Cocoa (Theobroma cacao L.) is a valuable agricultural commodity with significant economic importance (Aprotosoaie, Luca, & Miron, 2016). The commercial relevance of cocoa is largely attributed to its well-documented health-promoting properties, which are primarily linked to the presence of various bioactive compounds, including epicatechin, catechin, caffeic acid, and theobromine. Notably, cocoa is rich in flavonoids, with proanthocyanidins comprising approximately 58 % of the total flavonoid content, followed by flavan-3-ols at 37 % and anthocyanins at around 4 % (Palabiyik, Kopuk, Konar, & Said, 2023). Cocoa beans are processed into various cocoa-derived products, among which cocoa powder is the most widely utilized (Zaid, Nasrul, & Hamid, 2025). Its broad application beyond chocolate production is largely attributed to the alkalization process, which enhances key functional properties such as solubility and color, thereby improving its suitability for diverse food industrial applications. The production of cocoa powder involves a series of processing steps, including harvesting, fermentation, drying, roasting, winnowing, grinding, pressing, alkalization, and sieving (Valverde García, Pérez Esteve, & Barat Baviera, 2020). The alkalization process typically involves mixing natural cocoa material with an alkaline solution, followed by treatment under controlled temperature and pressure conditions. Once cocoa undergoes alkalization, it is no longer considered a natural product. Based on the final pH of the product, it is classified as dark natural (pH 5.0–6.0), light alkalized (pH 6.0–7.2), medium alkalized (pH 7.2–7.6), or strongly alkalized cocoa (pH > 7.6) (Miller et al., 2008).

Numerous drawbacks are associated with conventional thermal alkalization, including low efficiency in enhancing solubility, substantial degradation of bioactive compounds, particularly flavonoids, longer wettability time and limited color development. Studies have reported flavonoid losses ranging from 85 % to 100 % during cocoa alkalization (Afoakwa, 2014). These limitations highlight the need to explore non-thermal techniques as alternative approaches for cocoa alkalization. Research employing non-thermal techniques has shown promising potential in enhancing the functional properties of cocoa powder. Fewer research findings, such as Rahadian, Muhammad, Pratama, Praseptiangga, and Ariviani (2024) have demonstrated that ultrasound-assisted thermal alkalization (10 min at 40 kHz) resulted in a 5 % increase in solubility and enhanced antioxidant activity. In contrast, Demirci observed that cold plasma treatment (30 min at 3 bar, 13.56 Hz, 14 cm) resulted in a 3.6 % increase in solubility, along with notable improvements in flavonoid and phenolic content retention of cocoa powder when compared to conventional thermal alkalization methods. These findings highlight the growing interest in non-thermal techniques, which offer the advantage of retaining bioactive compounds more effectively and enhancing the overall functional properties of cocoa powder. In the present study, emerging techniques, including PEF, PEF + T, and PEF + US, were investigated for their potential impact on cocoa powder alkalization and compared to conventional thermal alkalization. PEF processing involves the application of short, high-voltage pulses (20–80 kV/cm for microseconds to milliseconds), generating a transmembrane potential that exceeds a critical threshold and induces electroporation. This enhances cell membrane permeability, promotes the release of intracellular compounds, and can lead to enzymatic activation or inactivation depending on the electric field intensity (Raso et al., 2016). In contrast, US (above 20 kHz) operates through acoustic cavitation, where bubble formation and collapse produce instantaneous high temperatures and pressures, shear forces, microjets, high-velocity interparticle collisions, and reactive oxygen species (ROS), resulting in cell disruption and chemical modifications (Kutlu et al., 2022). When combined, PEF and US can exert synergistic effects, enhancing PEF-induced membrane weakening and US-driven cavitation, as reported by Aadil et al. (2018). The primary objective of alkalization in cocoa processing is to enhance solubility, neutralize acidity, and improve the functional properties of the cocoa. Previous studies have highlighted the potential of PEF and US in improving solubility and preserving bioactive compounds across various food systems. Quagliariello et al. (2016) reported that PEF enhances the antioxidant activity of Brown Rice extract. For instance, (Rahadian et al., 2024; Wu et al., 2020) reported that US significantly improved the solubility of cocoa powder and micellar casein powder. Additionally, Aadil et al. (2018) found that a combined PEF and US treatment applied to grapefruit juice resulted in substantial enhancements in bioactive compound levels, including carotenoids, lycopene, and anthocyanins. However, limited scientific evidence exists on the combined application of PEF and US. Therefore, the objective of this study was to evaluate the impact of T, PEF, PEF + T and PEF + US treatment on the quality attributes of cocoa powder. To the best of our knowledge, this is the first report addressing the synergistic effects of PEF and US on the physicochemical properties, bioactive retention, and functional quality of cocoa powder during alkalization.