Valorisation of oyster mushroom stems in meat formulations: Effects on physicochemical, technological and sensory properties

Pleurotus ostreatus, commonly known as the oyster mushroom, is widely valued for its nutritional and functional properties [1]. However, mushroom processing generates considerable amounts of stems, which are often discarded despite their potential as value-added food ingredients [2,3]. This study evaluated the incorporation of oyster mushroom stem flour as a functional ingredient in beef burgers. Four formulations were prepared: a control burger (CB) and burgers containing five percent (B5%), ten percent (B10%), and twenty percent (B20%) mushroom stem flour, based on meat weight.

Physicochemical, colour, technological, and sensory properties were assessed through moisture, ash content, pH, water activity, CIELab colour parameters, cooking yield, descriptive sensory analysis, and purchase intention testing. Mushroom stem flour significantly affected the physicochemical characteristics of the burgers. Moisture content decreased progressively from 72.84 in CB to 70.20, 66.88, and 62.47 in B5%, B10%, and B20%, respectively. In contrast, ash content increased from 1.91 in the control to 2.66 in B20%, suggesting an increase in mineral constituents derived from mushroom stem flour.

A slight increase in pH was observed, while water activity remained stable across formulations. Colour parameters were also affected, particularly at the highest incorporation level, which increased lightness and yellowness while reducing redness. This resulted in a lighter and more yellow product, with a reduced characteristic beef colour. Cooking yield improved with increasing mushroom flour incorporation, rising from 70.69% in the control to 77.76%, 81.71%, and 82.97% in B5%, B10%, and B20%, respectively.

Sensory analysis showed increased mushroom-related attributes as flour incorporation increased, while undesirable attributes remained low. However, purchase intention decreased with higher substitution levels, with B5% showing the highest acceptance among enriched formulations. Overall, oyster mushroom stem flour can be successfully incorporated into beef burgers, improving technological performance and contributing to the valorisation of mushroom-processing by-products. The five percent incorporation level provided the best balance between improved cooking yield and consumer acceptance, supporting its use in more sustainable meat products.