This study presents a comprehensive evaluation of starch-based gel formulations enriched with proteins and hydrocolloids for extrusion-based 3D food printing (3DFP). Food inks were prepared using corn or potato starch, protein concentrates (fava, whey, rice, pea and soya), and hydrocolloids (κ-carrageenan, arabic gum, xanthan gum, and carboxy methylcellulose). Their rheological, mechanical, and textural properties were systematically analyzed to assess printability. Among all formulations, those containing κ-carrageenan consistently demonstrated superior viscoelastic behavior (G′ > 4000 Pa), optimal tan δ values (0.096–0.169), and yield stress conducive to stable extrusion. These inks also achieved high structural fidelity (93–96% accuracy) and favourable textural attributes such as increased hardness and chewiness. Computational Fluid Dynamics (CFD) simulations further validated the inks’ performances by linking pressure and velocity profiles with rheological parameters. FTIR analysis revealed that gel strengthening was primarily driven by non-covalent interactions, such as hydrogen bonding and electrostatic effects. The integration of empirical measurements and simulation provided a robust framework for evaluating and optimizing printable food gels. These findings contribute to the advancement of personalized and functional 3D-printed foods through data-driven formulation design.

Mechanical processes impact (conventional mixing, high-speed shear mixing, and ultrasonication) on the physicochemical, mechanical, and thermal properties of starch gels combined with plant protein concentrates (pea, fava-bean, pumpkin, rice) and κ-carrageenan were evaluated. Conventional and high-speed shear mixing reduced values of strain (γl), yield stress (τf) storage modulus (G’), complex viscosity (η*), and increased tanδ magnitudes, being more prominent in fava-bean (G’_{PSF C}= 11416 ± 48, G’_{PSF HS} = 5421 ± 37), pea (G’_{PSP C}= 6188 ± 39 G’ _{PSF HS} = 2984 ± 30), and pumpkin protein-starch gels (G’_{PSPU C}= 14840 ± 107, G’_{PSF HS} = 7066 ± 42), (p < 0.05).While no significant rheological alterations were observed for rice-protein gels (G’_{PSR C}= 10802 ± 98, G’_{PSR HS} = 10044 ± 76). Ultrasonication process had a smaller effect on viscoelastic properties compared to other shear methods (e.g. G’_{PSP C}= 6188 ± 39, G’_{PSP US} = 5775 ± 72). Firmness increased with high shear processing, ∼ 3 times for fava bean and ∼ 2 times for pea and pumpkin protein-starch gels. In contrast, shearing of rice protein-starch complex resulted in softer gels, particularly with ultrasound treatment. The thermomechanical properties displayed shear-induced changes in onset, peak, and conclusion temperatures of gelatinization, and decreased enthalpy values, with varying sensitivity to each protein concentrate. Research findings have important implications for optimizing food product development by customizing processing techniques and hydrocolloids interactions to achieve desired texture and functionality in various food applications such as extrusion-based three-dimensional food-printing.

Gluten-free formulations (GF) were utilized as food inks enriched with sour-cherry powder (SCP) and lyophilized extract (SCLE), and their physicochemical, rheological, and thermomechanical properties were evaluated with respect to different leavening conditions. Post-printing drying was also assessed in terms of texture, color, and phenolic substances. SCP and SCLE enrichment decreased lightness by 15% and increased red hue by almost 30%, mainly in yeast formulations. SC addition reduced pH by more than 12% for SCP in both leavening conditions and at 10% to 12% for SCLE, depending on leavening agents. The SCLE addition doubled dynamic moduli and complex viscosity magnitudes and increased hardness at 75.7% compared to the control for baking-powder formulations. SC enrichment, compared to the control, increased the phenolic sum to more than 90% (87% SCLE, 96% SCP) in yeast formulations, presenting lower values (almost 70%) for baking powder. Antioxidant activity in 3D-printed snacks was positively influenced by SC incorporation, depending on the drying and leavening treatment. Phenolic content, in terms of total phenolic sum, origin, and composition, possibly impacts the product’s antioxidant activity by depicting antagonistic or synergistic phenomena. Ultimately, 3D printing is feasible for producing functional GF snacks enriched with sour-cherry extracts.

Sour and sweet cherries were evaluated as functional components in bread-making because of their bioactive microconstituent content. Five forms of enrichment for each fruit, including the hydroalcoholic extract, lyophilized pulverized fruit, lyophilized extract, and their combinations, were used for supplementation. The physicochemical (pH, color, moisture, rheology, and texture) and sensory properties of dough and bread were assessed in different environments (biological and chemical leavening). Sour cherry in pulverized and extract forms showed higher phenolic content than sweet cherry, especially in the pulverized form. The viscoelasticity of the doughs varied based on the proofing environment and the fortification form. Chemically leavened doughs exhibited higher moduli (G′, G″), complex viscosity (η*), and hardness. Biologically leavened doughs had a lower pH, influencing color, and swelling percentage, which is linked to the enrichment form and phenolic content. Extract-fortified doughs displayed increased G′, η*, and hardness compared to the control, whereas yeast-leavened doughs showed reduced swelling ability. Physicochemical changes were more significant in the yeast-leavened systems, which also scored higher on the sensory evaluations. Supplementing bakery products with bioactive fruit components enhances antioxidant status, but the enrichment form and proofing conditions significantly affect the physicochemical and sensory properties of the product.

Olive oil production generates large amounts of agricultural and agro-industrial residues, with olive leaves representing one of the most abundant by-products. This study investigated the valorization of olive leaves from two Greek cultivars, Koroneiki and Megaritiki, collected from the Aeghion, Heraklion, and Megara regions, by means of an optimized green extraction process for the effective recovery of phenolic compounds. Response surface methodology (RSM) was applied to optimize solvent composition and extraction time using ethanol/water mixtures (0/100, 30/70, 50/50, and 70/30, v/v) and extraction times ranging from 15 to 90 min. Total phenolic content (TPC), antioxidant activity (DPPH and FRAP), and color parameters were determined spectrophotometrically, while individual phenolic compounds were analyzed by HPLC-DAD. Both solvent composition and extraction time significantly affected phenolic recovery and antioxidant activity. The optimal extraction conditions were 37.5/62.5 (v/v) ethanol/water and 52.5 min. Extracts from Megara showed the highest TPC (32 ± 1 g GAE kg⁻¹ LL), antioxidant capacity (2556 ± 162 mmol Trolox kg⁻¹ LL), and phenolic compound levels. Significant differences were observed between the two cultivars, whereas Koroneiki samples from Heraklion and Aeghion exhibited similar phenolic profiles, indicating that cultivars had a greater influence than geographical origin.