The Effect of Soaking Duration on Zinc Leaching and Apparent Zinc Retention in Wheat (Triticum aestivum L.)

Zinc is an essential micronutrient whose concentration in cereal foods can be altered by production practices and post-harvest processing. This study evaluated the effect of soaking duration on zinc release into soaking water and apparent zinc retention in wheat (Triticum aestivum L.). Wheat grains obtained from Hausa Quarters, Ekpoma, Edo State, Nigeria, were cleaned and divided into 100-g portions. Each portion was soaked in 400 mL of distilled water at room temperature for 2, 4, 8, 16 or 24 h. Soaking filtrates were separated, filtered, acid-digested and analyzed for zinc by atomic absorption spectrometry at 213.9 nm. The recorded initial zinc content was 2.70 mg/100 g. Under the stated analytical scheme 1.0 mL filtrate aliquot diluted to a final digest volume of 100 mL. Zinc recovery increased from 0.01092 mg at 2 h to 0.16881 mg at 24 h, corresponding to calculated zinc losses of 0.40% and 6.25%, respectively, and apparent retentions of 99.60% and 93.75%. Descriptive regression gave R² = 0.9374 for zinc recovery and R² = 0.9372 for apparent retention. The findings indicate progressively greater reported zinc release with prolonged soaking.

wheat; zinc; soaking duration; zinc leaching; apparent mineral retention

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