168 research outputs found

    A1 Printed in the Islamic Republic of Iran

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    Abstract -Showing the occurrence of glass/rubber transition in bovine serum albumin (a globular protein) at low moisture levels and the occurrence of Maillard crosslinking in gelatin in previous works, the importance of the state of glass or rubber of BSA on the rate and extent of polymerisation, protein solubility, colour and SDS PAGE patterns in the presence and absence of ascorbic acid, diketogulonic acid and dehydroascorbic acid was investigated. BSA on storage with Ascorbic acid and its degradation products at low moisture contents (8.3% and 19.1%) at a relatively low temperature (40ºC) can undergo chemical changes resulting in marked increase in molecular weight, solubility decrease and formation of browning colour. The glassy state data established the occurrence of chemical changes (Maillard crosslinking and disulfide crosslinking) in the BSA system on storage below its glass transition temperature

    Accelerated Ripening of Kabkab Dates Using Sodium Chloride and Acetic Acid Solutions

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    ABSTRACT-In this research, the accelerated ripening of the Kabkab dates from Khalal to Tamr using NaCl and acetic acid solutions was studied. Fruits at Khalal stage were harvested and washed with distilled water before being treated with ripening inducers: 1. NaCl solutions, 2. acetic acid solutions and 3. Aqueous solution of NaCl (1%) and acetic acid. moisture, pH, colour, brix and textural firmness of the samples were monitored. Results indicated that during ripening the moisture content and colour changed significantly. The major change was observed for firmness where a maximum force for puncture test varied from about 1000 to 50 g force for all samples after 72 hours of incubation at 40 °C. Harvesting at Khalal stage followed by treating the fruits with NaCl and/or acetic acid solutions and an incubation stage at 40 °C showed to be a promising method for accelerated ripening

    Fructan Contents in Australian Wheat Varieties Released Over the Last 150 Years

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    Grain fructans play an important role in the physiology of wheat plants and also impact on the health of consumers of wheat-based products. Given the potential economic importance of fructan levels, if genetic variability could be identified for this trait, it may be a potentially useful breeding target for developing climate-resilient and nutritionally enhanced wheat varieties. The aim of the current study was to screen 78 genetically diverse Australian wheat varieties released between 1860 and 2015 to determine if historic breeding targets have resulted in changes in fructan levels and to identify potential breeding parents for the development of varieties with specific fructan levels. The impact of seasonal conditions on grain fructan levels were also investigated. Analysis of the varieties in this study indicated that historic breeding targets have not impacted on grain fructan levels. Fructan content in flours varied between 1.01 to 2.27%, showing some variation among the varieties. However, a significant variation in fructan levels was observed between different harvest years (mean values for 2015 and 2016 samples were 1.38 and 1.74%, respectively). While large variations in fructan contents of different varieties were not found, there were some varieties with consistently higher or lower fructan contents which could be used to breed varieties with specific fructan levels

    Ohmic-assisted hydrodistillation technology: A review

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    Volumetric heating techniques such as ohmic heating have emerged as alternatives to conventional processing methods for diverse applications in the food industry. One of the novel applications of ohmic heating is ohmic-assisted hydrodistillation (OAHD), which utilizes the volumetric heating benefits to overcome traditional distillation shortcomings. This technique proffers benefits such as saving time and energy and has gained increasing interest as a preferred approach for ethanol distillation and essential oil extraction from various plant materials. Scope and approach This paper reviews the principles and current applications of OAHD. The effects of OAHD on process time, energy consumption, and distillate quality are discussed. Considerations for industrial application of OAHD are highlighted and its salient drawbacks are also taken into account. Key findings and conclusions Advantages of OAHD over conventional distillation include high thermal efficiency, short processing time and reduced operational cost. Further research on safety and sustainability along with economic study are prerequisites for commercial application of this technology

    Ohmic-Assisted Texture Softening of Cabbage, Turnip, Potato and Radish in Comparison with Microwave and Conventional Heating

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    Recently, ohmic heating has shown promising advantages for accelerated and controlled texture softening of some vegetables over conventional cooking. Textural properties of ohmically cooked cabbage, radish, turnip and potato were measured by texture profile analysis, and compared with microwave and conventional cooking. The data were experimentally modeled into an exponential model and softening rate and residual texture were calculated. Ohmic heating at 380V softened the texture of all four studied vegetables at greater rates in comparison with microwave and conventional methods. Comparing the texture softening rate, k value, of the cooked vegetables indicated that they were in the order of radish>turnip>potato>cabbage, and among the four studied vegetables the maximum and minimum texture response changes to cooking were found in radish and cabbage, respectively. In contrast to conventional and microwave cooking, an interesting and emerging finding was the significant increase in cohesiveness of ohmically processed vegetables with cooking time. Practical Applications: Ohmic cooking had recently been introduced as an emerging method to shorten cooking time and speed up texture softening of vegetables. In this research, four vegetables were cooked with ohmic technology and their textural properties were compared with the samples treated with conventional and microwave cooking. The results showed the ability of ohmic technology to soften the texture of vegetables faster than other methods with greater constant rate values and less residual textures. By applying ohmic processing, food industry can benefit from controlled texture modification of vegetables leading to higher textural quality of processed foods

    An investigation on physical ageing of β-lactoglobulin and implications for its storage

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    Due to the importance of physical ageing in functional properties of the globular protein of β-lactoglobulin as the main protein of whey powder (the by product of cheese manufacturing industry) the possible occurrence of physical ageing in dry powder of β-lactoglobulin with moisture content of 15.9% was studied at different temperatures below and close to the glass transition.Endothermic peaks that corresponded to relaxation enthalpy were observed for a β-lactoglobulin with 4 % moisture. Enthalpy and peak temperature increased on storage of β-lactoglobulin when it was held in the glassy state at different temperatures (20, 40, 60 º C). The general characteristics of the endothermic peaks were similar to those previously reported for synthetic polymers

    STUDY OF COLOURING, AROMATIC STRENGTH AND BITTERNESS OF SAFFRON (CROCUS SATIVUS L.) CULTIVATED IN THE UK

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    Ultrasound assisted cold gelation of kappa carrageenan dispersions

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    Usually to prepare a gel from kappa carrageenan, an aqueous dispersion of carrageenan powder is heated. This research presents evidence of cold gelation of carrageenan dispersions while no heat is needed. The occurrence of cold gelation is investigated in the absence or presence of potassium ions during ultrasound treatment by studying the mechanical and microstructural properties of the prepared gels using a texture analyzer and scanning electron microscopy, respectively. Carrageenan gels were obtained by applying power ultrasound. By increasing sonication time, gel hardness increased up to a certain level (in absence or presence of K+ during ultrasound treatment) and further ultrasound application had a negative effect. Moreover, the mechanical properties of the gels in which K+ ions were added before ultrasound were weaker than the samples when K+ ions were added after sonication. Relaxation times of gels were calculated using the generalized Maxwell model with three elements
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