Journal of food science and technology
Year:2009 | Volume:6 | Issue:2|Papers Count:16

Macaroni and pasta products are one of the favorite dishes in the world. In Iran, it improves its position in family food programs. In recent years, using additives and different components to improve quality and nutritional properties of this product have been used.Soy protein isolate (SPI) added to semolina to improve quality and quantity of protein and amino acid profile of final product such as macaroni. The aim of this study was the effects of adding different level of SPI (1, 2, 4 and 6% on semolina basis) on the properties of macaroni have been investigatedResult showed that by increasing the amount of SPI, water absorption of dough was decreased. Also by increasing the amount of SPI, the value of protein and ash contents were increased. Although the amount of soluble solid, cooking quality index, moisture content and pH value had fluctuation.Sensory evaluation of products in terms of color, taste, chew ability and stickiness were determined by 5 trained panelists. These two samples and control sample were evaluated by 30 untrained panelists with using preference test. The result showed that the sample contained 2% SPI was recognized the best regarding chemical, rhological and cooking quality index. In order to determine amino acid profile, the sample containing 2% SPI and the control sample were analyzed by HPLC. The result indicated that the amounts of amino acids were increased but methionine did not. Lysin and Hysidin showed maximum and minimum increase respectively 32.1% and 2.2%.

Drying is one of the most important steps in raisin processing. During this step, initial moisture content is decreased up to 15 – 17 percent (d.b) for suitable storage. Achieving optimum drying conditions can affect the processing time and improvement of raisin quality. Temperature, air velocity and pretreatment are important factors in grape drying process and its qualityIn this research, effect of the following conditions on time and drying rate of Black currant grape was studied: temperature at four levels of 50,60,70, and 80oC, air velocity at three levels of 1, 2 and 3 m/s, and four pretreatments including hot water, %5 potassium carbonate, %0.4 olive oil, %0.5 sodium hydracids and no pretreatment. Diffusivity and activation energy of all treatments were determined.The results show that factors such as temperature, air velocity and pretreatment have significant effects on drying time and average drying rate. Pretreatment has a significant effect on drying process and decreases the time of drying up to 68 percent in some temperature levels. Also by increasing the temperature, drying time decreases up to 66.5 percent in some pretreatments. Increasing the hot air velocity decreases it about 8.3 percent.

Farinograph quality number (FQN) is a conventional index introduced by BrabenderTM company. This rheological index, which is a resultant of all Farinogram indices, is used in wheat research studies. In this study, the relationship between FQN and wheat quality as well as breadmaking quality of 13 Iranian wheat cultivars was investigated. A significant (a=0.01) correlation was obtained between FQN and all wheat quality characteristics, except that of protein content. Among the characteristics investigated, Dough Stability with a correlation coefficient of 0.835 showed the highest correlation coefficient. Between the wheat cultivars studied, Alamoot and Bezostaya showed the lowest and the highest FQN values, respectively. FQN gives the possibility for classification of wheat cultivars based on a single quality index.

Carboxymethyl cellulose is the most abundant carbohydrate biopolymer that has excellent film - forming properties. But its main problem is its poor resistance to water vapour transport. In this study the effect of glycerol as plasticiser and oleic acid as an edible hydrophobic agent were investigated. Results showed that by increasing of oleic acid up to a certain content, moisture uptake decreased significantly (about 53/5%). By Increasing the concentration of glycerol significantly increased moisture uptake (about 64%). Studying of mechanical properties, showed that both glycerol and oleic acid have plasticizing effect on the films but glycerol showed more effective role on decreasing tensile strength and increasing flexibility then oleic acid. Both glycerol and oleic acid are able to decrease glass transition temperature of films. But the effect of the glycerol on the thermal properties of films was higher than oleic acid.

In this research using a digital camera, a PC and a graphical software; a simple and low cost method for the evaluation of colour of food materials is introduced. Analysis of digital pictures of the surface of samples can give L, a, b Hunter colour parameters and colour distribution. Drying of Kabkaab rutab in a range of temperatures (56, 66 76, 86 and 96oC) and times using a cabinet drier was investigated. colour changes of the dried samples and the control were evaluated by analysing the digital pictures of the samples and showed that increase of temperature and time caused a systematic reduction of L, a, and b values. Taken into account colour changes of the samples and their drying rates at different temperatures, the drying temperature of 76oC seemed to be the best condition for drying of Kabkaab rutab.

Studying dough microstructure is considered as a useful and effective tool to understand the effect of different process parameters on dough and the final product characteristics. In this study, sample preparation and staining protocols were established to study the dough micro-structure with epi - fluorescence light microscope (EFLM). For this purpose, dough sample preparation and staining conditions with respect to the type of staining dye, solvent, dye concentration, staining time and the type of filter used for EFLM were studied. The results showed that sodium Fluorescein (1% w/v) and Rhodamine B (0.1% w/v) in 2-methoxyethanol solvent give the best staining results. The double staining technique used enabled us to simultaneously and successfully observe the starch granules and protein network in the dough. The resting time after the addition of the dye had an impact on the quality of microscopic images. Among different resting times investigated, 60 min time gave the best results. Among the different EFLM filters, the MWBV2 filter for 420 nm spectrum gave the best results. Using image processing software and the specialized plug - ins the quality of EFLM images was improved. When a suitable protocol and methodology was established, the microstructure of dough was studied under different mixing regimes (under - mixing, optimal mixing and over - mixing). Overall, the results indicated that EFLM can be successfully used for studying the dough microstructure and this technique gives comparable results to well - known CSLM technique.

Khorasan Razavi Province with 6.83 % Iran milk production is an important area of animal husbandry. In this study, the relationship between milk composition and total bulk milk somatic cell counts was investigated. 123 samples of bulk tank milk were randomly selected from 41 dairy farmers in the Province of Khorasan Razavi (Iran) during April - March 2006, every month. A total of 1476 samples were analyzed. Samples were analyzed for acidity, fat, protein content and somatic cell counts. The results showed that the season of raw milk production did not have significant effect on the acidity. Fat concentration increased gradually from spring to winter and there were significant difference between spring and other seasons (P<0.05). Higher levels of the protein content were observed in samples collected during the autumn and winter seasons. The highest total bulk milk somatic cell counts were in July. Total bulk milk somatic cell counts had significant impact on acidity, fat and protein content. Moreover, the level of acidity and fat in milk decreased with increasing SCC (P<0.01, P<0.05 respectively). A significant (P<0.001) positive relationship was observed between total bulk milk somatic cell and protein content in milk. Also, positive correlation (R2= 0.91) were established between direct microscopic cell count and Somatos instrument.

In the present study, effects of Entroccocus faecium, Lactobacillus agilis, Lactobacillus plantarum, Strepoccucus thermophilus and a mixed culture from 3 former isolates were investigated on organoleptic characteristics of Iranian white cheese. The isolates used in this study that had been isolated from the Iranian Lighvan cheese, collected from central labrotory of Gorgan University. Ten cheeses were manufactured according to method of making of white Iranian cheese using ewe’s and cow’s milk which had been bought from Gorgan city. Organoleptics test performed by 8 trained panelists revealed that there is significant difference at 5 % significant level in organoleptics scores between Lighvan and manufactured cheese so that lighvan cheese and cheese prepared with ewe’s milk and mixed culture had most and least sensory score respectively. However, there was no significant difference between other prepared cheeses but the cheese prepared with cow’milk and mixed culture had the most score of organoleptic test. Results of organoleptic test showed that, type of milk has very important role in the development of organoleptic charectrestics of cheese. Also different speices of lactic acid bacteria associate in its flavor development.

Fruit juices are among heat sensitive foods. Vitamins, proteins and other organic materials present in most fruit juices may be easily decomposed during heat processing. Therefore, evaporators with minimum residence time and maximum efficiency for concentrating fruit juices should be applied. So,tubular type falling and climbing film evaporators are suitable devices.In the present investigation, certain important factors in concentration of in digenous orange juice from north region of Iran in a pilot - plant double effect falling-climbing film evaporator have been studied. Variation of liquid film tickness, heat transfer coefficient, hydrodynamic and thermal properties show that evaporation of the fruit juices take places in turbulent regime and required concentration and ratio of the product concentration to acidity can be achieved by six stages evaporation.

The objectives of this study were to investigate the potential of faba bean protein isolate (FPI) in preparation of an edible film and to determine the effects of film forming solution pH and plasticizer concentration on film properties. So film samples were prepared in three different pH levels (7, 9 and 12) and plasticizer concentrations (40, 50 & 60% w/w protein isolate). Results showed that increasing of pH improved mechanical properties (tensile strength and elongation) and solubility of films but caused water vapor permeability (WVP) and lightness of films to decrease. Plasticizer concentration did not affect WVP over the studied range. Elongation and solubility of films increased and tensile strength decreased by increasing of plasticizer content of film forming solutions. The lowest WVP and the highest tensile strength was observed at pH 12 and 40% (w/w of FPI ) glycerol concentration.

The consumption of different kinds of fish has been increasing in Iran, during the recent decade. Therefore, high microbial content and contamination of such food with pathogen bacteria can cause infection or food poisoning. The objective of this study is investigation of salted fish bacteriologic quality that is produced traditionally in one of the North states of Iran (Guilan).72 fish samples from two species of Rutilus frisi kutum and Mugil auratus were collected, immediately after traditionally salting and their total count of aerobic and coli form bacteria and contamination to E.coli and vibrio parahaemoliticus were investigated due to standard APHA method.The total number of aerobic bacteria differs from 5×105 to 1×103 cfu/g and the mean numbers were 3.2×103 cfu/g for Mugil auratus and 5.4×105 cfu/g for Rutilus frisi kutum . 11.1 percent of the samples were contaminated with coliform bacteria with mean number of 2×102 cfu/g but no contamination with E.coli was confirmed. Moreover, in 57 samples (79.16%) contamination with vibrio parahaemoliticus was observed that were comprised 26 samples (45.6%) of Mugil auratus fish and 31 samples (54.3%) of Rutilus frisi kutum In conclusion, the results of this study and the similar ones in other countries demonstrated that there is the possibility of seafood products poisoning with pathogen bacteria. Therefore, health training, improvement of processing, avoiding raw consumption and finally, regular controlling of health care managers can be effective in prevention of infectious diseases and food poisoning following consumption of these products.

Effect of variety, moisture and drying temperature on mechanical properties of soybean (failure force and energy, apparent modulus of elasticity and toughness) were studied. These properties were measured through quasi - static loading experiment by material testing machine. Factorial test with Randomized Block design was used to study the effect of drying parameters including final moisture content (3 levels: 10, 12 and 14% d.b.) and temperature (at 3 levels: 50, 60 and 70oC) and varieties (Hill, Pershing and Gorgan3) on mechanical properties of soybean. The results showed that both drying factors (final moisture content and temperature) had significant effect on the force and energy failure. So that by increasing final moisture content from 10% to 14%, the failure force and energy increased from 47.5 N and 10 mJ to 82 N and 56 mJ, respectively. This different behavior of soybean in relation to other grains is due to a high amount of fat in soybean structure. Also by increasing drying temperature from 50oC to 70oC, the seed failure force was increased. Investigation of the effects of variety and moisture factors on toughness and apparent elasticity modulus showed that variety and moisture content had significant effect on three factors. Soybean elasticity modulus was 80.95 MPa at 10% moisture content, which by increasing moisture content to 14%, it decreased to 25.56 MPa.

Spices are used all over the world to prepare foods mainly because of their flavoring properties however , these are grown and harvested in warm, humid areas of the world where the growth of a wide variety of microorganisms is readily supported. The aims of the present work were to evaluate the hygienic quality of some spices,in the chain stores of Tehran.We collected 151 packed samples of three kinds of spices, black pepper, turmeric , cinnamon in the chain stores of Tehran. we investigated to determine their microbial status based on ISIRI. we found these results: average of total aerobic mesophilic count for turmeric was 3.6×107cfu/gr , black pepper: 7×106cfu/gr. cinnamon: 1.92×104cfu/gr average of coliforms count was: tumeric: 6.26×103cfu/gr, black pepper: 8.83×103cfu/gr , cinnamon: 4.7×103cfu/gr. Feacal coliform tests for 3 kinds of spices were: turmeric 13%, black pepper 34%, cinnamon 6%,average of yeast and mold count was for turmeric: 1.23×103 cfu/gr, black pepper: 2.94×103cfu/gr and cinnamon 2.9×103cfu/gr. We compere our results to ISIRI standard and we found that, some of them were out of standard limit, therefor: it is suggested to provide legislation on the sanitary and hygienic quality of spices in our country.