage significantly increased moisture, color, microbial growth, phenolic compounds and radical scavenging power of dried cherries but had no effect on other factors. The microbial conditions of samples were on the standard limits.
Soudabeh Einafshar; Parvin Sharayei; Mozhgan Shormij; Razieh Niazmand
Abstract
Saffron is the most important Iranian non oil export. Improper conditions of saffron flower storage increases microbial contamination and decreases saffron quality. This study was done for prolonging the shelf life of saffron flower in modified atmosphere packaging and subsequent to producing a new method ...
Read More
Saffron is the most important Iranian non oil export. Improper conditions of saffron flower storage increases microbial contamination and decreases saffron quality. This study was done for prolonging the shelf life of saffron flower in modified atmosphere packaging and subsequent to producing a new method for exporting the fresh saffron flower as cut flower. Saffron flowers were packed in a polymer (Polyamide- Polyethylene bags) and three gas combinations of CO2, O2, and N2 (30%,5%,65%; 50%,5%,45% and 70%,5%,25% respectively). Samples and Control (without packaging) were kept at 0˚c for 15 days. Every three days the concentrations of oxygen and carbon dioxide inside the packages, the yield of product, physical (weight loss, percent of the flowers welter, the length and diameter of fresh stigma) and chemical properties (percent of moisture and the amount of Crocin, Safranal and Picrocrocin of dried stigma) were measured. The existence of E.Coli and enumeration of yeasts and moulds also were done. The results showed that modified atmosphere packaging increased the shelf life of saffron flowers. The chemical and physical qualities of control were lost strongly during 9 days. There were no evident for E.Coli growth in the samples. Enumeration of yeasts and moulds showed that most treatments were seen the national standard of Iran (103cfu/gr).
