Phycobiliprotein C-phycocyanin from Spirulina platensis is powerfully responsible for reducing oxidative stress and NADPH oxidase expression induced by an atherogenic diet in hamsters

The effects of spirulina and its chromophore phycocyanin, both without bound Se or selenium-enriched, were studied on plasma cholesterol, early atherosclerosis, cardiac production of superoxide anions, and NAD(P)H oxidase expression in hamsters. Forty hamsters were divided into 5 groups of 8 and fed an atherogenic diet for 12 weeks. They received by gavage either 7.14 mL/(kg day) phycocyanin (PC), Se-rich phycocyanin (SePC), spirulina (SP) or Se-rich spirulina (SeSP) in water, or water as control. SeSP and SePC supplied 0.4 microg of Se per 100 g body weight. Plasma cholesterol and non-HDL cholesterol concentrations were lower in group consuming SePC. HDL-cholesterol was never affected. SePC significantly increased plasma antioxidant capacity by 42% compared with controls. A sparing effect in liver glutathione peroxidase (87% on average) and superoxide dismutase (56% on average) activity was observed for all the groups compared to controls. Aortic fatty streak area was significantly reduced in the experimental groups, especially by PC (82%) and SePC (85%). Cardiac production of superoxide anion significantly decreased by approximately 46-76% in the four experimental groups and especially in SePC group (76%). The expression of p22phox subunit of NAD(P)H oxidase decreased by 34% after consumption of SePC. The results indicate that chronic consumption of Se-rich spirulina phycocyanin powerfully prevents the development of atherosclerosis. The underlying mechanism is related mainly to inhibiting pro-oxidant factors and at a lesser extent improving the serum lipid profile.     

Physicochemical Properties of Starch in Extruded Rice Flours

The effects of extruding temperatures and subsequent drying conditions on X‐ray diffraction patterns (XRD) and differential scanning calorimetry (DSC) of long grain (LG) and short grain (SG) rice flours were investigated. The rice flours were extruded in a twin‐screw extruder at 70–120°C and 22% moisture, and either dried at room temperature, transferred to 4°C for 60 hr, or frozen and then dried at room temperature until the moisture was 10–11%. The dried materials were milled without the temperature increasing above 32°C. XRD studies were conducted on pellets made from extruded and milled flours with particle sizes of 149–248 μm; DSC studies were conducted from the same material. DSC studies showed that frozen materials retrograded more than the flours dried at room temperature. The LG and SG samples had two distinct XRD patterns. The LG gradually lost its A pattern at >100°C, while acquiring V patterns at higher temperatures. SG gradually lost its A pattern at 100°C but stayed amorphous at the higher extruding temperatures. DSC analysis showed that retrograded flours did not produce any new XRD 2θ peaks, although a difference in 2θ peak intensities between the LG and SG rice flours was observed. DSC analysis may be very sensitive in detecting changes due to drying conditions, but XRD data showed gradual changes due to processing conditions. The gradual changes in XRD pattern and DSC data suggest that physicochemical properties of the extruded rice flours can be related to functional properties.     

Effect of Small and Large Wheat Starch Granules on Thermomechanical Behavior of Starch

The physicochemical properties of small‐ and large‐granule wheat starches were investigated to reveal whether gelatinization properties and rheological behavior differ between size classes of wheat starch. All samples contained 60% water (w/w, wb). The starch granule size and shape were examined by scanning electron microscopy in the separated A‐ and B‐type granule populations and in the whole wheat starch granule population. Differential scanning calorimetry (DSC) and electron spin resonance (ESR) analyses were performed in parallel with rheological measurements using dynamic mechanical thermal analysis (DMTA) to relate the viscoelastic changes to modifications in dynamic properties of aqueous solutions and structural disorganization of starch. The small (B‐type) granules had slightly higher gelatinization temperature and lower gelatinization enthalpy than did the large (A‐type) granules. Also, B‐type granules had higher enthalpy for the amylose‐lipid complex transition. Moreover, our results suggested that small granules have higher affinity for water at room temperature. It seems that there is a less ordered arrangement of the polysaccharide chains in the smaller granules when compared with the larger ones. These differences in functional properties of small and large granules suggested that the granule size distribution is an important parameter in the baking process.