Assessing the microstructural and rheological changes induced by food additives on potato puree

Recent research and applications in lipid-based food and lipid-incorporated bioink for 3D printing

Three-dimensional (3D) printing, as an emerging digital production technology, has recently been receiving increasing attention in food processing. It is important to understand the effect of key ingredients of food materials on the printing, which makes it possible to achieve a wider range of structures using few nozzles and to provide tailored nutrition and personalization. This comprehensive review delves into the latest research on 3D-printed lipid-based foods, encompassing a variety of products such as chocolate, processed cheese, as well as meat. It also explores the development and application of food bioinks that incorporate lipids as a pivotal component, including those based on starch, protein, oleogels, bigels, and emulsions, as well as emulsion gels. Moreover, this review identifies the current challenges and presents an outlook on future research directions in the field of 3D food printing, especially the research and application of lipids in food 3D printing.

3D printing: trends and approaches toward achieving long-term sustainability in the food industry

Global food security has recently been under serious threat from the rapid rise in the world's population, the problems brought on by climate change, and the appearance of new pandemics. As a result, the need for novel and innovative solutions to solve the existing problems and improve food sustainability has become crucial. 3D printing is expected to play a significant role in providing tangible contributions to the food industry in achieving sustainable development goals. The 3D food printing holds the potential to produce highly customized food in terms of shape, texture, flavor, structure and nutritional value and enable us to create new unique formulations and edible alternatives. The problem of whether the cost of the printed meal and 3D printing itself can be sustainably produced is becoming more and more important due to global concerns. This review intends to provide a comprehensive overview of 3D printed foods with an overview of the current printing methodologies, illustrating the technology's influencing factors, and its applications in personalized nutrition, packaging, value addition, and valorization aspects to fully integrate sustainability concerns thus exploring the potential of 3D food printing.

Effect of free radicals on rheological properties, antioxidant activity, and molecular conformation of chitosan under solution pulsed plasma process based on radical scavengers

Radical scavengers were employed to evaluate the influence of various active species (•OH, •O, and H2O2) on the rheological properties, antioxidant activity, and molecular conformation of chitosan under solution plasma process (SPP) degradation. ESR analysis showed that •OH and •O radicals played important roles in SPP degradation. The results of rheological properties and antioxidant activity indicated that the •OH scavenger (tert-butanol), •O scavenger (1, 4-benzoquinone), and H2O2 scavenger (MnO2) remarkably inhibited the decrease of G' and G" of the degraded chitosan, the formation of gel structure, and the increase of antioxidant activity. The analysis of molecular conformation of the chitosan by particle size analysis, atomic force microscopy (AFM), and high performance size exclusion chromatography coupled with multi-angle laser light scattering (HPSEC-MALLS) revealed that the decrease of particle size, molecular aggregation, and molecular weight of chitosan was inhibited after the addition of radical scavengers. An evident effect of radical scavengers on the hard sphere conformation of chitosan was observed. It was found that the above effects were strongly dependent on the scavenger concentration. These results proved that •OH, •O, and H2O2 played important roles in SPP treatment. For the rheological properties and molecular conformation, H2O2 exhibited the greatest impact. For the antioxidant activity and molecular weight, •OH presented the biggest influence. Besides, •O expressed the weakest effect. This study will be beneficial to reveal the action mechanisms of SPP technology to the degradation of chitosan.

3D/4D printed super reconstructed foods: Characteristics, research progress, and prospects

Super reconstructed foods (SRFs) have characteristics beyond those of real system in terms of nutrition, texture, appearance, and other properties. As 3D/4D food printing technology continues to be improved in recent years, this layered manufacturing/additive manufacturing preparation technology based on food reconstruction has made it possible to continuously develop large-scale manufacture of SRFs. Compared with the traditional reconstructed foods, SRFs prepared using 3D/4D printing technologies are discussed comprehensively in this review. To meet the requirements of customers in terms of nutrition or other characteristics, multi-processing technologies are being combined with 3D/4D printing. Aspects of printing inks, product quality parameters, and recent progress in SRFs based on 3D/4D printing are assessed systematically and discussed critically. The potential for 3D/4D printed SRFs and the need for further research and developments in this area are presented and discussed critically. In addition to the natural materials which were initially suitable for 3D/4D printing, other derivative components have already been applied, which include hydrogels, polysaccharide-based materials, protein-based materials, and smart materials with distinctive characteristics. SRFs based on 3D/4D printing can retain the characteristics of deconstruction and reconstruction while also exhibiting quality parameters beyond those of the original material systems, such as variable rheological properties, on-demand texture, essential printability, improved microstructure, improved nutrition, and more appealing appearance. SRFs with 3D/4D printing are already widely used in foods such as simulated foods, staple foods, fermented foods, foods for people with special dietary needs, and foods made from food processingbyproducts.

Encapsulation of lutein in gelatin type A/B-chitosan systems via tunable chains and bonds from tweens: Thermal stability, rheologic property and food 2D/3D printability

Lutein could be stabilized in gelatin type A/B-chitosan systems by different polyoxyethylene sorbitan fatty acid esters (tweens) via tunable chains and bonds, and the homogeneous system held potential in food 2D/3D printing. During encapsulation of lutein in gelatin-chitosan matrix complexes, tween 40, tween 60 and tween 80 assisted in the excellent centrifugation stability, freeze-thaw stability, chemical stability as well as thermal stability. The tweens contained systems also possessed excellent rheological properties, including shearing thinning property, self-supporting characteristics, and favorable thixotropy. Especially, tween 80 performed well in facilitating the stability and rheological properties of systems with uniform micromorphology due to its long alkyl chains and carbon-carbon double bonds (two sp2 hybridized C-atoms) (from FTIR, XRD, SEM, etc.); and gelatin type B illustrated higher protection effects on lutein because of its strong electrostatic interaction with chitosan. The optimal systems could work as edible ink for 2D/3D printing on food with great UV-irradiation stability and high definition. Surimi could be modified by the optimal complex and possessed excellent shear-thinning property, proper yield stress, low dependence on frequency and stable structure, which was successfully applied for innovative 3D printing with sophisticated shapes. The practical food 2D/3D printing (like bread and surimi) demonstrated high potential in food creation and food innovation.

Three-Dimensional Printing Parameter Optimization for Salmon Gelatin Gels Using Artificial Neural Networks and Response Surface Methodology: Influence on Physicochemical and Digestibility Properties

This study aimed to optimize the 3D printing parameters of salmon gelatin gels (SGG) using artificial neural networks with the genetic algorithm (ANN-GA) and response surface methodology (RSM). In addition, the influence of the optimal parameters obtained using the two different methodologies was evaluated for the physicochemical and digestibility properties of the printed SGG (PSGG). The ANN-GA had a better fit (R2 = 99.98%) with the experimental conditions of the 3D printing process than the RSM (R2 = 93.99%). The extrusion speed was the most influential parameter according to both methodologies. The optimal values of the printing parameters for the SGG were 0.70 mm for the nozzle diameter, 0.5 mm for the nozzle height, and 24 mm/s for the extrusion speed. Gel thermal properties showed that the optimal 3D printing conditions affected denaturation temperature and enthalpy, improving digestibility from 46.93% (SGG) to 51.52% (PSGG). The secondary gel structures showed that the β-turn structure was the most resistant to enzymatic hydrolysis, while the intermolecular β-sheet was the most labile. This study validated two optimization methodologies to achieve optimal 3D printing parameters of salmon gelatin gels, with improved physicochemical and digestibility properties for use as transporters to incorporate high value nutrients to the body.

Effects of different hydrocolloids on the water migration, rheological and 3D printing characteristics of β-carotene loaded yam starch-based hydrogel

The effects of guar gum (GG), xanthan gum (XG), carrageenan gum (CG), xanthan-guar gum blend (XG-GG), chitosan (CS), gum arabic (GA) on the water migration, rheological and 3D printing properties of β-carotene loaded yam starch-based hydrogel (BCH) were investigated to expand product form of β-carotene. The results showed that CS addition promoted the migration of weakly bound water to tightly bound water in BCH. Addition of GG, CG, XG-GG, CS and GA enhanced apparent viscosity, G', G'', hardness and gumminess of BCH. CG, XG-GG, CS and GA addition improved printing stability of BCH. The printed objects added with GG and CS displayed smooth lines with fine resolution and higher formability, which showed a more uniform pore distribution and thinner gel skeleton structure. The results of XRD showed that hydrocolloids addition decreased the relative crystallinity of BCH. A combination of physicochemical parameters could be used to discriminate samples through hierarchical cluster analysis.

Characterization of rice flour and pastes with different sweeteners for extrusion-based 3D food printing

This work aims at investigating the impact of commonly used sweeteners-sugar and jaggery on 3D printability of rice flour (RF) paste. The physicochemical characteristics of rice flour suitable for 3D food printing have been investigated. Three mixes, rice flour with water (M₁ : RF-50.86%, water-49.14%), rice flour with sugar and water (M₂ : RF-36.75%, sugar-14.10%, water-49.14%) and rice flour with jaggery and water (M₃ : RF-36.75%, jaggery-14.10%, water-49.14%) were compared on 3D printability based on visual inspection and properties supporting 3D printability and shape retention. The effect of the three mixes was characterized on color, rheological, thixotropic, and handling properties. Out of the three mixes, M₃ is found to have the best printability characteristics with shear thinning behavior, yield stress of 157 Pa, flow stress of 121 Pa, and extrusion force of 6.62 kg.

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.

Self-assembly of gelatin and phycocyanin for stabilizing thixotropic emulsions and its effect on 3D printing

Nutritional phycocyanin (PC) may be non-covalently bound to gelatin (GE) and form the self-assembly complex proteins, which could stabilize high internal phase emulsions (HIPEs) by one-pot homogenization. The effects of PC on physicochemical, structural, extrudable, thixotropic properties and practical printability of HIPEs were investigated. The electrostatic interaction and hydrogen bonds between GE and PC facilitated the compact structure, promoted the interfacial adsorption behavior at oil-water interface, enhanced emulsion stability, and reduced creaming index of HIPEs. Shearing-thinning property and proper yield stress proved the excellent extrudability of HIPEs. Moreover, thixotropy results indicated that low-content PC resulted in high hysteresis area and large recovery rate of HIPEs, suggesting the outstanding structure rebuilding capacity and structure maintainability. 3D printing of HIPEs illustrated the high printing definition and shape retention conforming to the original models. Overall, this study provides reference for developing functional thixotropic emulsions with high potential in customizing special three-dimensional food.

Effect of different microwave power levels on inactivation of PPO and PME and also on quality changes of peach puree

The effect of microwave (MW) treatment with different power densities (4.4, 7.7, and 11.0 W/g) on polyphenol oxidase (PPO) and pectin methyl esterase (PME) inactivation in peach puree were studied, and the changes in color, rheological properties, total polyphenol and flavonoid and antioxidant capacity were evaluated. By using time/temperature data collected during MW heating, three cook values levels (0.36, 10, 24 min) for each power density were calculated. The PPO was significantly decreased from ca. 50% to ca. 5% when increasing the cook value level, regardless of power density applied. While PME significantly decreased from 40.6% to 10.2% when power density increased from 4.4 to 11.0 W/g at cook value 24 min. MW treatment did not alter the flow behaviour of peach puree. The apparent viscosity values of peach puree significantly increased after MW treatment with increasing cook value, regardless of power density applied. The L* values of peach puree significantly increased from 36.98 to 38.10 or more after MW treatment at cook value 10 min and 24 min. MW treatment could maintain the amount of total polyphenol, total flavonoid and antioxidant capacity, preserving the nutritional and functional values of the product.

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Same cook value of MW treatment resulted in similar inactivation level of PPO.

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PME significantly decreased when power density increased at cook value 3.

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PME was more resistant to MW treatment than PPO in peach puree.

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Higher cook value better preserved the antioxidants and antioxidant capacities.

Formation by high power ultrasound of aggregated emulsions stabilised with milk protein concentrate (MPC70)

In this work, oil-in-water emulsions stabilised by milk protein concentrate (MPC70) were investigated. The MPC70 concentration was kept constant at 5% (close to the protein content found in skim milk) and the oil volume fraction was varied from 20 to 65%. Sonication was performed at 20 kHz and at a constant power of 14.4 W for a total emulsion volume of 10 mL. Under certain oil concentration (≥35%) and sonication times (≥3s) the emulsion aggregated and formed high-viscosity pseudo plastic materials. However, the viscosity behaviour of the emulsion made with 35% oil reverted to that of a liquid if sonicated for longer times (≥15 s). Confocal laser scanning microscopy showed clearly that the oil droplets are aggregated under the sonication conditions and oil concentrations indicated above. An attempt to explain this behaviour through a simple model based on the bridging of oil droplets by the MPC70 particles and, taking into account the oil droplet and MPC70 particle sizes as well as the oil volume fraction, was made. The model fails to describe in details the aggregation behaviour of these emulsions, likely due to the inhomogeneous protein layer, where both free caseins and casein micelles are adsorbed, and to the packing of the oil droplets at concentrations ≤55%. Nonetheless, this work demonstrates the potential of ultrasound processing for the formation of dairy emulsions with tailored textures.

The effects of cellulose nanocrystal and cellulose nanofiber on the properties of pumpkin starch-based composite films

Pumpkin starch (PS) was extracted from Cucurbita maxima and utilized to prepare films in combination with cellulose nanocrystal (CNC) and cellulose nanofiber (CNF), using a solvent casting strategy. The PS was characterized to contain 26.6% of amylose, exhibiting a "B"-type crystalline structure and high stability against thermal degradation. PS/CNF films showed better thermal stability than PS/CNC films, whereas the CNC was more effective than CNF for enhancing the tensile strength (TS) of the films. The nanocomposite films containing 1% CNC showed the highest TS of 30.32 MPa. Fourier transform infrared spectra revealed stronger hydrogen bonding in the PS/CNC films, likely contributing to the observed high mechanical strength. CNC and CNF both decreased the transparency of PS films, by 5.2% and 13.1%, respectively. Overall, the properties of PS composite films can be effectively modified by incorporating CNC and CNF, as PS/CNC films with high mechanical strength and PS/CNF films with good thermal stability. Our results indicate that PS is a suitable material for CNC/CNF composite film fabrication. These films are expected to be especially useful in food packaging applications.

Effects of proanthocyanidins on the pasting, rheological and retrogradation properties of potato starch

BACKGROUND

Proanthocyanidins (PAS) were complexed with potato starch (PS) to prepare polyphenol-starch complexes. The pasting, rheological and retrogradation properties of the complexes were investigated.

RESULTS

The addition of PAS markedly affected the pasting, rheological and retrogradation properties of PS, especially at a concentration of 5% (w/w). Rapid viscosity analysis indicated that PAS significantly changed the viscosity, breakdown and setback value of PS. The rheological results showed that PAS decreased the flow behavior index and consistency coefficient, but increased the viscoelasticity of PS. Differential scanning calorimetry and X-ray diffraction indicated that PAS delayed the retrogradation of PS. Furthermore, scanning electron microscopy indicated that the morphologies of retrograded PS gels were greatly altered to a less compact structure with the presence of PAS. Moreover, Fourier transform infrared spectroscopy elucidated that PAS interacted with PS via a noncovalent interaction, and inhibited the retrogradation of PS.

CONCLUSIONS

The findings suggested that supplementing PS with PAS might be an effective and convenient method for modifying the physicochemical properties of PS. © 2021 Society of Chemical Industry.

A 3D Food Printing Process for the New Normal Era: A Review

Owing to COVID-19, the world has advanced faster in the era of the Fourth Industrial Revolution, along with the 3D printing technology that has achieved innovation in personalized manufacturing. Three-dimensional printing technology has been utilized across various fields such as environmental fields, medical systems, and military materials. Recently, the 3D food printer global market has shown a high annual growth rate and is a huge industry of approximately one billion dollars. Three-dimensional food printing technology can be applied to various food ranges based on the advantages of designing existing food to suit one’s taste and purpose. Currently, many countries worldwide produce various 3D food printers, developing special foods such as combat food, space food, restaurants, floating food, and elderly food. Many people are unaware of the utilization of the 3D food printing technology industry as it is in its early stages. There are various cases using 3D food printing technology in various parts of the world. Three-dimensional food printing technology is expected to become a new trend in the new normal era after COVID-19. Compared to other 3D printing industries, food 3D printing technology has a relatively small overall 3D printing utilization and industry size because of problems such as insufficient institutionalization and limitation of standardized food materials for 3D food printing. In this review, the current industrial status of 3D food printing technology was investigated with suggestions for the improvement of the food 3D printing market in the new normal era.

Assessment of 3D printability of composite dairy matrix by correlating with its rheological properties

In this study, the potential of heat desiccated milk powder (HDMP) in a composite dairy matrix with semi skimmed milk powder (SSMP) was assessed for hot melt extrusion-based 3D printing. The rheological characteristics of formulations at three stages i.e., pre-printing, printing, and post-printing were investigated. The shear thinning with rapid shear recovery and thermoresponsive behavior of the formulations were analyzed to mimic the prevailing conditions of pre-processing, processing, and post-processing of formulations to understand the temperature induced variations in their rheological characteristics during each stage. The rheological properties were correlated with printability through assessment of the consistency of straight lines (1D), average area of lattice scaffolds (2D), and dimensional stability of the 3D printed constructs. Results demonstrated that an increase in the level of incorporation of SSMP and a decrease in the proportion of HDMP increased the shear thinning behavior, viscosity (ɳ), yield stress (τ₀), storage modulus (G') and a decline in the shear recoverability of the formulations. The thermoresponsive behavior of the formulations was established with gelation temperature ranging from 28.1 to 29.4˚C. The formulation SSMP (35): HDMP (25) resulted in sagging of the printed constructs, whereas the formulation SSMP (55): HDMP (5.0) exhibited the highest dimensional stability and shape retention post printing, owing to its maximum τ₀ (1211.8 Pa) and G' (7026.4 Pa). The results obtained could provide insight into improving the performance of an HME based 3D printing in the dairy and food industries.

Assessing Mechanical and Rheological Properties of Potato Puree: Effect of Different Ingredient Combinations and Cooking Methods on the Feasibility of 3D Printing

The effects of agar, alginate, butter, olive oil, and carrots on the mechanical and rheological properties of potato puree prepared by two different cooking methods (microwave heating (MP) and boiling (BP)) were investigated and interpreted in terms of starch microstructural changes. Microscopic observations revealed more aggregated and densely concentrated starch granules in MP samples. This consequently led to a significant increase (p < 0.05) in mechanical and rheological properties up to five times more than BP samples. All samples exhibited shear thinning non-Newtonian behavior. Butter proved its ability to maintain stiff network formation with starch molecules forming lipid-starch complexes characterized by high retention properties and increased stability due to high thixotropic and yield stress values. The pseudo-plasticity combined with high self-supporting ability (high yield stress and mechanical values) comprised by MP samples allows them to better behave during advanced technological processes such as extrusion 3D food printing.

Characterization of food additive-potato starch complexes by FTIR and X-ray diffraction

Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) techniques were used to study the effect of four food additives, agar, alginate, lecithin and glycerol, at three different concentrations, 0.5, 1 and 1.5%, on the molecular structure of potato puree prepared from commercial potato powder. Vibrational spectra revealed that the amylose-amylopectin skeleton present in the raw potato starch was missing in the potato powder but could be fully recovered upon water addition when the potato puree was prepared. FTIR peaks corresponding to water were clearly present in the potato powder, indicating the important structural role of water molecules in the recovery of the initial molecular conformation. None of the studied puree samples presented a crystalline structure or strong internal order. A comparison of the FTIR and XRD results revealed that the additives exerted some effects, mainly on the long-range order of the starch structure via interacting with and changing -OH and hydrogen bond interactions.