Rye is nutritionally dense, yet its utilisation is constrained by antinutrients and structural features that limit nutrient release. This study applied an industrial soaking–germination–fermentation–stabilization process with time-resolved sampling to characterise compositional, microstructural and digestive changes within whole rye. Scanning electron microscopy showed progressive matrix loosening, extensive starch gelatinisation and protein disorganization during stabilization. Phytate levels decreased by 51–54%, while soluble phenolics increased by 180%. Starch content declined by 35% accompanied by a rise in free glucose; early intestinal starch digestion increased ≥30-fold, yet estimated glycaemic index remained moderate (65–69). Processing redistributed proteolysis across stages, increasing intestinal digestion rates despite reduced residual protein. Mineral bioaccessibility improved substantially: Fe increased from 11% to 38%, Zn from 22% to 34%, while Ca and Mg exceeded 70–90% in later stages. This first industrial-scale, time-resolved analysis shows that controlled bioprocessing is associated with improved nutritional bioaccessibility in whole rye, supporting its use in healthier cereal-based foods. • Sequential processing caused progressive matrix disassembly and starch gelatinization. • Sequential processing reduced phytate ~50% and increased phenolics ~180%. • Fermentation and early stabilization sharply enhanced digestive proteolysis rates. • Starch digestibility increased across stages with eGI consistently between 65 and 69. • Final product showed markedly enhanced bioaccessible Ca, Mg, Fe and Zn versus raw rye.
Herrero et al. (Wed,) studied this question.