Research and Innovation in Food Science and Technology
Year:2016 | Volume:5 | Issue:4|Papers Count:8

In this study, yogurt was fortified with iron and zinc in equal concentrations, 20, 40 and 60 mg per 1 kg of milk and the samples were tested in 1, 7 and 14 days of storage in terms of different properties of product including physicochemical properties (acidity, pH, syneresis, water holding capacity, viscosity), textural properties (hardness, elasticity, firmness, cohesiveness, adhesiveness) and sensory properties (texture, flavor, color, odor and acceptance). For predicting the changes in qualitative indices, neural network tool in MATLAB 2013Ra was used. In different networks, the Feed-Forward-Back-Propagation networks by 2-2-3-14 and 2-4-14 topology, with 0.997 and 0.991 correlation coefficients and 0.4090 and 0.1040 mean square errors, including hyperbolic tangent sigmoid transfer function, Levenberg-Marquardt learning algorithm and 1000 epoch was determined as the best neural models for yoghurt fortified with Fe and Zn, respectively. Optimal models were also investigated and the results of these models with high correlation coefficients (more than 0.98) and very low standard deviation were able to predict trends.

Carotenoids are a great category of natural pigments that have some features as antioxidant activity, provitamin and healthy properties. In most food wastes in industry, there are several components by antimicrobial, antioxidant and nutritional properties. Pumpkin peel as a waste of the foodstuff contains carotenoids specially Lutein, which has beneficial supplement in human health. The aim of this study was the extraction of carotenoids by ethanol, methanol and ethyl acetate as solvent in 25 and 40oC. For investigation of extracts antioxidant power, the FRAP and DPPH tests were examined. Since the retention time of pure Lutein obtained at 2.243 min in HPLC, carotenoids extract prepared by methanol at 40 oC had the highest Lutein content. The area under the peak of lutein in mentioned extract was approximately 9561. Evolution by UV-VIS method showed methanol extract at 40 oC was the best sample as lutein content, too. According to FRAP and DPPH test, methanol extract had the highest antioxidant power by 1.044 Fe (II) / lit and 1973 (EC50), respectively.

Today, sucrose intake caused problems for people’s health. So, the demand for low-caloric natural sweeteners with good taste properties such as sweet proteins increased. Among the sweeteners, Brazzein is an attractive alternative to sucrose. Because of its intense sweetness, natural origin and good stability. Brazzein was isolated from the fruit of the African plant Pentadiplandra hrazzeana Baillon, that is impractical to produce economically on a large scale. Therefore, widespread commercial production of this protein will probably require the transfer of protein expression to a heterologous system by means of recombinant DNA technology. In this study, due to the unavailability of genome of P. brazzeana Baillon plant for Brazzein gene isolation, artificial synthesis of Brazzein gene was done by the assembly of PCR and SOEing PCR. Amino acid sequence of Brazzein protein was translated to 162 nucleotides based on the preferred codon usage of maize using the Emboss Backtranseq program. Then, by using six overlapping primers in five consecutive PCR reactions Brazzein gene sequence was synthesized. The results of the PCR reaction showed accuracy. Then the synthetic fragment was cloned into pBI121 plant expression vectors that contained a constitutive promoter CaMV35S and seed-specific promoter Napin, which was confirmed by nucleotide sequencing.

Microbial transglutaminase (MTGase) belongs to the transferase enzyme family that cans formation crosslinking between glutamine amino-acid from a protein and lysine from another protein. It can be used in meat products industries for production of reprocessing meats by attaching the meat residues. In this study, MTGase used at 0.5, 1 and 1.5% for steak production from chicken meat residues and physicochemical, textural and sensorial properties of product were investigated. The results showed that MTGase reduced pH and increased shear force in MTGase-treated steaks. Cooking loss and diameter reduction after cooking were also decreased in MTGase-treated in comparison to control sample. In addition, the percentage of thickness significantly increased (P<0.5) in MTGase-treated samples. By adding enzyme level, a* was decreased and b* increased however no significant differences was observed in L* (P>0.5) andΔE. According to the panelists, there was no significant differences between control and treatment samples for flavour and color but the mean value of texture (3.96, 4.02, 4.05 for 0.5, 1 and 1.5%) was higher in treatment samples rather than control ones (3.45). This study showed that MTGase can be used to attach the chicken meat bits for production of steak in industry.

In this research, the effects of three variables, Konjac Glucomannan gum (KGM) (0-0.4% w/w), Xanthan gum (XG) (0-0.4% w/w) and Butter (3-9% w/w) on firmness, flavor, spread ability, color, total acceptance and pH of spreadable processed cheese were investigated. The central composite experimental design (CCD) was used and the data were analyzed using response surface methodology (RSM). Coefficients of determination (R2) of fitted regression models for firmness, flavour, spreadability, colour, total acceptance and pH were 0.834, 0.852, 0.959, 0.886, 0.813 and 0.871, respectively. The Results of analysis of variance (ANOVA) table showed that the lack of fit was not significant for all response surface models at 95%. Therefore, the models for all response variables were highly adequate. The results showed that the effects of adding hydrocolloids and butter content were significant for sensory and chemical specifications. The optimum processing conditions for producing spreadable processed cheese with the best overall values for response variables were 0.066% (w/w) KGM, 0.024% (w/w) Xanthan gum and 8.53% (w/w) butter. The response values for such product were: firmness: 2.88, flavour: 3.99, spreadability: 4.88, colour: 4.11, total acceptance: 4.03 and pH: 5.51 and the desirability value was 93.06%.

Despite all the progresses made in the field of pest control, bug is yet the hazardous pest in Iran. This insect injects a salivary proteinase into immature wheat kernels resulting in poor rheological properties, which leads to having bread with low volume and unacceptable texture. On the other hand, protein hydrolysis of gluten can improve the functional properties and also body physiological mechanisms according to producing bioactive peptides. In this study wheat samples with variable proportion of bug-infested grains (25, 50, 75 and 100%) were initially prepared and then qualitative, functional and bioactive tests were performed to evaluate the effect of suni-bug damage. Results showed that Zeleny sedimentation value decreased by increasing bug damage in samples indicating low quality in gluten for bread making. On the other hand, by increasing proportion of bug damage, degree of hydrolysis increased and functional properties of wheat samples such as solubility and emulsifying capacity were improved. By increasing the degree of hydrolysis, protein solubility also increased and the highest emulsifying capacity was observed in 25% suni-bug wheat sample. The results of evaluating bioactive properties in wheat samples indicated that by increasing the degree of bug attack, producing short peptides with ACE inhibitory and antioxidant activity increased, therefore the highest percentage of ACE inhibition and antioxidant ability is observed in 100% suni-bug damaged sample whereas the lowest was evidenced in the sound wheat sample.

The ability of starch chains to form structures in baked foods during storage, a process called retrogradation, drastically influences the texture and shelf-life of these products. Hydrocolloids are added to bakery products to improve shelf life by retaining more moisture and retarding staling. On the other hand, using freezing method interest due to increased shelf life and improved quality of bread. The effect of different levels of tragacanth and Lallemantiaroyleana (balangu) gums (0, 0.3 and 0.5%) on quality, texture and sensory properties of Barbari bread were investigated. Data Analysed by complete randomized design based on factorial with twofactor with used SPSS software and Duncan test, for mean comparisons. The result showed tragacanth decreased firmness, increased volume, porosity and sensory score while balangu increased the moisture. Interaction between tragacanth and balangu gums on 0.3% concentration of them had the best results to improve the quality of part baked frozen (PBF) Barbari bread.

The effects of hydroxypropyl cellulose (HPC) on oxygen and water vapour permeability and mechanical properties of gluten-containing glycerol (10 and 20 wt% gluten) at different relative humidity (RH=32, 52 and 75%) were studied. Water vapour permeability (WVP) has been measured using a vial coated by a film. Oxygen transmission rate (OTR) of a film was determined from measurement of peroxide value for a definite amount of oil in a vial and coated by a film. Mechanical properties were measured using a tensile machine. Microstructure and structure of the films were investigated by scanning electron microscopy (SEM) and infrared spectroscopy (FTIR), respectively. Results showed that WVP of all films increased with the increase of relative humidity (P<0.05).The amounts of water vapor permeability for the gluten-HPC-glycerol film increased with increasing glycerol concentration (P<0.05). Oxygen permeability for gluten-glycerol (containing 20 wt% glycerol) and gluten-HPC-glycerol films (containing 10 wt% of glycerol) were smaller than other films, in relative humidity of 32% and 52% (P<0.05). Tensile strength of the films increased with an increase in HPC, whereas their amounts decreased with an increase in glycerol (P<0.05). The percentage of elongation for the films increased with an increase in glycerol.