Selenium loss during boiling processes and its bioaccessibility in different crops: Estimated daily intake

Area of Science:

• Nutritional Science
• Food Chemistry
• Agricultural Science

Background:

• Food crops are a primary source of selenium (Se) for populations with Se deficiency.
• Understanding how processing affects nutrient bioavailability is crucial for human health.
• Selenium's role in human health necessitates accurate intake estimations from dietary sources.

Purpose of the Study:

• To evaluate the impact of boiling on selenium concentration, speciation, and bioaccessibility in staple food crops.
• To determine the effect of boiling on the potential for food crops to meet recommended daily selenium intake.
• To identify discrepancies between estimated daily selenium intake and bioavailable selenium from consumed crops.

Main Methods:

• Analysis of selenium concentration and speciation in raw and boiled common food crops (rice, sorghum, vegetables).
• In vitro assessment of selenium bioaccessibility following boiling.
• Comparison of Se content and bioaccessibility against recommended daily intake (RDI) standards.

Main Results:

• Boiling reduced Se content in rice (11.9%) and sorghum (up to 34.9%), with 21%-40% loss in vegetables.
• Significant decreases in selenomethionine and selenocysteine were observed in cereals; Se-methylselenocysteine reduced in vegetables.
• Selenium bioaccessibility decreased significantly in most crops post-boiling, except cabbage and potato.
• Cereal crops, particularly rice (providing up to 39.2% of RDI), were more effective than vegetables in meeting Se RDI.

Conclusions:

• Boiling substantially alters selenium concentration, speciation, and bioaccessibility in food crops.
• Current estimated daily intake (EDI) standards may overestimate actual bioavailable selenium from consumed crops.
• Revising EDI standards is essential to accurately reflect human selenium intake from dietary sources, especially after common food preparation methods.