Fiber-rich Fraction Research Articles

Kinetics of lycopene degradation in tomato pulp solids under different processing and storage conditions

Kinetics of lycopene degradation during heating of tomato pulp at 100 °C under different conditions followed a pseudo first order reaction. When concentrating tomato pulp during heating, the rate of lycopene degradation was higher ( K = 0.0023 min −1) compared with when heating was done without concentration ( K = 0.0017 min −1). In another case, when water insoluble tomato pulp solids were heated in distilled water without concentration, rate of lycopene degradation was lowest ( K = 0.0011 min −1), indicating that acids and sugars contributed towards loss of lycopene. When the fibre-rich fractions of tomato pulp were stored at −20, 5 and 25 °C under different storage conditions, the activation energy and Q 10 values of lycopene loss ranged from 19.87 to 27.74 kJ/mole and 1.35 to 1.52, respectively. When these fractions were freeze-dried and oven-dried (at 25–75 °C), lycopene content was not affected by heating temperature ( P > 0.05).

Cereal dietary fibers affect post-prandial lipoproteins in healthy human subjects

Normolipidemic males (six) ingested on separate days a low-fiber (2·8 g) testmeal (70 g fat, 0·75 g cholesterol), enriched or not with 10 g dietary fiber in the form of either oat bran, rice bran or wheat fiber or 4·2 g fiber as wheat germ. Fasting and post-meal blood samples were obtained for 7 h. Chylomicrons, VLDL, LDL and HDL were isolated from the baseline samples and the samples of the 2–3 h triglyceride peak. Chylomicron triglycerides were significantly ( p ≤ 0·05) reduced with wheat fiber. All fiber sources reduced chylomicron cholesterol. VLDL lipid components were not markedly changed. LDL cholesterol decreased post-prandially and this was reversed after adding oat bran and wheat germ. HDL triglycerides were unchanged but the post-prandial HDL cholesterol decrease was significantly amplified after adding oat bran and wheat germ. In conclusion, dietary fiber-rich fractions from cereals can alter post-prandial lipoproteins in humans to a variable extent.

The bile acids binding of the fibre-rich fractions of three starchy legumes.

The bile acid binding to undigestible fibre has a significance on bile acids excretion. This was known to result in lowering blood cholesterol (for the use of cholesterol in bile acid formation) as well as reducing the colorectal cancer risk (through decreased formation of secondary bile acids). Compared to the model fibres Solka floc and carboxymethylcellulose (CMC), the investigated fibre fractions of lentils, broad beans and butter beans, were found to bind more cholic acid and chenodeoxycholic acid under conditions simulating the small intestine.

Purification of an Active Gelatinase from Collagen Fiber Fraction of Granulation Tissue in Rats

Gelatinase was extracted at 60 degrees C from the collagen fiber-rich fraction of granulation tissue induced by carrageenin in rats. A large part of the extracted gelatinase was unbound to Zn-chelating Sepharose. The unbound gelatinase gave a single band corresponding to a molecular mass of 57 kDa on SDS-substrate PAGE, but showed a much higher molecular mass (greater than 200 kDa) on Sephadex G-150 gel filtration. In addition, that unbound fraction contained gelatin fragments was revealed by SDS-PAGE. When the unbound fraction of Zn-chelating Sepharose was incubated at 37 degrees C, the gelatin fragments disappeared and the apparent molecular mass of gelatinase in gel filtration decreased. This gelatin degradation of the unbound fraction was enhanced by treatment with a 4-aminophenylmercuric acetate (APMA). The results suggest that the gelatinase is bound to gelatin fragments in the unbound fraction. After the treatment with APMA, the gelatinase was purified to to homogeneity; the purified gelatinase gave a single band corresponding to a molecular mass of 57 or 67 kDa on SDS-PAGE under nonreducing or reducing conditions, respectively. The purified gelatinase is a metalloproteinase, and extensively degraded gelatin, but showed no proteolytic activity toward alpha-casein or types I and IV collagens. The results suggest that the 67-kDa active gelatinase is bound to collagen fibers and plays an important role in a rapid degradation of collagen fibers in granulation tissue.