RELATIONSHIP BETWEEN METABOLISM AND GLYCOGEN CONTENT IN SKELETAL MUSCLE FIBERS OF LARGE WHITE AND HAMPSHIRE CROSSBRED PIGS

Glycolytic potential (an estimator of intra vitam glycogen level) was determined at slaughter in the M. longissimus lumborum muscle from 6 Large White pigs and 6 Pen Ar Lan pigs (Pen Ar Lans are Hampshire × Pietrain × Large White crossbred pigs). Muscle samples (M. longissimus lumborum) were taken at slaughter and 24 h later. Muscle glycolytic potential was much higher in Pen Ar Lans than in Large Whites. Samples were cut at – 25°C for histochemistry. Serial cuts were stained for ATPase activity, succinate dehydrogenase activity     

Isolation and characterization of Lactobacillus strains involved in koumiss fermentation

Koumiss is a slightly alcoholic fermented milk beverage, originally obtained by using natural mix starters (lactic acid bacteria and yeast). Seven Lactobacillus strains from lyophilized koumiss were isolated and identified as L. salivarius, L. buchneri and L. plantarum. The process of lactic acid fermentation caused by koumiss strains was faster (9–13 h) than that with other lactobacilli. The conversion ratio of glucose to lactic acid ranged from 47% to 79% and was strain dependent. All strains were resistant to low pH. Three of the strains isolated were viable during prolonged cold storage in fermented milk (3 weeks at 4°C).     

Zn and Zn–Sn alloy coatings with and without chromate layers. Part I: Corrosion resistance and structural analysis

The aqueous corrosion resistances of Zn and Zn–Sn ( 20 wt% Sn) electrodeposits, passivated by immersion in chromating solution with different ratios of Cr(vi) to activating ions, are compared. The electrochemical behaviour of various chromated and nonchromated coatings were investigated in deaerated 0.5 mol dm^–3 Na₂SO₄/pH 5 solution using a.c. impedance and d.c. polarization techniques. The polarization curves revealed that the chromate layers influence both the cathodic and anodic reactions. The corrosion rate of each specimen decreases with time due to the accumulation of corrosion products. The dark yellow (DY) chromate film on the Zn–Sn alloy and the iridiscent yellow (IY) on Zn yields the best protective ability in agreement with the assessment of prolonged salt spray chamber tests. These chromate layers resembling cracked mud become permeable to the electrolyte after immersion and, as a consequence of the transformation and the leaching of certain Cr compounds, a very porous agglomerate of corrosion products forms. The morphology and structure of dark yellow chromated Zn–Sn alloy was also investigated by transmission electromicroscopy (TEM) and scanning electronmicroscopy with microprobe (SEM/EDS) analyses before and after corrosion. The depth profile of the corroded surface chemical composition was determined by X-ray photoelectron spectroscopy (XPS).