A long-term goal for the food industry is to produce food products with maximum conservation of endogenous bioactive compounds. In the present study, we found that SS processing did not cause the loss of the non-starch nutrients (fat, protein, ash and soluble dietary fibre) and energy value of LMR, even leading to a small increase in the content of insoluble dietary fibre. Fatty acid composition analysis showed that the monounsaturated and polyunsaturated fatty acids in LMR were not thermally oxidized by SS processing owing to the low oxygen levels associated with this technology. SS processing may enhance the extractability and the release of bound phenolics, which led to a significant increase in total phenolic content and antioxidant activity of LMR. According to these results, SS processing should be considered as a suitable method for the stabilization of LMR. On the other hand, compared with widely consumed WMR, SS–LMR possessed appreciably higher antioxidant activity and higher contents of non-starch nutrients, unsaturated fatty acids, and phenolics. Although the long- and short-range structures of starch were moderately disturbed by SS processing, SS–LMR still exhibited a much slower digestion rate than WMR with notable higher contents of slowly digestible starch and resistant starch. From a health perspective, SS–LMR may therefore be a potential alternative to WMR.