Hot water and cellulase hydrolysis extraction methods were used to obtain soluble and insoluble fractions of dietary fiber (DF). Concentrates of the DF fractions were used to study their structure, physical properties (particle size, density, porosity, and oil adsorption capacity), hydration properties (swelling, water binding capacity, and viscosity), and glucose dialysis retardation index. Hydrolysis with cellulase modified the physical and hydration properties of the different samples analyzed, since this enzyme reduced the particle size in soluble and insoluble dietary fiber (SDF and IDF, respectively), while increasing the water binding capacity of IDF and decreasing that of SDF. Correlation studies carried out between the different properties analysed, showed that the behavior of hydrated fiber and the delay in glucose diffusion are determined by the physical properties of fiber. Keywords: Dietary fiber; functional properties; fiber extraction and artichoke

The effect of infant formulas supplemented with functional ingredients on calcium (Ca), magnesium (Mg) and phosphorus (P) bioavailability was investigated in rats. Seven follow-up infant formulas containing probiotics (Bifidobacterium bifidum and Bifidobacterium longum), prebiotics (galactooligosaccharides at 12, 50 and 100 g kg −1 ) or synbiotics (bifidobacteria and galactooligosacccharides) were administered to weanling rats for 30 days. A 3 day mineral balance was performed over three periods (8-10, 18-20 and 28-30 days) to monitor mineral apparent absorption and retention ratios and physiological and nutritional parameters. Feeding rats on infant formula-based diets showed high feed efficiency (≥0.46). It was found that infant formulas supplemented with probiotics and/or prebiotics for 30 days increased Ca, Mg and P bioavailability in rats. Mineral apparent absorption and retention ratios were higher than 90% for Ca and P and 80% for Mg during the first balance period regardless of the infant formula used, but they decreased during the next two balance periods. Although it was not possible to select one infant formula as the best to improve mineral absorption, the 100 g kg −1 prebiotic and 50 and 100 g kg −1 synbiotic infant formulas were the most efficient at increasing Ca, Mg and P bioavailability compared with the control group.

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The effects of powder functional follow-up infant formulas on the morphology of the large intestine and the bone mineral content in rats were investigated. Infant formulas were supplemented with probiotics (Bifidobacterium bifidum and Bifidobacterium longum), prebiotics (galacto-oligosaccharides (4 -GOS) at 12, 50 and 100 g kg −1 ) or synbiotics (bifidobacteria and 4 -GOS) and administered to seven groups of weanling rats over 30 days. After sacrificing the animals, the caecum and colon were removed and the luminal content pH and the crypt depth and cell density within the epithelial layer were measured. Results showed that groups fed synbiotic diets had significantly (P < 0.05) lower caecal and colonic content pH values compared with the control group. However, no test diet significantly modified the crypt depth or cell density in the caecum. In contrast, all seven test diets significantly increased (P < 0.05) the crypt depth in both the proximal and distal portions of the colon. There was a high correlation (Pearson correlation coefficient 0.870) between caecal and colonic content pH values. On the other hand, colonic content pH was negatively correlated with crypt depth in both the proximal and distal colon and with cell density in the distal colon. The authors previously reported increases in calcium, magnesium and phosphorus absorption using the same infant formulas. In the present study it was concluded that the increase in calcium absorption took place in the distal colon whereas magnesium absorption increased in both the proximal and distal colon, and their contents (especially that of calcium) increased in both the femur and tibia.  2007 Society of Chemical Industry Keywords: epithelial cell proliferation; infant formula; probiotics; prebiotics; synbiotics INTRODUCTIONRecent work has shown that certain non-digestible oligosaccharides (NDO) may improve the absorption of calcium (Ca) and possibly other minerals in both adolescents and adults.1 Ca and magnesium (Mg) absorption takes place mainly in the small intestine; however, absorption can also occur in the colon and caecum, 2,3 where NDO are mainly fermented.