Organic Acid-Induced Structural Modifications Improve Melt-Stretch Properties and Mouthfeel of Plant-Based Cheese...

Developing plant-based cheeses that replicate the melt-stretch property of dairy cheese remains challenging because plant proteins are brittle and thermally unstable. We hypothesized that combining acetic acid (plasticizer) with lactic or citric acid (acidulants) would enhance the melt-stretch behavior of zein-based cheese alternatives. Small-angle X-ray scattering analysis showed that the zein network formed semi-crystalline lamellar structures. Acetic acid promoted smaller, more uniformly distributed oil droplets and a denser protein matrix. Fourier transform infrared spectroscopy and rheological results indicated appropriate combinations of acetic acid and acidulants, which increased protein structural disorder and network flexibility. Melt-stretch and tribological evaluations further confirmed that the L/A2 formulation (lactic acid: acetic acid = 2:1) achieved a stretch length of 19.5 cm and a transition speed of 0.38 mm/s, closely resembling Cheddar cheese (26.2 cm; 0.38 mm/s), and outperforming a commercial plant-based Violife cheese (2.5 cm; 597.16 mm/s). This study provides practical guidance for designing appealing, allergen-conscious dairy alternatives.