Evaluation of Zinc Bioavailability in Humans from Foliar Zinc Biofortified Wheat and from Intrinsic vs. Extrinsic Zn Labels in Biofortified Wheat.

Objectives: Zinc biofortification may be a sustainable way to improve Zn status, but questions remain on Zn bioavailability. We produced a novel biofortified wheat by Zn foliar application, and a separate wheat cultivar was intrinsically labeled with a Zn stable isotope. Goals were: a) To compare fractional and total Zn absorption (FAZ-TAZ) from chapattis prepared with biofortified, regular and postharvest fortified wheat; b) Compare the absorption of intrinsically and extrinsically Zn labels from biofortified wheat. Methods: Chapattis were prepared from flours with 100% and 80% extraction rates (ER). Meals were administered to 2 women's groups (N=44) in randomized order. Bioavailability was measured with double isotopic urinary technique with stable isotopes; four-day urines were collected and isotopic enrichment measured. Results: Foliar Zn application resulted in an increase of 45.6% of grain Zn. The control and biofortified wheat contained 25±0.12 ppm and 46±1.37 ppm Zn and 0.830±0.04 g/100 g and 0.807 ±0.03 g/100 g PA. The Zn:PA molar ratio for the unfortified, fortified and biofortified meals were 36, 63, 63 (100% ER) and 40, 67, 67 (80% ER). Mean total Zn in the intrinsically labeled wheat was 19.9±1.6 ppm. FAZ-TAZ data from the absorption studies are being analyzed. Conclusions: Foliar application increased Zn concentration without significantly changing PA concentration, and extraction rate is a determinant of the Zn:PA ratio. Assessment of FAZ-TAZ will provide: a) Data on the potential of foliar zinc biofortified wheat, and b) proof that the double isotope technique used to assess absorption of extrinsic Zn labels in biofortified wheat is valid.

Biological utilization of naturally fermented pearl millet flour (Pennisetum typhoideum)

Natural fermentation of pearl millet flour at 20, 25 and 30 degrees for 72 h brought about an improvement in its apparent and true protein digestibility. Utilisable protein, net protein retention and protein retention efficiency values were also enhanced as a result of fermentation. Rats fed on flour fermented at 20 and 25 degrees C had higher food as well as protein efficiency ratios than the flour fermented at 30 degrees C. Feeding of the fermented products did not bring about any histopathological abnormality in rats. Cutlets prepared from the fermented flour were organoleptically acceptable to a panel of judges