Quality and environmental impact of meat burgers fortified with tomato by-products

The current paper aims to reveal the benefits of implementing by-products recycling as potential circular economy practice in the food system. To this aim, two different burgers were developed starting from beef and turkey meat, also adding tomato peels and seeds (TPS), as by-products of tomato processing. TPS were properly dehydrated at 50 °C and ground to obtain a fine powder. The burgers were prepared considering two different levels of TPS addition (110 g and 130 g per 600 g of ground meat) and two different solvents (water and semi-skimmed milk) to hydrate the powder. The different products, in addition to two controls, were all assessed for centesimal composition, chemical properties and sensory acceptability. Considering the energy consumption to dehydrate TPS by a proper mathematical model, a fully Life Cycle Assessment (LCA) was also applied to estimate the carbon footprint associated with by-product recycling, also comparing this scenario with other two different biowaste treatment options, such as composting and landfilling. All the experimental data recorded on both quality and environmental impact of the burgers were used to elaborate a global quality index (GQI) able to balance pro and cons of by-product addition to meat formulation. Results demonstrated that the fortification with TPS is a valid strategy from the nutritional, chemical and environmental point of view, even though TPS slightly compromised the sensory quality. The GQI allowed defining the burger that best balanced the pro and cons of by-product recycling.