Recent advances on enhancing 3D printing quality of protein-based inks: A review.

3D printing is an additive manufacturing technology that locates constructed models with computer-controlled printing equipment. To achieve high-quality printing, the requirements on rheological properties of raw materials are extremely restrictive. Given the special structure and high modifiability under external physicochemical factors, the rheological properties of proteins can be easily adjusted to suitable properties for 3D printing. Although protein has great potential as a printing material, there are many challenges in the actual printing process. This review summarizes the technical considerations for protein-based ink 3D printing. The physicochemical factors used to enhance the printing adaptability of protein inks are discussed. The post-processing methods for improving the quality of 3D structures are described, and the application and problems of fourth dimension (4D) printing are illustrated. The prospects of 3D printing in protein manufacturing are presented to support its application in food and cultured meat. The native structure and physicochemical factors of proteins are closely related to their rheological properties, which directly link with their adaptability for 3D printing. Printing parameters include extrusion pressure, printing speed, printing temperature, nozzle diameter, filling mode, and density, which significantly affect the precision and stability of the 3D structure. Post-processing can improve the stability and quality of 3D structures. 4D design can enrich the sensory quality of the structure. 3D-printed protein products can meet consumer needs for nutritional or cultured meat alternatives.

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.

Hepatic conversion of acetyl-CoA to acetate plays crucial roles in energy stress.

Accumulating evidence indicates that acetate is increased under energy stress conditions such as those that occur in diabetes mellitus and prolonged starvation. However, how and where acetate is produced and the nature of its biological significance are largely unknown. We observed overproduction of acetate to concentrations comparable to those of ketone bodies in patients and mice with diabetes or starvation. Mechanistically, ACOT12 and ACOT8 are dramatically upregulated in the liver to convert free fatty acid-derived acetyl-CoA to acetate and CoA. This conversion not only provides a large amount of acetate, which preferentially fuels the brain rather than muscle, but also recycles CoA, which is required for sustained fatty acid oxidation and ketogenesis. We suggest that acetate is an emerging novel 'ketone body' that may be used as a parameter to evaluate the progression of energy stress.

H3K4me3 as a target of di(2-ethylhexyl) phthalate (DEHP) impairing primordial follicle assembly.

Di (2-ethylhexyl) phthalate (DEHP) is a widely used plastics additive that growing evidence indicates as endocrine disruptor able to negatively affect various reproductive processes both in female and male animals, including humans. However, the precise molecular mechanism of such actions is not completely understood. In the present study, scRNA-seq was performed on the ovaries of offspring from mothers exposed to DEHP from 16.5 days post coitum to 3 days post-partum, when the primordial follicle (PF) stockpile is established. While the histological observations of the offspring ovaries from DEHP exposed mothers confirmed previous data about a distinct reduction of oocytes enclosed in PFs. Focusing on oocytes, scRNA-seq analyses showed that the genes that mostly changed by DEHP were enriched GO terms related to histone H3-K4 methylation. Moreover, we observed H3K4me3 level, an epigenetics modification of H3 that is crucial for chromatin transcription, decreased by 40.28% (P < 0.01) in DEHP-treated group compared with control. When the newborn ovaries were cultured in vitro, the DEHP effects were abolished by tamoxifen (an estrogen receptor antagonist) or overexpression of Smyd3 (one specific methyltransferase of H3K4me3), in particular, the percentage of oocyte enclosed in PF was increased by 15.39% in DEHP plus Smyd3 overexpression group than of DEHP group (P < 0.01), which was accompanied by the upregulation of H3K4me3. Collectively, the present results discover Smyd3-H3K4me3 as a novel target of the deleterious ER-mediated effect of DEHP on PF formation during early folliculogenesis in the mouse and highlight epigenetics changes as prominent targets of endocrine disruptors like DEHP.

Effect of xylose on rheological, printing, color, texture, and microstructure characteristics of 3D-printable colorant-containing meat analogs based on mung bean protein.

A similar color change to meat would promote the appetite of consumers for meat analogs. In this study, three-dimensional (3D) printable colorant-containing meat analogs were developed to mimic the red and brown color of meat before and after cooking. These color changes were realized based on the thermal lability of beet red and the Maillard reaction. Moreover, we studied the influence of the addition of xylose on the shear modulus, printing performance, color, texture, chemical structure, and microstructure of colorant-containing meat analogs. Upon increasing the amount of xylose added, the raw colorant-containing meat analogs showed an increase in shear modulus, dimensional stability, and hardness; whereas, cooked colorant-containing meat analogs showed an increase in hardness, and a decrease in lightness, yellowness, hue angle, and chroma. Moreover, adding xylose changed the interactions and microstructure of colorant-containing meat analogs, leading to texture changes. This study would provide guidelines for the color and texture change by adding reducing saccharides to protein-rich gels.

Potato starch altered the rheological, printing, and melting properties of 3D-printable fat analogs based on inulin emulsion-filled gels.

Plant-based oil inks that imitate the texture and melting behavior of traditional animal fats using 3D printing have been developed. The influence of the incorporation of potato starch and the type of oil on rheology and meltability was investigated. The results showed that the dynamic modulus and hardness of fat analogs increased, whereas fat analog meltability decreased with an increase in potato starch content. Coconut oil and soybean oil-containing fat analogs incorporated with proper potato starch levels exhibited good printability and similar meltability to commercial beef and pork fats. The addition of potato starch suppressed fat analog meltability as it disrupted the inulin matrix. Fat analogs containing coconut oil could be texturized at temperatures lower than those required for their soybean oil counterparts. The fat analogs were solid at room temperature, demonstrated good printability, and imitated the melting behavior of fat contained in real meat throughout the cooking process.

[Applicability analysis and evaluation of aglycones in single-pass intestinal perfusion technique based on PBPK model].

Single-pass intestinal perfusion( SPIP) is the common carrier of biopharmaceutics classification system( BCS) to study compound permeability. With the application and deepening study of BCS in the field of traditional Chinese medicine( TCM),SPIP model is becoming more and more common to study the intestinal absorption of TCM ingredients. Based on the limitations of the SPIP model in some researches on TCM permeability,it was speculated in this study that aglycone may be more suitable than the glycoside to study the intestinal absorption problem by using SPIP model. Furthermore,applicability of aglycone components was analyzed and evaluated. In this study,with quercetin,daidzein,formononetin,genistein and glycyrrhetinic acid used as research objects,the quantitative study of SPIP was used to evaluate the intestinal permeability of these aglycones and to predict the effective permeability coefficient( Peff) and absorption fraction( Fa) in human body. By combining studies comparison and analysis on multiple permeability research methods and prediction of human body absorption of aglycones in physiological-based pharmacokinetic models,this paper can further illustrate that the SPIP model is a good tool for studying the permeability of aglycones and predicting human absorption,which can provide data foundation and theoretical reference for researches on SPIP technique and BCS in intestinal absorption of TCM ingredients.