Iranian Food Science and Technology Research Journal
Year:2015 | Volume:11 | Issue:3|Papers Count:6

In this study, mathematical modeling of hot air baking-drying of thin-layer crisp bread was investigated.Thin-layer drying process were conducted under three different temperatures of 110, 150 and 190 °C at a constant air velocity of 0.5±0.1 m/s and absolute humidity of 0.6 ± 0.04g water/kg dry air. It was found that the baking-drying process occurred in falling rate period over the baking-drying times. Eight well-known thin-layer baking-drying models were fitted to the baking-drying experimental data of crisp bread, implementing non-linear regression analysis techniques. Based on the coefficient of determination (R2) and root mean square error (RMSE) values, it was concluded that the best models in terms of fitting performance for hot air baking-drying of bran free crisp bread were Wang & Singh and Logarithmic while for whole-wheat crisp bread were Page, Logarithmic and Wang & Singh. The moisture transfer from crisp bread was described using the Fick’s diffusion model. The effective diffusivity was within the range of 2.88×10-8 to 1.11×10-7 m2/s for bran free crisp bread and from 2.47×10-8 to 8.84×10-8 m2/s for whole-wheat crisp bread over the temperature range. The activation energy for bran free and whole-wheat crisp bread was found to be 25.22 and 23.43 kJ/mol, respectively.

Ohmic-assisted hydrodistillation (OAHD) is an advanced hydrodistillation (HD) technique utilizing ohmic heating process and could be considered as a novel method for the extraction of essential oils. Long extraction time is one of the major problems with traditional methods. OAHD of essential oils from the aerial parts of peppermint was studied and the results were compared with those of the conventional HD. The results showed that OAHD method had the extraction time of 19.71 min while this value was about 55.88 min for HD. Scanning electron micrographs of mint leaves showed a sudden eruption of essential oil glands for OAHD samples. GCMS analysis did not indicate any noticeable changes in the compounds of the essential oils obtained by OAHD in comparison with HD. The results introduced OAHD as a green technology.

This paper presents a novel approach to monitor food process based on Modular Neural Networks (MNNs) and fuzzy inference system. The proposed MNN consists of three separate modules, each using different image features as input including: edge detection, wavelet transform, and Hough transform. The sugeno fuzzy inference system was used to combine the outputs from each of these modules to classify the images of quince during osmotic dehydration process. To test the method, for classification, database was made of 108 quince samples’images (12 classes). In experiments, the developed architecture achieved 91.6% recognition accuracy. Next step, solid gain, water loss and moisture content of quince samples were considered as MNNs outputs, whereas osmotic dehydration time and classified images were MNNs inputs. The minimum %MRE (18.153) with 89% prediction ability for water loss (WL) was obtained when applying two hidden layers with 6 neurons per each two layers. The lowest %MRE (35.5335) with 93% prediction ability for solid gain (SG) was obtained when using 6 and 8 neurons per first and second layer, respectively. And finally %MRE was at least (7.4759) with 96% prediction ability for moisture content (MC) by 6 and 5 neurons per first and second layer, respectively.The results show that this model could be commendably implemented for quantitative modeling and monitoring of food quality changes during osmotic dehydration process.

Incorporation of whey protein products (WPPs) namely whey protein concentrate, isolate and whey protein powder with the different levels (1, 2, 3 and 4%) in buffalo meat was investigated for production, quality characteristic of emulsion sausage (ES). Quality of emulsion sausage was evaluated in term of microbiological characteristics like total plat count (TPC) and Yeast and mould count, coliform count andSalmonella shigella count. Refrigerated Storage (0oC) significantly (p<0.05) increased total plate count, yeast and mould count, coliform count of emulsion sausages incorporated with different levels of whey protein concentrate, isolate and powder. The total plate count was found to be between 7.11- 7.39 log cfu/g, 6.74- 7.23 log cfu/g and 6.76-7.21 log cfu/g, yeast and mould count was found to be 3.34-3.86 log cfu/g, 3.45-3.57 log cfu/g and 3.58-3.95 log cfu/g on 25th day of storage for samples prepared with different levels (1, 2, 3 and 4%) of whey protein concentrate, isolate and whey protein powder respectively. After 25 days of refrigerated storage (0oC) total plate count and yeast and mould count of all samples were found to be in the safe limit (3.32 - 3.93 log cfu/g).Coliform count were detected in emulsion sausages samples and it was found to be in the range of 2.06-2.34 log cfu/g, 2.15-2.28 log cfu/g and 2.08-2.22 log cfu/g in emulsion sausages incorporated with whey protein concentrate, isolate and powder respectively after 15 days of storage. In final stage of storage, coliform count was found to be in the range of 2.16-2.54 log cfu/g, 2.30-2.41 and 2.30-2.43.Salmonella shigella was not detected in all samples of emulsion sausages at all during refrigerated storage at 0oC for 25 days.

Ohmic heating has an advantage over conventional indirect heating methods because heater (electrode) surfaces temperatures are comparatively lower as heat is generated within bulk fluid. This process could develop the electrodes decay or corrosion.Food preparation and safety are major issues in this modern world.in this study we focus on migration of ohmic heating electrode components into a liquid-solid food and comparison migration in this method with conventional heating method. Concentrations of Fe, Cr, Ni, Mn, and Mo from the stainless steel electrode migrated into ohmically and conventionally treated soup were measured. Migration of the major key metal ions from stainless steel measured by Atomic Absorbtion shows that overall ohmic treatment yielded reduced migration residues of all metal ions, compared to the conventional retorting with similar electrodes.Concentrations of all metal ions migrated into food samples after ohmic treatment were far lower than dietary exposure levels so that this technique can ensure the safety and quality of food supplies.

These work deals with the study of changes in the microstructure of the sweetened condensed milk with sugar substitution for starch syrup during its long storage period. The research has been carried out with the transmission electron microscope. The authors have analyzed the microstructure of the condensed milk with sugar and the microstructure of the condensed milk with 40% and 100% sugar substitution for the starch syrup. It is established that filamentous bridges are formed between the casein micelles in the microstructure of the condensed milk with the partial sugar substitution for the starch syrup. These bridges are pseudo-polymers, formed by glucose monomers. During the long-storage period the number and density of these bridges increase, influencing, consequently, the organoleptic and rheological properties of the condensed milk. The studies have shown that there is a critical concentration of the starch syrup in the condensed milk, which limits the syrup use in the manufacture of the product.