Cellulose nanocrystals (CNCs) from the upcycling of pumpkin seed hulls (PSHs): effect of incorporation on the textural, thermal, and structural properties of paneer (soft cheese)

Abstract The study aimed to develop cellulose nanocrystals (CNC) from pumpkin seed hull waste, referred to as pumpkin seed hull cellulose nanocrystals (PSHCNCs), and further evaluated the effect of incorporation (2.5–10.0 mg/100 ml of milk) on the different properties of paneer (soft cheese). PSHCNCs exhibited an average size and zeta potential values of 116.5 ± 19.2 nm and − 14.2 ± 1.6 mV, respectively, and a high degree of crystallinity (85.98%) and thermal stability. SEM showed an irregular surface topology and the presence of prominent holes over PSHCNCs. A dose-dependent variation in the structural, textural, and thermal properties of paneer was observed upon addition of PSHCNCs. FTIR spectra confirmed the integration of PSHCNCs into paneer matrix through enhanced H-bonding, important to modulate textural properties. The morphological analysis of paneer samples showed overstructuring at higher CNC concentrations (10.0 mg), while in moderate amounts (2.5–7.5 mg), the incorporation brought desired reinforcement within the paneer matrix. Hardness and cohesiveness improved by 35.59% and 11.75%, respectively, while springiness showed no significant variation. CNC incorporated paneer samples showed better thermal stability [Tonset (214.64–296.75 °C) and Tpeak (233.98–299.62 °C)] as a result of CNC-casein stabilization with enhanced intermolecular bonding. Conclusively, this study demonstrated the upcycling of agricultural waste through the development of CNCs, combined with the reinforcement of paneer through enhanced H-bonding within the protein-fat-CNC system, providing a sustainable and effective approach to modulate its structural, textural, and thermal characteristics.