Research and Innovation in Food Science and Technology
Year:2017 | Volume:6 | Issue:3 |Papers Count:8

In this study, different electric field intensity (0.25, 3.25 and 6.25 kV/cm) and different number of pulse (10, 30 and 50) were used for optimizing the process of oil extraction from black cumin seeds using pulsed electric field pretreatment and then after using these pretreatments, the oil of seeds was extracted with screw press with different rotation speeds (11, 34 and 57 rpm), then parameters including oil extraction yield, color index, oxidative stability, refractive index and a and total phenolic of the extracted oil were studied. Statistical analysis and process optimization was performed with the use of response surface methodology (RSM). The results showed that oil color index increased with increasing of electric field intensity and the number of pulses, but oxidative stability of obtained oil decreased. The results also showed that the studied parameters had non-significant effects on the refractive index; moreover the oil extraction yield reduced by increasing the rotational speed of the screw press. Increasing the electric field intensity and the number of pulses to enhance the oil extraction yield and total phenolic was but a further increase of these variables, the two parameters decreased. According to the process optimization results, it might be stated that with applying electric field intensity for about 1.18 kV/cm number of pulse 48 and screw-rotation speed of the press of 11.01 rpm, the maximum oil extraction yield, oxidative stability and total phenolic components were reached.

Since the amount of fiber consumption in Iran is less than 30 grams per day, it prepare the ground for cardiovascular diseases, diabetes and cancer. Therefore, given the per capita consumption of bread, this study was designed to optimize the bread formula enriched with sugarcane bagasse. For this purpose, FSB in four levels of 0, 5, 10 and 15% and xanthan gum in four levels of 0, 0.5, 1 and 1.5% (w/w based on flour) were added to the formula of bread. The results indicated that adding FSB to the formula, caused the rheological properties to improve.This is despite the fact that the volume of all types of breads decreased. Also, Sensory evaluation shows that increasing the amount of FSB in the samples causes a drop in the porosity, chewiness and texture of the bread, but samples enriched with FSB had the best smell and taste. The overall assessment suggests that the texture of breads enriched with FSB is much softer than the control sample. During the storage, this situation continued, and delayed the bread stalling. In general, the study of the properties of flour, dough and bread indicated that adding FSB in the range of 5 to 10% (without xanthan gum) is suitable for the production of functional bread.

Sourdough is a proper fermented ecosystem for isolation of lactic acid bacteria (LAB) with antifungal effects. In this research, dominant LAB isolated from rice bran and wheat bran sourdoughs were identified based on molecular method. Antifungal activity of the isolates and their cell free culture filtrate (CCF) obtained from logarithmic and stationary phases were also investigated based on overlay and spore spot methods respectively, againstAspergillus flavus andAspergillus niger. According to sequencing the results of PCR products, Lactobacillus paraplantarumin wheat bran sourdough and Pediococcus pentosaceus in rice bran sourdough were identified as dominant isolated LAB. The results of overlay method also confirmed the inhibitory potential of the isolates against indicator fungi in comparison to control sample.Furthermore, inhibitory effect of the LAB isolates againstA. flavus was significantly higher than theA. niger (P<0.05). The inhibitory effect of CCF obtained from each bacterium logarithmic and stationary phases againstA. flavus were also significantly different but between inhibitory effect ofL. paraplantarum stationary CCF and P. pentosaceus logarithmic CCF against this fungus, significant difference was not observed (P<0.05). The inhibitory effect of CCF obtained from the isolates logarithmic and stationary phases againstA. niger were also not significantly different (P<0.05).

Okara is the valuable by-product of soymilk industry that is a suitable source of protein, fiber and micronutrients in nutritional aspects. Therefore, its application in food industry is suitable in order to increase the nutritional value of food products and also to increase the added value of soybean processing industry. The aim of this study was to investigate the effect of wheat flour replacement by okara (0, 10, 20, 30 and 40%) in order to benefit its suitable nutritional characteristics and the utilization of protease enzyme (0, 60 and 120 ppm) in order to improve the qualitative properties of biscuit. In this regards, qualitative characteristics including dimensions and spread ratio, density, hardness, color and sensory properties were investigated.Results showed that thickness, density and hardness increased by increasing okara amounts and on the contrary the addition of protease had a reverse influence on the mentioned factors. Also the average diameter and spread ratio of the samples decreased by the addition of okara and increased by the addition of protease enzyme. Increasing okara and protease enzyme had similar effects on color characteristics so that redness and yellowness increased and the lightness decreased by increasing the percentage of replacement. According to the results of sensorial and instrumental analysis, the sample with 20% of okara and 60 ppm of protease enzyme was selected as the best sample. Finally, evaluation of nutritional properties of the best sample showed a significant enhancement in protein, crude fiber, total phenolic, calcium, magnesium as well as potassium content and significant reduction in carbohydrates content in comparison with the control.

Analysis of internal and external mass transfer coefficient can be a useful means to control the drying process of food and agricultural products better. Accordingly, in this study, the effects of different treatments (thermal pretreatment by blanching, pulsed pretreatment with microwave radiation, mechanical pretreatment by ultrasound waves, and chemical pretreatment by osmotic dehydration) on the internal mass transfer coefficients (effective moisture coefficient), external mass transfer coefficients and activation energy were investigated. Experiments included three temperatures (45, 55 and 65 °C) and various pretreatments including thermal blanching with hot water (at 70, 80 and 90 °C), microwave pulses (90, 180 and 360 W), chemical osmosis (at 30, 50 and 70% concentrations), and mechanical ultrasound (at 15, 30 and 45 min intervals). The results showed that microwave and osmotic pretreatments had the largest and smallest effects on internal and external mass transfers compared with the control treatment. The highest internal (36.21×10-10 m2/s) and external (3.49×10-6 kgwater/m2s) mass transfer values observed under 360 W microwave pretreatment with the drying temperature of 65 °C, whereas the lowest internal (7.61×10-10 m2/s) and external (3.49×10-6 kgwater/m2s) values were observed in the control treatment at the drying temperature of 45 °C. The activation energy also ranged from 18.52 to 32.04 kJ/mol under various pretreatments and temperatures.

Low solubility, oxidation and isomerization of resveratrol limit its application in food formulation. In this study the effect of bovine serum albumin (BSA) -resveratrol interaction on droplet size and Zeta potential of complex, solubility and antioxidant activity of resveratrol was investigated. Droplet size, Zeta potential and morphology of nanoparticles were analyzed using dynamic light scattering (DLS) and scanning electron microscopy (SEM). Complex formation and solubility of resveratrol were measured using spectrophotometric techniques. Antioxidant activity was measured by ferric reducing antioxidant power (FRAP) assays. The results indicated that resveratrol was solubilized in BSA solution at a 2.3: 1 molar ratio as a colloidal stable solution with droplet diameter of about 30 nm and PDI<0.6 and Zeta potential -18±3. In SEM image the nanoparticles were seen as globular particle with sizes between 30-50 nm. The result of FRAP showed that the antioxidant activity of BSA-resveratrol complexes in the molar ratio of (60: 60) was nearly 58% of antioxidant activity of equivalent amounts of resveratrol in ethanol. Therefore, formation of the complexes protects resveratrol from rapid oxidation that is an essential step in functional food formulation.

Foam is a colloidal system in which air bubbles are scattered in solid or liquid medium.Considering the importance of overrun and stability in pasteurized egg white foam in the food industry and due to limited number of researches on the pasteurized egg white foam, the aim of this study was to investigate the effect of Tween 80, sodium lauryl sulphate, copper and aluminium ions on specific density, overrun, whipping index, durability index, gas phase, textural properties, interfacial tension, microstructure of egg white foam (after adjusting the pH and heat treatment similar to pasteurization conditions).The best treatment for improving the physical properties of the foam were 0.21 and 0.63 mM copper and aluminium, respectively.The most stability and overrun were observed in samples containing 1500 ppm sodium lauryl sulphate and Tween 80. The results from this research proved that in case of lack of access to natural additives, the mentioned additives can be used. Liquid egg white processing factories can apply the optimized level of the additives to overcome the problems originated from foam loss and instability and consequent rejection from industrial consumers, considerably.

Grape is one of the most important fruits in the world. Phenolic compounds are antioxidants are important compositions of grape. Phenolic compounds phrase includes all the aromatic molecules consisting amino acids to complex molecules like tannins and lignin’s. Near infrared spectroscopy is one of the most common nondestructive methods for fruits and vegetables qualification analysis. This research is conducted to evaluate the possibility of the quantification of total phenol in grape by near infrared spectroscopy and artificial neural network (perceptron).The number of 444 samples (107 Asgari, 106 Bidane, 111 shahroodi and 120 khoshnav varieties) were selected to model calibrating and test as well. Developed ANNs were compared on phenol prediction by residual prediction deviation (RPD) index in the test sample dataset (101 samples).The maximum RPD was 1.66 by 8-5-1 topology with correlation coefficient and root mean square (RMSE) equal to 0.79 and 48.66 respectively. It was concluded that NIR spectroscopy and back propagation perceptron ANN could be used to discriminate low and high amounts of grape total phenol as a nondestructive method.