Anne V. F. Nielsen, Anne S. Meyer*
*Corresponding author
Center for BioProcess Engineering, Department of Chemical and Biochemical Engineering,
Technical University of Denmark, Soeltofts Plads 229, 2800 Kgs. Lyngby, Denmark

Abstract

Phytase catalysis has been shown to improve iron absorption by dephosphorylation of the potent iron chelator, phytic acid, found in high amounts in cereals. Recently, the World Health Organization evaluated the phytase from Aspergillus niger as safe for use in human food. The phytase may work either prior to ingestion, i.e. in the food, or post ingestion, i.e. in the human gastrointestinal tract. We have assessed the technical aspects of formulation and release of phytase added to chewing gum as a delivery vehicle. Phytases from Aspergillus niger and Escherichia coli incorporated into chewing gum were released quantitatively upon chewing and retained phytase activity (50-80% of the enzyme activity added was released within 10 minutes). Initial evaluations of phytase chewing gum shelf life showed good stability after 48 days of storage of the chewing gum at ambient conditions.

INTRODUCTION

Iron deficiency persists as a major nutritional problem worldwide and has been estimated to affect more than 2 billion people globally (1). Many of the major cereal staple foods contain significant amounts of iron, but this iron has very limited bioavailability, often in the range of only 2-3 % (2). Phytic acid (myo-inositol (1,2,3,4,5,6)-hexakisphosphoric acid) is the major phosphorous storage compound in cereal kernels. The phosphate groups of phytic acid are negatively charged at physiological pH conditions making phytic acid a potent iron chelator, which is why phytic acid has been associated with the low bioavailability of iron from cereal foods. The low uptake of iron from plant foods, including cereals, is a major problem in developing countries and an issue in developed countries as well. For instance, a Scandinavian study has shown that the consumption of the recommended daily intake of fibre-rich wheat bread reduces the iron status in young women initially having sufficient iron stores (3). Whereas there is no efficient innate mechanism in the human gastro-intestinal tract whereby iron can be released from phytic acid, dephytinisat ...