Journal of food science and technology
Year:2010 | Volume:7 | Issue:1|Papers Count:14

In this research physicochemical properties of three potato varieties (Agria, Satina and Kenebek) of Golestan province were studied and the effects of these parameters on quality attributes of French fries were investigated. Statistical analysis showed that there were differences between amount of dry matter in three varieties, with the maximum and minimum dry matter contents found in Kenbek and Satina (P<0.05) respectively. Also the highest amount of starch, sucrose and energy were found in Satina and the lowest content of energy and starch were found in Agria and Kenebek in compared with other variety which had the lowest content of sucrose. Differences between starch content, sucrose and energy of three varieties were significant (P<0.05). The highest and lowest amount of fat content were observed in Agria and Kenebek, respectively (P<0.05). The highest amount of dry matter content related to Agria French fries and three varieties had the significant differences in amount of dry matter content in final French fries (P<0.05).The highest and lowest amount of shear force were found related to Agria and Kenebek strips, respectively (P<0.05). According to results of this study, Kenebek potato variety due to suitable dry matter content, higher specific gravity and lower reducing sugars in comparison with others varieties lead to better products as regard to texture, color, dry matter content and amount of oil absorption and so it can be suggested as a suitable variety for processing.

Liver and kidney of Iranian water buffalo used to consume as protein sources. The aim of this study was to evaluate macro- and micro-elements content of liver and kidney of water buffalo. The samples were collected from both sexes of slaughtered buffalos (n=40) from two different age groups (mature and immature). A sequence of steps including drying, weighting, and dry ashed and acid extract was used to determine mineral composition in liver and kidney. Analysis of the acid digested samples was measured by a atomic absorption apparatus calibrated with standard solutions of the minerals. The results indicated that Potassium is the uppermost mineral found in liver and kidney (326.4 and 212.69 mg/100gr fresh tissue, respectively). Sodium was the second highest mineral was found in liver and kidney (72.2 and 172.32 mg/100gr fresh tissue, respectively). There were no significant differences in mineral of liver and kidney between different sexes of the buffalos. No significant differences in mineral content of both organs were found between mature and immature buffalos.

Effect of gamma irradiation on total volatile base nitrogen (TVB-N) and sensory evaluations of Indian white shrimp (P. indicus) held frozen (-18°C), for 9 months and every 1.5 months, was studied. TVB-N values increased gradually during the storage period and decreased with increasing irradiation dose that reached 20.64, 27.45, 34.14, 35.45 mg N/100g flesh, respectively for irradiated and control samples. Also with organoleptic evaluation indicated that, shelf-life of 5, 2.5 KGy samples increased up to 3 months and 1 KGy samples increased up to 1.5 months compared to control samples.

Seventy walnuts (Juglans regia L.) genotypes were selected in Markazi province in 4 different geographical locations, based on their regular bearing and high productivity, and were evaluataed for several pomological characters during 2007 growings- season. Among the 70 preselected genotypes, 12 superior ones were considered for further evaluation for kernel’s oil and fatty acid compositions. In these genotypes, the fatty acids compositions in three oil samples were determined by gas chromatography. In the evaluated genotypes, the oil percentage varied from 51.0 to 73.0. The fatty acids palmitic, stearic, oleic, linoleic, and linolenic composition were variable greatly among studied genotypes. Result indicated that palmitic acid was the main saturated fatty acid component (6.09-8.12%) followed by stearic acid (2.19-4.10%). The oleic acid was the only monounsaturated fatty acid componenet and was varied from 20 to 43 percent. The highest content among fatty acids was belong to linoleic (37.39-58.95%). Unsaturated fatty acids were found as 85% of the total fatty acids content of the oil. While maximum content of the saturated fatty acids was found 12.36%. It seems that the differences in oil percentage and the fatty acids compositions will be related to both genetic diversity of studied genotypes as well as cultural and ecological conditions of the growing regions. In conclusion, the kernel of the genotypes MS10, MS68, MS69 and MS70 with higher linoleic and linolenic acid percentage, have a higher food quality from the genotypes of MS11 MS12, MS15, MS23, MS27, MS43, MS52 and MS54.

Citrus, especially orange, are of great important among agricultural products in the world. In this study thin-layer drying of orange (var. Thompson) was modeled using artificial neural network (ANN). An experimental dryer was used. Thin-layer of orange slices at five air temperatures (40, 50, 60, 70 & 80°C), three air velocities (0.5, 1 & 2 m/s) and three thicknesses (2, 4 & 6 mm) were artificially dried. Initial M.C. during all experiments was between 5.4 to 5.7 (g/g) (d.b.). Mass of samples were recorded and saved every 5 sec. using a digital balance connected to a PC. MLP with momentum and LM were used to train the ANNS. In order to develop ANN's models, temperatures, air velocity and time are used as input vectors and moisture ration as the output. Results showed a 3-6- 1 topology for thickness of 2 mm, 3-7-1 topology for thickness of 4 mm and 3-5-1 topology for thickness of 6 mm, with LM algorithm and TANSIG activation function were able to predict moisture ratio with R2 of 0.99906, 0.99919 and 0.99930 respectively. The corresponding MSE for this topology were 0.00013, 0.00012 and 0.00009 respectively.

Aim of pre-treatment drying of mulberry was to reduce the moisture content to a level that allows safe storage over an extended period. In this research after different combination of ethyl oleate pretreatments, mulberry was dried industrially (cabin dryer). Dried mulberries packed in polyethylene and polystyrene and preserved for 5 months in 20°c. Non Enzymatic Browning was tested at 440 nm by spectroscopic method. Organoleptic tests were done by trained panelists. Hardness, Cohesiveness, Springiness and Chewiness of dried mulberries were measured by a texture analyzer. Statistical method was factorial in frame of completely randomized design with two factors and three replicates. Factor A was different pretreatments and factor B was packaging type. The results showed that Least intensity of brown color was in dried white mulberry pretreated by ethyl oleate 2%+ ascorbic acid1% and then in ethyl oleate 2%+ potassium meta bisulfate 0.5% treatments . The lowest total count was in white mulberry in ethyl oleate 2%+ potassium Meta bisulfate 0.5%. The results of Panel tests showed highest score for texture, color, odor, taste and overall acceptance in pretreatment of fruits with ethyl oleate 2%+ potassium meta bisulfate 0.5%. The results of rheological tests showed that the highest score for chewiness was in white mulberry pretreated with ethyl oleate 2%+ potassium meta bisulfate 0.5%. White mulberry pretreated and packaged in poly styrene had the lowest scores for brown color and total count after 5 months storage. Totally it is concluded that dried white mulberry pretreated with combination of ethyl oleate 2% and potassium meta bisulfate 0.5% and packed in poly styrene preserved its qualitative, sensory and rheological characteristics after 150 days in 20°c .

The biogenic amines content of whole rainbow trout (Oncorhynchus mykiss) and its related bacterial load (psychrotroph and psychrophiles, pseudomonads and mesophiles) were monitored during ice storage in a period of eighteen days (zero, 3, 6, 9, 12, 15 and 18). The levels of putrescine, cadaverine and histamine and bacterial loads increased (P<0.05) during storage but tyramine was not detected in any of the samples. Initial concentration of putrescine was 0.4 and finally reached to 8.97 mg/g, and psychrotroph and psychrophiles were the dominant microorganisms. The best correlatios were found among putrescine and psychrotroph and psychrophile and its regression equation derived relating PUT, pse and psy (R=./98): [PUT =0.83 pse + 0.69psy+ 0.41]. In adition another regression equation derived relating CAD and time (R=0.955): [CAD =0.576 time - 3.49].It is therefore concluded that although the quality control of Rainbow trout can be approximately estimated by measurement of either putrescine or psychrophiles with the usage of derived equation, but it's much better to evaluate some of these factors simultaneously to accomplish a precise quality assessment.

Simple and corresponding impacts of organic acidifiers ( Lactic acid, Acetic Acid and Citric acid) with three levels (0%,0.25% and 0.5 %) on specific volume and dough fermentative parameters was conducted by a completely randomized design with factorial arrangement and three replications. At the next stage an orthogonal comparison between selected acidified treats (having control sample) with sourdough treats was made.The study showed that addition of each of these acidifiers had a significant effect on the mentioned property. Also statistical analyses revealed that, corresponding impacts of all the three acidifiers on the feature was significant (P<0/05).Finally the studies distinguished that type and amount of acidifiers used in this study don’t have any bad impact on the structure of dough gluten, so that the increase of acidity of these samples resulted in increase of bread specific volume .Also, orthogonal comparison between selected acidified treats (having control sample) with sourdough group indicated that considering specific volume property, these two groups did not show any significant differences.

In this study, binding ability of Saccharomayces cerevisiae to aflatoxin of pistachio was investigated. Results indicate that the yeast has aflatoxin surface binding ability of 40% (with initial concentration of 10 ppb aflatoxin) in exponential phase. Acid and heat treatment increase this ability 60% and 55%, respectively. Binding appears to be a physical phenomenon that reaches to saturation point within first 2-3 hours of process. Also, results showed that yeast immobilization on aflatoxin contaminated pistachio in order to toxin reduction, have no effect on color factor. In this condition, Hunter Lab factors (L*, a*, b*) indicate no significant changes. Yeast cells, viable or nonviable, are effective in aflatoxin binding and this property, especially for foods having high risk of aflatoxin contamination is considered as a good solution.

The application of modern biotechnology in food production presents new opportunities and challenges for human health and development. Use of advanced genetic engineering techniques in food crops production, and transferring genetic material from one species to another has developed the genetically modified (GM) food. The development of GM organisms (GMOs) offers the potential for increased field-crop production, reduced agricultural chemical usage, and improved crop sustainability and food security, particularly in developing countries. On the other hand, application of genetic engineering techniques could be lead to improve nutritional value and enhanced production of functional foods. Increasing global biotech crop area from 2 millionth hectares in 1996 to more than 100 millionth hectares in 2006 indicates the continuous development in the first decade of their cultivation. It is expected that stellar growth in biotech crops, witnessed in the first decade of commercialization, 1996 to 2005, will continue and probably be surpassed in the second decade 2006-2015. Despite the potential benefits of genetic engineering of foods, the technology is surrounded by controversy. Many concerns and risks of GMO related to human health and environment are allergy, extension of antibiotic resistance genes, horizontal gene transfer, and effect on biodiversity. During the two last decades, several international committees have instituted guidelines and legislations for risk assessment of GM foods. One of them is the Cartagena Protocol on Biosafety which covers environmental safety of GMOs. According to the regulations, safety assessment relies on establishing that the food is substantially equivalent to its non-GM counterpart and specific testing for allergenicity of proteins and toxicity of metabolites and the whole food. Regarding to significance of biotechnology in permanent development, Islamic republic of Iran approved the Cartagena Protocol in 2001 and officially has been obligated to accomplish it from the beginning of 2004. Therefore, government established the national biosafety council, but the related regulation has not been approved yet. As a result, there is not any legal control on the genetically modified food imports at the moment in our country. So, it is necessary to pass the related regulation as soon as possible. Otherwise, the country will encounter heavy losses.

Production of evaporated milk from fresh milk and skim milk was studied. The method of evaporated milk production is on the base of evaporation in the single effect evaporator. Products were stored three months at 4, 25 and 37°C. To study the quality of evaporated milk, organoleptic tests were performed. The obtained results were analyzed with randomized complete block design and split plot design. With increasing the temperature from 4°C and above and storage time changes in colour of the evaporated milk appeared. Increasing temperature caused changes in viscosity of evaporated milk. Keeping the product at temperatures above 37°C caused gel formation. Two stage homogenization caused prevention of gel formation in evaporated milk.

Nowadays, edible films are commonly and increasingly used for covering food products, as a replacement for synthetic films. Their advantages are being edible, safe and functionally effective. Many researches have been being done in this regard. This article reviews fundamental and applied aspects of edible films in food industry including definitions, classifications, applications and common types of used materials.