Plant-based burgers: prototypes development, study of protein digestibility, and safety assessment

In recent years large switch to plant-based diets has brough to increase the market offer for meat-analogues. This led to high variability of products, with different nutritional characteristics that may introduce or increase dietary exposure to risks, such as mycotoxins occurrence. This work aims to deepen these aspects, exploring if soy-burgers can be an adequate and safe substitute to beef-burgers. Six different protypes – using combinations of soy-based textures (low and high moisture) and binders (methylcellulose and transglutaminase) – were developed miming meat in all its attributes and compared to high-quality beef. Samples were investigated to determine nutritional characteristics, protein quality, and digestibility. Results highlighted comparable nutritional profile of products (averagely 225 kcal, 15 g protein, 10 g total carbohydrates, 13 g of fat, on 100 g), nevertheless, new formulations had good amino acidic profile with great content in essential amino acids. The study showed good digestibility of products, with some differences according to the ingredients used. Protease inhibitors (Kunitz and Bowman-Birk) were also detected through UHPLC/ESI-MS/MS analysis, with a trend concordant with extrusion and cooking treatments. Moreover, occurrence of 11 mycotoxins was investigated. Only tentoxin (from Alternaria alternata) was detected, particularly in protein isolate (7.37 μg/kg)and, in lower amount, in textures (0.88–1.24 μg/kg) and burgers (1.21–2.27 μg/kg). Results obtained confirmed, above all, that beyond the nature of the product – whether it is animal or vegetable – a good choice of raw materials is needed. Furthermore, results on mycotoxins occurrence point out the importance of their evaluation.