Research and Innovation in Food Science and Technology
Year:2017 | Volume:6 | Issue:2|Papers Count:8

Sourdough is a complex biological system, consisting of such components as cereal carbohydrates and proteins, lactic acid bacteria and yeasts and different enzymes from which each of these taste, flavor and shelf life of bread can be improved with optimal use ofsourdough. The aim of this study was to determine the effect of spray dried sourdough addition on gluten development through studying dough microstructure using epi-flurescence microscope. Therefore, the traditional dough was prepared by adding 15% sourdough powders containing three lactobacillus strains, which were previously isolated from Iranian traditional sourdoughs (Lactobacillus plantarum, Lactobacillus curvatus and Lactobacillus Paralimentarius), to the dough. According to microscopic observation with simultaneous staining of dough samples with rhodamine 1% and FITC 0.1%, it was showed that samples had continuous gluten network layer and protein network was not destroyed. Which can be attributed to the insufficient amount of microorganisms, low resting after preparing the dough and insufficient activity of microorganisms.

Olive leaf is one of the richest sources of phenolic compounds with antioxidant properties. Use of these compounds as food and pharmaceutical ingredients face challenges like protecting them during storage and food processing. In this study, bioactive compounds of olive leaf aqueous extract were encapsulated into a sucrose matrix using co-crystallization process. The co-crystallized powders were characterized in terms of their morphology, thermal behavior, chemical structure and also polyphenols and antioxidant activity retention rate, under various storage conditions such as light, moisture and temperature for period of 4 months. DSC thermograms for all samples, indicated the peaks around 190°C typical of sucrose melting behavior. FT-IR analysis for all samples showed typical bands of sucrose molecule. At the end of storage time, co-crystallized products containing 10% extract which were stored at dark condition, showed the highest preservation rate of polyphenols around 92% and antioxidant activity around 77.35%. A significant decrease (P ˂0.05) was observed in preservation rate of polyphenols and antioxidant activity for powders stored in artificial light and RH=75% conditions compared to storage at dark and 4°C conditions.

The effects of peppermint extract (PE) (220-660mg/g cheese), starter (1.3-2.7 g/100 Kg retentate), rennet (1.3-2.5 g/100 Kg retentate) and ripening time (10-50 days) were investigated on physicochemical, sensory andrheological properties of Ultra-filtrated Feta cheese. In order to attain properties similar to the commercial UF-Feta cheese, their optimized values were predicted by response surface methodology. Analysis of obtained data showed that PE had positive effect on pH whereas in sensory quality it had negative effect significantly. None of treatments had effect on dry matter. Rennet had significant effect on storage modulus(G').Significant effects of rennet and significant interaction of PE and rennet were detected on loss modulus (G"). In tan (d), significant effect of PE and rennet was seen simultaneously. Finally, optimized values for preparation of samples similar to commercial UF-Feta cheese were as follows: peppermint extract: 660 (mg/g cheese), starter: 1.63-2.25 (g/100 Kg retentate), rennet: 2.14-2.34 (g/100 Kg retentate) and ripening time of 26 days.

The aim of this study was extracting Salvia mirzayanii essential oil (EO) with microwaveassisted hydrodistillation (MAHD) and hydrodistillation (HD) methods, comparison of extraction yield and kinetic parameters, chemical composition, physicochemical properties, and antioxidant and antifungal activities of extracted EOs. The final EOs yields obtained using HD after 150 min and MAHD after 45 min were 1.74% and 1.71%, respectively. Although there was no significant difference between the final EO yields extracted with HD and MAHD, but MAHD was performed in shorter time. IC50 values for MAHD and HD EOs were 3.70 and 3.41 mg/mL, respectively. Chemical composition of HD and MAHD EOs were similar. Antifungal activity against 6 fungi species (Aspergillus niger, Aspergillus oryzae, Trichoderma harzianum, Byssochlamys spectabilis, Paecilomyces variotiiand Penicillium chrysogenum) was different and the MIC values were variable between 78.1-2500 mg/mL.T. harzianum was the most resistant fungi andB. spectabilis was the most susceptible fungi against EO. Therefore, MAHD did not have any adverse effects on quantitative and qualitative characteristics of EO composition and antioxidant and antifungal activities ofS. mirzayanii EOs.

Growing consumption of fried foods can cause various diseases; therefore it is important to create an appropriate method to reduce oil absorption uptake in these products. In this study, the effects of sage seed gum and Persian gum coating (0.25 and 0.5% w/w) by immersion and spraying methods on fried potato chips properties (coating rate, oil absorption, oil fractions, color, texture and sensory properties) in deep frying were studied. Both methods reduced oil uptake significantly. However, oil effective penetration was different depending on the coating.The highest coating rate (3.6%) and the least oil absorption (31.24 percent) with 0.27±0.001 1/s absorption rate was contributed to sage seed sample at 0.5% (w/w) concentration by immersion method, whose difference was significant in the control sample (37.21%) (P<0.05).According to texture analysis results, chips stiffness increased significantly by immersion method. Although, the most desirable texture was contributed to coated samples by immersion method according to sensory evaluation results. There was no significant difference between coated samples and control in smell, appearance, taste and overall acceptance (P>0.05). As a result, sage seed gum at 0.5% concentration and immersion coating method with the lowest oil absorption and similar organoleptic properties to the witness is recommended to be used in potato chips production.

Nowadays, studies on the functional and nutritional values of bread are being developed in order to improve these characteristics as well as application of various dietary fibers and prebiotic compounds in bakery products. The aim of this research was application of prebiotic inulin in the formulation and production of functional Taftoon, a kind of Iranian traditional bread widely used in the country, and evaluation of its nutritional value and qualitative effects.For this purpose, specific percentages of wheat flour (ratios of 2, 4, 6 and 8%) were replaced by commercial inulin with average polymerization of 23 and the produced Taftoon was assessed in terms of qualitative characteristics. The results of Farinograph assessment showed that the sample containing 6% inulin received the maximum sensory score for improvement and stability indexes compared with the control sample. Moreover, based on the results the added 6% inulin, regardless of its amount, not only lacked any negative effect on visual quality and color of bread samples, but also improved the product concerning total titratable acidity, rate of flour water absorption, textural features, owing to its viscoelastic behavior, compared to the control sample. Therefore, using inulin as a well- known prebiotic compound improves the nutritional and healthful characteristics of the traditional bread, Taftoon. However, it did not display any negative effects on rheological and sensory properties of the final product.

In the oil extraction, the suitable treatment of the seeds before extraction is the most critical steps to produce high quality and efficiency products. In this research, in order to model the process of oil extraction from flax seeds, the researchers applied pre-treated with microwave within different processing times (90, 180 and 270 S) and powers (180, 540, and 900 W) and the efficiency of oil extraction, acidity, refractive index, density, acid number, and the oil color were studied. To predict the changes' trend the artificial neural network in MATLAB R2013a software was used. The results showed that by increasing microwave time and power efficiency of oil extraction, index acid and acidity, density and oil color increased. Analysis of variance results showed that the studied microwave pre-treated had no effect on the refractive index. By studying the various networks of back propagation feed forward network with topologies 2-8-6 with a correlation coefficient of more than 0.999 and the mean squared error of less than 0.001 and with using sigmoid hyperbolic of tangent activation function, the Resilient back propagation and learning cycle of 1000 were specified as the best neural model. The results of the optimized and selected models were evaluated and these models with high correlation coefficients (over 0.844), were able to predict the changes' trend. According to the complexity and multiplicity of the effective factors in food industry processes and the results of this research, the neural network can be introduced as an acceptable model for modeling these processes.

In current study, the effect of two plasticizers, sorbitol and poly ethylene glycol 400 (PEG 400), at different ratios (5: 5, 5: 10, 5: 15, 10: 5, 10: 10, 10: 15, 15: 5, 15: 10 and 15: 15) of on physicochemical properties of gelatin films from black pomfret (Parastromateus niger) were investigated. Plasticizers are low-molecular-weight Compounds which compounded into polymer molecules to improve its flexibility. With increasing amount of plasticizers, tensile strength and elastic modulus of gelatin films decreased whereas elongation at break (EAB) increased. That effect was the result of plasticizer molecules diffusion into polymer and weaken the polymer-polymer interactions which significantly led to increasing film elongation. High degree of opacity of the films was observed in the high plasticized films and the opacity of PEG plasticized films at 15% concentration was higher than the sorbitol ones at the same concentration (P<0.05). Water vapor permeability (WVP) of the films was mainly dependent on the amount of plasticizer, regardless of the plasticizer type, WVPs increased from 1.001 to 1.901 mm.gr/pa.h.m2 for the films, those contained lowest and highest plasticizers, respectively.There was a significant difference in the solubility of films depending upon plasticizer concentration, the highest and lowest water solubility belonged to the sample containing 15% and 5% sorbitol or PEG around 70% and 15.5% respectively (P<0.05). The solubility of the films mostly depending upon plasticizers concentration than plasticizers type and increased with increasing in plasticizer content. Totally, the increase in film solubility and WVP was the result of plasticizer molecules penetration between polymers and subsequent increase in free volumes.