Research Institute of Food Science and Technology RIFST


Research Institute of Food Science and Technology RIFST

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Rafe A.,Research Institute of Food Science and Technology RIFST | Razavi S.M.A.,Ferdowsi University of Mashhad
Food Hydrocolloids | Year: 2017

The scaling behavior and fractal analysis of basil seed gum (BSG) cross-linked with sodium trimetaphosphate (STMP) have been investigated by rheological small amplitude oscillatory shear measurements. Storage modulus and critical strain (γo) of the gels exhibited power law relationships with BSG concentration. Based on the power-law exponent values, the fractal dimension (df) of gels was estimated using scaling models, revealed the weak-link regime of BSG. The df values lied well within the range of fractal dimension values (1.5–2.8) reported for protein gels. However, they slightly differed from df for diffusion-limited and reaction limited cluster-cluster aggregation processes. Stress sweep test was shown that STMP addition to BSG made a stronger gel than that of BSG lacking STMP. Mechanical spectrum of gels was also revealed that adding STMP can improve the elasticity of gels. BSG had a tan δ of >0.1, indicating paste-like weak gel, while tan δ of BSG-STMP has approached to 0.1 exhibited the character of a cross-linked network near to “true gel”. BSG-STMP was also recognized as a thermo-reversible physical gel, which gelation and thermal properties did not affect by STMP. Therefore, the scaling behavior can be applied for hydrocolloids gels to extract structural information through rheological measurements. Moreover, the rheological characteristics of BSG-STMP showed it can be used as a proper hydrogel in food and pharmaceutical applications. © 2016 Elsevier Ltd

Shahbazi M.,Research Institute of Food Science and Technology RIFST | Rajabzadeh G.,Research Institute of Food Science and Technology RIFST | Ahmadi S.J.,Nuclear Science and Technology Research Institute, Iran
Carbohydrate Polymers | Year: 2017

Different electron beam doses (10, 20, 30 and 40 kGy) were tested with the purpose of investigating their influences on chitosan/clay (cloisite 20A) nanocomposite film to improve its functional performance by providing a crosslinked matrix. Water resistance, water contact angle and water barrier property of nanocomposite film were increased up to 30 kGy, and then drastically decreased at the level of 40 kGy. Characteristic diffraction peak of chitosan shifted to low angle with an increase in the interlayer spacing of the nanoclay after 30 kGy irradiation, indicating a superlative intercalation. Crystallinity degree of chitosan/clay nanocomposite was increased in the amorphous region as the irradiation dose increased up to 30 kGy. However, irradiation at level of 40 kGy was converted the crystalline region of nanocomposite film to the amorphous state with losing the chitosan crystallinity. Irradiation increased the film tensile strength due to crosslinking of chitosan chains, with more pronounced effect at 30 kGy and decreased it by chain degradation at 40 kGy. A glass transition temperature was detected in DSC thermogram of chitosan/clay film, and it shifted to higher temperatures as the irradiation dose increased. Moreover, cold-crystallization exothermic peak of the chitosan/clay film moved to the lower temperature after irradiation, suggesting a faster crystallization rate. FE-SEM showed that the chitosan chains were more intercalated between the nanoclay platelets with increasing the irradiation dose. A progressive decrease in the roughness parameters of 20 and 30 kGy irradiated nanocomposite films revealed by atomic force microscopy, whereas irradiation at 40 kGy increased roughness values. © 2016 Elsevier Ltd

Verdian A.,Research Institute of Food Science and Technology RIFST
Talanta | Year: 2018

In an effort to achieve high sensitive and selective detection of pesticide residues, numerous nanomaterial-based aptasensors are currently being developed for acetamiprid analysis. Recently, aptamers as a potent alternative of antibodies are used in biosensing platforms. There is tremendous interest in utilizing of nanomaterial as basic building blocks and signaling elements in aptasensors. The nanomaterials have the unique optical and electrical properties. The combination of nanomaterial and aptamer technology has opened a new window in pesticide residues monitoring. In this review, recent advances and applications of optical and electrochemical nanomaterial-based aptasensors for the detection and quantitative determination of acetamiprid in details have been discussed. © 2017 Elsevier B.V.

Rafe A.,Research Institute of Food Science and Technology RIFST | Sadeghian A.,Research Institute of Food Science and Technology RIFST
Journal of Cereal Science | Year: 2017

Extrusion is a multi-step thermal process which has been extensively utilized in food preparations. Effects of temperature, moisture content and speed screw on the stabilization of rice bran were optimized using response surface methodology. Furthermore, the effect of extrusion processing on the physicochemical, nutritional and functional properties of Tarom and Domesiah cultivars stabilized rice bran (SRB) were studied. The colour of rice bran was improved by extrusion processing, but the protein content was reduced, which can be related to the denaturation of protein. Extrusion had also a reduction significant effect on the phyitic acid and vitamin E in stabilized rice bran. However, the content of vitamins B2, B3, B5 and folic acid were remained unchanged, but the dietary fibre was enhanced which has beneficial health effect. In comparison with raw rice bran, water holding capacity was enhanced, but the oil absorption capacity was reduced. Foaming capacity and foaming stability of SRB was more than that of untreated rice bran. Although, they were less than that of rice bran protein concentrate/isolate. As a result, extrusion process improves some functional and nutritional properties of rice bran which are valuable for industrial applications and have potential as food ingredient to improve consumer health. © 2017 Elsevier Ltd

Dabestani M.,Research Institute of Food Science and Technology RIFST | Kadkhodaee R.,Research Institute of Food Science and Technology RIFST | Phillips G.O.,Phillips Hydrocolloid Research Ltd | Abbasi S.,Tarbiat Modares University
Food Hydrocolloids | Year: 2017

Persian gum is an exudate polysaccharide from the trunk and branches of wild almond tree which has recently attracted the attention of many researchers owing to its unique properties and the diverse possible applications it may find in the food industry. This article provides a comprehensive review on the physicochemical, structural and functional characteristics (e.g., emulsifying properties) of the gum and introduces a number of attempts made with the view to use it for improving the flow behavior, texture or shelf life stability of food products. © 2017 Elsevier Ltd.

Shahbazi M.,Research Institute of Food Science and Technology RIFST | Rajabzadeh G.,Research Institute of Food Science and Technology RIFST | Sotoodeh S.,Islamic Azad University at Qūchān
International Journal of Biological Macromolecules | Year: 2017

Two types of multi-walled carbon nanotubes (CNT and CNT-OH) at different levels (0.1–0.9 wt%) were introduced into starch matrix in order to modify its functional properties. The optimum concentration of each nanotube was selected based on the results of water solubility, water permeability and mechanical experiments. The physico-mechanical data showed that CNT up to 0.7 wt% led to a notable increase in water resistance, water barrier property and tensile strength, whilst regarding CNT-OH, these improvements found at 0.9 wt%. Therefore, effects of optimized level of each nanotube on the starch film were evaluated by XRD, surface hydrophobicity, wettability and surface energy tests. XRD revealed that the position of starch characteristic peak shifted to higher degree after nanotubes introducing. The hydrophobic character of the film was greatly increased with incorporation of nanoparticles, as evidenced by increased contact angle with greatest value regarding CNT-OH. Moreover, CNT-OH notably decreased the surface free energy of the starch film. Finally, the conformity of both nanocomposites with actual food regulations on biodegradable materials was tested by cytotoxicity assay to evaluate the possibility of application in food packaging sector. Both nanocomposite films had potential of cytotoxic effects, since they could increase cytoplasmic lactate dehydrogenase release from L-929 fibroblast cells in contact with their surface. © 2017 Elsevier B.V.

Rafe A.,Research Institute of Food Science and Technology RIFST | Razavi S.M.A.,Ferdowsi University of Mashhad
International Journal of Food Properties | Year: 2015

Attenuated total reflection Fourier transform infrared spectroscopy was used to compare the structure of β-lactoglobulin, basil seed gum, and β-lactoglobulin-basil seed gum mixtures, at different states (powder, solution, and gel). The effects of heating and different ratios of β-lactoglobulin-basil seed gum were also investigated to determine their impact on chemical structure and understand their interaction. The results showed that gelification process proved a pronounced effect upon β-lactoglobulin secondary structure, leading to the formation of intermolecular hydrogen-bonding β-sheet structure. These results confirmed that this structure may be necessary for the formation of a gel network. Basil seed gum had a distinct peak at around 1603 cm-1 that relates to -COO-1 stretching of carboxylate salts, probably uronic acids, which approved its anionic structure. The Fourier transform infrared spectroscopy findings strongly suggested that these two polymers are thermodynamic incompatible as amide I peak was increased in the β-lactoglobulin-basil seed gum mixed system and carbon-nitrogen (CN) stretching peak was observed at 2125 cm-1. On the basis of these findings, it was possible to modify the ability of β-lactoglobulin-basil seed gum to form a gel and as a consequence to control the gelling and emulsifying properties. © 2015 Taylor & Francis Group, LLC.

Rafe A.,Research Institute of Food Science and Technology RIFST | Razavi S.M.A.,Ferdowsi University of Mashhad
International Journal of Food Science and Technology | Year: 2013

Summary: Effect of pH (4.5-7.5) and Ca2+ (0.01-0.5 m) on gelation of single and mixed systems of 10% β-lactoglobulin (BLG) and 1% basil seed gum (BSG) was investigated. The gelling point of BLG and BSG gels was strongly pH-dependent, and stiffer gels formed at higher pH. The BLG gels were formed upon heating to 90 °C and reinforced on cooling to 20 °C; however, the gelation of BSG occurred at temperatures below 70 °C. By increasing Ca2+ concentration, storage modulus of BLG and BSG gels were increased, although pH had a greater effect than Ca2+. In contrast, mixed systems showed two distinct types of behaviour: BLG gel formation and BSG network, suggesting that phase-separated gels were formed. In addition, higher strength was obtained for BLG-BSG mixture at higher Ca2+ concentration. © 2013 Institute of Food Science and Technology.

Ahmadian-Kouchaksaraie Z.,Research Institute of Food Science and Technology RIFST | Niazmand R.,Research Institute of Food Science and Technology RIFST | Najafi M.N.,Agricultural and Natural Resources Research Center of Iran
Innovative Food Science and Emerging Technologies | Year: 2016

Subcritical water extraction was investigated as a green technology for the extraction of phenolic compounds from Crocus sativus petals. A Box-Behnken design was utilized to determine the optimal extraction conditions. Extraction temperature (120–160 °C), extraction time (20–60 min) and water to solid (W/S) ratio (20–40 mL/g) were considered as the variables for the extraction of phenolic compounds. A second order polynomial model was fitted to each response and the regression coefficients were determined using least square methodology. There was a good correspondence between the experimental data and their predicted counterparts. The optimum conditions of extraction were estimated to be W/S ratio of 36 mL/g, temperature of 159 °C and time of 54 min. Extraction using these optimized conditions achieved the best TPC (1616 mg/100 g), TFC (239 mg/100 g), %DPPHsc (86.05%) and FRAP value (5.1 mM). Principal components analysis (PCA) allowed a better understanding of interactions between properties of extracted phenolic antioxidants. Industrial relevance Application of subcritical water was shown to be a practical technique to extract the phenolic compounds of saffron petals as an underutilized bulk agro-waste. The higher phenolic antioxidants obtained in extractions carried out by this technique is of major interest from an industrial point of view, since solvent amounts were reduced and extraction times shortened. Thus, the application of this emerging technology for extraction uses and low-cost raw materials is an economical alternative to conventional extraction methods according to industry demands and a sustainable development. © 2016 Elsevier Ltd

Ghorani B.,Research Institute of Food Science and Technology RIFST | Tucker N.,University of Lincoln
Food Hydrocolloids | Year: 2015

Encapsulation of bioactive compounds and probiotic bacteria within prebiotic substances to protect or even enhance their survival whilst passing upper gastro-intestinal tract, is an area of great interest for both academia and the food industries. Different methods have been suggested, examined and applied to encapsulate and dry probiotics and bioactive compounds, for example spray drying. However, the harsh processing conditions of these methods can significantly reduce the viability of bacteria or damage the structure of the target molecules. Electrospinning (and the related process of electrospraying) both show promise as a novel delivery vehicle for supplementary food compounds because the process can work with an aqueous solution, at room temperature and without coagulation chemistry to produce matrices in the micro- and nano-range. The production of nanofibers (fiber diameters less than 1μm) is a commonplace. Nanofiber materials produced by electrospinning have attracted particular attention in the food industry because of their potential as vehicles for sustained and controlled release. The room temperature process route is compatible with food grade polymers and biopolymers, and allows efficient encapsulation by reducing denaturation, and enhancing stability of bioactives. Consequently, there is clear potential to develop electrospun fibrous assemblies to advance the design and performance of novel products and delivery systems for supplementary food compounds. To optimize production conditions and maximize throughput, a clear understanding the mechanism of electrospinning is essential. This paper presents a comprehensive review of the fundamentals of electrospinning to produce nanofibers suitable for food technology application particularly for use in encapsulation and as nano-carriers. © 2015 Elsevier Ltd.

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