Mudasir Ahmad Malik

High intensity ultrasound treatment of protein isolate extracted from dephenolized sunflower meal: Effect on physicochemical and functional properties

The influence of high intensity ultrasound (HIUS) on physicochemical and functional properties of sunflower protein isolates was investigated. Protein solutions (10% w/v) were treated with ultrasound probe (20kHz) and ultrasound bath (40kHz) for 5, 10, 20 and 30min. Thermal stability of protein isolates was reduced as indicated by differential scanning calorimetry. Minimum thermal stability was observed at 20min of sonication and increased further with increase in treatment time indicating aggregation at prolonged sonication. SDS-PAGE profile of proteins showed a significant reduction in molecular weight. Further, surface hydrophobicity and sulfhydryl content increased after HIUS treatment indicating partial unfolding of proteins and reduction in the intermolecular interactions. The particle size analysis showed that HIUS treatment reduced the particle size. Less turbid solution were observed largely due to reduction in particle size. HIUS decreased the available lysine content in protein isolates. Solubility, emulsifying capacity, emulsion stability, foaming capacity, foam stability and oil binding capacity were improved significantly, while as, water binding capacity was decreased. The effect of HIUS on physicochemical and functional properties of sunflower protein isolates was more pronounced in probe sonication rather than bath sonication. Protein isolates with improved functional properties can be obtained using high intensity ultrasound technology.

Effect of removal of phenolic compounds on structural and thermal properties of sunflower protein isolate

The present study evaluated the effect of removal of polyphenols on the structural properties of protein isolates extracted from sunflower seed and kernel. The structural and thermal changes in protein upon phenolic interaction were studied using circular dichroism, differential scanning calorimetry, thermal gravimetric analysis, X-ray diffraction, sodium dodecyl sulphate–polyacrylamide gel electrophoresis (SDS–PAGE), and Fourier Transform Infrared (FT-IR) spectroscopy. Presence of phenolic compounds in proteins decreased the ordered structure content with parallel increase in unordered structure content. Denaturation temperature was higher for protein isolates with phenolic compounds while, enthalpy decreased upon phenolic interaction. In the presence of phenolic compounds, higher mass loss was observed upon heating. Crystalinity and crystal size got increased after removal of phenolic compounds. Protein isolates from kernels had higher percentage of crystalinity and crystal size as compared to seed protein isolates. Higher molecular weights were observed for protein isolates with phenolic compounds. Presence of polyphenols reduced the hydrophobicity as well the sulfhydryl content and increased the particle size of proteins.

Engineering properties of sunflower seed: Effect of dehulling and moisture content

Abstract The study diagnosed engineering properties on varying moisture content of sunflower seed and kernel from 7.6 to 25% (wet basis). On increasing moisture, dimensional values increased for both seed and kernel. Bulk density, true density and porosity were found higher for kernel as compared to seed at each moisture content. On increasing the moisture content from 7.6 to 25%, true density, porosity and thousand kernel weight increased. Coefficient of static friction on plywood was found maximum for kernel at 25% moisture content, while it was minimum for seed on glass at 7.6% moisture content. The angle of repose was maximum for kernel as compared to seed. Initial cracking force, average rupture force and average rupture energy for seed and kernel decreased with an increase in the moisture content. The kernel was found to be more resistant to initial cracking than seed.

Heat treatment of sunflower protein isolates near isoelectric point: Effect on rheological and structural properties

In the present study sunflower protein isolates were subjected to heat treatment (80 °C for 5 min, 15 min and 25 min) at three pH values (3.5, 4.5 and 5.5). The strength of gel prepared from treated protein isolates was lower than the gels from native protein isolates and gel strength increased with increase in temperature treatment. Higher denaturation temperatures were observed in treated protein isolates than native protein isolates and increased with increase in thermal treatment time. Treated protein isolates showed more resistance against thermal degradation than native protein isolates as was evident from thermal gravimetric analysis. Secondary and tertiary structure determined by circular dichroism and intrinsic fluorescence respectively were significantly altered after thermal treatment. Lower crystal size along with reduced crystallinity was observed in treated protein isolates than native protein isolates and was further reduced with increase in heating time as was determined by X-ray diffraction.

Physical, milling, cooking, and pasting characteristics of different rice varieties grown in the valley of Kashmir India

Abstract In the present study, three different rice varieties, namely frome chena (FC), safaid chena (SC), and barkat chena (BC), were evaluated for various quality aspects in terms of physical, milling, cooking, and pasting characteristics. Among the three rice varieties SC had the highest thousand kernel weight and length breadth ratio (L/B). While as, BC had the lowest thousand kernel weight and FC had lowest L/B. Bulk density was found to be highest for FC followed by SC and BC. FC had density of 769.01 kg/m3. Milling characteristic in terms of broken percentage and head rice yield showed non-significant difference between the varieties. Head rice yield was below 70% in all the three varieties. All the three varieties took similar time to cook and cooking time varied non-significantly between 23.66 and 25.83 min. L/B ratio after cooking was found to be highest for FC followed by BC and SC. Elongation ratio of rice after cooking did not varied significantly between varieties. Elongation ratio after cooking ranged from 1.60 to 1.70. Pasting profile of rice flour was determined using rapid visco analyzer. Significant difference was observed in pasting profile of studied rice varieties.