Structural characterization and fluidness analysis of lactose/whey protein isolate composite hydrocolloids as printing materials for 3D printing.

In this study, the lactose/Whey Protein Isolate (WPI) composite hydrocolloids were prepared as an printing material for subsequent 3D printing. The results showed that the rheological, viscoelastic, thermal and mechanical properties of the studied hydrocolloids were composition dependent, which was directly linked to the printing fidelity of printed objects. The morphology of all printed objects showed a porous microstructure, and their porosity was changed by lactose addition. This outcome resulted from lactose-derived co-solvation discouraging WPI aggregation during the printing process, which was necessary for improving printing performance. Moreover, an innovative Fluidness concept (F), using material-specific WLF analysis of relaxation times, was introduced to quantify the fluidness of lactose/WPI composite hydrocolloids at a certain decay of timescales (from 102 to 10-3 s). This F concept was superior for the description and control of printing fidelity, dimensional deviation, and textural properties of 3D-printed objects. Therefore, the F concept is a "printable indicator" for dairy by-products that may possess proper printability and provides an alternative approach to make attractive designs for 3D printing foods.

A cell-laden hydrogel as prophylactic vaccine and anti-PD-L1 amplifier against autologous tumors.

Immune checkpoint blockade (ICB) can elicit anti-cancer response against tumors growing at normal organs while sparing adjacent tissues. However, many orthotopic tumors respond poorly to ICB therapy due to the lack of pre-existing immune effector cells. Here, we describe a vaccine strategy that induces protective immunity and benefits ICB therapy. An injectable hydrogel platform that forms scaffold subcutaneously was applied to deliver autologous cancer cells undergoing oncolysis (ACCO) as immunogenic antigen source and toll-like receptor 9 agonists (CpG) as additional adjuvant. When administered as a prophylactic, the hydrogel-based vaccine, denoted as (ACCO+CpG)@Gel, successfully built a durable and tumor antigen-specific immune memory against subsequent challenges with orthotopic engraftment of autologous tumors including melanoma, colon carcinoma, and lung carcinoma. Although the vaccination did not completely prevent tumor occurrence, tumors orthotopically established in vaccinated mice acquired significant enhancement in tumor-infiltrating CD8+ T cells and intratumoral PD-L1 expression, which ameliorated the immune status and rendered the originally irresponsive tumors responsible to anti-PD-L1 therapy. Further treatment with PD-L1 blockade therapy efficiently delayed the tumor growth and prolonged the survival of these orthotopic cancer models. Thus, without the need for precisely delivering immunoactivatory agents to tumor or locally remodeling tumor microenvironment, "priming" intractable or inaccessible tumors for subsequent ICB therapy could be achieved by prophylactic vaccination with (ACCO+CpG)@Gel. These findings highlighted (ACCO+CpG)@Gel as a generalized framework of protective vaccine strategy that could be broadly applicable to potentiate ICB therapy against multiple types of orthotopic tumors growing in different regions.

Enhancement of γ-aminobutyric acid, avenanthramides, and other health-promoting metabolites in germinating oats (Avena sativa L.) treated with and without power ultrasound.

Power ultrasound as an emerging processing technology has been investigated for stimulating seeds to enhance germination and accumulation of health-promoting metabolites, such as γ-aminobutyric acid (GABA) and phenolic compounds. This work was undertaken to evaluate the effects of power ultrasound (25 kHz) on the nutritional properties of germinated oats, and the microstructure of oat groats after treatment. The changes in the external and internal microstructures of the ultrasound-treated oats kernel were investigated using Environmental Scanning Electron Microscopy (ESEM) and 3D X-ray Micro Computed Tomography (Micro-CT). Physicochemical properties of oats including GABA, free sugars, avenanthramides, total phenolic content, and antioxidant capacities were enhanced after germination. Furthermore, the power ultrasound treatment for 5 min after soaking significantly enhanced the GABA (48-96 h), alanine (24-96 h), succinic acid (48-72 h), total phenolic content (24 h), and total avenanthramides (24 h) in the germinated oats.

Physicochemical properties of germinated dehulled rice flour and energy requirement in germination as affected by ultrasound treatment.

Limited data are published regarding changes in the physicochemical properties of rice flours from germinated de-hulled rice treated by ultrasound. This work was undertaken to evaluate the effect of ultrasound treatment (25 kHz, 16 W/L, 5 min) on starch hydrolysis and functional properties of rice flours produced from ultrasound-treated red rice and brown rice germinated for up to 36 h. Environmental Scanning Electron Microscopy (ESEM) microimages showed that the ultrasound treatment altered the surface microstructure of rice, which helped to improve moisture transfer during steam-cooking. The flours from sonicated germinated de-hulled rice exhibited significantly (p < .05) enhanced starch hydrolysis, increased the glucose content, and decreased falling number values and viscosities determined by a Rapid Visco Analyzer. The amylase activity of the germinating red rice and brown rice displayed different sensitivity to ultrasonic treatment. The ultrasonic pre-treatment resulted in a significant reduction in energy use during germination with a potential to further reduce energy use in germinated rice cooking process. The present study indicated that ultrasound could be a low-power consumption method to modify the rheological behavior of germinated rice flour, as well as an efficient approach to improve the texture, flavor, and nutrient properties of steam-cooked germinated rice.

Microencapsulation of docosahexaenoic acid (DHA) with four wall materials including pea protein-modified starch complex.

Omega-3 fatty acids, specifically docosahexaenoic acid (DHA, 22 carbons and 6 double bonds) are fundamental compounds for a healthy diet. However, due to their unsaturated nature, omega fatty acid-rich oils are chemically unstable and susceptible to oxidative deterioration. The oxidation results in production of free radicals and unpleasant tastes, negatively impacting the shelf-life, sensory properties, and acceptability of food products. This study was conducted to examine the effect of wall materials on protection of DHA in canola oil against oxidation. A total of 4 wall materials including pea protein isolate (PPI), pea protein isolate - modified starch complex (PPI-MS), Tween 20, and SDS were used for microemulsion preparation with canola oil containing DHA. The freeze-dried powders were analyzed with respect to physicochemical characteristics, oxidative stability, and release properties. The results showed that the PPI-MS as a natural polymeric wall material exhibited similar or better encapsulation efficiency and acceptable level of peroxide value compared to the synthetic surfactants (Tween 20 and SDS). The utilization of protein-polysaccharide complexes enabled the incorporation of specific properties of each biopolymer to further improve emulsion stability for the production of capsules with improved oxidative stability.

Effects of controlled germination on selected physicochemical and functional properties of whole-wheat flour and enhanced γ-aminobutyric acid accumulation by ultrasonication.

Using hard red spring (HRS), hard white (HW), and soft white (SW) wheat, this study examined how germination time affected the functionality of whole-wheat flour (WWF) and enhancement of γ-aminobutyric acid (GABA) content through ultrasonication. The falling number values significantly decreased and the glucose content increased by 227-357% after 15h of controlled germination. The setback value of WWF paste decreased from 654 to 6cP (HW), 690 to 9cP (SW), and 698 to 7cP (HRS), respectively, showing significant decreases of starch retrogradation in an aqueous system. The gluten quality and dough mixing performance of WWF after 5-15h of controlled germination was enhanced since gluten is less weakened during the dough heating stage of Mixolab testing. After a 72h germination, the GABA content increased by 339% of the non-sprouting counterpart. Furthermore, the GABA content in the ultrasound-treated SW sample was 30.7% higher than that without ultrasound treatment.

Enhancement of gama-aminobutyric acid (GABA) and other health-related metabolites in germinated red rice (Oryza sativa L.) by ultrasonication.

Red rice (Oryza sativa L.) that has a red (reddish brown) bran layer in de-hulled rice is known to contain rich biofunctional components. Germination is an effective technique to improve the nutritional quality, digestibility, and flavor of de-hulled rice. Ultrasonication, a form of physical stimulation, has been documented as a novel approach to improve the nutritional quality of plant-based food. This study was undertaken to test the use of ultrasound to enhance the nutritional value of red rice. Ultrasonication (5min, 16W/L) was applied to rice during soaking or after 66h germination. Changes of metabolites (amino acids, sugars, and organic acids) in red rice treated by ultrasonication were determined using a GC/MS plant primary metabolomics analysis platform. Differential expressed metabolites were identified through multivariate statistical analysis. Results showed that γ-aminobutyric acid (GABA) and riboflavin (vitamin B2) in red rice significantly increased after germination for 72h, and then experienced a further increase after treatment by ultrasound at different stages during germination. The metabolomics analysis showed that some plant metabolites, i.e. GABA, O-phosphoethanolamine, and glucose-6-phosphate were significantly increased after the ultrasonic treatment (VIP>1.5) in comparison with the untreated germinated rice. The findings of this study showed that controlled germination with ultrasonic stress is an effective method to enhance GABA and other health-promoted components in de-hulled rice.

Modifying the physicochemical properties of pea protein by pH-shifting and ultrasound combined treatments.

The effect of a pH-shifting and ultrasound combined process on the functional properties and structure of pea protein isolate (PPI) was investigated. PPI dispersions were adjusted to pH 2, 4, 10, or 12, treated by power ultrasound for 5min, and incubated for 1h before the sample pH was brought back to neutral. After treatment, water solubility, protein aggregate size, solution turbidity, surface hydrophobicity (Ho), free sulfhydryl content (SH), and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) of the soluble PPI were determined. pH-shifting at pH 12 and ultrasound combined treatment (pH12-US) significantly improved protein properties, while property modification of the samples treated under acidic conditions was less pronounced. The pH12-US treated PPI had a solubility seven times higher than the control, reaching an average particle size of 45.2nm. In addition, the pH12-US treated PPI significantly improved Ho due to disulfide bonds disruption, and produced more protein sub-units than other treatments. The soluble PPI obtained through this process may be a promising emulsifier for the enrichment of fat-soluble nutrients in foods.

Enhancing Contents of γ-Aminobutyric Acid (GABA) and Other Micronutrients in Dehulled Rice during Germination under Normoxic and Hypoxic Conditions.

Biofortification of staple grains with high contents of essential micronutrients is an important strategy to overcome micronutrient malnutrition. However, few attempts have targeted at γ-aminobutyric acid (GABA), a functional nutrient for aging populations. In this study, two rice cultivars, Heinuo and Xianhui 207, were used to investigate changes in GABA and other nutritional compounds of dehulled rice after germination under normoxic and hypoxic conditions. Forty-one metabolites were identified in both cultivars treated by normoxic germination, whereas the germinated dehulled rice of Heinuo and Xianhui 207 under hypoxic treatment had 43 and 41 metabolites identified, respectively. GABA increased in dehulled rice after germination, especially under hypoxia. Meanwhile, a number of other health-beneficial and/or flavor-related compounds such as lysine and d-mannose increased after the hypoxic treatment. The accumulation of GABA exhibited genotype-specific modes in both normoxic and hypoxic treatments. With regard to GABA production, Xianhui 207 was more responsive to the germination process than Heinuo, whereas Heinuo was more responsive to hypoxia than Xianhui 207. This study provides a promising approach to biofortify dehulled rice with increased GABA and other nutrients through metabolomic-based regulation.