FOOD ENGINEERING RESEARCH (JOURNAL OF AGRICULTURAL ENGINEERING RESEARCH)
Year:2018 | Volume:17 | Issue:2 (65) |Papers Count:8

In this research, the effect of different levels (0, 0. 3, 0. 6 and 1%) of xanthan and Lepidium Sativum gum was evaluated on moisture, specific volume, porosity, crust color and crumb firmness of gluten free cake (rice-corn). These samples were compared with wheat cake. Gums were increased moisture, L* and b*. The highest porosity and the lowest crumb firmness were observed in the sample containing 1 % Lepidium Sativum. Also the sample containing 0. 6 and 1 % Lepidium Sativum and 0. 6 % xanthan gum had the highest specific volume. Finally, the positive function of Lepidium Sativum gum (especially in 1 %) on technological properties of gluten free cake was more than xanthan gum and this sample was better than wheat flour cake.

In the recent years, numerous studies have been focused on the production and application of biodegradable polymers due to increasing concerns about environmental pollution of plastic packaging materials, and also increasing consumer’ s interest for improvement of quality and appearance of food products. The aims of the present study were to evaluate the physicomechanical properties of polylactic acid film (PLA) incorporated with propolis ethanolic extract collected from Kermanshah province (PE; 1 and 2%), cellulose nanoparticle (1%) and Ziziphora clinopodioides essential oil. The chemical compositions of the Ziziphora clinopodioides essential oil were identified by gas chromatography coupled with mass spectrometer detector (GC-MS). The physicomechanical properties of designated films were evaluated using ASTM method. Carvacrol (65. 22%), thymol (19. 51%), ɣ-terpinene (4. 63%) and p-cymene (4. 86%) were the most representative components of the essential oil. Based on the results of the present study, incorporation of PE, ZEO and cellulose nanoparticle improved the water vapour permeability coefficient (WVPC) and tensile stress of investigated films. The lower lightness (L*) and higher redness (a*) and consequently a darker color was found in the film incorporated with PPE. The PLA film incorporated with ZEO, PPE and cellulose nanoparticle have shown good physical and mechanical properties which can be used in food products.

In this study, the effect of chitosan coating (0, 0. 5 and 1%) and cinnamon extract (0, 2 and 4%) were evaluated on moisture content, texture and sensory properties and fungal growth of oily breakfast cake during 21 days storage at room temperature. The results showed that during storage, the moisture content of control sample decreased about 42. 7% but the growth of fungi increased about 3. 9 log cfu/g. Application of chitosan coatings at 0. 5% and 1% levels, increased moisture content 19. 5% and 25. 4%, and springiness 1. 5% and 0. 4%, while decreased hardness 63% and 49%, and the number of fungi 1. 5 and 1. 7 log cfu/g, respectively, compared to the control sample (p <0. 05). The increase of cinnamon extract also has a synergistic effect. According to the sensory evaluation results, using chitosan coating significantly increased the texture and flavor score of cake compared to the control sample. Adding cinnamon extract also increased the color score of cake brain compared to the control sample. According to the results obtained in this study, using 0. 5% chitosan coating containing 2% cinnamon extract is recommended for coating sponge breakfast cake.

Storage of potato is essential for the continuous supply of raw materials for domestic and industrial use. Due to structural changes (tissue) and followed by changes in the mechanical properties of the tubers during storage and its impact on product quality, the information of the mechanical properties of potato tubers reduces losses and economic losses partly along with other factors. In this research two potato genotype (Agria and Clone 397009-8) were stored in two technical and non-technical storage for three months in Ardebil. The uniaxial compression test was used to measure the effect of variety, storage temperature and storage duration on elastic modulus, failure force and failure energy, and penetration test to measure hardness and penetration energy. Measurement was done weekly and the final results were reported after the storage period. The results showed that cultivar, storage temperature and storage duration have a significant effect on all mechanical properties in both cultivars. With increase storage time, the elastic modulus, failure force, failure energy, hardness and penetration energy in technical storage were lower than non-technical storage, which this difference was statistically significant (P <0. 05). The results showed that cultivar Agria has a higher elastic coefficient and rigidity than Clone genotype because of rigid texture and as a result, the storage period is longer.

This study was aimed to fabricate O/W emulsions of Descurainia Sophia seeds oil in order to be stabilized against oxidation. Response surface methodology (RSM) was used to optimizing the process in which the gum Arabic (GA), whey protein concentrate (WPC), and sonication time were selected as independent variables where the peroxide value (meq/kg oil) was considered as a response factor. The optimum point was obtained when the WPC, and GA, and ultrasound treatment time were as 19. 78%, 11. 08%, and 0. 1 s, respectively. In the associated optimum point, peroxide value was determined as 0. 59 meq/kg oil. The emulsion oil droplets varied dependently to ultrasound time and WPC concentration which both decreased the oil droplets sizes with more exposing and high concentration inclusion. Conversely, ultrasound applying resulted in higher peroxide values at the instantaneous determinations. The optimum emulsion indicated 916 nm with the-48 mV Zeta potential. The respective sample exhibited shear thinning behavior which more effectively attributed to WPC existence. Oxidation stability of the emulsion samples compared with crude oil and the oil treated with 30 s ultrasound. The results indicated that the GA and WPC effectively preserved the oil during 28 d at the intensifying circumstances (50 ° C) and the free oils were oxidized more intensively. GA due to steric repulsion structure forming in the vicinity of oil droplets and WPC due to electrostatic repulsion, produced a complex biopolymer structure which had potentially antioxidant and coating attributes.

Nowadays, a refresh interest is rising to extend the viability of probiotics by direct incorporation of them in edible coats and films to prevent lethal phase transition in food processing and storage. In current study, four probiotic bacterial strains (Lactobacillus acidophilus, L. casei, L. rhamnosus and Bifidobacterium bifidum) were used for the immobilisation in edible film based carboxymethyl cellulose (CMC) during 42 days of storage at 25 ᵒ C and 4 ᵒ C respectively. Results showed a clear decrease in bacterial cell viability. But, viability of L. acidophilus and L. rhamnosus were always in the range of recommended levels at 4 ᵒ C during the storage (106– 107 CFU/g). CMC-based edible films could act as a suitable carrier for some probiotic strains in food packaging during refrigerated temperatures.

In this study, the synthesis of nanoparticles of doped Copper-zinc oxide and aluminum-zinc oxide by co-precipitation method and investigation of structural and morphological properties of related nanoparticles by using Fourier infrared spectrum, X-ray diffraction and transmission electron microscopy were carried out. In FTIR analysis, existence peaks at 1365, 1638 and 2402 cm-1 attributed to copper in zinc oxide structure and appearance of peaks at 1364, 1740 and 2362 cm-1, showed aluminum in zinc oxide structure. Results obtained from XRD and TEM also confirmed that doping process is successfully done. Results showed that the doping of copper and aluminum elements on zinc oxide nanoparticle structure is successfully performed via y co-precipitation method. In order to investigate the antimicrobial effects of these nanoparticles, the inhibition zone (mm) and the minimum inhibitory concentration against Shigella flexneri (PTCC 1234) were applied. The results of antimicrobial tests showed that cu-Zn oxide nanoparticles have more antimicrobial effects on Shigella flexneri (32mm inhibition zone) than Al-zinc oxide (14mm inhibition zone). Additionally, both doped nanoparticles have more antibacterial effect than zinc oxide nanoparticles alone (p≤ 0/01). Minimum inhabitation concentration of cu and al doped nanoparticles were 70 and 100mg/ml, respectively. Combination of studied nanoparticles with two common biocides (Hypochlorite sodium, hydrogen peroxide) have synergistic effects.

Fresh walnut kernel is very spoilable in natural storage conditions. Storage under unfavorable conditions, leads to weight change due to moisture absorption, oxidative reactions and molding. Due to these changes, the texture of the product is destroyed and quality loss. The aim of this study is to evaluate the effect of Farsi gum as an edible coating on shelf-life of walnut (prevents moisture absorption, oxidative reactions, and mold activity). For this purpose, firstly, the gum was collected, fractionation (separation of soluble phase from insoluble phase), and dried. Then the solutions were prepared in concentrations of 1% and 2% V/W from soluble phase of Farsi gum and coated on walnuts. Moisture absorption, oxidative corruption and microbial tests were studied. The results showed that Farsi gum at 2% concentration prevents moisture absorption and weight change and it had a significant effect (p<0. 05) on reduction rate of oxidation. But it had no significant effect (p<0. 05) on inhibition the growth of mold.