مجله علوم غذایی و تغذیه
سال دوازدهم شماره 2 (بهار 1394)

Date stone is one of the by-products of date processing factories with a high nutritional value and high fiber content. Therefore، it has a great potential for enrichment of different food products. The main aim of this study was to determine the effects of date stone powder on the quality of dough and the biscuits produced. Date powder was added to the biscuit formula at different levels of 0، 5، 10 and 15% (flour weight basis) and the rheological properties of dough and physical and sensory characteristics of the made biscuits were studied. Farinograph results showed that by increasing the level of date stone powder، the dough water absorption capacity is increased، dough consistency is decreased and dough softening character is increased. In addition، the resulted biscuit density is increased while the volume is decreased. The results of the Texture Analyser indicated that by increasing the percentage of the date stone powder، the resulted biscuit hardness is increased. Most of these changes were statistically significant (P<0. 05) at 10 and 15% addition of date stone powder as compared to the 0 and 5%. Addition of less than 15% date stone powder resulted in a product with appropriate sensory properties. Considering the low cost، availability and the nutritional value of date stone powder particularly fiber، carbohydrates، mineral، protein and oil، the powder might be employed for enrichment of biscuits. Based on the findings، the addition of less than 15 powder to the dough resulted in biscuits with increased nutritional value particularly higher fiber content and desirable sensory characteristics.

Gelatin is a natural biopolymer that is most widely used in food industry. Commercial gelatin due to its social, cultural and religious reasons are not acceptable by some therefore, gelatin extracted from fish processing waste might be employed as an alternative source for commercial gelatin. In order to optimize the extraction of gelatin from the skin of Iranian beluga fish (Huso huso), the effect of different concentrations of NaOH (0.01, 0.05 and 0.075 N) and Ca(OH) 2 (0.01, 0.05 and 0.075N) on the extraction yield, melting point, viscosity, gel strength, colour and the molecular weight of extracted gelatin were investigated. The results indicated that the highest extraction yield was obtained when 0.05 N Ca (OH) 2 was employed. The highest and lowest melting points (30.98 and 28.0°C) were related to the treatments concerned with 0.01N NaOH and 0.05 N Ca (OH)2 respectively (p< 0.05). The viscosities were increased as the alkali concentrations were reduced, however sodium hydroxide concentration affected the viscosity more than calcium hydroxide (p<0.05). Gel strength was affected more by 0.01N sodium hydroxide. There were not significant differences between the treatments concerning colour changes. The results indicated that 0.01 N NaOH treatment produced gelatin with improved functionality and characteristics.

Plants are rich source of phenolic compounds (phenolic acids, flavonoids and tannins) that are natural antioxidants. The purpose of the present study was to use two ultrasonic methods including probe and bath for the extraction of phenolic compounds and flavonoids from autumn olive and evaluate the ability of the extracts to scavenge DPPH free radical using three extraction solvents consisting of water, 80% methanol and 70% ethanol. Water, 80% methanol and 70% ethanol were used as extracting solvents and the effect of different extraction periods (30, 60 and 90 min) for bath method and 5, 10 and 20 min for probe method were evaluated on the extraction of phenolic compounds. The results showed that in the probe method of ultrasonic, the highest phenolic compounds (13.8 ± 0.05 milligrams gallic acid/ g dried sample) and DPPH radical scavenging activity (98.94%) were obtained using70% ethanol as solvent within 20 minutes of extraction period. In the ultra sound bath, the highest extraction rate of phenolic compounds (15.82 ± 0.057mg gallic acid equivalent/ g dry sample) and flavonoids (7.09 ± 0. 110 mg of quercetin per gram of dry sample) were obtained by the application of 70% ethanol within 90 minutes. The results indicated that the probe and bath methods of ultrasound had different effects on extraction of bioactive compounds from autumn olive. In each extraction method, the rate of extraction of phenolic compounds and flavonoids were solvent dependent and in all the extraction method, 70% ethanol showed the best effect as extracting solvent.

The applications of natural antioxidants with medicinal values are growing in the preventive medicine and food industries. This study investigates the antioxidant ability of five species of Rosaceae family and compares the activities with the synthetic antioxidants BHT, BHA as well as the natural ascorbic acid.

In this study, the phenolic content of the methanolic extract of the samples were isolated and the antioxidant activities of five species of Rosaceae were determined by using DPPH free radical and nitric oxide scavenging, and the results were compared to the synthetic antioxidant

The results showed that the content of studied plant samples ranged from 0.51±0.4 – 35.53±0.89 mgGAEg -1. Concentraition of extract for scavening 50 percent of free radicals and nitric oxide radicals varied from 77.42 ± 0.91 to 1484.2 ± 96.44 and 233.24±3.39- 1572.46±203.76 Ug/ml. The highest phenolic amount was related to the Rosa damascena Mill leaf and next grade Cydonia oblonga Mill leaf. Extract of damask Rose, Quince leaves, damask Rose petals, Quine fruit and seed and Almond seed had high antioxidant activity and no significant difference was observed between them and the synthetic antioxidants (BHT, BHA and Vit C).

The results of this study clearly suggested that there is a significant relationship between the antioxidant activity and the phenolic concentration and the extracts of damask Rose, Quince leaves, damask Rose petals, Quince fruit and seed and almond seed might be employed as appropriate alternatives to the synthetic antioxidants.

processes develop specific flavor and aroma and color in foods. Microbial contamination of spices, like most of the agricultural products, is quite important regarding the health and hygiene. The aim of this research is to evaluate and assess the microbial status of packed and unpacked spices, in Zanjan city. Total of 80 samples of packed and unpacked spices (black pepper, red pepper, sumac, cinnamon) were collected randomly from the food supplying centers and local retail stores in Zanjan city. Experiments were carried out for the presence of aerobic spores according to the Iranian standards. Average of total aerobic mesophilic spores count based on CFU/g were 1.6×107 for red pepper, 6.6×106 for black pepper, 4.3×104 for cinnamon and 3.5×102 for sumac. Averages of total aerobic mesophilic spore counts for packed and unpacked spices were 3×106 CFU/g and 8.4×106 CFU/g, respectively. The average loads of total aerobic mesophilic spores were highest in red pepper and lowest in sumac. Average of total aerobic mesophilic bacteria count in the red pepper and black pepper as compared to the international standard (ICMSF) were higher. It is therefore recommended to apply disinfection and sterilization methods such as gamma irradiation at the rate of 10 KG to reduce the contamination of the spore forming bacteria in spices, especially the spices that are consumed without undergoing cooking process.

of syrup. Raw cane sugars are most widely used and are important as raw materials in the sugar industry. The purpose of this study is to evaluate and compare the quality of raw cane sugar and the factors influencing and controlling the refining process and compare the results with the domestically produced sugars. This study evaluates the physical and chemical properties such as moisture, ash, sucrose content, pH, refractive index, colour, invert content, dextran and starch concentrations in the raw sugar. The result indicated that the imported samples of raw sugars had higher concentration of sucrose but lower percentages of invert, dextran, colour and ash as compared to the domestic samples. This might affect the cost of the refining operation. It is worth to mention that the imported raw sugars had generally higher starch concentrations than the domestic samples. The imported samples with high polarization and low impurities are recommended to produce the white sugar.

The children who eat breakfast, have better cardiorespiratory fitness (CRF), and enhanced ability to learn as compared to others who do not follow this pathway. The aim of this study is to analyse the relations between the eating breakfast, body composition and CRF in school children. A cross-sectional study was carried out including 164 girls aged between 9 to 11 years. Body composition, CRF and Physical Activity level were assessed during school time. Frequency of eating breakfast was assessed by a questionnaire and classified as never, sometimes or always. Fitness was estimated from a 540 m test and the participants were classified as having low or high CRF. Body composition was evaluated and children were classified as obese or non-obese. PA was estimated from physical activity questionnaire and the participants were classified as having low or high PA. Frequency of eating breakfast showed that 18% of school children never had breakfast, 24% ate sometimes and 58% always ate breakfast. There was no significant relation between the frequency of breakfast and anthropometric characteristic. Breakfast consumption was not associated with physical activity (p=0.3) and with CRF (p=0.3). fitness level, body composition and PA are not associated with the frequency of eating breakfast in schoolchildren

Enzymatic extraction of the oil is a method that the cell wall degradation occurs by the enzyme and the components of the cell are transferred to the aqueous phase that facilities pure separation by centrifugation. Cell wall complex structure of different varieties and regions has caused the suitable enzymatic extraction conditions to be different. The aim of the present study is to evaluate and assess the enzymatic extraction of rapeseed oil and its effect on the extracted oil. In this study for the enzymatic extraction of oil, pectinex ultra SPL and protease were employed. The statistical analyses were carried out using factorial experiment with three levels of enzyme concentrations (1, 2 and 3%), temperatures (3, 45 and 55ºC) and times (3, 4 and 5 h) on the oil extraction yield, phosphorous content, acidity, peroxide and protein contents of meal where Okapi variety of Khorasan region was chosen to be investigated. The results indicated that the enzyme concentration, temperature and time, had significant effects (p<0.01) on the extracted yield, phosphorous content and protein of meal. The enzyme concentration at 2 and 3 %, with temperature at 44 and 55 and time of incubation for 4 and 5 hours showed to be the most suitable conditions. There were no significant differences (p<0.05) between mean values of acidity and peroxide at different extraction conditions. The changes of acidity and peroxide values under different enzymatic extractions were not statistically significant and they were low at all conditions. The enzyme concentration of 2% and the temperature of 45 ºC and time of 4 hours incubation were selected as the optimum conditions for the enzymatic extraction of canola oil.

Aflatoxin contamination might occur due to the improper storage conditions of harvested pistachios. Different environmental factors affect the fungal growth and mycotoxin production as the harmful secondary metabolites. Improved storage conditions can be effective to prevent the contamination of pistachios. Environmental factors consisting of kernel moisture content, relative humidity, temperature, water activity and fungi and pests might affect the contamination of pistachio. These were studied in 47 stores and warehouses in the cities of Kerman, Sirjan, Zarand and Rafsanjan regions at three month intervals for the storage period of 12 months. The levels of water activity and kernel moisture content in this study ranged from 0.12 to 0.46 and 3.1 to 5.3 (%), respectively. In most stores, the average of relative humidity ranged from 24 to 26 % with minimum and maximum values of 13.7 and 36.5 respectively and average temperature of 23.3 to 26.1 ZC. On the other hand, observed low levels of kernel moisture content and water activity remained at a constant level for most sampling times. These results indicated that equilibrium moisture content was not in favor of Aspergillus flavus growth and aflatoxin production. The observation also showed that the frequency of storage pest contamination was less than 1% and Aspergillus contamination varied from undetectable to 1 %. The stores or warehouses conditions concerned with pistachio in Kerman province are not in situations to create and promote fungal growth and aflatoxin production.

Microextraction is regarded as an extraction technique where the volume of the extracting phase is much smaller than the sample. Therefore extraction does not take place completely and thus a fraction of analytes is transferred in to the extracting phase. However in some cases after the extraction the concentration of extractable correlates with the initial concentration. Therefore the aim of this research work is the optimization of liquid –liquid micro extraction of Menthe piperita floral water. Floral water of Menthe piperita was obtained from the local market. Ethanol and chloroform were used as extracting solvents and the obtained chemical compounds were applied onto a GC- MS. Taguchi method was applied to determine the optimum extraction of active compounds in the sample. The application of Taguchi method indicated that ethanol and chloroform tetra chloride at the concentrations of 500 and 60 showed the highest microextraction rate respectively. 93% of the chemical compounds present in the sample were identified using the least quantity and volume of the extracting solvent.