Binding capacity of 18 fiber sources for calcium

Eighteen fiber sources were analyzed for protein, phytic acid (PA), soluble (SF) and insoluble (IF) fiber, total dietary fiber, water-holding capacity (WHC), and endogenous calcium concentration. Calcium-binding capacity (CaBC) was determined in acid-washed fiber sources. Protein content varied from 0.0% in cane fiber and cellulose to 22.2% in tomato fiber. Acid-wash treatment significantly (P < 0.05) reduced the protein content. PA in acid-washed samples ranged from 0 micrograms/g of sample in cane fiber, cellulose, corn bran, and orange fiber to 15312 micrograms/g of sample in rice bran. SF ranged from 1.9% in corn bran to 28.3% in orange fiber. IF varied from 34.9% in orange fiber to 87.0% in cellulose. WHC ranged from 2.36% in oat fiber to 10.85% in sugar beet fiber. Endogenous calcium varied from 304 micrograms/g of sample in cane fiber to 12432 micrograms/g of sample in orange fiber. CaBC ranged from a low of 480 micrograms/g of sample for cellulose to a high of 20137 micrograms/g of sample for orange fiber. No relationship was found between protein, PA, SF, IF, WHC, and CaBC.