Mehran Ghasemlou

Application of inulin in cheese as prebiotic, fat replacer and texturizer: A review

Inulin is a food ingredient that belongs to a class of carbohydrates known as fructans. Nutritionally it has functional properties and health-promoting effects that include reduced calorie value, dietary fiber and prebiotic effects. Inulin is increasingly used in industrially processed dairy and non-dairy products because it is a bulking agent for use in fat replacement, textural modification and organoleptic improvement. Addition of inulin to different kinds of cheese can be beneficial in the manufacture of a reduced- or low-fat, texturized, symbiotic product. This paper gives an overview of some aspects of the microstructural, textural, rheological, prebiotic and sensorial effects of inulin incorporated in cheese as fat replacer, prebiotic and texture modifier.

Characterization of new biodegradable edible film made from basil seed (Ocimum basilicum L.) gum

It is well known that the market for edible films is experiencing remarkable growth and expected to continue. This study investigated the using of basil seed gum (BSG) as a new film-forming material under the influence of addition of glycerol (GLY) as plasticizer. Edible films based on BSG and three different concentrations of GLY (25%, 35%, and 50% w/w BSG) were developed, and their water vapor permeability (WVP), as well as physical, thermal and mechanical properties were measured. The addition of glycerol significantly increased water vapor permeability and solubility of the film (p<0.05). As expected, the increase in GLY concentration from 25% to 50% (w/w) increased the extensibility, but decreased tensile strength. This suggests weaker mechanical strength and higher mobility of polymer chains by plasticizing effect of GLY. The color measurement values showed that increasing the glycerol concentration in polymer matrix caused the b and L values increased while ΔE value decreased. The electron scanning micrograph showed plasticized films as smooth, and uniform which lacked pores or cracks compared with those were not plasticized. This study revealed that the BSG had a good potential to be used in producing edible films for various food applications.

Effect of glycerol concentration on edible film production from cress seed carbohydrate gum.

In this study an edible film plasticized with glycerol was successfully prepared from cress seed gum (CSG). The physical, optical, water vapor permeability (WVP) and mechanical properties of CSG films incorporated with three levels of glycerol (25%, 35%, and 50% w/w) as plasticizer were determined. Dynamic mechanical thermal analysis was used to determine the glass transition temperature. WVP of the films was found to increase as the glycerol content increased from 25% to 50% w/w in the formulation, resulted in improvement of films flexibility and significantly lower tensile strength and higher elongation at break. The color measurement values showed that increasing the glycerol concentration in polymer matrix caused the b and L values increased while ΔE value decreased. The electron scanning micrograph indicated smooth and uniform surface morphology without signs of phase separation between the film components. The results of the present study demonstrated that CSG can promisingly be used in producing edible films with improved quality characteristics.

Characterization of edible emulsified films with low affinity to water based on kefiran and oleic acid

New edible composite films based on kefiran and oleic acid (OA) at the ratio of 15, 25, and 35% (w/w) were prepared using emulsification with the aim of improving their water vapour barrier and mechanical properties. Film-forming solutions were characterized in terms of rheological properties and particle-size distribution. The impact of the incorporation of OA into the film matrix was studied by investigating the physical, mechanical, and thermal properties of the films. The water vapour permeability (WVP) of the emulsified films was reduced by approximately 33% by adding OA. The mechanical properties of kefiran films were also affected by adding OA: tensile strength was diminished, and elongation increased considerably. Differential scanning calorimetry showed that the glass transition temperature (T(g)) of the kefiran film was -16°C and was not considerably affected by adding OA. Therefore, OA could be incorporated into these films for some food-technology applications that need a low affinity toward water.

Characterization of nanobiocomposite kappa-carrageenan film with Zataria multiflora essential oil and nanoclay.

In this study, we aimed to improve the physical, mechanical and water-vapor permeability (WVP) properties of kappa-carrageenan (KC) films by including montmorillonite (MMT) nanoclay in the film-forming solution. To further improve these properties, the combined effect of Zataria multiflora Boiss essential oil (ZEO) and MMT was also investigated. The incorporation of MMT improved the physical and mechanical properties of KC film. Film made from KC alone had a tensile strength (TS) of 26.29MPa, while the KC film with 10% nanoclay had a TS of 34.67. Further analysis was provided by X-ray diffraction and scanning electron microscopy that confirmed the dispersion of MMT in the KC matrix. It was also shown that the combined effect of nanoclay and ZEO significantly improved the TS and EB of KC films. ZEO decreased the WVP of the nanocomposite films; for example, 3% ZEO reduced WVP by around 78%. The antimicrobial activity of nanocomposite films was also studied using the overlay and vapor-phase methods; the films effectively inhibited the growth of five pathogens tested. Thus, the incorporation of both nanoclay and ZEO into KC films is a promising way to manufacture films with better mechanical, antimicrobial and WVP properties.

Development of new active packaging film made from a soluble soybean polysaccharide incorporated Zataria multiflora Boiss and Mentha pulegium essential oils

An active edible film from soluble soybean polysaccharide (SSPS) incorporated with different concentrations of Zataria multiflora Boiss (ZEO) and Mentha pulegium (MEO) essential oils was developed, and the films optical, wettability, thermal, total phenol and antioxidant characteristics were investigated, along with their antimicrobial effectiveness against Staphylococcus aureus, Bacillus cereus, Escherichia coli O157:H7, Pseudomonas aeruginosa and Salmonella typhimurium. The films colour became darker and more yellowish and had a lower gloss as the levels of ZEO or MEO were increased. Antioxidant activity of the films was determined using 2,2-diphenyl-1-picrylhydrazyl (DPPH), and ferric-reducing antioxidant power assays. DPPH was reduced in the range of 19.84-74.12% depending on the essential oil type and concentration. Film incorporated with 3% (v/v) ZEO showed the highest DPPH radical scavenging activity and ferric reducing antioxidant power (IC50=4188.60±21.73mg/l and EC50=8.86±0.09mg/ml, respectively), compared with the control and MEO added film. Films containing ZEO were more effective against the tested bacteria than those containing MEO. S. aureus was found to be the most sensitive bacterium to both ZEO or MEO, followed by B. cereus and E. coli. A highest inhibition zone of 387.05mm(2) was observed for S. aureus around the films incorporated with 3% (v/v) ZEO. The total inhibitory zone of 3% (v/v) MEO formulated films was 21.98 for S. typhimurium and 10.15mm(2) for P. aeruginosa. Differential scanning calorimetry (DSC) analysis revealed a single glass transition temperature (Tg) between 16 and 31°C. The contact angle increased up to 175% and 38% as 3% (v/v) of ZEO or MEO used: it clearly shows that films with ZEO were more hydrophobic than those with MEO. The results showed that these two essential oils could be incorporated into SSPS films for food packaging.

Structural investigation and response surface optimisation for improvement of kefiran production yield from a low-cost culture medium.

Kefiran, a water-soluble heteropolysaccharide with molecular weight of 1.35×10(6)Da and a specific optical rotation of +64° (c 1.0, H2O), was isolated from kefir grains grown in cheese whey and further purified through DEAE-Sepharose XK26. Response surface methodology was employed to optimise the culture conditions for kefiran production from kefir grains to be lactose concentration 67 g/l, yeast extract 13g/l, pH 5.7 and temperature 24°C. Intrinsic viscosity was 5.84 dl/g using the Huggins extrapolation and 5.53 dl/g using the Kramer extrapolation. Monosaccharide analysis revealed that kefiran is composed of glucose (Glc) and galactose (Gal) in a relative molar ratio of 1.0:1.1. Its structural features were elucidated by a combination of FT-IR, methylation and GC-MS analysis, periodate oxidation-Smith degradation, partial acid hydrolysis and NMR spectroscopy ((1)H, (13)C and HMBC). The data obtained indicated that kefiran possessed a backbone of (1→6)-linked Glc, (1→3)-linked Gal, (1→4)-linked Gal, (1→4)-linked Glc and (1→2,6)-linked Gal, with a branch attached to O-2 of Gal residues and terminated with Glc residues.

Effect of autochthonous starter cultures isolated from Siahmazgi cheese on physicochemical, microbiological and volatile compound profiles and sensorial attributes of sucuk, a Turkish dry-fermented sausage.

The effect of adding autochthonous starter cultures isolated from Siahmazgi cheese, on the physicochemical parameters and microbial counts of sucuk was investigated during the ripening period. SPME-GC/MS was used in volatile compound analysis and a trained group of panelists carried out sensory analysis of the final product. After preliminary screening, three strains of Lactobacillus plantarum, which possess desirable technological properties, were used to prepare three starter cultures: LBP7, LBP10 and LBP14. The addition of LBP7 and LBP14 starter cultures had a significant effect (P<0.05) on lightness, leading to higher L values compared to control sausages during the ripening period. Both LBP7 and LBP14 sausages showed higher counts of lactic acid bacteria, lower growth of Enterobacteriaceae and Gram-positive catalase-positive cocci and greatly lowered the pH value compared to control sausages throughout the ripening process. At the end of the ripening process, lactic acid bacteria counts were affected (P<0.05) by the addition of starter culture since higher counts were observed in sausages prepared with LBP7 (9.14logCFU/g) and LBP14 (8.96logCFU/g) batches. The decrease of water activity during the ripening of sausages was not affected by the various starters. The texture profiles of all sausages were similar except for LBP10, which showed lower hardness and gumminess during ripening. Under the conditions of the study, volatile compounds were mainly from spices, and no marked differences were found among inoculated sausages. However, sensory evaluation revealed that most of the sensory attributes were scored higher for inoculated sausages than for the control ones. Therefore, LBP7 and LBP14 could be promising candidates for inclusion as starter cultures for the manufacture of sucuk.

Novel Active Surface Prepared by Embedded Functionalized Clays in an Acrylate Coating

The research on a self-decontaminating surface has received significant attention because of the growth of pathogenic microorganisms on surfaces. In this study, a novel and simple technique for producing an active surface with antimicrobial functionality is demonstrated. A tethering platform was developed by grafting the biocide ampicillin (Amp) to a nanoclay and dispersing the nanoclay in a UV-curable acrylate coating applied on polypropylene films as the substrate. A coupling agent, [3-(glycidyloxy)propyl]trimethoxysilane, was used as a linker between the nanoclay and Amp. The Amp-functionalized clay was further modified with an organic surfactant to improve the compatibility with the coating. Several characterization assays, such as Fourier infrared transform analysis, thermogravimetric analysis, and X-ray diffraction, were conducted to confirm the presence of Amp in the nanoclay. Transmission electron microscopy images revealed that the clay particles were well dispersed in the coating and had a partial exfoliated morphology. The active coating surface was effective in inhibiting the growth of Gram-positive Listeria monocytogenes and Gram-negative Salmonella Typhimurium via contact. These findings suggest the potential for the development of active surfaces with the implementation of nanotechnology to achieve diverse functionalities.

Study on Postharvest Physico-Mechanical and Aerodynamic Properties of Mungbean [Vigna radiate (L.) Wilczek] Seeds

Determination of physical and mechanical properties can facilitate the design calculations of harvesting, handling, sorting and processing equipments. In this study, these properties of mungbean have been evaluated as a function of seed moisture content varying from 8.72 to 27.41% (d.b.). In this moisture range, the length, width, thickness, geometric mean diameter and surface area increased significantly (p < 0.05) from 4.32 to 5.10 mm, 3.33 to 3.54 mm, 3.30 to 3.59 mm, 3.62 to 4.01 mm and 41.1 to 50.6 mm2, respectively, whereas sphericity, porosity, bulk and true density decreased significantly (p < 0.05) from 83.80 to 78.63%, 39 to 36.56%, 841.3 to 730.7 kg/m3 and 1379.1 to 1151.8 kg/m3, respectively. Moreover, thousand seed mass, angle of repose and terminal velocity increased (p < 0.01) from 37.3 to 43.8 g, 31.6 to 40.3° and 4.9 to 5.8 m/s, respectively, by increasing the moisture content. The static coefficient of friction of mungbean seed increased against the surfaces of four structural materials, namely plywood (31.54 %), glass (29.54%), stainless steel (21.56%) and galvanized iron sheet (11.41%) as the moisture content increased from 8.72% to 27.41% d.b. Also, the results showed that the force required for initiating seed rupture decreased from 40.56 to 23.04 N and 59.82 to 19.51 N, and the energy absorbed at seed rupture increased from 7.20 to 27.36 mJ and 9.87 to 31.22 mJ by increasing in moisture content from 8.72% to 27.41% d.b. for vertical and horizontal orientations, respectively (p < 0.01).