Seyed Mohammad Mousavi

Comparison of Artificial Neural Network (ANN) and Response Surface Methodology (RSM) in the Prediction of Quality Parameters of Spray-Dried Pomegranate Juice

Response surface methodology (RSM) is a frequently used method for empirical modeling and prediction in the processing of biological media. The artificial neural network (ANN) has recently grown to be one of the most efficient methods for empirical modeling and prediction, especially for nonlinear systems. This article presents comparative studies between an ANN and RSM in the modeling and prediction of quality parameters of spray-dried pomegranate juice. In this study, the effects of the carrier type, carrier concentration, and concentration of crystalline cellulose in a pomegranate juice spray-drying process were investigated on five quality parameters—drying yield, solubility, color change, total anthocyanin content, and antioxidant activity—using RSM and ANN methods. A central composite rotatable experimental design (CCRD) and a feed-forward multilayered perceptron (MLP) ANN trained using back-propagation algorithms for three independent variables were developed to predict the five outputs. The final selected ANN model (3-10-8-5) was compared to the RSM model for its modeling and predictive abilities. The predictive abilities of both the ANN and RSM were compared using a separate dataset of 18 unseen experiments based on RMSE (root mean square error), MAE (mean absolute error), and R2 (correlation coefficient) for each output parameter. The results indicate the superiority of a properly trained ANN in capturing the nonlinear behavior of the system and the simultaneous prediction of five outputs.

Ultrasound-assisted formation of the canthaxanthin emulsions stabilized by arabic and xanthan gums

There is interest in incorporating canthaxanthin (CTX) into food emulsions due to its high potential health benefits. The used CTX in this study was produced by the bacterium of Dietzia natronolimnaea HS-1. Then, the influence of main emulsion components (gum arabic (GA), xanthan gum (XG) and coconut oil (CO)) on the surface-weighted mean diameter (D32), polydispersity index (PDI), specific surface area (SSA) of droplets and density of the emulsions containing CTX was optimized using response surface methodology (RSM). Polynomial equations between the responses and independent variables were derived. The linear effect of GA had a significant (p<0.0001) term in all reduced models. The optimal formulation for emulsions was composed of GA content of 9.85% (w/w), XG content of 0.13% (w/w) and CO concentration of 3.50% (w/w). This optimum formulation yielded D32 of 0.752 μm, PDI of 1.533, SSA of 9.995 m(2)/ml and density of 1.0357 g/cm(3).

Psyllium husk gum: An attractive carbohydrate biopolymer for the production of stable canthaxanthin emulsions

The physical stability of the ultrasonically prepared emulsions containing canthaxanthin (CX) produced by Dietzia natronolimnaea HS-1 strain was maximized using a face central composite design (FCCD) of response surface methodology (RSM). The linear and interaction effects of main emulsion components (whey protein isolate (WPI, 0.4-1.2 wt%), psyllium husk gum (PHG, 1.5-4.5 wt%) and coconut oil (CO, 5-10 wt%)) on the stability were studied. The density, turbidity and droplet size of emulsions were also characterized to interpret the stability data. A significant second-order polynomial model was established (p<0.0001). Maximum stability of 98.8% was predicted at the optimum levels of formulation variables (WPI concentration 1.20 wt%, PHG content 3.30 wt%, CO concentration 5.43 wt%). The results also demonstrated that CO and WPI concentration had greater effect on the droplet size and density values, whereas the PHG:WPI ratio had a rather greater effect on the turbidity values.

Optimization and characterization of walnut beverage emulsions in relation to their composition and structure

A central composite rotatable design (CCRD) was used to evaluate the effects of walnut oil (WO, 3-6%, w/w) and gum arabic (GA, 5-10%, w/w) on the average droplet size (D(32)), specific surface area (SSA), polydispersity index (span), apparent viscosity, interfacial tension and opacity of walnut-beverage emulsions. The response surface methodology (RSM) showed that the significant second-order polynomial regression equations with high R(2) (>0.95) were successfully fitted for all responses as function of independent variables. The linear effect of WO had a significant term in all reduced models. The overall optimum region was found to be at the combined level of 10% (w/w) GA content and 5.84% (w/w) WO concentration. At this optimum point, D(32), SSA, span, apparent viscosity, interfacial tension and opacity of emulsions were 0.609 μm, 8.236 m(2)/ml, 0.886, 1.336 Pa s, 51.37 mN/m and 0.810, respectively. No significant (p>0.05) difference was found between the actual values and predicted values. Moreover, principal component analysis (PCA), conducted via PCA variable loadings and cluster dendrogram was able to discriminate the emulsions with different formulations into separate classes.

Determination and characterization of kernel biochemical composition and functional compounds of Persian walnut oil.

Kernel chemical composition and fatty acids profile of three walnut cultivars (Toyserkan, Chaboksar and Karaj) was analyzed. Some physicochemical properties, total phenolics content (TPC), ortho-diphenols content (ODC) and total tocopherol concentration (TTC) of extracted oils from the walnuts were also determined. The antioxidant activity of oil was measured by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capacity and β-carotene bleaching assays. The analysis of chemical composition revealed that protein and dietary fiber was highest in Toyserkan cultivar. Phosphorus was the most abundant element in the walnut kernels, followed by potassium, magnesium and calcium. The linoleic acid and linolenic contents ranged from 50.15% to 51.36% and 10.48% to 12.04%, respectively. Also, the results demonstrated that acid value, saponification value and viscosity of extracted oil had significantly varied between all cultivars. The extracted oil from Chaboksar cultivar illustrated more hydro peroxides and secondary products than those obtained from other cultivars. A positive correlation was found between Rancimat values and oleic acid content (r = 0.60), but considerably negative correlation with TTC (r = −0.81) and TPC (r = −0.92). The relationship between percentage of remaining DPPH radical and β-carotene of walnut oils showed high correlation among three selected cultivars (r = −0.94 to −0.97).

Alcohol-free Beer: Methods of Production, Sensorial Defects, and Healthful Effects

Beer is a universally popular beverage, consumed worldwide. Recently, the beer market is witnessing a significant increase in the consumption of low- and non-alcoholic beer. This is mainly due to health reasons, safety reasons in the workplace or on the roads, and strict social regulations. Also, there are countries where alcohol consumption is completely forbidden by law. Consumers in such conditions are willing to consume products as close as possible to the conventional types, from a sensory point of view (especially flavor characteristics). However, non-alcoholic beer suffers from artificial and dull flavor as well as improper body and foaming properties. Therefore, production of alcohol-free beer with satisfactory organoleptic characteristics that can be compared with conventional beers has recently given rise to increased technological and economic interest. In this article, methods of production of alcohol-free beer (and to some extent, low-alcohol beer), its sensory characteristics as well as its health-related aspects are reviewed.

Investigation of the Effects of Microwave Treatment on the Optical Properties of Apple Slices During Drying

The objective of this work was to study the changes of optical properties of apple (Golden Delicious) slices during drying. The optical parameters compared on the basis of Hunter values (L, a, b) changes as well as total color difference (Δ E) and browning index (BI). The effect of coating materials including carboxymethylcellulose (CMC), starch, and pectin as well as microwave treatment on optical properties and microstructure of dried samples were investigated. To analyze the effects of these processes on microstructure, scanning electron microscopy (SEM) was employed. Results showed that optical properties as well as microstructure of apple were affected by coating material and drying condition. Coated samples by CMC had a lower L and higher BI, but different results in the presence of starch were obtained. Microwave treatment in the presence of appropriate coating materials could improve the optical properties of dried apple slices.

Developing an emulsion model system containing canthaxanthin biosynthesized by Dietzia natronolimnaea HS-1

An acceptable strategy to incorporate canthaxanthin (CX) as a natural colorant into products is by means of oil-in-water emulsions. The used CX in this study was produced by bacterium Dietzia natronolimnaea HS-1 using a batch bioreactor system. A central composite rotatable design-response surface methodology (CCRD-RSM) consisting of three-factored factorial design with five levels was applied for analysis of the results to obtain the optimal formulation of emulsions. Three independent variables including fenugreek gum (FG, 0.2-0.5%, w/w), coconut oil (CO, 6-10%, w/w), and CO/CX ratio (10:1-50:1) were transformed to coded values and second-order polynomial models was developed to predict the responses (p<0.0001). The studied independent variables were the stability, viscosity and droplet size properties such as volume-weighted mean diameter (D₄₃), specific surface area (S(v)) and polydispersity index (PDI) of emulsions. The 3-D response surface plot derived from the mathematical models was used to determine the optimal conditions. Main emulsion components under the optimum conditions ascertained presently by RSM: 50:1 CO/CX ratio, 0.49% (w/w) FG content and 6.28% (w/w) CO concentration. At this optimum point, stability, viscosity, D₄₃, S(v) and PDI were 90.6%, 0.0118 Pas, 0.595 μm, 12.03 m²/ml and 1.380, respectively.

Halal authenticity of gelatin using species-specific PCR.

Consumption of food products derived from porcine sources is strictly prohibited in Islam. Gelatin, mostly derived from bovine and porcine sources, has many applications in the food and pharmaceutical industries. To ensure that food products comply with halal regulations, development of valid and reliable analytical methods is very much required. In this study, a species-specific polymerase chain reaction (PCR) assay using conserved regions of mitochondrial DNA (cytochrome b gene) was performed to evaluate the halal authenticity of gelatin. After isolation of DNA from gelatin powders with known origin, conventional PCR using species-specific primers was carried out on the extracted DNA. The amplified expected PCR products of 212 and 271 bp were observed for porcine and bovine gelatin, respectively. The sensitivity of the method was tested on binary gelatin mixtures containing 0.1%, 1%, 10%, and 100% (w/w) of porcine gelatin within bovine gelatin and vice versa. Although most of the DNA is degraded due to the severe processing steps of gelatin production, the minimum level of 0.1% w/w of both porcine and bovine gelatin was detected. Moreover, eight food products labeled as containing bovine gelatin and eight capsule shells were subjected to PCR examination. The results showed that all samples contained bovine gelatin, and the absence of porcine gelatin was verified. This method of species authenticity is very useful to verify whether gelatin and gelatin-containing food products are derived from halal ingredients.

Effect of Fermentation of Pomegranate Juice by Lactobacillus plantarum and Lactobacillus acidophilus on the Antioxidant Activity and Metabolism of Sugars, Organic Acids and Phenolic Compounds

The effect of lactic acid bacterial fermentation on sugars, organic acids, bio-transformation of phenolic compounds (anthocyanins and ellagic acid), and antioxidant activity was investigated in pomegranate juice. L. plantarum and L. acidophilus were used as probiotic starter organisms. Both bacteria were able to grow in the juice and their viable cells reached to 3.9×108 CFU/mL after 72 h of fermentation. Fructose and glucose of the juice were significantly consumed by both probiotic starter cultures, and L. plantarum utilized more sugars in comparison with L. acidophilus. Glucose degradation rate was higher than fructose. The concentration of citric acid, as the main acid found in the juice, was significantly reduced by both bacteria through the first 48 h of the process (P < 0.05). Lactic acid was detected as the most abundant acidic metabolite (6.1 g/L) produced within the fermentation, especially by L. plantarum. LC/MS analysis of different anthocyanins, revealed that these compounds (except pelargonidin 3-glucoside) were significantly decreased in the pomegranate juice after fermentation. DPPH Radical scavenging studies showed that fermentation of pomegranate juice using selected probiotic starters increased the antioxidant activity significantly (P < 0.05). In addition, L. acidophilus improved the antioxidant activity of the juice more extensively than L. plantarum. The results of this study showed that fermentation of pomegranate juice by probiotic bacteria would enhance the health benefits of the juice.