Enhancement of the Stability of Insoluble Calcium Particles Using a Phospholipid Coating

Calcium is one of the most important elements in the human body. Insoluble calcium particles are often used in calcium-fortified food products, such as calcium-fortified milk, dairy beverages or protein powders. However, their suspension may be unstable often leading to precipitation in such products. In this study, three different kinds of insoluble calcium particles, i.e. hydroxyapatite (HA), tricalcium phosphate (TCP) and calcium carbonate (CaCO₃) were coated with amphiphilic phospholipids using a solvent-exchange method. Suspension stability of these insoluble calcium particles was effectively improved with phospholipid coating, especially for HA and TCP, as more phospholipids were coated on the surface of these two calcium particles than CaCO₃. Phospholipid coating increased the electrostatic repulsions between particles, preventing the particles from aggregating and precipitating. In addition, the digestibility of phospholipid-coated insoluble calcium particles was tested in simulated gastric juice, and the dissolution time of these insoluble calcium particles was prolonged through phospholipid coating.     

Characterization of Fish Gelatin at Nanoscale Using Atomic Force Microscopy

Atomic force microscopy (AFM) was used as a meaningful tool to characterize the nanostructure of gelatin from catfish (Ictalurus punctatus) skin. The gelatins extracted with pretreatments including acid pretreatment, alkaline pretreatment, and alkaline followed by acid pretreatment (optimized extraction conditions). The resulting gelatins were imaged using AFM and their nanostructure was studied. The AFM images showed that gelatin extracted with acid pretreatment had a coacervate structure while with alkaline pretreatment there were separate aggregates. Spherical aggregates and annular pores were observed in AFM images of gelatin with the optimized extraction conditions. AFM imaging of gelatin with a relative high concentration (0.5%) was successfully done and the results help researchers to understand gelatin structures at the nanoscale.     

Structural analysis and in vitro antitumor effect of polysaccharides from Pholiota adiposa

Glycoconjugate Journal - Pholiota adiposa is an edible chestnut mushroom with many health benefits, such as antioxidant and anticancer activity. In this paper, polysaccharides were extracted from...     

Studies to improve the extraction of mannitol and alginic acid fromMacrocystis pyrifera,a marine brown alga

Yields of mannitol and alginic acid from dry and freshMacrocystis pyrifera under different extraction conditions were characterized. Using seawater as the solvent for mannitol extraction, yields up to 98.5% of the total mannitol (12.4%) were obtained. A 4% Na₂CO₃ solution at 60°;C gave the highest yield of alginic acid (21.5%), but a 2% Na₂CO₃ extraction at room temperature (20.4%) was almost as effective. Thus crude mannitol and alginic acid can be obtained more economically than previously.     

Regulatory proteins of lobster striated muscle.

The regulatory proteins of lobster muscles consist of tropomyosin and of troponin. Troponin contains a 17,000 chain weight component, two closely related components of about 30,000 and a 52,000 chain weight component. In addition to troponin, tropomyosin is required for the inhibition of the magnesium activated actomyosin ATPase activity in the absence of calcium and for the reversal of this inhibition by calcium. Lobster tropomyosin interacts with rabbit actin and lobster troponin interacts with rabbit tropomyosin. The 30,000 doublet component corresponds to the troponin-I of rabbit and inhibits the ATPase activity of actomyosin both in the presence and in the absence of calcium. The 17,000 component corresponds to the troponin-C of rabbit; it binds calcium and reverses the inhibition of the ATPase activity by troponin-I in the presence of calcium. No more than 1 mol of calcium is bound by a mole of troponin-C or by troponin. The 52,000 component interacts with tropomyosin and has been tentatively identified as troponin-T; however, it has not been demonstrated as yet that this component had a role in the regulation of lobster actomyosin.     

Lobster (Homarus americanus) striated muscle myosin.

1. Myosin from the thin-filament regulated flexor muscle of lobster contains 2 moles of each of 2 light chains. 2. The Lb 1 light chain of 19,000 daltons which can be removed by DTNB is heavier than the DTNB light chain of chicken. The Lb 2 light chain of 17,000 daltons can be removed with urea. 3. On electrophoresis in 8 M urea (pH 8.7) the Lb 2 light chain migrates with a mobility similar to that of chicken A2, but the Lb 1 migrates significantly faster than any of the chicken light chains. 4. In lobster, the DTNB treatment destroys the Ca and K-EDTA ATPase activity of lobster myosin.