Evaluation of ionic calcium and protein concentration on heat- and cold-induced gelation of whey protein isolate gels as a potential food formulation for 3D food printing

• Published in: Food hydrocolloids 2023-09, Vol.142, p.108777, Article 108777
• Main Authors: Uribe-Alvarez, Ricardo, Murphy, Craig P., Coleman-Vaughan, Caroline, O'Shea, Norah
• Format: Article
• Language: English
• Subjects: 3D printing; Gelation; Rheology; Whey protein
• ISSN: 0268-005X
• DOI: 10.1016/j.foodhyd.2023.108777

3D food printing (3DFP) is an innovative food process, but developing foods with ideal printability can prove challenging. Whey protein isolate (WPI) gels can be difficult to print due to their rigidity. This study evaluated the cold- and heat-induced gelation properties of WPI for use in 3DFP. Initially, the effect of WPI concentration ([WPI]) (8–12% (w/w)) and ionic calcium concentration ([Ca2+]) (0–8 mM) was evaluated on the heat-induced gelation capability and thermal reversibility. Treatments were categorised into three groups: thermo-irreversible, thermo-reversible, and non-gelling. Non-gelling treatments were used for cold-induced gelation by mixing the denatured WPI solution with 150 mM Ca2+ solution. Thermo-reversibility and cold-induced gelation properties were assessed using oscillatory rheometry. Finally, thermo-irreversible gels (TIRG) were characterised using extrudability and texture profile analysis. The thermo-reversible gels had an unsuitable range of G' (5–60 Pa) and δ (40–60°) for obtaining a self-standing object. Cold gelation using [WPI] = 10%, G' > 500 Pa and δ 85%) with the addition of [Ca2+] > 4 mM. TIRG using the following treatments [WPI]-[Ca2+] = 12% - 2 mM, 11% - 4 mM, and 10% - 6 mM demonstrated good printability. Principal component analysis showed TIRG with low hardness, resilience, and extrusion force loss during heating are potentially suitable for 3DFP. [Display omitted] •Thermo-reversible gels can be achieved by adjusting [WPI] and [Ca2+].•Cold-induced gelation of WPI could be adapted for 3D printing applications.•Adding [Ca2+] > 4 mM makes heat-induced WPI gels more heat-sensitive.•Adding CaCl2 at an optimum point enhances printability of heat-induced WPI gels.•Extrudability and textural tests can contribute to predict printability of foods.