Food loss and waste constitute a substantial threat to global food system sustainability, representing 38% of energy consumption in the supply chain. The 2030 Agenda for Sustainable Development highlights a vision integrating social, economic, and environmental pillars. Addressing environmental impact requires recycling (destruction for new creations) and upcycling (converting waste into valuable products). This review highlights nonthermal green extractions and sustainable techniques in upcycling raw materials such as olives, red beetroot, sugar beet, and coffee, which are widely used in the food industry. Nonthermal processing efficiently extracts bioactive compounds and utilizes waste. Key approaches for its valorization include life cycle assessment, environmental footprint analysis, energy efficiency strategies, digitalization, and sustainability considerations. However, challenges remain in calculating their environmental impact. Waste and by-product valorization from raw materials address disposal issues, offering economic and environmental benefits. Nonthermal techniques show optimistic opportunities in green extraction and sustainable upcycling. The focus is on raw materials including olives, red beetroot, sugar beet, and coffee byproducts, and possible product development. There are powerful connections offering industry tools for impactful sustainability management and guiding decisions on waste-to-value or ‘upcycling’ products. The review contributes to filling the gap in usage of nonthermal processing in upcycling of waste and by-products.

Ultrasound with water as a green solvent is an effective strategy for reducing losses and increasing the utilization of by-products. The extraction of proteins and specialized plant metabolites from sugar beet leaves (Beta vulgaris subsp. vulgaris var. altissima) promotes sustainability in the agro-food chain. Guided by sustainability, samples treated with ultrasound showed lower energy consumption and lower CO₂ emissions. Furthermore, the spectrophotometric determination revealed higher protein and phenol yields in ultrasonically treated samples compared to thermally treated ones. The highest yield of total proteins, 147.91 ± 4.58 mg (g_d.m.)⁻¹, was observed during ultrasound treatment (amplitude 100%, treatment time 9 min). Under the same extraction conditions, the same trend was observed in the yield of total phenols 17.89 ± 0.38 mg (g_d.m.)⁻¹. High-power ultrasound, compared to the thermal extraction method, has increased the yield of proteins and specialized plant metabolites with significantly lower energy consumption and CO₂ emissions. The obtained results are in accordance with the foundations of sustainable development. From an economic and environmental point of view, ultrasound with the use of green solvents would be an excellent replacement for conventional extraction methods.

• Waste utilization is in line with sustainable goals. • Sugar beet leaf, a waste from sugar industry, is a good source of RuBisCO enzyme. • US and HVED showed to be a good techniques for the extraction of Rubisco enzyme. • Higher yield of RuBisCO enzyme is achieved by US.

Thermal characteristics of dried sugar beet pulp, leaves and leaf fractions obtained after extraction: fibrous leaf pulp and fibre rich leaf fraction, were investigated by differential scanning calorimetry and thermogravimetry. The sugar beet samples showed a similar thermal behaviour associated with a similar composition. Two endotherms are found on the differential scanning calorimetry curves. First one in the temperature range 31–153 °C and the second from 150–160 °C. Thermal degradation kinetics was studied by thermogravimetric analysis. Four degradation stages were observed within the temperature range 25–700 °C. The kinetic parameters of the degradation, obtained by Ortega and Friedman non-isothermal isoconversional methods did not significantly differ between models: Ea-activation energy at a conversion degree 0.1–0.9 ranged 50–200 kJ/mol; lnA- the natural logarithm of the pre-exponential factor 8–48; kp₁-thermal degradation rate constant at a conversion extent of 0.5 ranged of 0.19–2.55 min⁻¹. Constant rate of degradation is highest for the sugar beet leaves kp₁ (2.58–2.55 min⁻¹), and kp₂ (70.1–70.4 min⁻¹). The results obtained are valuable for sugar beet leaf industrial processing. A positive environmental impact is achieved by transforming the waste into high-value food additives.

Sustainable development integrates social, economic, technological, scientific, and environmental challenges through the framework of 17 Sustainable Development Goals. Industry 4.0, digitalisation, plant-based processing, environmental challenges, and alternative protein sources are vastly researched and present the foundation of innovative processing in the food processing industry. The exploitation of agroindustrial discards and plant-based by-products as an alternative source of valuable nutrients, including proteins, highlights the potential of upcycling (new economic value) while addressing sustainability challenges. Within the idea of nonthermal extraction of proteins and its process digitalisation, it is crucial to innovate, connect elements of Industry 4.0 and valorise the term sustainability. Innovative approaches in extractions such as ultrasound, plasma, pulsed electric fields, high-intensity pulses, and others, have an energy-saving effect with limited use of toxic chemicals and/or solvents. Usage of software for solvent selection, incorporating digitalisation, and development of protein and peptide databases can help in the prediction, optimisation, and efficiency of nonthermal extractions of proteins from agroindustrial discards. It is also important to select optimal delivery systems like electrospinning, electrospraying, or encapsulation as useful and efficient processes. The environmental, economic, and societal impact of innovative processing needs to be monitored and valorised using specific tools. Life cycle assessment methodology assesses the environmental impact throughout the life cycle of a commercial product, service, or process. The current review shows that extracting protein from agroindustrial discards and by-products of plant and animal origins is a complex matter. The need for a comprehensive approach that considers various viewpoints on extraction is suggested.