Impact of Sodium and Starch Reduction on the Mineral Profile and Bioaccessibility of Mortadella Enriched with Agaricus bisporus and Pleurotus ostreatus By-Products

Mushroom stems, which represent around 20% of total mushroom production, are frequently discarded despite their valuable nutritional content. At the same time, high sodium consumption—primarily from processed foods—continues to pose a major global public health issue. This study addresses both global problems by investigating the application of edible flours obtained by dehydrating the stems of Agaricus bisporus (ABSF) and Pleurotus ostreatus (POSF) as partial replacements for sodium chloride, sodium tripolyphosphate, and potato starch in mortadella formulations.

Five prototypes were produced: one control with a traditional recipe; two formulations with a 50% sodium reduction and potato starch substitution using either ABSF or POSF; and two with a 50% sodium reduction along with a complete (100%) replacement of potato starch using the same mushroom flours. Mineral analysis was conducted on all mortadella samples using ICP-MS. All prototypes were digested following the INFOGEST method, and the mineral profile was also determined in all intestinal phases of the mortadella digestion to calculate mineral bioaccesibility.

Results demonstrated an effective sodium reduction of up to 49%, qualifying the reformulated products for a “reduced sodium” label under European Regulation (EC) No. 1924/2006. The ABSF formulation notably increased calcium content (from 13.22 to 37.71 mg/100g, p < 0.05). However, in vitro digestion tests showed that calcium and zinc bioaccessibility remained below quantification limits in all samples. In contrast, the bioaccessibility of copper, magnesium, and manganese significantly increased in the mushroom-enriched samples compared to the control.

These results highlight the promising role of mushroom stem flours as sustainable ingredients for the reformulation of processed meat products. Their incorporation not only improves the nutritional profile—particularly through sodium reduction and mineral enhancement—but also increases the bioaccessibility of copper, magnesium, and manganese. This study aligns with the principles of sustainability and circular economy by revalorizing an underutilized agro-industrial by-product.