Improvement in nutritional attributes of rice using superheated steam processing

• Superheated steam (SS) enhanced antioxidant activity of lightly milled rice (LMR).
• SS processing increased the total phenolics and phenolic acid contents in LMR.
• SS processing did not cause the oxidation of unsaturated fatty acids in LMR.
• SS processing increased the starch digestion rate in LMR.
• LMR stabilized by SS may be a potential alternative to well milled rice.

Superheated steam (SS) was used for the stabilization of lightly milled rice (LMR), and the nutritional properties of the LMR stabilized by SS (SS–LMR) were assessed. SS processing did not cause the loss of non-starch nutrients (fat, protein, ash and dietary fibre) or promote the oxidation of unsaturated fatty acids in LMR. SS processing significantly increased the total phenolic content and antioxidant activity of LMR probably by enhancing the extractability and release of bound phenolic acids. However, SS processing moderately disturbed the long- and short-range structures of starch, and thereby increased the starch digestibility of LMR. Compared with well milled rice (WMR), SS–LMR had a higher antioxidant activity, higher contents of non-starch nutrients and phenolics, and slower starch digestion rate. From a health perspective, SS processing could be considered a suitable method for the stabilization of LMR and the resultant SS–LMR may be a potential alternative to WMR.

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