Effects of thermal processing on the in vitro bioaccessibility and microstructure of β-carotene in orange-fleshed sweet potato.

The effects of different preparation methods on the bioaccessibility of β-carotene in orange-fleshed sweet potato (OFSP), an important food crop in sub-Saharan Africa, have been evaluated using an in vitro digestion procedure. The preparation methods included, on fresh roots, boiling followed by puréeing and oil addition (BOL) and homogenization followed by boiling and oil addition (HOM); on milled flour from freeze-dried fresh roots, cooking of porridge followed by oil addition (POA) and oil addition to flour followed by cooking of porridge (POB). The retention of all-trans-β-carotene ranged from 58% (POB) to 72% (BOL).

In vitro bioaccessibility of beta-carotene from heat-processed orange-fleshed sweet potato.

Orange-fleshed sweet potato (OFSP) is currently promoted in parts of sub-Saharan Africa as a biofortified staple food with large potential to provide considerable amounts of provitamin A carotenoids. However, the bioaccessibility of provitamin A carotenoids from OFSP has not been widely investigated, especially not as an effect of different preparation methods. In this study, we used an in vitro digestion model to assess the bioaccessibility of beta-carotene from differently heat-processed OFSP.

Phytate degradation by human gut isolated Bifidobacterium pseudocatenulatum ATCC27919 and its probiotic potential.

The growing awareness of the relationship between diet and health has led to an increasing demand for food products that support health above and beyond providing basic nutrition. Probiotics are live organisms present in foods, which yield health benefits related to their interactions with the gastrointestinal tract. Phytases are a subgroup of phosphatases that catalyse the desphosphorylation of phytate, which reduces its negative impact on mineral bioavailability, and generates lower inositol phosphates.

Impaired uptake of beta-carotene by Caco-2 human intestinal cells in the presence of iron.

At present, there are conflicting data regarding whether or not beta-carotene has a positive effect on iron absorption. This study was undertaken to evaluate possible interactions involved in the uptake of beta-carotene and iron in a human intestinal cell model (Caco-2). The Caco-2 cells were incubated with test solutions containing different amounts of ferrous chloride (10-50 microM) and beta-carotene (0.

Rhizopus oligosporus and yeast co-cultivation during barley tempeh fermentation--nutritional impact and real-time PCR quantification of fungal growth dynamics.

Barley tempeh was produced by fermenting barley kernels with Rhizopus oligosporus. The potential of the yeasts Saccharomyces cerevisiae (three strains), S. boulardii (one strain), Pichia anomala (one strain) and Kluyveromyces lactis (one strain) to grow together with R.

Degradation of phytate by high-phytase Saccharomyces cerevisiae strains during simulated gastrointestinal digestion.

Hydrolysis of extracellular phytate (InsP(6)) by high-phytase yeast strains and survival of yeast cells were studied at simulated digestive conditions using yeast peptone dextrose growth medium and wheat gruel as model meals. An in vitro digestion method was modified to better correlate with the gastric pH gradient following food intake in vivo. High-phytase yeast gave a strong reduction of InsP(6) (up to 60%) in the early gastric phase, as compared to no degradation by wild-type strains.

Prolonged transit time through the stomach and small intestine improves iron dialyzability and uptake in vitro.

The iron dialyzability and uptake in relation to transit time through the stomach and small intestine was investigated using a dynamic in vitro gastrointestinal model in combination with Caco-2 cells. Three test meals were evaluated, consisting of lactic fermented vegetables with white (I) or whole meal bread (II) and of sourdough-fermented rye bread (III). Three transit times were tested (fast, medium, and slow transport).

The pathway of dephosphorylation of myo-inositol hexakisphosphate by phytate-degrading enzymes of different Bacillus spp.

The pathway of dephosphorylation of myo-inositol hexakisphosphate by the phytate-degrading enzymes of Bacillus subtilis 168, Bacillus amyloliquefaciens ATCC 15841, and Bacillus amyloliquefaciens 45 was established using a combination of high-performance ion chromatography analysis and kinetic studies. The data demonstrate that all the Bacillus phytate-degrading enzymes under investigation dephosphorylate myo-inositol hexakisphosphate by sequential removal of phosphate groups via two independent routes; the routes proceed via D-Ins(1,2,4,5,6)P5 to Ins(2,4,5,6)P4 to finally Ins(2,4,6)P3 or D-Ins(2,5,6)P3 and via D-Ins(1,2,4,5,6)P5 to D-Ins(1,2,5,6)P4 to finally D-Ins(1,2,6)P3. The resulting myo-inositol trisphosphate D-Ins(1,2,6)P3 was degraded via D-Ins(2,6)P2 to finally Ins(2)P after prolonged incubation times in combination with increased enzyme concentration.

Pathway of dephosphorylation of myo-inositol hexakisphosphate by phytases of legume seeds.

Using a combination of high-performance ion chromatography analysis and kinetic studies, the pathway of dephosphorylation of myo-inositol hexakisphosphate by the phytases purified from faba bean and lupine seeds, respectively, was established. The data demonstrate that the legume seed phytases under investigation dephosphorylate myo-inositol hexakisphosphate in a stereospecific way. The phytase from faba bean seeds and the phytase LP2 from lupine seeds degrade phytate by sequential removal of phosphate groups via D-Ins(1,2,3,5,6)P(5), D-Ins(1,2,5,6)P(4), D-Ins(1,2,6)P(3), and D-Ins(1,2)P(2) to finally Ins(2)P, whereas the phytases LP11 and LP12 from lupine seeds generate the final degradation product Ins(2)P via D-Ins(1,2,4,5,6)P(5), D-Ins(1,2,5,6)P(4), D-Ins(1,2,6)P(3), and D-Ins(1,2)P(2).