Improvement of 3D printability of buckwheat starch-pectin system via synergistic Ca2+-microwave pretreatment

Higher molecular weight pectin inhibits ice crystal growth and its effect on the microstructural and physical properties of pectin cryogels

Understanding the formation of ice crystals is essential for tailoring the microstructure and physical properties of cryogels. This study investigated the effects and mechanisms of pectin molecular weight (Mw) on impacting ice crystal formation. Pectin fractions various Mw (10.13-212.20 kDa) were prepared by hydrothermal method. The solution of high Mw pectin fractions exhibited higher contact angle, lower water freedom, and stronger adsorption of water molecules. The splat experiment and molecular dynamic (MD) results confirmed that higher Mw pectin have stronger ice crystal growth inhibition activity than lower Mw pectin. Furthermore, the pore size distribution of the cryogel increased from 98-203 μm to 105-267 μm as the molecular weight decreased from 212.2 kDa to 121.0 kDa. Additionally, in the higher Mw pectin cryogel, stronger mechanical strength was observed. These findings suggested that changing the molecular weight of pectin has the potential to regulate the ice crystal growth, microstructure and physical properties of frozen products.

Effects of Incorporating Ionic Crosslinking on 3D Printing of Biomass-Fungi Composite Materials

Biomass-fungi composite materials primarily consist of biomass particles (sourced from agricultural residues) and a network of fungal hyphae that bind the biomass particles together. These materials have potential applications across diverse industries, such as packaging, furniture, and construction. 3D printing offers a new approach to manufacturing parts using biomass-fungi composite materials, as an alternative to traditional molding-based methods. However, there are challenges in producing parts with desired quality (for example, geometric accuracy after printing and height shrinkage several days after printing) by using 3D printing-based methods. This paper introduces an innovative approach to enhance part quality by incorporating ionic crosslinking into the 3D printing-based methods. While ionic crosslinking has been explored in hydrogel-based bioprinting, its application in biomass-fungi composite materials has not been reported. Using sodium alginate (SA) as the hydrogel and calcium chloride as the crosslinking agent, this paper investigates their effects on quality (geometric accuracy and height shrinkage) of 3D printed samples and physiochemical characteristics (rheological, chemical, and texture properties) of biomass-fungi composite materials. Results show that increasing SA concentration led to significant improvements in both geometric accuracy and height shrinkage of 3D printed samples. Moreover, crosslinking exposure significantly enhanced hardness of the biomass-fungi mixture samples prepared for texture profile analysis, while the inclusion of SA notably improved cohesiveness and springiness of the biomass-fungi mixture samples. Furthermore, Fourier transform infrared spectroscopy confirms the occurrence of ionic crosslinking within 3D printed samples. Results from this study can be used as a reference for developing new biomass-fungi mixtures for 3D printing in the future.

Applications of physical and chemical treatments in plant-based gels for food 3D printing

Extrusion-based three-dimensional (3D) printing has been extensively studied in the food manufacturing industry. This technology places particular emphasis on the rheological properties of the printing ink. Gel system is the most suitable ink system and benefits from the composition of plant raw materials and gel properties of multiple components; green, healthy aspects of the advantages of the development of plant-based gel system has achieved a great deal of attention. However, the relevant treatment technologies are still only at the laboratory stage. With a view toward encouraging further optimization of ink printing performance and advances in this field, in this review, we present a comprehensive overview of the application of diverse plant-based gel systems in 3D food printing and emphasize the utilization of different treatment methods to enhance the printability of these gel systems. The treatment technologies described in this review are categorized into three distinct groups, physical, chemical, and physicochemical synergistic treatments. We comprehensively assess the specific application of these technologies in various plant-based gel 3D printing systems and present valuable insights regarding the challenges and opportunities for further advances in this field.

Effect of dielectric barrier discharge (DBD) plasma treatment on physicochemical and 3D printing properties of wheat starch

In recent years, the focus has shifted towards carbohydrate-based hydrogels and their eco-friendly preparation methods. This study involved an investigation into the treatment of wheat starch using dielectric barrier discharge (DBD) plasma technology over varying time gradients (0, 2, 5, 10, 15, and 20 min). The objective was to systematically examine the impact of different treatment durations on the physicochemical properties of wheat starch and the suitability of its gels for 3D printing. Morphology of wheat starch remained intact after DBD treatment. However, it led to a reduction in the amylose content, molecular weight, and crystallinity. This subsequently resulted in a decrease in the pasting temperature and viscosity. Moreover, the gels of the DBD-treated starch exhibited superior 3D printing performance. After a 2-min DBD treatment, the 3D printed samples of the wheat starch gel showed no significant improvements, as broken bars were evident on the surface of the 3D printed graphic, whereas DBD-20 showed better printing accuracy and surface structure, compared to the original starch without slumping. These results suggested that DBD technology holds potential for developing new starch-based gels with impressive 3D printing properties.

Using waste biomass to produce 3D-printed artificial biodegradable structures for coastal ecosystem restoration

The loss of ecosystem functions and services caused by rapidly declining coastal marine ecosystems, including corals and bivalve reefs and wetlands, around the world has sparked significant interest in interdisciplinary methods to restore these ecologically and socially important ecosystems. In recent years, 3D-printed artificial biodegradable structures that mimic natural life stages or habitat have emerged as a promising method for coastal marine restoration. The effectiveness of this method relies on the availability of low-cost biodegradable printing polymers and the development of 3D-printed biomimetic structures that efficiently support the growth of plant and sessile animal species without harming the surrounding ecosystem. In this context, we present the potential and pathway for utilizing low-cost biodegradable biopolymers from waste biomass as printing materials to fabricate 3D-printed biodegradable artificial structures for restoring coastal marine ecosystems. Various waste biomass sources can be used to produce inexpensive biopolymers, particularly those with the higher mechanical rigidity required for 3D-printed artificial structures intended to restore marine ecosystems. Advancements in 3D printing methods, as well as biopolymer modifications and blending to address challenges like biopolymer solubility, rheology, chemical composition, crystallinity, plasticity, and heat stability, have enabled the fabrication of robust structures. The ability of 3D-printed structures to support species colonization and protection was found to be greatly influenced by their biopolymer type, surface topography, structure design, and complexity. Considering limited studies on biodegradability and the effect of biodegradation products on marine ecosystems, we highlight the need for investigating the biodegradability of biopolymers in marine conditions as well as the ecotoxicity of the degraded products. Finally, we present the challenges, considerations, and future perspectives for designing tunable biomimetic 3D-printed artificial biodegradable structures from waste biomass biopolymers for large-scale coastal marine restoration.

Effect of ferulic acid incorporation on structural, rheological, and digestive properties of hot-extrusion 3D-printed rice starch

The influence of ferulic acid (FA) on rice starch was investigated by incorporating it at various concentrations (0, 2.5, 5, 7.5, and 10 %, w/w, on dry starch basis) and subjecting the resulting composites to hot-extrusion 3D printing (HE-3DP) process. This study examined the effects of FA addition and HE-3DP on the structural, rheological, and physicochemical properties as well as the printability and digestibility of rice starch. The results indicated that adding 0-5 % FA had no significant effect; however, as the amount of FA increased, the printed product edges became less defined, the product's overall stability decreased, and it collapsed. The addition of FA reduced the elasticity and viscosity, making it easier to extrude the composite gel from the nozzle. Moreover, the crystallinity and short-range ordered structure of the HE-3D printed rice starch gel decreased with the addition of FA, resulting in a decrease in the yield stress and an increase in fluidity. Furthermore, the addition of FA reduced the digestibility of the HE-3D-printed rice starch. The findings of this study may be useful for the development of healthier modified starch products by adding bioactive substances and employing the 3D printing technology.

Investigation of the structure, rheology and 3D printing characteristics of corn starch regulated by glycyrrhizic acid

This study aimed to construct a novel corn starch-glycyrrhizic acid (CS-GA) ink and systematically investigate the effects of GA on the water distribution, microstructure, rheology and 3D printing properties of CS hydrogels. The results showed that the CS chains could form strong hydrogen bonds with GA molecules, inhibit the formation of short-range ordered structure of CS and reduce the content of B-type starch. The low-field nuclear magnetic results showed that the introduction of GA could increase bound water content in CS-GA hydrogels. With the increase of GA content, the CS-GA hydrogel changed from CS-dominated to a GA-dominated gel network system. Rheological results showed that all samples exhibited typical shear thinning behavior. High GA concentration was beneficial to increasing the self-supporting properties and thixotropic recovery of CS-GA hydrogels. Compared with the pure CS hydrogel, the 3D printing characteristics of CS-GA hydrogels were significantly enhanced due to the increased bound water content and the enhancement of rheological properties. At 40 % GA content, CS-GA hydrogel showed the highest printing accuracy of 96.4 % ± 0.30 %. The printed product could perfectly replicate the preset model. Therefore, this study provided a theoretical basis for regulating starch's rheology and 3D printing characteristics and developing novel food-grade 3D printing inks.

Modulation of starch structure, swallowability and digestibility of 3D-printed diabetic-friendly food for the elderly by dry heating

Elderly people often experience difficulty in swallowing and have impaired regulation of the nervous system. Furthermore, their blood glucose level can rise easily after eating. Therefore, functional foods that are easy to swallow and can maintain blood glucose at a lower level have been an important research topic in recent years. In this study, 3D printing was combined with dry heating to modify the starch in white quinoa and brown rice to develop whole grain foods with Osmanthus flavor that meet the dietary habits of the elderly. The samples were tested for printability, swallowing performance, and in vitro digestion. The results showed that after dry heating, all samples had shear-thinning properties and could pass through the extrusion nozzle of the printer smoothly. Both white quinoa and brown rice showed improved printability and self-support compared to the control. B45 (white quinoa, dry heating for 45 min) and C45 (brown rice, dry heating for 45 min) had significant elasticity and greater internal interaction strength during swallowing to resist disintegration of food particles during chewing. B45, C30, and C45, conformed to class 4 consistency and were characterized by easy swallowing of the diet. Further, dry heating resulted in greater resistance to enzymatic degradation of white quinoa and brown rice starch, with overall in vitro digestibility lower than the control.

Undaria pinnatifida gel inks for food 3D printing are developed based on the colloidal properties of Undaria pinnatifida slurry and protein/colloidal/starch substances

Currently, people eat Undaria pinnatifida (UP) in a single way, and processing homogeneity is serious. However, UP has not gained any traction in the 3D printing industry to date. This study explored the incorporation of soy protein isolate (SPI), pea protein (PP), xanthan gum (XG), guar gum (GG), corn starch (CS), and potato starch (PS) into UP slurry liquid, the primary component of the study, to formulate a UP gel ink. The UP gel 3D printing ink system based on UP paste was established and characterized. The results show that hydrogen bonds are formed, and three-dimensional gel network structure is formed in all UP gel inks. UP gel inks containing high concentrations of SPI and GG exhibited good texture and rheological qualities and good 3D printing effect, with storage modulus (G') values of 8440.405 ± 3.893 and 8111.730 ± 3.585 Pa. The loss of modulus (G″) values were 1409.107 ± 3.524 and 1071.673 ± 3.669 Pa. Unfortunately, the properties of other UP gel inks are not suitable, resulting in poor 3D printing results. The food 3D printing method developed in this study provides valuable insights for expanding food 3D printing material choices and achieving high-value applications of UP.

Tailoring microstructure and mechanical properties of pectin cryogels by modulate intensity of ionic interconnection

Porous morphology and mechanical properties determine the applications of cryogels. To understand the influence of the ionic network on the microstructure and mechanical properties of pectin cryogels, we prepared low-methoxyl pectin (LMP) cryogels with different Ca2+ concentrations (measured as R-value, ranging from 0 to 2) through freeze-drying (FD). Results showed that the R-values appeared to be crucial parameters that impact the pore morphology and mechanical characteristics of cryogels. It is achieved by altering the network stability and water state properties of the cryogel precursor. Cryogel precursors with a saturated R-value (R = 1) produced a low pore diameter (0.12 mm) microstructure, obtaining the highest crispness (15.00 ± 1.85) and hardness (maximum positive force and area measuring 2.36 ± 0.31 N and 12.30 ± 1.57 N·s respectively). Hardness showed a negative correlation with Ca2+ concentration when R ≤ 1 (-0.89), and a similar correlation with the porosity of the gel network when R ≥ 1 (-0.80). Given the impacts of crosslinking on the pore structure, it is confirmed that the pore diameter can be designed between 56.24 and 153.58 μm by controlling R-value in the range of 0-2.

Effect of compositions and physical properties on 3D printability of gels from selected commercial edible insects: Role of protein and chitin

Compositions and rheological properties of alternative protein sources, including honey bee pupa, grasshopper, cricket, earthworm, and scorpion, and their relationships with 3D printing behaviors were investigated. Protein was found to be the major composition in all insects, while chitin exhibited the most variation. At optimal moisture contents, honey bee pupa and earthworm gels displayed sufficient fluidity but resulted in unstable printed structures, as observed visually and microstructurally. Grasshopper and scorpion gels possessed weak fluidity but produced more stable printed structures. Cricket gel exhibited the most balanced flow behavior and self-supportability. Protein-to-chitin mass ratio proved to be a main factor affecting the 3D printing behavior of the gels. Possible mechanisms on how compositions and properties affected the printing behavior of the gels were proposed. Suggestions for improving the 3D printability of insect and invertebrate resembling insect gels were provided based on these proposed mechanisms.

Reducing meat consumption in Central Asia through 3D printing of plant-based protein-enhanced alternatives-a mini review

3D food printing (3DFP) is emerging as a vital innovation in the food industry's pursuit of sustainability. 3DFP has evolved to significantly impact food production, offering the capability to create customized, nutritionally balanced foods. Central Asia has a higher than global average level of meat consumption per capita, which might be influenced by its historical and cultural background of nomadism. This dietary trend might potentially result in negative impacts on both the environment and human health outcomes, as it leads to increased greenhouse gas emissions and increased risk of chronic diseases. Reducing meat consumption holds the potential to address these sustainability and health issues. A possible strategy to reduce meat consumption and promote plant-based foods is 3D Food Printing (3DFP), which can rely on plant-protein sources from the region to create appealing and tasty alternatives for these populations. This review summarizes recent studies on plant protein-rich materials for 3DFP as a substitute to meet the growing global demand for meat as well as the 3DFP printing parameters associated with the different plant-based proteins currently used (e.g., lentils, soybeans, peas, and buckwheat). The findings revealed that buckwheat, a dietary staple in Central Asia, can be a promising choice for 3DFP technology due to its widespread consumption in the region, gluten-free nature, and highly nutritious profile.

The synergistic effect of κ-carrageenan and l-lysine on the 3D printability of yellow flesh peach gels: The importance of material elasticity in the printing process

This study investigated the effect of κ-carrageenan and l-lysine on the physical, chemical and textural properties of yellow flesh peaches and their suitability for 3D printing. The addition of κ-carrageenan and l-lysine was found to improve the apparent viscosity, elasticity, gel strength, and Young's modulus of the yellow flesh peach with κ-carrageenan and l-lysine gels (PCLG) and increase the minimum piston pressure required for 3D printing, thereby improving the printing performance. Optimum levels of κ-carrageenan and l-lysine (0.1 mmol/mL and 3.42 × 10-2 mmol/mL, respectively) were found to enhance mechanical strength, viscoelasticity and print fidelity. On the other hand, when the addition of κ-carrageenan is 0.1 mmol/mL, the addition of l-lysine causes an increase in the G0 value and a decrease in the η0 value of the PCLG according to Burger's model, indicating a transition from viscosity to elasticity and an increase in maximum extrusion force, while the apparent viscosity does not change significantly. The results of 3D printing showed that when the addition of κ-carrageenan and l-lysine reached 0.1 mmol/mL and 6.84 × 10-2 mmol/mL, respectively, the PCLG could not be smoothly extruded, indicating that elasticity also plays an important role during the extrusion process of the mixed gel.

Elaboration of dimensional quality in 3D-printed food: Key factors in process steps

Three-dimensional (3D) printing has been applied to produce food products with intricate and fancy shapes. Dimensional quality, such as dimensional stability, surface smoothness, shape fidelity, and resolution, are essential for the attractive appearance of 3D-printed food. Various methods have been extensively studied and proposed to control the dimensional quality of printed foods, but few papers focused on comprehensively and deeply summarizing the key factors of the dimensional quality of printed products at each stage-before, during, and after printing-of the 3D printing process. Therefore, the effects of pretreatment, printing parameters and rheological properties, and cooking and storage on the dimensional quality of the printed foods are summarized, and solutions are also provided for improving the dimensional quality of the printed products at each step. Before printing, incorporating additives or applying physical, chemical, or biological pretreatments can improve the dimensional quality of carbohydrate-based, protein-based, or lipid-based printed food. During printing, controlling the printing parameters and modifying the rheological properties of inks can affect the shape of printed products. Furthermore, post-processing is essential for some printed foods. After printing, changing formulations, incorporating additives, and selecting post-processing methods and conditions may help achieve the desired shape of 3D-printed or 4D-printed products during cooking. Additives help in the storage stability of printed food. Finally, various opportunities have been proposed to regulate the dimensional properties of 3D-printed structures. This review provides detailed guidelines for researchers and users of 3D printers to produce various printed foods with the desired shapes and appearances.

Combined effect of heating temperature and content of pectin on the textural properties, rheology, and 3D printability of potato starch gel

Three-dimensional (3D) printing is one of the emerging techniques which fabricates customized foods with desired sensory characteristics. Rheological properties of 3D printing materials are vitally important in printability which govern the flowability and structural stability. Due to its unique gel-forming characteristics, potato starch has been extensively used in myriad food applications, such as 3D printing. However, little attention has been paid to the combined effect of heating temperature and pectin addition on the properties of potato starch gels. Thus, this study investigated the impact of different pectin contents (1, 1.5, and 2 %) on printability and the rheological and textural properties of potato starch gels heated at different temperatures (70, 80, and 90 °C). The gel heating temperature governs pectin-driven modifications in potato starch gels. Pectin addition increased the 3D printability, viscosity, storage modulus, hardness, gumminess, and springiness of starch gel at higher temperatures (80 °C and 90 °C). In contrast, at lower temperatures (70 °C), pectin addition decreased printability, viscosity, storage modulus, hardness, gumminess, and springiness. Therefore, the gel heating temperature influences the impact of pectin on printability, rheology, and textural properties. Accordingly, the combined effects of pectin and heating temperature should be considered in pectin-based 3D food-printing ink formulations.

Formulation and characterization of 3D printed chickpea protein isolate-mixed cereal dysphagia diet

The feasibility study of making 3D printed dysphagia diet was undertaken. A mixture of corn flour and buckwheat flour was used as the model cereal and chickpea protein isolate (CPI) was used as the model protein. Printing gels (inks) of the mixed cereal (control) and CPI-cereal mixture were produced by heating the formulations at 95 °C for 30 min and then cooling them to room temperature. The results showed that all the ink formulations containing CPI had higher apparent viscosity, preferable shear thinning behavior and shape supporting characteristics than that of the control. The cohesiveness and shape supporting ability of 10%CPI-cereal and 20%CPI-cereal formulations were poor and could not produce stable printing shape. The 30%CPI-cereal and 40%CPI-cereal formulations had suitable apparent viscosity, shear thinning behavior, storage modulus, yield stress and printing accuracy and the 3D printed products were stable. The control ink and 10%CPI-cereal ink had low cohesion and also could not pass the spoon tilt test. The 50%CPI-cereal formulation had high hardness and also could not pass the fork pressing test. The 30 % to 40 % CPI-cereal formulations were found to be suitable as dysphagia products as they could be classified as level 5 dysphagia diet.

Investigation of 3D printing of toddler foods with special shape and function based on fenugreek gum and flaxseed protein

The practicability of using corn and flaxseed protein as printing inks for manufacture of printed products specifically designed for toddlers as a dysphagia diet with high precision and special shapes with addition of fenugreek gum (FGG) was investigated. 3D printing was used to process grains and dysphagia-compatible food (corn) into a dietary product with attractive appearance which was also easy to swallow. Rheological measurements shown that appropriate amount of flaxseed protein (FP, 0-10 %) can reduce the stickiness and yield strength of printing material. Based on FTIR measurements, FP weakened the hydrogen bond strength of inks, but it was still an important gradient for the formation of the ink suitable for precision 3D printing. The TPA results shown that the addition of FP (0-10 %) remarkably reduced both the stickiness and hardness of the ink. These results shown that compared with the control group, materials with FGG additions possessed higher printing accuracy and self-supporting ability. Ink with 5 % FP content exhibited the best printability and swallowability, while ink with 10 % FP content had the lowest viscosity and hardness, but it was not suitable for 3D printing. 3D printing of objects printed using Ink-C (5%FP and 0.8 %FGG) showed high support characteristic and attractive appearance. According to the international IDDSI testing standards, Ink-C (5%FP and 0.8 %FGG), Ink-E (15%FP and 0.8 %FGG), and Ink-F (20%FP and 0.8 %FGG) were defined as level 5-minced and moist foods.

Development and characterization of emulsion gels prepared via gliadin-based colloidal particles and gellan gum with tunable rheological properties for 3D printed dysphagia diet

Dysphagia, a condition characterized by difficulty swallowing, has emerged as a threat to health. Herein, we investigated the feasibility of preparing a novel 3D-printed dysphagia diet using emulsions and gellan gum. A gel network was facilitated by the inclusion of gellan gum, which also helped to reduce the size of the oil droplets. Emulsion gels (with 0.3 %-0.5 % gellan gum) were stable at 25 °C for 30 days and tolerated a high ionic concentration of 800 mmol L-1. Emulsion gels remained stable after heat treatment and centrifugation. The excellent stability of the emulsion gels was related to the three-dimensional network developed by the gellan gum. The rheological results validated the solid-state behavior, shear thinning behavior and structural recovery of emulsion gels. Emulsion gels with 0.3 %-0.5 % gellan gum were suitable for 3D printing since they had high printing accuracy, self-support, and smooth surface texture. International Diet Standardization Initiative (IDDIS) tests have shown that emulsion gels can be classified as a level 3-5 dysphagia diet. In addition, the bioaccessibility of astaxanthin increased 1.7 times after being encapsulated by emulsion gels. Overall, these results demonstrate the potential of emulsion gels in the development of novel 3D-printed diets for dysphagia and bioactive protection.

Structural, rheological, and gelling characteristics of starch-based materials in context to 3D food printing applications in precision nutrition

Starch-based materials have viscoelasticity, viscous film-forming, dough pseudoplasticity, and rheological properties, which possess the structural characteristics (crystal structure, double helix structure, and layered structure) suitable for three-dimensional (3D) food printing inks. 3D food printing technology has significant advantages in customizing personalized and precise nutrition, expanding the range of ingredients, designing unique food appearances, and simplifying the food supply chain. Precision nutrition aims to consider individual nutritional needs and individual differences, which include special food product design and personalized precise nutrition, thus expanding future food resources, then simplifying the food supply chain, and attracting extensive attention in food industry. Different types of starch-based materials with different structures and rheological properties meet different 3D food printing technology requirements. Starch-based materials suitable for 3D food printing technology can accurately deliver and release active substances or drugs. These active substances or drugs have certain regulatory effects on the gut microbiome and diabetes, so as to maintain personalized and accurate nutrition.

Effect of Na+ and Ca2+ on the texture, structure and microstructure of composite protein gel of mung bean protein and wheat gluten

To investigate the change of ionic strength on the gel characteristics during the processing of mung bean protein-based foods, the effects of NaCl and CaCl2 at different concentrations (0-0.005 g/mL) on the properties of mung bean protein (MBP) and wheat gluten (WG) composite protein gel were studied. The results showed that low concentration (0.001-0.002 g/mL) could significantly improve the water holding capacity (WHC), storage modulus (G') and texture properties of composite protein gel (MBP/WG), while the surface hydrophobicity (H0) and solubility were significantly decreased (P < 0.05). With the increase of ion concentration, the secondary structures of MBP/WG shifted from α-helix to β-sheet, and the fluorescence spectra also showed fluorescence quenching phenomenon. By analyzing the intermolecular forces of MBP/WG, it was found that with the addition of salt ions, the hydrogen bonds was weakened and the electrostatic interactions, hydrophobic interactions and disulfide bonds were enhanced, which in turn the aggregation behavior of MBP/WG composite protein gel was affected and larger aggregates between the proteins were formed. It could be also demonstrated that the gel network was denser due to the addition of these large aggregates, thus the gel properties of MBP/WG was improved. However, too many salt ions could disrupt the stable network structure of protein gel. This study can provide theoretical support to expand the development of new mung bean protein products.

The incorporation of peach gum polysaccharide into soy protein based microparticles improves probiotic bacterial survival during simulated gastrointestinal digestion and storage

The objective of this research was to investigate the in vitro gastrointestinal digestion and storage properties of Lactobacillus plantarum 550 encapsulated in soy protein isolate (SPI) and peach gum polysaccharide (PG) through spray drying. High survival rates (>8.1 Log CFU/g) were obtained for all encapsulation formulas containing PG. Combination of SPI and PG showed positive effects on both gastric resistance and storage stability of cells. Among the formulas tested, sample of SPI:PG = 3:1 showed the highest survival (7.88 ± 0.12 Log CFU/g), corresponding to the strongest electrostatic interaction between SPI and PG. With PG content increasing, the storage stability of probiotic was also enhanced, as PG could reduce the moisture content within microcapsules as well as scavenge free radicals generated during storage. In conclusion, the current study demonstrates that SPI combined with PG may provide effective protection to cells not only during spray drying, but also during storage and gastrointestinal digestion.

Effects of CaCl2 on 3D Printing Quality of Low-Salt Surimi Gel

In order to develop low-salt and healthy surimi products, we limited the amount of NaCl to 0.5 g/100 g in this work and studied the effect of CaCl₂ (0, 0.5, 1.0, 1.5, and 2.0 g/100 g) on the 3D printing quality of low-salt surimi gel. The results of rheology and the 3D printing showed that the surimi gel with 1.5 g/100 g of CaCl₂ added could squeeze smoothly from the nozzle and had good self-support and stability. The results of the chemical structure, chemical interaction, water distribution, and microstructure showed that adding 1.5 g/100 g of CaCl₂ could enhance the water-holding capacity and mechanical strength (the gel strength, hardness, springiness, etc.) by forming an orderly and uniform three-dimensional network structure, which limited the mobility of the water and promoted the formation of hydrogen bonds. In this study, we successfully replaced part of the salt in surimi with CaCl₂ and obtained a low-salt 3D product with good printing performance and sensory properties, which could provide theoretical support for the development of healthy and nutritious surimi products.

Investigation of the mechanism of different 3D printing performance of starch and whole flour gels from tuber crops

This study aims to reveal the variation in 3D printing performance of whole flour and starch gels as derived from different varieties of tuber crops including cassava, potato, and yam, along with its mechanism. The whole flour of the same tuber crops showed a higher branching degree, average molecular weight (R¯_h), and the proportion of AM chains for 100 < X ≤ 1000 than its starch. Due to the higher degree of branching, the crystallinity of whole flour reached a higher level. In this circumstance, G2' of the dispersion system decreased, which facilitated smooth extrusion of ink from the nozzle, thus improving the precision of printing for the final product. Besides, a higher R¯_h and the percentage of AM chains for 100 < X ≤ 1000 made it easier for the material to extrude, thus enhancing the printing accuracy of the product. The higher short-range ordered structure of whole flour also enhanced the printing performance of 3D printed products. This research contributes an effective solution to the selection of starch and whole flour for food 3D printing.

Effect of starch-protein interaction on regulating the digestibility of waxy rice starch under radio frequency treatment with added CaCl2

This study investigated the effect of starch-protein interaction on regulating the digestibility of waxy rice starch under radio frequency (RF) treatment with added salts. The results showed that starch-protein interactions could significantly reduce the digestibility of waxy rice starch (WRS) under synergetic Ca²⁺-RF treatment. With the increase of Ca²⁺ content (0-2 %), the resistant starch content of WRS-WPI, WRS-SPI and WRS-PPI increased from 35.53 %, 36.12 % and 38.78 % to 51.05 %, 52.82 % and 55.93 %, respectively. The addition of appropriate Ca²⁺ content could increase the short-range ordered structure and lamella structure and form a more compact and uniform microstructure. In addition, the interaction between WRS and protein was mainly through hydrogen bonding and hydrophobic interactions during RF treatment. Furthermore, the presence of Ca²⁺ could improve the distribution and mobility of water molecules and regulate the rheological properties of WRS-protein complexes. This study offers theoretical guidance for the design and production of rice starch-based products with lower digestibility.

Starch as edible ink in 3D printing for food applications: a review

Three-dimensional (3D) printing has attracted more attention in food industry because of its potential advantages, including the ability to create customized products according to individual's sensory or nutritional requirements. However, the production of high-quality 3D printed foods requires the availability of edible bio-inks with the required physicochemical and sensory attributes. Starch, as one of the important sources of dietary energy, is widely used in food processing and is considered as one kind of versatile polymers. It is not only because starch has low prices and abundant sources, but also because desirable modified starch can be obtained by altering its physicochemical properties through physical, chemical and enzymatic methods. This article focuses on the utilization of starch as materials to create food-grade bio-inks. Initially, several kinds of commonly used 3D printers are discussed. The factors affecting the printing quality of starch-based materials and improvement methods are then reviewed, as well as areas where future researches are required. The applications of 3D printed starch-based materials in food industry are also introduced. Overall, starch appears to be one kind of useful substances for creating edible bio-inks that can be utilized within 3D food printing applications to create a wide variety of food products.

Development of Functional Kiwifruit Jelly with chenpi (FKJ) by 3D Food Printing Technology and Its Anti-Obesity and Antioxidant Potentials

With the growing popularity of the concept of healthy diet, modern obesity treatment is gradually shifting from surgical or pharmacological treatment to nutritional intervention. As a safe and effective measure, natural product interventions are a potential strategy of obesity management. The present study aimed to develop a kind of functional food rich in bioactive compounds (chenpi, kiwifruit, and pectin as raw materials) and investigate their bioactive effects on a mouse model. For development of functional kiwifruit jelly with chenpi (FKJ), the results of single-factor and response surface experiments showed that the optimized formulation was composed of a 30.26% addition of chenpi, 35% addition of kiwifruit juice, and 2.88% addition of pectin. The FKJ obtained with the optimal formulation could be used as a 3D printing raw material to print the desired food shapes successfully. For bioactivity evaluation of FKJ, the results with a mouse model showed that the food intake, liver weight, and adipose tissue weight were significantly decreased after administration of FKJ with dose-dependent effect compared to the CON group (p < 0.05). Meanwhile, the serum levels of several inflammatory factors (TG, IL-6, and TNF-α) were decreased and the activities of several antioxidant-related enzymes (SOD, GSH-PX, and CAT) were increased. In short, a functional kiwifruit jelly with chenpi was developed in this study. It is a functional snack food rich in active phenolic compounds, low in calories, with antioxidant and anti-inflammatory activity, and prevents fat accumulation. FKJ could well meet the needs of modern people for nutrition and health and also promote the processing and utilization of natural products, and has good development prospects in the functional food industry.

Research progress in fluid and semifluid microwave heating technology in food processing

Microwave is a form of electromagnetic radiation that has high penetration and heating efficiency in food processing. Uneven heating is the main problem of microwave processing, especially in solid foods. Fluid and semifluid media, which are good carriers in microwave processing, have uniform dielectric properties and good material fluidity. Herein, we review the development, application prospects, and limitations of microwave in fluid and semifluid food processing and the research progress in microwave heating with steam as carrier. The mixture of generated steam and tiny micro droplets from food material under the action of microwave can absorb microwave and transfer heat evenly, which effectively improves the uniformity of microwave heating. Due to the relatively uniform dielectric properties and consistent texture of fluid and semifluid food materials, uneven heating phenomenon during their microwave processing can be significantly inhibited. Based on the development of microwave heating technology and equipment design, the microbial inactivation and enzyme inhibition in fluid and semifluid food were improved and food product with better retention of nutrients and sensory profile were produced. Also, microwave radiation can be used to prepare the printing material or process the printed product for 3D food printing, which enhances the added value of 3D printed products and the personalization of food manufacturing. In future research, intelligent control technology can be applied in the microwave processing of fluid and semifluid food materials for various applications. Therefore, the processing conditions can be adjusted automatically.

Trends in functional food development with three-dimensional (3D) food printing technology: prospects for value-added traditionally processed food products

One of the recent, innovative, and digital food revolutions gradually gaining acceptance is three-dimensional food printing (3DFP), an additive technique used to develop products, with the possibility of obtaining foods with complex geometries. Recent interest in this technology has opened the possibilities of complementing existing processes with 3DFP for better value addition. Fermentation and malting are age-long traditional food processes known to improve food value, functionality, and beneficial health constituents. Several studies have demonstrated the applicability of 3D printing to manufacture varieties of food constructs, especially cereal-based, from root and tubers, fruit and vegetables as well as milk and milk products, with potential for much more value-added products. This review discusses the extrusion-based 3D printing of foods and the major factors affecting the process development of successful edible 3D structures. Though some novel food products have emanated from 3DFP, considering the beneficial effects of traditional food processes, particularly fermentation and malting in food, concerted efforts should also be directed toward developing 3D products using substrates from these conventional techniques. Such experimental findings will significantly promote the availability of minimally processed, affordable, and convenient meals customized in complex geometric structures with enhanced functional and nutritional values.