HarvestPlus is searching for consultant partners to submit proposals to study the effect of High phytase wheat for improved mineral bioavailability.
HarvestPlus improves nutrition and public health by developing and promoting biofortified food crops that are rich in vitamins and minerals while providing global leadership on evidence and technology. HarvestPlus is part of the CGIAR Research Program on Agriculture for Nutrition and Health (A4NH).
CGIAR is a global agriculture research partnership for a food secure future. Its science is carried out by its 15 research centres in collaboration with hundreds of partner organizations. The HarvestPlus programme is headquartered at the International Food Policy Research Institute (IFPRI) in Washington, DC and collaborates with multiple CGIAR centres and partner organizations around the world.
HavestPlus and its partners have successfully developed and released biofortified wheat with high levels of zinc (up to 37 µg/g) in Pakistan and India. The additional zinc in such wheat varieties could increase the zinc intake of zinc deficient populations.
However, the additional zinc may not be absorbed efficiently due to the presence of phytic acid. It is known that wheat contains relatively high levels of phytic acid which binds nutrients such as phosphorus, calcium, iron and zinc.
In order to improve the absorption of the zinc, it is important to reduce the levels of phytic acid in wheat without reducing the zinc contents before consumption. Phytic acid (IP6) binds calcium, iron and zinc, but once a significant fraction of IP6 and IP5 is broken down by hydrolysis to smaller molecules (such as IP4, IP3 and IP2) by the enzyme phytase, the zinc attached to the resulting molecules is more bioavailable than when bound to IP6 and IP5.
An approach to reduce the phytic acid content in wheat is by breeding for varieties with lower phytic acid content (measured at harvest). Alternatively, wheat with higher phytase activity can also be produced either by natural selection and breeding or by genetic engineering approaches.
They have available at least 3 lines of wheat with competitive agronomic performance that appears to have higher phytase activity based on secondary information. It will be important to confirm the actual phytase activity of these 3 lines to determine if they have a high phytase activity that will break down phytic acid sufficiently to affect the absorption of the minerals in question. Considering that the phytase activity depends on moisture, pH, physical access to phytic acid and temperature conditions, it is also important to evaluate how much phytate complex becomes degraded into inositol, minerals and phosphate released during hydrolysis when the wheat is processed using common processing methods.
For these reasons, HavestPlus is seeking partners to submit proposals to complete the following tasks:
Quantify the phytic acid (IP6) and other inositol phosphates (IP5, IP4, IP3, IP2 and IP1) content in the 3 lines of interest and controls: up to 10.0 kg of grain is available for each line.
Evaluate phytase activity for each line with a standardized method (phytase activity units per g dry matter of grain) with or without validated modifications. This will help determine the potential that each wheat line possesses to decrease the phytic acid content. For example, determine the apparent phytase activity (PAC) by measuring liberated inorganic phosphate (IP) from PA in a certain time interval, using a reference method for inorganic phosphate (e.g. van Veldhoven’s and Mannaerts, 1987; Anal Biochem 161: 45–48) and estimating PAC by linear regression.
Evaluate the reduction in phytic acid and changes in each inositol phosphate (IP5, IP4, IP3, IP2 and IP1) after preparing a target food product. This will help to understand if the conditions used are enough to have a significant reduction in phytic acid for the varieties with high phytase activity.
Evaluate the phytic acid to zinc molar ratios before and after each food preparation process using standardized recipes and cooking conditions to make traditional wheat-based foods for Sub-Saharan Africa and South Asia where improving zinc absorption would be relevant. If the amount of wheat available allows, products can be tested with low extraction flour (e.g. 70–75%).
Budget: Funds available for this RFP are approximately $25,000
- Shipping of material (October)
- Test of phytase activity with standard methodology (November), and
- Phytic acid retention and PA:Zn molar ratios in food products using common processes (December)
How to apply: Please submit a statement of your institution’s experience and expertise, CVs of each lead researcher, detailed work plan for the activities outlined in this TOR and detailed budget of activities.
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