The Mediation of NO-Enhanced Chilling Tolerance by GSK-3 in Postharvest Peach Fruit Abstract The role of glycogen synthase kinase-3 (GSK-3) in nitric oxide (NO)-enhanced chilling tolerance in postharvest peach fruit was investigated. The fruits were immersed in sodium nitroprusside (SNP; exogenous NO donor) and bikinin (GSK-3 inhibitor). Results showed that the chilling injury (CI) index declined following the exposure of the peach fruit to exogenous SNP. SNP treatment also induced GSK-3 expression. Furthermore, SNP treatment reduced malondialdehyde (MDA) content and electrolyte leakage in the peach fruit. In addition, SNP treatment induced the increase in alternative oxidase (AOX) activity and the upregulation of the gene expression of 18.1-kDa class I heat shock protein (HSP), WRKY2, and C-repeat binding factor (CBF). The effects of SNP treatment were partly weakened by the addition of bikinin. These findings indicate that GSK-3 mediated the reduction of MDA content and electrolyte leakage and the activation of AOX, 18.1-kDa class I HSP, WRKY2, and CBF by NO, thereby inducing chilling tolerance in peach fruit.

The inhibitory effect of chlorogenic acid on lipid oxidation of grass carp ( Ctenopharyngodon idellus ) during chilled storage Abstract Grass carp (Ctenopharyngodon idellus) is a kind of freshwater fish which is rich in polyunsaturated fatty acids and easily exposed to lipid oxidation during refrigeration. The effect of chlorogenic acid (CGA) on lipid oxidation, protein oxidation, enzymatic activities, and color stability of grass carp muscle during chilled storage was investigated. The lipid oxidation was inhibited by CGA, as evidenced by lower thiobarbituric acid values, peroxide values, carbonyl valence, less free fatty acid content, and higher amount of unsaturated fatty acid compared to the control group. CGA also had a positive effect on the whiteness value and the stability of protein oxidation of fish samples. In addition, the inhibitory study of CGA on endogenous lipase and lipoxygenase activities of fish muscle can help to partly illustrate the mechanism that retains its freshness effect. The results indicate that CGA is a novel natural additive which can be used to inhibit lipid and protein oxidation and be applied in the storage of aquatic products or some similar fields.

Vacuum Belt Dehydration of Chopped Beetroot ( Beta vulgaris ) and Optimization of Powder Production Based on Physical and Chemical Properties Abstract Beets contain the red and yellow pigments known as betalains, as well as nitrates and other phytochemicals that may affect human health, and have been studied for possible effects on lowering blood pressure and enhancing athletic performance. Betalains are heat-labile, so developing relatively low-temperature drying methods is one way to turn the perishable root vegetable into a value-added ingredient. The objective of this study was to determine if continuous vacuum belt drying (VBD) could be used to produce powdered ingredients with good color, physical properties, and retention of betalains. Drying studies showed that drying rate could be increased somewhat by increasing temperatures from 75 to 95 °C, with drying times ranging from 160 to 115 min. Drying times were substantially shorter than for powders produced by freeze drying (FD) (26 h) or hot air drying (HAD) (~ 6 h). Properties such as flowability or color did not depend on drying temperature. VBD beet powders had a red-purplish color that was slightly darker (L* = 25.74) than for freeze-dried powders (L* = 38.92). In contrast, HAD samples were much darker than VBD or FD powders, and showed signs of browning. Flowability was improved by the addition of maltodextrins, but at the expense of some increase in drying time. VBD powders were less hygroscopic than FD powders, but reached the same final moisture content. HAD powders were less hygroscopic. VBD samples had slightly lower betalain levels (261–273 mg betanin/g dry beet) than FD powders (291.2 mg betanin/g dry beet). Both had much greater levels than HAD powders (127.8 mg betanin/g dry beet). Powder dried at 95 °C without maltodextrin was optimal as it dried most quickly and had minimal betalain loss.

Correction to: Fabrication of Gel-like Emulsions with Whey Protein Isolate Using Microfluidization: Rheological Properties and 3D Printing Performance The original version of this article unfortunately contained some mistakes. The Fig. 7 was published with incomplete content due to incorrect image processing.

Behavioral Solubilization of Peanut Protein Isolate by Atmospheric Pressure Cold Plasma (ACP) Treatment Abstract The solubilization of peanut protein isolate (PPI) powders modified by atmospheric pressure cold plasma (ACP) treatment was studied by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), low-field nuclear magnetic resonance (low-field NMR) spectroscopy, and FTIR spectroscopy. Significant improvements in both the solubility and water holding capacity (WHC) of the PPI gel were observed after treatment with ACP. The PPI solubility reached a maximum value after 7 min of treatment, with a 12.17% increase over the values observed for the untreated samples. In addition, the WHC increased by 17.90% after 3 min of treatment. The SEM and EDS data revealed that following the 7-min treatment, the PPI surface was rougher and more loosely bound than that of the untreated sample. This indicated an increase in the PPI specific surface area and exposed protein–water binding sites on the treated PPI surface as well as a marked increase in its oxygen content, suggesting an increase in the hydrophilic groups on the PPI surface. The low-filed NMR measurements revealed that the trend in the T21 peak area of the relaxation time was consistent with the data observed for the WHC. The FTIR results revealed a decrease in the proportion of β-sheets and an increase in that of the β-turns within 3 min of treatment, suggesting that the polarity and hydrophilicity of the protein surface were enhanced. The protein structure changed from a compact folding to a loose unfolding configuration after ACP treatment.

Microencapsulation of Microbial Transglutaminase by Ultrasonic Spray-Freeze Drying Abstract Microencapsulation of partially purified microbial transglutaminase (mTG) was investigated using ultrasonic spray-freeze drying (USFD), and the optimum coating materials (gum arabic, maltodextrin, inulin) ratio and the process parameters (flow rate and nozzle frequency) were determined using a D-optimal combined design. Also, the microencapsulated samples by USFD were compared with microencapsulated samples by conventional freeze drying (CFD) and conventional spray drying (CSD) in terms of microencapsulation efficiency, enzyme stability at extreme pH and high temperature conditions, and the presence of metal ions, physical (moisture content, particle morphology, particle and pore size, surface area, pore volume distribution, density and flow properties, caking degree, color), and reconstitution (wettability and solubility) properties. As a result, the optimum coating materials composition was determined as 60% gum arabic and 40% inulin, and process conditions were found to be flow rate of 6.83 ml/min and nozzle frequency of 48 kHz applying desirability function method. Microcapsules with smaller particle size, pore volume, and porosity, with lower moisture content and good reconstitution characteristics, were obtained by USFD with a maximum microencapsulation efficiency of ~ 97%.

The Effect of Ultrasonic Probe Size for Effective Ultrasound-Assisted Pregelatinized Starch Abstract This study aimed to investigate the suitability of ultrasonication as an innovative pregelatinization method. The effect of ultrasonic probe diameter for effective pregelatinization on the physicochemical properties (color, solubility, and swelling), crystallinity (by X-ray diffraction), pasting properties (by rapid visco analysis, RVA), morphology (by scanning electron microscopy), and thermal behavior (by differential scanning calorimetry) of wheat and tapioca starch were compared. The ultrasonication power, temperature, frequency, time, and probe diameter were optimized via response surface methodology (RSM). The RSM results demonstrated that increasing temperature raised the solubility of ultrasound-pregelatinized wheat and tapioca starch, more than increasing the power input and treatment time. According to the RVA data, the cold and complex viscosity of the samples decreased as follows: ultrasound-assisted pregelatinized wheat starch (probe diameter, 100 mm) > ultrasound-assisted pregelatinized tapioca starch (probe diameter, 100 mm) > ultrasound-assisted pregelatinized wheat starch (probe diameter, 20 mm) > ultrasound-assisted pregelatinized tapioca starch (probe diameter, 20 mm). Overall, ultrasound-assisted pregelatinization using a probe of 100 mm in diameter had a stronger effect on wheat starch than tapioca starch. In conclusion, ultrasonication using a probe with a high surface area is a suitable method of starch pregelatinization.

Unfolding and Inhibition of Polyphenoloxidase Induced by Acidic pH and Mild Thermal Treatment Abstract The activity of polyphenoloxidase (PPO) treated by acidic pH and mild thermal processing was found to be closely related to the conformational changes. Weakly acidic environment (pH 4.0–6.0) resulted in reversible inhibition of activity and slight changes in the conformation, and refolding of PPO was observed after readjusting pH to 6.8. At pH lower than 4.0, PPO activity was strongly inhibited with great unfolding in conformation and all changes were irreversible. Acidic environment increased the susceptibility of PPO to thermal treatment, and greater changes in activity and conformation of PPO were observed under the combined treatment of acidic pH and mild thermal treatment. Besides, the inactivation of PPO induced by thermal treatment followed a biphasic kinetic model, and acidic pH increased the inactivation rate of labile and stable PPO. The combination of acidic pH and mild thermal processing expected to avoid the nutritional loss and sensory damage in fruits and vegetables caused by severe acid or temperature.

Changes in enzyme activities and amino acids and their relations with phenolic compounds contents in okra treated by LED lights of different colors Abstract Light-emitting diodes (LEDs) of different wavelengths or colors (i.e., white, red, blue, and green) were used to treat postharvest okra, which is a rich source of phenolic compounds. Relationships between changes in the activities of key enzymes involving in the formation of phenolics (i.e., 3-deoxy-D-arabino-heptulosonate 7-phosphate synthase, chorismate mutase, anthranilate synthase, and phenylalanine ammonia lyase) and their contents upon different LED light treatments were for the first time investigated and are fully discussed. The contents of three intermediate amino acids (i.e., phenylalanine, tyrosine, and tryptophan) that formed during light treatments were also measured to confirm the enzyme activities data. White and blue light treatments increased the content of phenolics in the treated okra, while red and green lights increased the formation of other compounds. These results could be well explained by the changing levels of the measured enzyme activities and amino acids contents.

Physical Properties of Fish Oil Microcapsules Prepared with Octenyl Succinic Anhydride–Linked Starch and Maltodextrin Abstract The microcapsules of fish oil were prepared through spray drying with octenyl succinic anhydride–linked starch (OSA-S) and maltodextrin (MD) as wall materials. The physical properties of microcapsules were evaluated, such as microstructure, hygroscopicity, dissolution, the average particle size, and rheological properties. It was found that the microcapsules were spherical with some wrinkle on the surface as observed by an optical microscope and a scanning electron microscope. Furthermore, the holes in the shell of microcapsules were fish oil droplets as shown in a laser confocal microscope, indicating that the fish oil microcapsules were a typically multinucleated system. In addition, there was no significant change in average particle size (0.2–0.9 μm) after 1-month storage at room temperature, and there was no chemical reaction between the wall materials and fish oil as was proven by infrared spectra. Finally, reconstituted emulsions (RCE) of microcapsule exhibited shear-thinning behavior at low shear rate, which was helpful to the processing, transportation, and storage of emulsion.