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Shahidi Noghabi M.,Research Institute of Food Science and Technology RIFST | Razavi S.M.A.,Ferdowsi University of Mashhad
Journal of Food Processing and Preservation | Year: 2015

Interest in membrane filtration in the sugar industry is increasing. Sugar, as the final product of technology of sugar production, has to satisfy rigorous quality demands. Among others, it means low content of nonsucrose compounds, as well as the smallest possible share of colored matter. This work aimed to investigate the performance of ultrafiltration in purification of thin sugar beet juice. Thin juice was processed using polysulfonamide spiral wound membrane module of 20kDa molecular weight cutoff on a pilot plant under different operating conditions including; temperature at three levels of 30, 40 and 50C, transmembrane pressure at three levels of 1, 2 and 3 bar and operation time at levels of 15, 30 and 45min. The trials displayed satisfactory separation with an average purity rise of 0.72 unit, 7% lower CaO content, 86.9% lower turbidity and 10% lower color in the permeate on a 45-min operation and at different TMP and temperature. The average flux was 21.84kg/m2h. © 2015 Wiley Periodicals, Inc.

Rafe A.,Research Institute of Food Science and Technology RIFST | Vahedi E.,Islamic Azad University at Amol | Hasan-Sarei A.G.,Islamic Azad University at Amol
Journal of the Science of Food and Agriculture | Year: 2016

BACKGROUND: Rice bran protein (RBP) is a valuable plant protein which has unique nutritional and hypoallergenic properties. Whey proteins have wide applications in the food industry, such as in dairy, meat and bakery products. RESULTS: Whey protein concentrate (WPC), RBP and their mixtures at different ratios (1:1, 1:2, 1:5 and 1:10 w/w) were heated from 20 to 90 °C at different heating rates (0.5, 1, 5 and 10 °C min−1). The storage modulus (G′) and gelling point (Tgel) of WPC were higher than those of RBP, indicating the good ability of WPC to develop stiffer networks. By increasing the proportion of WPC in mixed systems, G′ was increased and Tgel was reduced. Nevertheless, the elasticity of all binary mixtures was lower than that of WPC alone. Tgel and the final G′ of RBP–WPC blends were increased by raising the heating rate. The RBP–WPC mixtures developed more elastic gels than RBP alone at different heating rates. RBP had a fibrillar and lentil-like structure whose fibril assembly had smaller structures than those of WPC. CONCLUSION: The gelling structure of the mixed gel of WPC–RBP was improved by adding WPC. Indeed, by adding WPC, gels tended to show syneresis and had lower water-holding capacity. Furthermore, the gel structure was produced by adding WPC to the non-gelling RBP, which is compatible with whey and can be applied as a functional food for infants and/or adults. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry

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.

Emadzadeh B.,Research Institute of Food Science and Technology RIFST | Emadzadeh B.,Ferdowsi University of Mashhad | Razavi S.M.A.,Ferdowsi University of Mashhad | Schleining G.,University of Natural Resources and Life Sciences, Vienna
International Journal of Food Properties | Year: 2013

The small and large deformation properties of different low-calorie pistachio butter formulas were studied in order to develop a background understanding of the changes in viscoelastic and textural characteristics that occur due to different types of fat replacers and sweeteners. Frequency, temperature, and time sweep analysis and also back extrusion and texture profile analysis tests were performed. The magnitudes of dynamic moduli increased in the frequency sweep test with loss tan values <1. The elastic structure of all samples changed to viscous behavior with increasing temperature (5-65°C), regardless of the type of fat replacers and sweeteners level. The temperature sweep test on heating and cooling samples resulted in higher viscoelastic properties and more solid-like behavior. There was no time dependency for loss tan at 45°C. A modified Cox-Merz rule could superimpose the steady and complex viscosity data. There was a good agreement between the results of G′ and hardness in small and large deformation tests. Copyright © 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.

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