نشریه فرآوری و نگهداری مواد غذایی
سال دوم شماره 1 (پیاپی 5، بهار 1389)

To establish the optimum conditions for extracting gelatin from whitecheek shark (Carcharhinus dussumieri (skin, response surface methodology (RSM) was adopted. The effects of concentration of NaOH (0.01-1 N) (X1), concentration of HCl (0.01-1 N) (X2) and extraction time (3-8 h) (X3) on the gel strength, were studied using central composite design (α= 1.682). Based on the results, shark skin gelatin gel strength on different extraction conditions, were within 54.5-1075 g. The results showed that the concentration of NaOH and HCl had significant effect on gel strength (P≤0.05) but the extraction time had no significant effect on this property.

With regard to the importance of bread in the people’s food basket and the key role of this basic food commodity in household economy and nutrition, selecting the best method of bread baking that can improve it’s nutritional quality and also decrease the production costs is of great importance. In this study, the nutritional quality of the dough and the sensory properties of Barbari bread in terms of the amount of used yeast and the fermentation time in the stage of first proof in both traditional and controled baking methods at 4 bakeries of Golestan province were examined. The comparison results of the average least significant difference (LSD) test at the significance level of 5% in resultion to quantitative and qualitative properties of the produced bread showed that fermentation time, amount of yeast and baking method have a significant effect on the phytic acid level in the produced bread. In addition, the controled baking method regarding the level of phytic acid was more effective than the traditional method in terms of preserving the nutritional quality. Evaluating the sensory properties of the dough by panelists showed that the fermentation time and the amount of yeast have a significant effect on chewiness, texture, taste, shape and upper and lower surfaces of the bread and in general, it is known that the controled baking method is more suitable in all cases. Thus, with regard to the change trend of the dough’s phytic acid and the bread’s sensory properties. Standardization of the first proof conditions of Barbari bread in the 2.5 hour first proof and the yeast use of 0.25% was recommended for increasing the nutritional quality and marketability in controled method.

The effect of browned product of fructose on lipid oxidation and sensory attributes of Indian shrimp (Penaeus indicus) was investigated during 6 month storage at-18°C. Sugar browning carried out at 100°C under alkaline condition (pH=10), then the browned sugar added to the shrimps in the rate of 15%. The assessment related to quality changes has been done at months 0, 1, 3 and 6th. The results showed that browned product of fructose reduced TBARS and FFA as compared with the control. Also, browned product of fructose resulted in reducing the rate of heme iron reduction of shrimp meat. Sensory assessment revealed that the use of browned product of fructose produced better sensory attributes (odor, taste and color) in comparison to the control. With respect to the results, browned product of fructose is a potential antioxidant to maintain the quality and improve sensory attributes of Penaeus indicus.

Nowadeys, formulation of fruit and vegetable based snacks is considered widely to their hight edible quality and nutritional value. Iran (specially, khorasan province) is one of the most important Cantaloupe producer in the word. Cantaloupe is consumed as fresh fruit in the most of the countries. Due to different factors, such as lack of suitable processing techniques for this product, more than 30% of it is wasted during supply chain from field to table. The aim of this research was evaluation of a new product (Gel Mac) production and optimization of its formulation. Cantaloupe pastille was produced from cantaloupe puree, a mixture of hydrocolloids (starch and gelatin), sweeteners, pH adjutants and other ingredients. Pectin (0-0.6 %) and xanthan (0-0.5) were selected as effective factors on overall acceptability. To evaluate the effect of pectin and xanthan, Response Surface Methodology (RSM) and central composite deslgn was used. In order to study sensory properties and relationships between them, Principal Component Analysis (PCA) was used. The results showed that the overall acceptability was mainly related to color intensity, flavour, rubbery and hardness.

The effect of temperature on viscosity of six Azerbaijan honey samples with various floral sources was investigated. Modeling the effect of temperature on viscosity was performed with Arrhenius, Vogel-Taumman-Fulcher (VTF) and power law models at three temperature levels (19, 24 and 28 oC). Evaluation of the models was done by coefficient of determination (R2), P value and root mean square error (RMSE). At smaller amounts of studied shear rate (0.04-0.63 s-1) all of the samples showed nearly non-Newtonian behavior. Among three applied models, samples were well fitted with Arrhenius and VTF models.

Using canola meal in spite of suitable protein compound is limited due to existunce of some antinutritional compounds such as fiber, phytate, glucosinolate and tannin. This study aimed to evaluate the effect of phytase and washing with ammoniated methanol on the chemical composition (crude protein, phytate, glucosinolate, tannin, acid detergent fiber and neutral detergent fiber) of three processed products of canola meal with hemicellulase (0.10 and 0.15% CM) and pectinase (0.15% CM) at three doses (4000, 5000 and 6000 IU/Kg, n=3) of phytase in a factorial design. With an increase in phytase concentration, phytate content decreased and crude protein content increased. Washing with ammoniated methanol decreased the glucosinolate content of all processed products of canola meal with carbohydrases (4.93 vs 1.98 μmole/g dry matter) and tannin content (1.53 vs 1.14%) but it increased contents of crude protein (41.87 vs 42.79%), phytate (2.06 vs 3.02%), acid detergent fiber (24.50 vs 26.84%) and neutral detergent fiber (27.35 vs 29.11%). Processed product with pectinase 0.15% CM, phytase and ammoniated methanol had the lowest content of glucosinolate (3.26 μmole/g dry matter) compared to those of others. Finally, the relative priority of treatments were determined based on the weighted average using principal component analysis as pectinase (0.15% CM) and 5000 and 6000 IU phytase/Kg and then pectinase (0.15% CM) with 4000 IU phytase/Kg.

In this study the influence of ultrasound pre-treatment on water absorption kinetics of chickpea seed was investigated. The chickpea seeds were exposed to ultrasonic irradiation at vibration amplitude setting 40%, 70% and 100% of nominal power for 3 and 10 min at 24 kHz. Water absorption characteristics and moisture content at five different soaking temperatures (25, 30, 40, 50 and 60◦C) and various soaking times up to 10 h were studied. The soaking rates of treated samples were compared with untreated seeds. Peleg’s model was used to describe the hydration kinetics of chickpea seeds during soaking process at different temperatures by weight gain method. Ultrasound treatment was very effective in water uptake of seeds and was observed that ultrasound pre-treatment could decrease the soaking time by up to 4 h. The Peleg constant K1 decreased from 10.8 10-3 to 0.99 10-3 h %-1 with increasing temperature from 25 to 60◦C and constant K2 increased linearly from 6.72 10-3 %-1 to 9.9 10-3 %-1with increasing the temperature.