Battol Attar; Seyedeh Zahra Seyed Alangi; Sara Jorjani
Abstract
Introduction: Value-added products, referring to the fact that a raw commodity or commodities are transformed into a processed product through use of materials and technology, may have different appearances, textures, tastes and smells than their raw material. Fried product is one of the most popular ...
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Introduction: Value-added products, referring to the fact that a raw commodity or commodities are transformed into a processed product through use of materials and technology, may have different appearances, textures, tastes and smells than their raw material. Fried product is one of the most popular ready to eat foods all around the world. They have excellent sensory qualities due to their appealing flavor and texture. Products such as shrimp usually coated with breading before frying to induce additional sensory and quality attributes. The process of battering and breading provides special functions in food products, including improved appearance of the products, increased texture crispness, reduced oil uptake during the frying process and increased the shelf life of the coated products.
Hydrocolloids are used extensively in food technology as thickening and gelling agents, stabilizers, and emulsifiers. In addition, the hydrocolloid coatings are of great interests due to their desirable barrier properties to gas/moisture and good mechanical characteristics. Thus, a variety of foods have been coated with hydrocolloids to prevent moisture loss, preserve texture, and maintain color, consequently extending the product shelf-life. Specifically, the hydrocolloid coatings are often known to reduce the oil uptake of fried foods. The mechanisms of the oil uptake during frying are associated with heat transfer from the frying oil to the food and the migration of water and oil. Various hydrocolloids have been tested as an oil barrier coating material and the effectiveness of hydrophilic and thermo-gelling hydrocolloids in reducing oil uptake during frying has been well reported in previous studies.
Material and Methods: Fresh peeled shrimp (Litopenaeus vannamei) was purchased from Gomishan city, Golestan province, Iran. Xanthan gum was bought from Asia Research Petrochemisry (Iran). White flour, corn flour, breading powder, oil and salt were prepared from the local supermarket. All other chemicals used in this study had analytical grade and were gained from Fluka or Merck companies.
The freezed shrimps were thawed at room temperature before processing. Four different formulations were applied in pre-dusting and battering as following:
Control= without xanthan in pre-dust and batter,
A=2% xanthan in predust,
B=2% xanthan in batter,
C=1% xanthan in predust + 1% xanthan in batter.
The batter formulation was consisted of wheat flour (75%), corn flour (24.5%), salt (0.5%). The dry ingredients were blended for 3 min at speed 2 m/s in a Kenwood Major Classic mixer (Kenwood-BL460) with water (1:1.4 solid to water ratio). In each treatment, firstly, pre-dusting was done and then, battering. Afterwards, it was allowed to drip additional batter for 30 s. For final coating, orange bread crumbs were used (Gols Company). The samples were pre-deep-fried by sunflower oil at 190 °C for 30 s (Fritaurus Professional 3 domestic fryer, Barcelona, Spain). The treatments were cooled to room temperature for 30 min. Then, they were placed in plastic freezer bags (LDPE film, thickness 150 μ) and stored at -18 °C.
Moisture content in the samples was determined in quadruplicate according to the Association of Official Analytical Chemists (AOAC) (2000) method. Fat content of fried products was distinguished using Soxhlet extractions according to the AOAC (2000) method No. 992.15.
Batter pickups (%) were determined as following equation:
Batter pickup (%) = (Weight of coated shrimp–Weight of uncoated shrimp)/(Weight of coated shrimp)×100
Product yield (%) was calculated by weight of the cooked shrimp block/ weight of the raw shrimp block × 100.
Quantitation of fatty acid methyl esters in raw and fried breaded shrimp was carried out by gas chromatography (Unicam-4600) with 30 mm×0.25 mm column (Film Tekness-0.22 μl) and FID detector, using glyceryl tritridecanoate (C13:0) as an internal standard (Sigma, Barcelona, Spain). Fatty acids were expressed as percentage of total fatty acid methyl esters or in absolute content (mg/100 g food).
Fried shrimp coated with the selected formulations was evaluated by a trained sensory panel of 12 members. Each sample was randomly numbered and presented to the panel member. A hedonic panel was also performed by the same panelists, who evaluated aroma, taste, texture, color, appearance and overall acceptability characteristics. A hedonic 5-point scale was used, 1s unusable, 2s dislike, 3s acceptable, 4s like and 5s like very much. All data are reported as mean± standard deviations of triplicate. One-way analysis of variance (ANOVA) was used to compare the means of all evaluated parameters. Differences were considered significant at P
Sodeif Azadmard Damirchi; Razagh Mahmodi; Mahood Sowti Khiabani; Majid Shirmohammadi
Abstract
Introduction: Pistacia is a genus of the family Anacardiaceae. Among the 15 known species of pistachios, only 3 species grow in Iran, including Pistacia vera, Pistacia Khinjuk and Pistacia atlantica. P. Khinjuk is a native plant in Iran. The plant is known as Khenjuk or Kelkhong in Persian. Resin of ...
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Introduction: Pistacia is a genus of the family Anacardiaceae. Among the 15 known species of pistachios, only 3 species grow in Iran, including Pistacia vera, Pistacia Khinjuk and Pistacia atlantica. P. Khinjuk is a native plant in Iran. The plant is known as Khenjuk or Kelkhong in Persian. Resin of this plant has been used as an indigestion, tonic, toothache and astringent. In addition, fruits of P. Khinjukare used as edible wild fruits in form of roasted or salted nuts. There are reports on extract obtained from wild pistachio. It has been shown that the extract is rich source of phenolic compounds and other antioxidant compounds. Oil obtained from wild pistachio also has high content of essential fatty acids which can reduce and prevent from different diseases. Extracts obtained from the wild pistachio tree has also been used in pharmaceutical and cosmetic industries. However, there is no scientific report on qualitative properties of wild pistacia species khinjuk. Therefore, the aim of this research was to study the chemical and nutritional composition hull and core of wild pistacia species khinjuk.Materials and Methods: The Pistacia Khinjuk was collected during flowering stage from Southwest of Iran (KouhgiloyeBoyerahmad province) and identified by the Herbarium. Separate tests were performed on the hull and core of wild pistachio. First, the fruit hull was isolated from its core and then they were crashed and their core was separated. Moisture, oil, protein and ash content and pH of the hull and core of the fruit were determined. The hull and core of fruit were used for oil extraction. The hull and core were powdered and their oil was extracted by hexane. For fatty acids profile, extracted oil samples were methylated and obtained fatty acid methyl esters were analyzed by gas chromatography. Also, the extracted oil stored for three month at room temperature, and every thirty day peroxide value (PV), acid value (AV) and chlorophyll content were determined. PV and AV were determined by titration methods. Chlorophyll content was determined by spectrophotometer. Extract of the dried hull and core of fruit were obtained with percolation in ethanol and its total phenol content and DPPH free radical scavenging activity were determined. Phenolic content was determined using folinciocalteu method. Also, the extracts were added at percentages of 1, 2 and 3% to the rapeseed oil and extracts antioxidant properties were evaluated by rancimat.Result and discussion: Analysis showed that hull has more oil and ash content and lower protein content than core. Hull oil content (84%) was two times more compared to the core of the fruit (47%), but core protein content (7%) was almost twice compared to hull protein content (3%). The results showed that the percentage of major fatty acids in hull and core of fruit was oleic acid 33% and 41.2%, linoleic acid 10.6% and 21.5%, alpha-linolenic acid 6% and 3.1%, palmitic acid 17.2% and 11% and palmitoleic acid 13.1% and 3.1%, respectively. Results showed that oil extracted from hull and corehave high content ofmonounsaturatedand polyunsaturated fatty acids with relatively high amount of essential fatty acids. Total phenolic content of hull and core of the fruit were 25.6 and 6.3 mg gallic acid per 1 gram of dried sample, respectively. This results show that hull is a rich source of phenolic compound which can be important from nutritional point of view. Peroxide value and acid value increased during 4 month storage significantly. Increase in PV was higher in oil obtained from hull than core oil. Increase in PV can be result of fatty acid oxidation which is affected by several factors such as fatty acid composition, antioxidant content, peroxidant content and storage condition. AV of oil extracted from hull was higher than oil obtained from core. AV was increased in oils obtained from core and hull, but increases in hull were higher. Increase of AV can be result of hydrolyses of triacylglycerols which produce free fatty acids.Chlorophyll content was higher (7 times) in oil obtained from core compared with oil obtained from hull. Oil obtained from core had green color because of high chlorophyll content. Chlorophyll content reduced significantly (P≤0.01) during storage. It should be mentioned that chlorophyll content is an important factor in oil oxidative stability because chlorophyll act. as a sensitizer and enhance oil photoxidation.Evaluation of oil stability by rancimat showed that highest rapeseed oiloxidative stability was obtained by addition 3% of hull extract. Hullextract was more effective onfree radicalscavenging(88%) than core(75%).Hull of wild pistachio in comparison to its core has more phenolic content, therefore more antioxidant activity is also is expected. Phenolic compounds can act as antioxidant and make oils more stable against oxidation. Conclusion: According to suitable fatty acid composition and total phenol content, wild pistachio need more attention in people’s diets as a cheap and useful nut.
Reza Farhoosh; Mohammad Hossein Hadad Khodaparast
Abstract
In the present study, the oxidative stability of nine Iranian commercial olive oils, including four virgin samples and five deodorized ones, was compared to that of two foreign virgin olive oils. In total, the foreign samples had the MUFA/PUFA ratios (av. 9.27) higher than those of domestic ones (av. ...
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In the present study, the oxidative stability of nine Iranian commercial olive oils, including four virgin samples and five deodorized ones, was compared to that of two foreign virgin olive oils. In total, the foreign samples had the MUFA/PUFA ratios (av. 9.27) higher than those of domestic ones (av. 5.70). The peroxide and acid values of the olive oils studied ranged from 8.5 to 14.5 meq/kg and from 0.1 to 4.27 mg/g, respectively. Tocopherols content of the foreign olive oils (av. 436.7 ppm) was averagely higher than that of the domestic olive oils and even about two times that of domestic virgin ones (223.4 ppm). On average, the foreign virgin olive oils contained phenolic compounds (154.0 ppm) higher than that of the domestic ones (112.3 ppm) and especially deodorized olive oils (46.0 ppm). The oxidative stability of oil samples was suitably interpreted in terms of chemical composition data, so that the foreign virgin olive oils had more appropriate chemical composition in total, and therefore, indicated oxidative stabilities higher than those of the domestic virgin and deodorized olive oils.
