فصلنامه پژوهش و نوآوری در علوم و صنایع غذایی
سال یکم شماره 2 (تابستان 1391)

In the present research, the power of antioxidant activity in Bene Hull subspecies (Mutica) extract was discussed using subcritical water technique, at 110,155 and 200°C temperatures with 45 minutes of constant time and the ratio of 1: 30 for Bene hull to water. The dependent variables of this study were measured based on Melanoidic impact extent, the power of resuscitating ferrous (Mg/Ml) the extent of controlling DPPH free radicals (Mg/ Ml) and total amount of phenolic compounds (Mg of Gallic Acid/ 100 G of material). The study revealed that at 200°C the Melanoidic impact extent, the power of resuscitating ferrous (Mg/Ml) the extent of controlling DPPH free radicals (Mg/ Ml) were at the maximum; meanwhile total Phenolic content was highest at 155°C. Under this circumstance, the amount of polyphenolic contents, reduction power according to EC50 and DPPH free radical scavenging activity according to EC50 were predicted to be 2096.41 mg Gallic acid / 100 g Bene hull, 0.213 mg /ml and 0.685 mg/ ml, respectively. The results proved that subcritical water extraction method was suitable to obtain biological materials out of Bene hull. Intense extraction yield, abundant solvent, cheap and non-environmental issues are its benefits.

Iran is one of the largest pistachio producers and exporter in the world. In case of improper storage the pistachio quality will drop down for proliferation of fungus and absorption of moist which causes tissue destruction, undesirable flavour in the product.The aim of this study is examination of anti-fungal activity of Chitosan and its impact on the organoleptic characteristics of pistachio nuts.Therefore, we coated the pistachios with acetic acid of 1% V/V, Chitosan in a concentration of 0.5%, 1% and 1.5% V/W. Acetic acid of 1% was used for coating to determine its antimicrobial effect on the pistachio.The coated pistachios were packed in polyethylene made bags and kept in a room with temperature (25-27 0C) for a six month period. During the storage, samples were examined every other week for total mold and yeast count, percent of Aspergillus development, moisture content and weight fluctuation and sensory evaluation. Experiments were performed in a factorial form in a completely randomized design. The results showed that Chitosan significantly (p <0.05) inhibit the growth of the Aspergillus and increasing Chitosan concentration, increases its anti-fungal activity. Chitosan also prevents moisture absorption and weight fluctuation in pistachio nuts, but concentration of Chitosan had no significant effect in this area. Chitosan at 1.5% concentration, had a significant effect (p <0.05) on the flavour of pistachio, but other concentrations had no effect on the flavour of pistachio. Chitosan also had no significant effect on the pistachio colour, texture and its general admission (p >0.05). Finally, Chitosan solution at 1% concentration was selected as the best treatment.

One hundred and twelve traditional dairy samples including yoghurt, doogh and raw milk were collected from Kermanshah, Kurdistan, Lorestan, Ilam and Markazi provinces in Iran. The bacteria were isolated based on standard procedure. The samples were sub-cultured on selective media, typical colonies were examined microscopically and finally ninety three bacteria were selected for further analyses. The isolated bacteria were characterized by fermentation of 19 sugars and growing in 15 and 45 ºC, nitrate reduction, gelatin solidification and esculin degradation. In order to confirm the biochemical results, molecular analysis such as amplification of lactobacillus genus specific fragment with specific primer was carried out. The results showed that all isolates belong to lactobacillus. Four lactobacillus with specific properties were further identified by amplification and sequencing of 16S rDNA gene. These genes were submitted to gene bank in NCBI. The phylogenetic tree was constructed after comparing with other 16S rDNA genes. Results showed that two strains were similar to Lactobacillus crustorum which was recorded recently.

Preparation of Gluten-free bread using gluten-free cereals appears to be necessary for people with Celiac disease in which the patients suffers from gluten sensitivity. For this purpose, blends of corn and chickpea at concentrations of 80/20, 60/40, 40/60 and 20/80 with 3% HPMC gums to provide this type of bread was studied. For quality evaluation of breads, some factors such as; specific volume, density, oven spring, shape index (height/width ratio), porosity, texture analysis and microstructure were studied. The texture and microstructure of samples were investigated within first& second days and 24 hours after cooking, respectively. Overall, by making gluten-like network in the bread crumb, chickpea flour was able to increase the specific volume, oven spring, shape index and porosity, and decreased the gluten-free bread density accordingly. Chickpea flour increases moisture content of the gluten-free bread and decreases hardness of the bread crumb as the result. According to all performed tests, it was shown that a formulation of 20% maize flour with +80% chickpea flour has greatest effect on improving the quality.

In this study, we investigated the effects of steeping and germination time on qualitative and quantitative characteristics of malt extract obtained from barley (line EBYT-88-20), including hot and cold water extract, color, soluble nitrogen, kolbach index and brix. A 3×3 factorial experiment with three levels of steeping time (24, 36 and 48 h) and three levels of germination time (3, 5 and 7 days) in Completely Randomized Design (CRD) with replications was applied. The steeping time 24 h and 5 days of germination time treatment had the highest hot water extract (60.87%). The color value was in the range 8.54 – 17.12 ASBC units and steeping time 24 h and 7 days of germination time had the maximum color. Increasing the steeping time flow, 24 to 48h leads to increase of brix up to 0.48 B° of the extract. Analysis correlation coefficients between parameters showed that the strongest correlation was between the kolbach index and soluble nitrogen (r=0.995).

In the present study, the drying kinetics of non-fat yoghurt with constant thickness of 2.2 mm) in a microwave–vacuum dryer to the power of (35, 130, and 260 W) as well as 5 absolute pressure levels (60, 200, 400, 600, and 800 mbar) were evaluated. To choose the best, also 12 experimental/ semi-theoretical and/or empirical thin-layer drying models were examined. Based on the findings of this study various ranges of microwave power affects drying time where by increasing the microwave power (from 35 to 260 W), drying time significantly decreases from 90 min to 15) which is (600%). However, no significant effects in drying time were observed when reduced the absolute pressure in the system. RMSE was picked to be the most suitable model when the comparison runs between Logistic, Middilli and coworkers models for it contained maximum R2 and minimum χ2 so it could satisfactorily describe the drying kinetics of non-fat yoghurt. The effective moisture diffusivity was increased by increasing the microwave power from 4.42×10-10 to 2.83×10-9 m2s-1 while the pressure had zero effect on this value. In addition, the activation energy was calculated using the modified Arrhenius equation method.