IRANIAN JOURNAL OF FOOD SCIENCE AND TECHNOLOGY
Year:2008 | Volume:4 | Issue:4|Papers Count:11

The effect of retrograded waxy corn starch on the rheologlcal properties of wheat flour dough and the final quality of baguette breads was investigated. Waxy corn starch pastes (10%) were stored at 5 °C for 7 days and the powder specimens of retrograded starches thus obtained were substituted of wheat flour for bread making at levels of 3, 5 and 7%.The rheological properties of dough were evaluated by farinograph and extensograph. Specific volume, moisture content and firmness of breads, were measured over a period of 0, 2, 4, 6 days. Sensory characteristics of breads were evaluated in the period of 24, 48, 72 storage hours. Water absorption was increased by retrograded waxy corn starch. Generally, the substituted flours developed viscosity rapidly but could not maintain the stability of paste viscosity. The dough made from the substituted flours exhibit weaker and less stability than that made from the wheat flour. The bread which contained retrograded waxy corn starch showed an increase in specific volume and the result of sensory evaluation showed that they were very acceptable. During the storage of bread, increase in firmness was suppressed by adding retrograded waxy corn starch. Results showed that incorporation of 5 % or 7% retrograded waxy corn starch produced considerable improvement in the shelf life of bread. During of storage (6 days), the bread including retrograded waxy corn starch maintained moistness and softness. As a result retrograded waxy corn starch could be used for bread making to improve the quality of bread.

According to mainly importance of the sensory characteristics of meat products from consumer viewpoint, increasing of the consumption of meat products, the existing articles addressed in literature about of principally effect of fat, water and fat replacers on sensory characteristics of meat products, this research carried out for evaluation of sensorial characteristics of high fat sausage and low fat sausages with 60% meat in National Nutrition and Food Technology Research Institute and Gooshtiran company in 2006. This study was done by explorer and experimental methods. The treatments were produced in three replicates totally twenty one formulas. Sensory characteristics of all treatments as color, taste, juiciness, firmness and palatability evaluated by 8 trained panelists using eight-point scale and acceptability evaluated by 31 in-house panelists using ranking test. The main treatments (three replications) were analyzed by Kruskal-Wallis and then the means were compared with Mann-Whitney U. Spearman’s rho Correlation was used to determine the correlation among sensory characteristics of treatments. All low fat formulas had higher red colors and were juicy and more acceptable than the control (P<0.05) but were not significantly different in taste and firmness. Color was medially and positively (r =0.55) correlated with firmness. The correlation between color and taste (r =0.47) and correlations between taste with juiciness (r=0.41) and firmness (r=0.38) was weakly and positively (P<0.05). The significant correlations were not observed between palatability and acceptability and with each other sensory characteristics. Juiciness was negatively correlated with firmness but was not significantly different. As a result, there is possibility of sensory evaluation of produced sausages and can be as criteria for selection of the best formulation. It is recommended that evaluation of sensory characteristics and the application of panelists be studied in future researches for formulation and production of meat products.

Various factors such as biological and environmental factors, harvest method as well as type and length of storage influence characteristics of agricultural products. This is particularly true for fruits and entails considerable economic consequences. The present study was undertaken to investigate the influence of fruit size, variety and length of storage time on soluble solids content, pH, moisture content and two mechanical properties i.e firmness and penetration energy of kiwifruit. Using factorial experiment with Completely Randomized design, effect of independent factors including storage time (0, 6 and 12 weeks), fruit size (small and large), and variety (Monty and Hayward) on measured properties of kiwifruit were investigated. Results showed that storage time and crop variety had significant effects on the measured properties. Soluble solid content and pH values increased while firmness and penetration energy decreased in both varieties with increasing storage time. Storage time (12 weeks) had no significant effect on fruit Moisture content. It was also shown that the Hayward variety could be stored longer than the Monty variety. Therefore, in order to increase storage time of fruits, sorting on the basis of variety and size before storage is recommended.

Introduction and cultivation of new oilseeds, is an important step to provide needed oil for the country. Milk thistle (Silybum marianum) is an annual or biennial plant that the extract of its leaf or seed has been used for treatment of liver diseases since 2000 years ago. In spite of compatibility of this plant to climate of Iran especially resistance to dryness, there is no information about the content and quality of the seed oil. In this study, the oil content was determined by Soxhlet and it was 22.7%, nearly similar to soybean and cottonseed (dehulled) oil content. Refractive index, Color and Specific gravity and Peroxide (1.59), Iodine(109.57), Saponification(180.9) and Acid(1.82) values of the oil were studied. Also, fatty acid profile of the oil was determined by GC. Linoleic acid (51.2%) and oleic acid (28.8%) were the most fatty acids of the oil, respectively. In regard to remarkable oil content of the seed and high nutritional value of the oil (high-linoleic acid), cultivation of this new valuable oilseed is necessary and beneficial.

Effects of fortification Setareh flour with iron, folic acid, zinc and calcium on chemical properties (dry gluten, wet gluten, gluten index, protein and zeleny value), rheologocal properties (water absorption, dough strength, dough extensibility, dough loses after 10 and 20 minutes, resistance to extensibility, extensibility index, maximum height of curve and energy), was considered in Barbary breads and compared with control treatment.  In this study we have 4 treatments as follows:1- Setareh pure flour without any fortificant/ as control.2- Flour which fortified with low dosage of fortificants : (ferrous sulfate 20, folic acid 1.5, zinc oxide 20 and calcium carbonate 900 p.p.m).3- Flour which fortified with middle dosage of fortificants : (ferrous sulfate 30, folic acid 2, zinc oxide 30 and calcium carbonate 1200 p.p.m).4- Flour which fortified with high dosage of fortificants : (ferrous sulfate 40, folic acid 2.5, zinc oxide 40 and calcium carbonate 1500 p.p.m).Statistical data have shown that, in all mentioned properties flour treatments fortified with minimum and middle amounts of fortificants had better results than the flour which fortified with maximum amounts of fortificants. Minimum and middle treatments didn’t have any significant differences, so with due attention to international organizations (WHO, FAO) and provide vital micronutrients for body, we propose middle treatment.  

Type and level of starter cultures are tow important factors influence the quality of concentrated yoghurt. The effects of type (CH1 and YC-380) and level (2,4 and 6%) of starter cultures on the sensory properties of concentrated yoghurt that produced by concentration of milk using a vacuum evaporator to 2 levels of total solids were studied. Results showed that the flavour and texture scores of samples that were prepared with YC-380 were significantly higher than those were prepared with CH1. Increasing the level of CH1 to 4% improved the acceptability of all samples but had no significant effect in the samples with higher levels.

In response to recent concerns regarding the enumeration of microbial load of raw milk in shorter time and lower cost and the need to ensure that milk destined for dairy plants has met the acceptable load therefore the mathematical models have been developed . The aims of the present study were to examine various factors (e.g.pH, Eh, fecal coliform and milk fat) as possible indicators of microbial load in different seasons and to assess the use of mathematical models for such correlation. Raw milk was collected from various industrial farms in Mashhad city at two different seasons-spring and summer-and the best model for prediction of total count in raw milk using various factors was then conducted by mathematical models. The result indicated that multiple linear regression model was the best equation (R2 = 0.65). The result also showed that the equations for two different seasons - spring and summer - were different, as interaction between fecal coliform and pH was the main determined factor of model in spring season equation. Also in summer season equation, fat and interaction between fecal coliform and fat were the main factors, but fat factor had the most effect in equation. In this study most of the effective factors in microbial quality and their effects for prediction of raw milk are investigated.

Sarcocyst is one of the obligatory heteroxenous protozoa which there is sporogony and gametogony stages of parasite in the intestine of final host and schizogony stage of parasite in the muscles of intermediate host.In this research 117 frozen raw handmade and industrial hamburgers which was ready to sell in Tehran, studied for detection of sarcocyst cysts contamination rate by Dab smear method. After defreezing, samples test for observation of macrocyst, then contacted to the surface of slid, fixed and stained with Giemsa staining method, and studied by light microscope. Results analyzed with SPSS.11 software.There was macrocyst of parasite only in one hand made sample, and also there were microcyst of sarcocyst in 56 hamburgers. Statistical analysis didn’t show any significant difference between the contamination rate of hand made and industrial samples.

Pinch technology used as a tool for energy calculation and target design in context of energy optimization. In 2004, after enthalpy-exergy analysis for Chahar mahal beet sugar factory and applying some changes in heat transfer system, the steam consumption per beet decreased by 34% compared previous year. To enhance the efficiency of energy utilization, pinch analysis was employed to get a better insight into the energy situation in 2004. Based on the results obtained, three tubular heat exchangers were added to the heat exchanging system at a position which by exergy analysis was founded tobe the best, the results showed that the steam consumption per unit weight of beet sugar decreased from 54% in 2004 to 46% in 2005.