Journal of Food and Bioprocess Engineering
Volume:3 Issue: 2, Summer-Autumn 2020

In this study, the drying kinetics of saffron stigmas pretreated by atmospheric pressure cold plasma pretreatment (15, 30, 45 and 60 s) followed by hot air drying (60°C and 1.5 m/s) were modeled using 10 conventional mathematical thin layer models. The use of cold plasma pretreatment reduced drying time and enhanced effective moisture diffusivity (Deff). The most accurate models describing behavior of drying process of stigmas were Two-term, Midilli and Kucuk and Wang–Singh models. These models were determined based on the higher value of coefficient of determination (R2) and the lower values of root mean square error (RMSE), chi-square (χ2) and sum of square errors (SSE). In addition, the Newton model did not in accordance with experimental data.  The value of Deff of pre-treated saffron stigmas were in the range of 8.7013×10-9 and 9.1139 ×10-9 m2/s depending on the time of pretreatment. The use of cold plasma pretreatment reduced the surface resistance to moisture transfer, improved the diffusion coefficient, and subsequently, reduced the drying time.

Thermal processing of the key lime juice leads to the inactivation of pectin methylesterase (PME) and the degradation of ascorbic acid (AA). These changes affect directly the cloud stability and color of the juice. In this study, an artificial neural network (ANN) model was applied for designing and developing an intelligent system for prediction of the thermal processing effects on the physicochemical properties of key lime juice during conventional and infrared (IR) heating. The inputs of this network were time and temperature and the outputs were changes in PME activity, AA content, browning index (BI) and also cloud stability of the juice.The feed-forward neural network with a logarithmic transfer function, Levenberg–Marquardt training algorithm and eight neurons in the hidden layer (topology 2-8-4) was chosen as the best ANN model (R2> 0.95, RMSE=0.47 and SE=0.28). The predicted values using the optimal ANN model vs. experimental values represented a correlation coefficient higher than 0.95 and 0.90 during IR and conventional thermal processing, respectively. This model can therefore be applied in prediction of the effects of thermal processing on the physicochemical properties of the lime juice in pilot plants, processing factories and online monitoring.

Sequential ultrasound-microwave associated extraction (SUMAE) is a combination of ultrasound waves and microwaves energies in which ultrasonic extraction is used as a pretreatment. It was performed to extract essential oil from Zataria multiflora. The extraction conditions were optimized by response surface methodology (RSM) and Central Composite Design (CCD). The antioxidant and antibacterial activities of the extracted essential oil were investigated. Moreover, the results were compared with microwave associated extraction (MAE) method in terms of process yield, chemical composition, antioxidant activity and environmental impacts. The results show that the optimal conditions were ultrasound power of 150W, microwave power of 800W, and extraction time of 12min. Under these conditions, the yield of the extracted essential oil was 0.812%, which was higher than that obtained by MAE method (0.6%). Regarding environmental impacts, the quantity of carbon dioxide emission was lower in case of SUMAE method (0.25kg) compared to MAE method (0.54kg). This is also true for energy consumptions, which were 0.3125kWh and 0.675kWh for performed SUMAE and MAE, respectively, at the same power level. Furthermore, antioxidant activity of essential oil extracted by SUMAE was higher than that of MAE. Generally, the SUMAE not only did not damage the antioxidant properties, but also improved it and had less environmental damage. Consequently, it can be introduced as a green and safe method for the extraction of essential oils from Zataria multiflora.

Thermal characteristics of egg white proteins (EWP) may differ in the presence of saccharides. Therefore, the influence of saccharides including carboxymethyl cellulose (CMC), pectin, sucrose and maltodextrin and heating time on physicochemical characteristics of EWP as a whole were studied. Investigation of Heat Coagulation Time (HCT), solubility, turbidity and protein secondary structure of heat-treated EWP solutions, indicated the reasonable characteristics of heat-treated protein as affected by saccharides (especially maltodextrin). Heat stability of EWP was increased in the presence of either CMC, pectin, sucrose or maltodextrin, as shown by a decrement in turbidity and an increase in solubility and HCT. The Fourier transform infrared spectroscopy analysis was also utilized to observe the EWP’s secondary structure in the presence of saccharides before and after heat treatment. Analyses manifested the enhanced heat stability of proteins in the presence of saccharides by indicating fewer changes in egg white’s physicochemical properties.

The aim of this study was to detect and identify meat species (beef, lamb, pork, chicken, donkey, and horse) in Kebab as a Halal meat-based food sold in on-road-restaurants of North Khorasan province (Iran) using TaqMan real-time polymerase chain reaction (PCR). Raw Kebab samples (150 samples) were obtained from on-road restaurants. The samples were prepared, DNA was extracted and TaqMan real-time PCR using beef, lamb, pork, chicken, horse, and donkey target genes was performed. The results indicated that 100% of samples yielded positive results of beef, but none of them generated donkey and pork amplicons. The samples of Kebab indicated 93.33% lamb, 83.33% chicken, 10% horse positive results. The information claimed for the source of meat was not correct for more than 95% of the samples and only one food center labeled the Kebab mix correctly. Except for one Kebab sample that showed a positive result for the presence of horse meat, no sample contained meat of species considered illegal in Halal foods.

The goal of this study was to investigate the most suitable kinetic models for pectin extraction by way of ultrasound-assisted extraction (UAE) and conventional heating extraction (CHE) with acid from melon peel. The ultrasound and acidic assisted extraction were performed on powdered melon peel in three different temperatures of 40-55-70°C and 50-70-90°C, respectively. It was observed that, in the UAE method, pectin yield increased significantly in a shorter time compared to CHE which reached its peak at a lower temperature so UAE can be considered as more reasonable method. The experimental data (pectin yield versus time) were suited to a variety of kinetic models by linear regression. The total extract yields from melon peel by UAE and CHE among five conditions displayed the closest fit in the condition of pH=2 at temp 55 ˚C to the power law model (R2 = 0.92) and in the condition of pH=2 at temp 70 ˚C to the parabolic diffusion model (R2 = 0.94), respectively. The theoretical models expressed the extractability, dissolution and degradation rates of pectin, and investigated the extraction kinetics. When ultrasound and acidic procedures were applied simultaneously a synergetic effect between heating and extractability, dissolution and degradation of pectin was observed leading to a higher yield (34.18%), extractable pectin (37.45%), degradation rate (0.23%), dissolution rate (5.37%), with a shorter extraction time (61.28 min).

In recent years, the attention on essential oils (EOs) as natural additives of food products have been rapidly growing due to the extended health risk of synthetic preservatives. Artificial additives can minimize food spoilage, though the current generation is very health-conscious and believes in natural preservatives rather than the synthetic ones owing to their potential toxicity and other challenges. The utilization of EOs for shelf-life extension in foods is mostly due to their antioxidant attributes which can be verified by the massive number of researches published in this area. The intention of this paper is to analyze the methods which have been utilized for antioxidant activity measurement of EOs, highlighting their potential and usefulness as well as discussing the impact of EOs on oxidative stability of food products such as vegetable oils, meat and dairy products, particularly with regard to their potency, synergistic effects and principal components.

Enzymes are useful to modify wheat proteins to preserve the gas better and to correct the rheological properties of the dough of weak flour and bread. Gluten proteins are highly impacting the quality of various gluten-based products, and transglutaminases (TGs) leading to the strengthening, stability and constancy of the dough as well as the improvement of the volume, texture and storage time of the bread. In the present study, the effect of transglutaminase enzyme on physicochemical and rheological properties of 18% wheat flour was examined as well as polymerization were achieved at the optimum mixing time. The use of transglutaminase (TG) has grown in popularity as they promote specific cross-linking between residues of glutamine and lysine in proteins and significantly increased the dough water absorption compared to the control sample. The results of bread staling  evaluation by a instrumental or by instron method showed that the required amount of compression of bread was significantly lower than other treatments during the third and fifth days (P <0.01). The results of the evaluation of gluten includes the use of heating and shear forces, which may impact gluten dough-forming ability, showed that the factors of form and shape, characteristics of the surface of bread, porosity, and bread score (qualitative number) were significantly higher than other treatments. Thus, increased understanding of the interplay of gluten functional and the impact of the TG origin in gluten dough functional properties is highly applicable in food industry.

In recent years, the production of nutritious snacks has received much attention. Food industry by-products represent an abundant source of nutrients and are often used as an animal feed. Sunflower seed meal is high in protein and essential amino acids, minerals and vitamins and mohammadi rose (R. Damascena) waste, contains high amounts of phenolic compounds. In the present study, sunflower seed meal flour (SSMF) at 15% and 20% (w/w) was substituted with wheat flour and mohammadi rose flower waste extract (MFWE) at (1% and 2%) were used in cookie formulation and chemical tests, antioxidant activity, sensory and optical properties of the samples were measured at 0, 10 and 20 day intervals. The results showed that the amount of ash, protein, fat and fiber of cookie samples were in the ranges of (1.84%-3.55%), (10.41%-15.45%), (16.49%-18.45%) and (2.04%-2.32%) respectively. The addition of SSMF led to a significant increase in ash, protein, fat, total fiber of the samples (p ≤0.05). Adding the MFWE did not result in a significant difference in the amount of ash, protein, fat, and pH of the samples (p >0.05). Addition of SSMF and MFWE increased the moisture content, antioxidant activity and yellowness (b*) and decreased the peroxide value and lightness (L*) of the samples (p ≤0.05). In all intervals, treatment 5 (cookie containing 0% SSMF and 2% MFWE) and treatment 6 (cookie containing 15% SSMF and 1% MFWE) had overal acceptance scores and sample 5 (cookie containing 0% SSMF and 2% MFWE) was selected as the best treatment.

Today, due to the interest of consumers in nutritional properties of food, the demands for the production of functional foods have increased. Pasta is one of the most important and high-quality cereals products that has gained a special position for the production of functional foods, due to its high nutritional value, reasonable prices, ease of production and maintenance, and quality stability during its storage. Pasta could be therefore considered as a unique and suitable matrix for enrichment with dietary fibers, which contain micronutrients, phenols, sterols, tocopherols, metal ions, and essential amino acids. The purpose of this paper is therefore to review the effects of adding various dietary fiber sources including cereals, legumes, fruits and vegetables, hydrocolloids and starch resistant, to the characteristics of the pasta product. In general, the study of all dietary fiber sources shows that resistant starches have the potential to improve the quality and sensory properties of the product.

The effect of whey protein concentrate based edible coating incorporating different concentrations of natamycin and lysozyme-xanthan gum conjugate on ultrafiltrated white cheese shelf life was investigated. Escherichia coli O157: H7 (as an indicator for gram negative bacteria), Staphylococcus aureus (as an indicator of gram-positive bacteria), and Penicillium chrysogenum (as a mold) were inoculated to the surface of experimental ultrafiltrated cheese samples followed by coating trials. The microbial, physicochemical, and organoleptic properties of cheese samples were evaluated during 60 days of ripening. The results showed that coating of cheese had inhibitory effect on growth of Penicillium chrysogenum. Natamycin-containing coatings were more effective in reducing the mold population than coatings incorporating lysozyme-xanthan. Coating with 600 ppm lysozyme-xanthan reduced 2.09 log E. coli O157:H7 growth compared to that of control (with no coating). Moreover, the populations of Staphylococcus aureus were lower in all coated samples containing lysozyme-xanthan than that of control. There was no significant difference (P> 0.05) between the pH, acidity, salt, and fat in the dry matter of the coated samples and those of the control sample during 60 days of ripening. Edible coatings reduced moisture loss in cheese (5.03%) during 60 days. Coating improved the textural properties of cheese samples, meanwhile did not have a significant effect (P > 0.05) on the taste and overall acceptance of cheese. The results of this study showed that whey protein based edible coating can be used as a carrier of natamycin and lysozyme-xanthan to increase the shelf life of ultrafiltrtated cheese.

Maintaining optimum quality and eliminating dates of contamination, cleanup and packaging to extend the shelf life is one of the country's priorities and policies. Edible coatings with vegetable oils are one way to prevent the growth of microorganisms. In this study, the influence of the coating with natural zein and chitosan polymers along with the essential oil of Roman anise on the microbial behavior of Matsafati dates during one-year storage at 2 and 4 °C and a second year at 10 °C was examined. The results showed that the microbial sample of Bam region with 32% moisture content had a high microbial burden. Aspergillus niger, Aspergillus flavus, Rhizopus stolonifer, and Alternaria alternata were growing on it. These fungi, especially Aspergillus niger were involved in the rotting and lactic acid bacteria were involved in the rancidity of Mazafat dates. In this study, the number of Aspergillus niger fungi using edible coatings of zein and chitosan as well as anise oil in three logarithmic cycles was reduced and the Penicillium fungi were eliminated. In general, the lowest microbial growth was observed in zein treatment and the highest in the control sample. The use of anise oil had the effect of reducing the total count of microorganisms. According to microbial results, the use of zein treatment is recommended.