engleski

Interrelation of zinc and phytic acid in wheat flour confectionary products

Cereals and cereal products are rich source of zinc in human diet, especially products produced from or with addition of whole flour. However, such products are rich in phytic acid too. Bioavailability of zinc in cereal products having high content of phytic acid is reduced due to production of insoluble phytic acid - zinc complex. Hydrolyse of phytic acid in conditions favourable for endogene phytase action during processing of cereal products can improve the bioavailability of zinc, which is directly related to the phytic acid / zinc molar ratio. To research the effect of technological processing on the phytic acid degradation and concequently on the phytic acid / zinc molar ratio, zinc and phytic acid contents were determined in classic wheat flour biscuits and in biscuits enriched with wheat whole flour, whole meal and soya flour. The results show significant decrease in phytic acid content (17.3 percent up to 29.7 percent) in relation to dough phytic acid content in classic biscuits dough of which has low content of phytic acid. The decrease correlates negatively to phytic acid content in dough (r=-0.9990, p=0.05). Since thermal treatment during backing does not change Zn content, the phytic acid / Zn molar ratio decrease in classic biscuits significantly as well (24 percent). In contraty, the unchanged content of phytic acid and phytic acid / Zn molar ratio were found in enriched biscuits having almost seven time higher content of phytic acid (200 mg/100 g dry matter and 29 mg/100 g dry matter, respectively) suggesting that significant destruction of phytic acid occusr only in low phytic acid content products.

confectionary products; zinc; phytic acid; zinc availability

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