جستجوی مقالات مرتبط با کلیدواژه "انجماد" در نشریات گروه "صنایع غذایی"

Increasing public awareness of the value, health, and hygiene of food, as well as changing lifestyles in industrialized and developing countries, has led to a demand for a variety of healthy, ready-to-eat fishery products. The paper, however, aims to evaluate the feasibility of producing fish fingers from (Sphyraena jello )and then comparing approximate compositions and spoilage indices under freezing conditions (-18) for four months. In this regard, fish finger treatments were considered, namely: Treatment 1: unwashed minced meat; Treatment 2: surimi; Treatment 3: unwashed minced meat + beef; Treatment 4: surimi + beef. Then, approximate factors (moisture, ash, fat, and protein) and spoilage indicators including free fatty acid peroxide, thiobarbituric acid, total volatile nitrogen bases were measured in products produced in zero (fresh sample), 1, 2, 3 and 4 month in freezing conditions. However, the results showed that Treatment 3 in fat (6.72%), ash (2.17%), and protein (5.61%) hold a significant difference with other treatments (P<0.05) at the end of the maintenance period. Compared to other treatments, Treatment 2 in moisture factor holds a significant difference (P<0.05), namely the highest amount of moisture (77.42). Moreover, increasing shelf life, chemical decay indices increased significantly in all Treatments (P<0.05). In the third month, peroxide index (4.56 meqO2/kg), free fatty acids (%19.3) and thiobarbituric acid (2.129 mg MA /kg), and free nitrogen bases reached their highest level in the fourth month in Treatment 3. As a result, the Treatment was declared unacceptable in the fourth month. Furthermore, holding a significant difference, Treatment 2 achieved shelf life up to the fourth month. However, the fish fingers prepared from surimi were acceptable in Treatments 2 and 4 until the end of the fourth month of storage.

The aim of this study was improvement of quality and appearance of frozen par baked strudel by using Lepidium Sativum seed gum (0, 0.25 and 0.50 %) and germinated quinoa flour (0, 5, 10 and 15%). Moisture (2 and 72 hours), specific volume, porosity, texture (2 and 72 hours), color of crust and crumb, sensory properties and overall acceptability of strudel were evaluated. The result showed moisture was increased by increasing gum and quinoa flour in the formulation. The lowest firmness and the highest specific volume and porosity were showed in the sample containing 5% quinoa flour and 0.5% gum and the sample containing 10% quinoa flour and 0.5% gum. Also, a* of crust and L* of crumb were increased by using quinoa flour. Replacement of wheat flour with quinoa flour (up to 10%) and Lepidium Sativum seed gum (0.25 and 0.50 %) were improved color, shape, chewiness, taste and odor and overall acceptability.

In the most of the human society, the issue of shortage of time for preparing food and the advantages of aquatic protein has brought about an appropriate motivation for introducing different kinds of ready-to-eat and semi-ready-to-eat products such as finger foods and burgers etc. made out of different aquatics. This research aims to conduct sensory evaluation on the fish finger made out of the meat of barracuda (Sphyraena jello) and to compare the sensory indices (texture, odor, color, taste and total utility) under freezing conditions -18ċ for four months. Four treatments of fish fingers including (first treatment: mince, second treatment: Surimi , treatment 3: mince+ red meat, treatment 4: Surimi +red meat) were considered. The indices in the products at the times of zero (fresh sample), 1, 2, 3, 4 months were measured under freezing conditions.  The evaluations of texture description between the exiting treatments indicate that there is significant difference between Surimi bearing treatments &minced fish during the storage period (P ≤ 0.05). Meanwhile, Second Treatment  at the time Zero, production and end of storage period (120 days) acquire the highest score of the texture factor by 4.74 ± 0.42 and 3.41 ± 0.64 respectively. The highest score in the color treatment at the time Zero is allocated to Second Treatment with 4.44 ± 0.20. As for the color factor, there has been a significant difference between minced meat and Surimi Treatments during storage period (P ≤0.05).

Sturgeon is the common name for the 27 species of fish belonging to the family Acipenseridae. The earliest sturgeon fossils date to the Late Cretaceous and are descended from other, earlier Acipenser form fish which date back to the Early Jurassic epoch. The Persian sturgeon is a species of fish in the family Acipenseridae. It is found in the Caspian Sea and to a lesser extent the Black Sea and ascends certain rivers to spawn, mainly the Volga, Kura, Aras, and Ural Rivers. Rigor mortis is a phenomenon where the fish, after death, becomes stiff. The rigor will get completed when almost all muscle fibers are contracted which lasts a while before it is resolved. The muscle then becomes more and more tender in the stage called meat tenderization. This locking of the muscles, called rigor mortis, can be slowed down by chilling the fish immediately after death. Rigor mortis starts immediately or shortly after death if the fish is starved and the glycogen reserves are depleted, or if the fish is stressed. The mechanism behind this is muscle contraction due to a shortage of ATP (adenosine triphosphate). However, ATP, carrier that provides energy to relax the muscle again, is no longer present, so the muscles remain rigid. Over time this rigidity disappears, but by then the fish has significantly deteriorated. Post-mortem factors such as glycolysis, pH, and rigor mortis have been shown to have profound effects on fish fillet texture. Rigor mortis is dependent on the fish species, temperature and handling before slaughter, slaughtering stress, the biological status of the fish, and the temperature of pre-rigor storage. The method used for stunning and killing the fish also influences the onset of rigor. Even when fishes are killed under the same conditions, there can be a high variation in the time of onset of rigor mortis. Therefore, the present study aimed to investigate the effect of rigor mortis on the nutritional, fatty acid changes, chemical, microbial and sensory characteristics of farmed A. persicus fillets during storage in freezing conditions.

The fish were caught using a cone net, and killed by pulling them out of the water. They were then transported to the laboratory by ice-containing units containing twice the weight of the fish. The fish were washed with drinking water immediately after death. To spend the period of freezing the corpse in the fish transport tanks (Chilled Sea Water), twice the weight of the fish was covered with ice powder prepared from drinking water. The fish layers were separated by ice and placed on the ice fish 5 cm thick. The water outlet valve of the CSW tank was left open during the storage period to drain the water from the ice thaw. The rigidity of the A. persicus was measured by dropping the tail from the edge of the table, and this stage ended with the softening of the fish muscles. The fish were washed after the rigor mortis had frozen. The fish were then beheaded, eviscerated, peeled, and washed again. The fish were filleted into 1-3 cm pieces weighing 250-200 g. The fillets were packed in polyamide plastics under vacuum and frozen in a fast freezing tunnel (temperature -40 ° C) for 8 hours. The farmed A. persicus fillet was used as a control before passing the coffin freezing and vacuum-packed. Experimental and control treatments were stored at -18 ° C for 6 months. Their quality was evaluated using chemical, microbial, sensory, and physical tests. The total bacterial counts, Staphylococcus, Pseudomonas, Coliform, Escherichia coli, and Clostridium were used for microbial characteristics. For chemical properties of peroxide, thiobarbituric acid, free fatty acid, total volatile nitrogen bases, polyan index, and the ratio of unsaturated fatty acids to saturated fatty acids were investigated. The quality of experimental and control fillets were assessed through physical experiments including pH and sensory such as tissue odor, color, taste and overall acceptance. Nutritional value and fatty acid profiles were determined.

The fish weight and length were 1.80 kg and 60 cm. In research and control treatments: pH, microbial, chemical, and sensory factors showed significant changes during storage (p<0.05). Pseudomonas, coliform, and Escherichia coli were not observed during the storage period. Nutritional value was not significantly different (p> 0.05). Palmitic acid was the highest (33.67 – 34.16%). The polyene index decreased in the experimental treatment (0.18) compared to the control (0.20). The ratio of unsaturated to saturated fatty acids in control and research treatments was 1.58 and 0.84, respectively. The shelf life of treatments was six months in freezing conditions. Color, texture, and overall acceptance in the experimental treatment were evaluated better than the control (p<0.05).

Increasing the shelf life of seafood is important not only for the processing industry but also for the companies that supply them. Freezing is currently one of the best fish preservation techniques that leads to maintaining the safety and quality of fish. However, pre-frozen treatment of the corpse and its storage in freezing conditions leads to the production of fillets with more contraction of the fillet length and more secretion during thawing. Compared to pre-corpse filleting, post-corpse filleting results in a threefold increase in efficiency, which is economically significant regardless of the time required for the process. Considering that microbial and chemical properties are lower in post-mortem fillets, but the sensory properties in these fillets are higher compared to fillets that have not undergone corpse. Because sensory characteristics such as color, texture, and appearance influence consumer decisions, Therefore, these properties are preferred over chemical and microbial agents. However, post-mortem processing in the industry is not easy and enough time must be taken to pass this stage, which leads to problems such as the need for a large pre-cooler as well as limiting the capacity of the processing plant. However, due to the benefits of corpse freezing on the quality of fillets, passing the corpse freeze is recommended for fish filleting.

In this study, three mathematical models (Plank, Pham and numerical model (finite element)) were used to predict the freezing time of potato samples. In order to develop the numerical model, thermophysical properties (density, thermal conductivity and specific heat) were predicted as a function of sample composition and temperature. Convective heat transfer coefficient was also estimated using the inverse problem method and dimensionless numbers. The results showed that the time calculated by the numerical model was the most accurate among three models and in the next step the best model was Pham model. In addition, an excellent agreement was obtained between observed temperature and temperature predicted by the numerical method in different freezing methods. In conclusion, the developed numerical model predicts the freezing temperature of potato samples correctly and can be used to simulate the freezing of suspended food in the air. In addition, the inverse problem method developed to predict convective heat transfer coefficient can be used in different freezing systems in order to choose the best system or optimize the process of food freezing.

Hamburgers are one of the most widely consumed meat products in the world. The shelf life of this product is rather short, therefore the freezing process is commonly used to reduce water activity and prevent the growth of microorganisms. Accurate temperature prediction during freezing is important in designing optimum cooling procedures and to avoid quality deterioration. Models for predicting freezing times range from relatively simple analytical equations to the more complicated numerical methods which require a lot of computing time and a sophisticated computer. In this research, thermal properties of hamburger, including ice fraction, thermal conductivity and specific heat were determined mathematically and then the freezing process of hamburger patty was investigated by two different numerical models (finite difference& finite element). The results were compared with experimental data and it was found that although both two models could reasonably forecast the temperature of hamburger patties during freezing, the finite element model demonstrated better goodness of fit than finite difference model. This study shows that the use of CFD packages such as COMSOL software can be considered as a suitable option for the estimation of freezing time of meat products.

Red meat is one of the most vital ingredients of human diet because of being an important source of protein, Further studies have proven that methods of cooking and processing of meat are effective not only on the fat, but also in increasing its oxidation index, as well. Freezing is a common practice in the meat industry because it preserves meat quality for an extended time and offers several advantages such as insignificant alterations in product dimension, and minimum deteriorations in product color, flavor, and texture. The limit of storage or shelf life of meat has been prevented from being reached by microbiological and physicochemical spoilage under conditions such as refrigeration and freezing. Today, due to the lack of time and employment of women, one of the concerns of home cooking is how to store meat. Usually the meat is kept frozen at home, and whether the meat is cooked in the frozen state or raw is one of the questions facing most women. Therefore, the purpose of this study was to compare the effect of freezing on the quality characteristics of raw and cooked meat to determine the quality characteristics of frozen and then cooked meat. In this research, effects of freezing treatment on beef was investigated in 6 replicates with two different treatments, precooked and then frozen (T1), pre-frozen first and then cooked (T2). The samples physicochemical features have been studied during 5 months of storage. A control sample was prepared without any treatment.

pH measurement, moisture content, fat, protein content and peroxide value of meat samples were all analyzed according to national Iranian standards.TBA index was measured according to the method described by AOAC (1990).Iron content was measured with a flame atomic absorption spectrometer according to national Iranian standard. Color measurement as ΔE was analyzed by image processing with Photoshop 8. Texture analyzing test was performed using a texture analyzer (Brookfield LFRA 4500, USA). In this method, the specimen was placed 2 cm in diameter on a porcupine and under a hemisphere. The test was accelerated to 1 mm / s, and the infiltration of the specimen was performed; the infiltration of the specimen and its perforation were reported at high power (Honika, 1997). Analysis of variance (ANOVA) was performed in a completely randomized design using linear plot (G.L.M) with Minitab 16 software. Comparisons of means were performed using Tukey's test at 95% confidence level. Treatments were performed in six replications.

The treatment effect was significant on all the analyzed parameters: pH, moisture, fat, protein, peroxide, TBA and cooking loss (p < 0.05). Results of the mean comparison showed that fat, pH and iron had significantly decreased (p < 0.05), while protein content, peroxide and TBA had remarkably increased (p < 0.05) during storage. The decrease in moisture after slaughter is inevitable due to the decrease in pH (close to the isoelectric pH of proteins), the completion of ATP, and the effects of myofibrillar contractions. These factors all lead to the release of water, which subsequently releases water into the extracellular and sarcoplasmic reticulum of proteins. Water retention was less for frozen samples. Although frozen foods are microbial-resistant, they are subject to chemical changes and their enzymatic activities continue at low intensity. The reason for the decrease in fat was due to the lipid oxidation Fresh meat fat was higher than frozen meat and cooked meat. Certainly, fat removal during baking causes this decrease. Fat content of treatment 2 was higher than treatment 1 and oxidation in treatment 1 was higher. In fact, initial cooking resulted in more fat removal in treatment 1 than in post-freezing cooking (treatment 2), which also differed during the storage period, resulting in lower fat content in the fifth month. Freezing damage the structure of muscle cells by releasing lysosomal and mitochondrial enzymes, iron and other peroxidants, which increase the intensity and speed of protein oxidation. In treatment 1 due to the thermal process initially and inactivation of some enzymes, the proteolysis process is slower. However, in treatment 2, the process of proteolysis has improved. The non-frozen water portion is important in determining oxidation, since some chemical reactions can also occur during freezing storage, primary oxidation during baking, for example, can lead to secondary lipid oxidation during melting (Own & Laurier 1975). As treatment 1 was first cooked and then frozen, oxidation began at the initial heating stage and continued at a lower rate during freezing. For this reason, it had a higher peroxide index than treatment 2 overall. In the overall study, the lowest thiobarbituric acid was in control and the highest in treatment 2 (frozen and cooked) after 5 months of storage. Both treatments (1 and 2) had oxidative corruption within 5 months of storage, although the severity of treatment 2 was higher than that of treatment 1. In fact, the initial curing by enzymatically deactivating was able to reduce the intensity of oxidation during frozen storage. The results of this study showed that the amount of iron decreased significantly over time. Freezing time in particular affects the retention of vitamins and minerals. Iron is in the structure of myoglobin, denaturation leads to increased sensitivity of myoglobin to auto-oxidation and co-oxidizes with iron myoglobin oxidation (Otter et al. 2012). In texture analysis, the results showed the meat become more stiff during storage. The raw state showed more stiffness due to the effect of annealing on protein deterioration. Finally, raw meat (treatment 2) showed higher firmness after 5 months and the nearest firmness to control raw meat. Increased stiffness of meat due to lower moisture content is one of the most common problems that occur due to freezing and storing of frozen fresh meat in the meat texture (Akhtar et al., 2013). Regarding the color, treatment 2 showed less difference with the raw meat which can be concluded that the raw meat in the freezer retains its color better.

This research showed that both samples had an oxidative spoilage within 5 months, which offers not to store frozen meat more than 3 months. Considering nutritional features expected from meat, it could be concluded that sample T1 which was the meat that was first cooked and then frozen was preferred to sample T2 because of preserving more iron, protein and having lower TBA index. In sum, cooking meat before freezing is recommended.

Rainbow trout (Oncorhynchus mykiss) is a species with high commercial value and much appreciated by consumers. This study was carried out to determine proximate analysis, amino acids composition and their changes in rainbow trout fillets during 9 months storage at -18°C. The results revealed that 17 amino acids were obtained in rainbow trout fillet,10 essential and 7non essential amino acids. In this research, Aspartic acid, Glutamic acid, Arginine, Leucine and Lysine were the main amino acids of rainbow trout fillets. The results of proximate analysis and its changes shown that moisture content of fillet s gradually reduced, protein content was decreased significantly, and fat and ash content were continually increased during frozen storage time (p<0.05). Primary and secondary lipid oxidation compounds measure by PV and TBA. PV was raised from 0.84±0.005 to 5±0.05meq O2/Kg and TBA from 0.65±0.03 to 1.92±0.05mg ma/Kg. In this research the increase was observed in FFA from 0.46±0.008 to 1.3±0.05g of Oleic acid/Kg. The TVB-N value raising from 10±0.1 to 40.5±0.02mg/Kg after 9 months (p<0.05). The results shown that the reduction of protein content related to breakdown of protein and all of essential and nonessential amino acids were changes. This changes, specially, shown after3 months and affected to the quality and nutrition value of fish fillets.

Mulberry is a fruit that has a considerable acceptance among consumers. The short harvest season and low persistence of this fruit have led to the use of methods such as freezing that have the least effect on phenolic compounds and antioxidant properties and sensory properties of the mulberry. One of the problems of sensory evaluation is the non-parametric results of the answers and the low accuracy of their analysis. Today, methods such as fuzzy logic allow inaccurate parameters to be analyzed by mathematical methods. In the present study, mulberry was stored in a freezer at -18 °C for six months and removed from the freezer at 0, 72 h, one month, two months and six months. After juice making, the sensory evaluation was performed using five-point hedonic method and the data were analyzed using fuzzy logic methodology, while attributes were color, aroma, taste, and feel mouth. Also, pH, acidity, antioxidant activity and total phenol content were evaluated. Sensory evaluation of the samples showed that the freezing of the mulberry increased the overall suitability of the samples in 72 hours and did not show a decrease in sensory properties during 6 months. Panelists assessed the importance of sensory attributes including taste, mouthfeel, fragrance, and color, as well. Although, sensory evaluation did not decrease the sensory of juice, significant decrease of pH (19.83%), increase in acidity (0.31%) and a decrease in antioxidant activity (about 14%) and phenolic compounds (about 21%) during freezing was observed. According to the obtained results, freezing can be suggested as an acceptable method for long storage of mulberry fruit.

Maintaining the nutritional quality and preserving pomegranate seeds is a major challange due to the fast degradation of the texture, color and overall quality of pomegranate seeds. In order to investigate the freezing of coated pomegranate seeds with chitosan and determine its quality during freezing storage, an experiment was conducted, in a factorial arrangement in a completely randomized design with three replications. Factors were: chitosan at three levels (0, 1 and 2%), freezing temperature at two levels (-14 ° -24 ° C) and time at 5 different storage times (14 days, 30 days, 60 days, 90 days, and 120 days). The highest tissue firmness was observed for 14 days of storage under both chitosan concentrations. Interaction of different levels of chitosan coating and time had an increasing effect on the color component changes, so that the most color changes in the brightness (L*), redness (a*), and yellowness (b*) was related to the use of chitosan coating 2%, were maintained at 60 days. The highest total soluble solids were related to 1% chitosan under 4 months of storage at -14°C. Maximum total acidity (1.36 mg / L) was also attributed to coated pomegranate seeds during 120 days of storage under both freezing temperatures of -14°C and -24°C. The results of mean compares showed that the total phenol stability under freezing temperature was higher at -14°C and after 120 days of storage, more phenol content was observed in the seeds in -24° C. The overall results indicated a positive effect of chitosan on maintaining the quality of pomegranate seeds during freezing, and the freezing temperature of -24° C with decreasing color changes during storage, played an important role in reducing metabolic activity and reducing anthocyanin degradation and was effective in maintaining fruit quality.

In modern life, access to fresh vegetables is limited and proper processing and storage techniques for vegetables are essential. Cabbage quality decreased over time, especially after 2-month storage. The bleaching and freezing can affect it. It is important for the industry to know how to treated cabbage after harvest till supermarket to decrease after harvest damage. The results of this research showed that vitamin C, phenolic compound and antioxidant decreased with storage. Vitamin C is decreased more than other characteristics of cabbage after storage almost 90%. Blanching methods affect the nutrient content of cabbage and Both freezing and storage times decreased cabbage texture (Turkmen et al. 2004). Therefore, in this study, a factorial experiment based on RCBD was designed with 3 replicates to investigate the effect of blanching and freezing method over time on frozen cabbage. by measuring the amount of vitamin C, phenolic compounds, antioxidant activity and elements, the effects of blanching (boiled water and steam) and freezing of two methods domestic (-18 °C) and semi-industrial (40° C) on the nutritional value of celery (Appium graviolens var. Dulce) was evaluated. The results showed that in general, after six months, the antioxidant activity,
vitamin C and phenolic compounds decreased and blanching with boiling water significantly reduced the amount of vitamin C and antioxidant capacity compared to blanching with steam treatment in celery. Over first two months, the reduction in phenolic compounds and antioxidant capacity was more than that of four and six months, but declined over time as the process slowed down. As time progressed, all elements reduced in celery. Vitamin C, has many biological activities in the human body. More than 85% of vitamin C in human diets is supplied by fruits and vegetables (Sahlin et al. 2004). The content of vitamin C among Brassica vegetables varies significantly between and within their subspecies. Generally, among Brassica vegetables, white cabbage is the poorest source of vitamin C (Saari et al. 1995). However, it is a very popular species of Brassica vegetables in Iran. According to our results, freezing of cabbage more than 2 months decreased vitamin C drastically. Loss of vitamin C after 7 and 14 days’ storage at 20 °C decreased to 44% and to 28% in broccoli However, when broccoli was stored at 4 °C, and did not decrease after 7 days and 20% loss after 21 days. Vitamin C content in broccoli reduced by 26% after 3 days of storage at room temperature, by reducing of the storage temperature to 5 °C resulted in an increase (25%) of vitamin C content in broccoli (Lisiewska and Kmiecik 1996). Before vegetables freezing, they washed and blanched to inactivate enzyme systems, especially oxidative enzymes (e.g. polyphenoloxidase, ascorbic oxidase, peroxidase) (Perry and Klein 1982). The effect of blanching in the retention time of vitamin C in different Brassica was investigated, although it depends on temperature and time of blanching method. Vitamin C after blanching was 84% for cauliflower, 70% of cabbage, loss of vitamin C was 28–32% in cauliflower, 41–42% in broccoli, 34% in broccoli (Leja et al. 2001). There was different report was shown that freezing decreased vitamin C in different Brassica differently. After blanching and freezing, about 30% in broccoli. The freezing did not change vitamin C in broccoli and
cauliflower during a 12-month storage and decreased by 3–18% for broccoli and 6–13% for cauliflower and 30%for cabbage (Saari et al. 1995; Leja et al. 2001). there are some reports was shown that Phenolic compounds in broccoli, which are stored 7 days at 1 °C, showed more decreased than ascorbic acid. Storage time effect on Phenolic compounds in different Brassica (Lisiewska and Kmiecik 1996). Phenolic compounds in broccoli, which are stored 7 days decreased 2–3 times (Papetti et al. 2002) On the contrary, total polyphenols did not significantly change in broccoli during 7 days’ storage (Leja et al. 2001; Lisiewska and Kmiecik 1996). Generally, among the qualitative characteristics of celery, reduction of vitamin C more than other traits was affected by different treatments. the type of freezing did not have a significant effect, but storage time was significant so that the values were reduced more rapidly in the first two months of storage.

Nowadays, frozen dough technology is used to produce bakery, pastry & cakes products. On the other hand, extrusion plays a role as a high-performance process in the food industry, which, given its unique characteristics, can replace many common methods of food processing. This study was carried out aimed to investigate the effect of freezing methods (slow and rapid) and the storage time of frozen dough under freezing conditions on physicochemical and sensory properties of extruded and non-extruded sorghum flour for producing a gluten-free product suitable for Coeliac patients. In this study, extruded sorghum flour (an extruder with a temperature of 150-160°C, a moisture content of 14%, a speed of 150 rpm, feeding of 40 grams per minute and circular matrix with a diameter of 5 mm and, in the last step, using a grinding mill and 0.599 mm mesh, flouring is done), non-extruded sorghum flour (100%), Xanthan gum (1% w/w) were used in cookie dough formulation. Two types of slow and fast freezing were used to freeze the dough of cookie. Slow freezing according to the method provided by X.u et al. (2009) and Ke et al. (2013). In a fast freezing method, rapid cooling rooms were used at -40°C for 30 minutes. After freezing, the samples were placed in polyethylene bags and stored for 0, 2, 4, 6 and 8 weeks in a refrigerator at -18°C (X.u et al., 2009). For the thaw process, dough pieces were placed in a refrigerator at + 4°C for 16 hours (Maizani et al., 2012). Baking was performed in a microwave oven at 180°C for 14 minutes. The properties of the final product, such as the ratio of expandability (AACC 10-52), textural properties (cookie texture were carried out using a TA.XTplus Texture Analyzer (Walker et al, 2012)), total gelatinization and enthalpy temperature(Using the DSC device and temperature range 7-157°C and heating temperature 10°C/min), color, percentage of porosity, shell thickness (Image processing technique and ImageJ software) and sensory evaluation were investigated in a completely randomized factorial. Statistical analysis of the results was done using a factorial arrangement of completely randomized design and comparison of the meanings using Duncan's multiple range tests at 5% level. Data analysis was performed with three replications using SPSS 18 software. The gelatinization temperature decreased with increasing times of storage; however, the total enthalpy of the process was increased. The results showed that with increasing freezing rate, the gelatinization temperature increased significantly (P≤0.05), and the total enthalpy of the process decreased and the cookie from frozen dough containing extruded sorghum flour has the highest gelatinization temperature and the minimum total enthalpy value. With increasing times of storage, the dough chewiness decreased significantly (P≤0.05) and the adhesion and stiffness of the dough texture increased. The dough chewiness increased with the increase in the freezing rate, however, the adhesion and stiffness of the dough texture decreased and cookie dough containing extruded sorghum flour resulted in a significantly higher chewiness and lower adhesion and stiffness (P≤0.05) of the texture compared to the non-extruded sorghum cookie flour in both methods of freezing. The extensibility ratio has significantly decreased (P≤0.05) with increasing the times of storage. The extensibility ratio of cookie was significantly increased with the increase in freezing rate (P≤0.05) and non-extruded sorghum flour samples showed a lower extensibility ratio relative to the extruded sorghum flour cookies. The dough freezing method also had a significant effect on the final cookie quality (P≤0.05). The stiffness of the cookie texture from the frozen dough decreased by increasing the dough freezing rate and its tissue was softer and cookie samples containing extruded sorghum flour have a significantly lower tissue stiffness compared to other samples. The stiffness of the cookie tissue increased significantly (P≤0.05) with increasing times of storage. L* parameter (lightness) significantly decreased (P≤0.05) with increasing the times of storage and decreased the yellowness factor (b*) and increased the redness factor (a*) significantly (P≤0.05) for the cookie made from frozen dough. The freezing rate had a significant effect (P≤0.05) on the lightness of the cookies. The parameters L* and b* decreased by increasing the freezing rate and the colors of these cookies were darker. Cookies containing extruded sorghum flour had the lowest level of L* and b* and highest level of a*. The porosity% and thickness of crust of cookie decreased significantly (P≤0.05) with increasing times of storage. These parameters increased significantly with increasing freezing rate (P≤0.05) and tissue porosity and thickness of crust of cookies obtained from the frozen dough containing extruded sorghum flour was significantly higher (P≤0.05). The results of the kinetics of cookie mass transfer from frozen dough showed that the effective moisture diffusivity of cookie was reduced by increasing times of storage. Overall, the results showed that the process of extruding sorghum flour has improved the physicochemical properties of the cookie, and the fast freezing process improves the quality of the cookie made from frozen dough, and in this condition extruded flour sorghum can be used as a suitable alternative to wheat. Also, the use of frozen dough for cookie production can be a good way to supply this product.

In this study, the effects of thermoelectric technology as a new freezing method and conventional system on changes in color (CIE L*, a* and b*), pH, freezing loss (FL) (%), thawing loss (TL) (%),water holding capacity (WHC) (%), microbial content and sensorial characteristics of beef meat were investigated. Results showed that thermoelectric freezer had a higher freezing rate compared to the conventional system. The pH value was significantly (p

Carrot as one of vegetables is rich of vitamin and minerals and can be used raw or fried; reduce in oil content of frying products is necessary and would be important to upgrade the level of society health, for the reason of inadequate information in the field of doing appropriate pre-treatment before deep and surface frying to obtain low fat products with the favorable qualitative properties; current research was designed. In the research by using blanching pre-treatment (0, 2.5 and 5 minutes), temperature (- 40, 0, and 40 degrees Celsius), and time of keeping in that temperature (1, 2, 3 hours) for determining appropriate pre-treatment by using statistical plan of RSM, both types of deep and surface frying were done, no blanching treatments which had been dried at 400 C for two hours by having the minimum amount of oil absorption ,minimum wrinkles and maximum moisture were chosen as the optimized treatments.

Freezing is one of the important refrigeration processes widely applied in food preservation, but textural defects can occur during process depending on freezing rate. These phenomena usually occur during freezing but become visible in the shape of crust cracking and flaking after final frying. This paper represents the effect of freezing and final frying conditions on some physical properties of chicken nugget. Three freezing temperatures (-20, -30 and -40°C) was used in this study. A texture analyzer by compression and penetration tests were used to assess the rigidity of sample after freezing and final frying respectively. Video capturing method was used during compression test for acquiring poison ratio; also, crust cracking and flaking of chicken nugget after freezing and final deep fat frying were evaluated by image analysis. The results showed that reduction in freezing temperature causes an increase in Young’s modulus especially at around of freezing point. But poison ratio decreased gradually by temperature reduction with the greatest change at freezing point. After final frying Young modulus of crust increased significantly (P

Freezing fish to prevent fish spoilage. Because microorganisms at temperatures below 18 ° C do not grow and speed of chemical reactions fish at this temperature reaches a minimum. In this project, the effect of freezing on fat oxidation of fish fillets Sparidentex hasta and Pampus argenteus were studied and results were compared together. 10 kg of Sparidentex hasta and Pampus argenteus randomly were purchased from Behbahan city market, respectively, with an average weight (350±2/20g, 750 ±38/15g), after wasing them, the fillets were prepared separately in closed packages in freezer with a temperature of -18 °C for 35, 65 and 95 days were maintained. Mentioned factors such as, TBA, PH, FFA, and peroxide of fresh and frozen samples were tested after each period freezing. The TBA, FFA and pH levels of both species increased in all during storage. Peroxide index in Pampus argenteus reduced but no significant change in Sparidentex hasta in the period.

Effects of Lepidium perfoliatum seed gum (LPSG) concentration (0, 0.3 and 0.6 wt%) and different processing treatments (freezing, pasteurization and sterilization) on physical and stability of oil-in- water emulsion prepared by whey protein (6 wt%) was investigated. For this purpose, particle size distribution, creaming index, microscopic characteristics, viscosity and flow behavior of emulsions were studied. Results showed that thermal processing increased the particle size of dispersed phase. Results also showed that the damage of membrane surface at high temperature such as sterilization was higher than other temperatures. At low Lepidium perfoliatum seed gum concentration, the emulsions were somewhat more resistant to thermal processes. However, at higher gum concentrations (0.3 and 0.6%), thermal processing did not have a negative effect on the emulsion stability. The viscosity and consistency coefficients also increased with increasing gum concentration. Shear thinning behavior for emulsions at all thermal treatments were also observed. Therefore, adding LPSG to the emulsion could increase its stability to the thermal processing.

Freezing is one of the ways to extend the shelf life and improve the chemical and microbiological stability of food products. Food products are exposed to different processes and the functional properties of the products change during these processing. Hydrocolloids are used to stabilize the products undergoing different food processing. However the addition of hydrocolloids to food products shifts the foods characters. On the other hand, hydrocolloids decrease the growing rate of ice crystals in dispersions. Lipidium perfoliatum locally called Qodume shahri. The study on the functional properties of Lipidium perfoliatum seed gum (LPSG) proved that this gum was able to bind with a large amount of water and increase the product consistency. The main purpose of this study was to understand the effect of freezing condition on functional properties including the rheological properties (steady shear rate), emulsion particle size distribution and foaming stability at different gum concentration of LPSG.
The materials were purchased from a local detailer. LPSG was extracted in optimum condition (T: 48±1 ºC, pH=8, proportion water to seed 30 to 1, t: 1.5 h) according to method previously described by koocheki et al. (2009). After the preparation of the freeze-dried gum powder, dispersions of LPSG were prepared in distilled water at different concentrations (0.5, 0.75 and 1% w/v). In order to study the effects of freezing condition on the functional properties of LPSG, the samples were freezed at slow and fast conditions. The flow behavior was described by fitting the shear stress (τ) to shear rate (γ) data with the models to determine the best model to describe the flow behavior of LPSG. For the Emulsion preparation, the aqueous phase was prepared by mixing 2 g WPC into 30 g distilled water and an appropriate amount of LPSG (0.1 and 0.2 g) into 50 g distilled water on a magnetic stirrer for 10 min at room temperature. The dispersions were then left overnight at 4 ºC prior to emulsion preparation. The emulsion was prepared by mixing 20 g sunflower oil with WPC using a magnetic stirrer for 10 min. The mixture was subsequently pre-homogenized with a laboratory homogenizer at a rate of 20,000 rpm for 2 min at room temperature. After that, the gum solution was added to the emulsion and homogenized for 4 min at the same rate. The particle size analyzer was used to measure the mean diameter. For the foaming stability, the gum dispersions were prepared at 0.5% gum concentration and left overnight in a refrigerator to ensure a complete hydration. Afterwards, they were treated with different temperatures. 2% of egg white powder was added to the solutions and mixed by a homogenizer for 2 min at 20000 rpm. The foam stability was calculated as the foam volume after 30 minutes. A completely randomized design with the factorial arrangement was used for statistical analysis. All experiments were statistically analysed by Analysis of Variance (ANOVA) in Minitab R14. The p-values of Results showed that the LPSG apparent viscosity increased insignificantly after the fast freezing condition. All samples illustrated non-Newtonian shear thinning behavior. Herschel- bulkley model was the best model to describe the flow behavior of the LPSG solution with the high determination coefficients. Among the selected rheological models, the flow behavior indices and consistency coefficients were unchanged. However freezing condition had no significant effect on the emulsion particle size. After 30 min foam stabilized by LPSG was constant. Therefore, LPSG can be considered as an appropriate stabilizer and thickening agent during freezing condition.