Control Efficacy of Salicylic Acid Microcapsules against Postharvest Blue Mold in Apple Fruit.

Salicylic acid (SA) is a natural inducer of disease resistance in fruit, but its application in the food industry is limited due to low water solubility. Here, SA was encapsulated in ß-cyclodextrin (ß-CD) via the host-guest inclusion complexation method, and the efficacy of SA microcapsules (SAM) against blue mold caused by Penicillium expansum in postharvest apple fruit was elucidated. It was observed that SAM was the most effective in inhibiting the mycelial growth of P. expansum in vitro. SAM was also superior to SA for control of blue mold under in vivo conditions. Enzyme activity analysis revealed that both SA and SAM enhanced the activities of superoxide dismutase (SOD) and phenylalanine ammonia lyase (PAL) in apple fruit, whereas SAM led to higher SOD activities than SA. Total phenolic contents in the SAM group were higher than those in the SA group at the early stage of storage. SAM also improved fruit quality by retarding firmness loss and maintaining higher total soluble solids (TSS) contents. These findings indicate that microcapsules can serve as a promising formulation to load SA for increasing P. expansum inhibition activity and improving quality attributes in apple fruit.

Antibacterial Effect and Possible Mechanism of Salicylic Acid Microcapsules against Escherichia coli and Staphylococcus aureus.

Microcapsules serve as a feasible formulation to load phenolic substances such as salicylic acid, a natural and safe antimicrobial agent. However, the antibacterial efficacy of salicylic acid microcapsules (SAMs) remains to be elucidated. Here, salicylic acid/ß-cyclodextrin inclusion microcapsules were subjected to systematic antibacterial assays and preliminary antibacterial mechanism tests using Escherichia coli and Staphylococcus aureus as target organisms. It was found that the core-shell rhomboid-shaped SAMs had a smooth surface. SAMs exhibited a minimum inhibitory concentration (MIC) and a minimum bactericidal concentration (MBC) of 4 mg/mL against both bacteria. In the growth inhibition assay, 1/4 × MIC, 1/2 × MIC, and 1 × MIC of SAMs effectively retarded bacterial growth, and this effect was more prominent with the rise in the level of SAMs. Practically, SAMs possessed a rapid bactericidal effect at the 1 × MIC level with a reduction of more than 99.9% bacterial population within 10 min. A pronounced sterilization activity against E. coli and S. aureus was also observed when SAMs were embedded into hand sanitizers as antimicrobial agents. Moreover, exposure of both bacteria to SAMs resulted in the leakage of intracellular alkaline phosphatases and macromolecular substances (nucleic acids and proteins), which indicated the disruption of bacterial cell walls and cell membranes. In conclusion, SAMs were able to inactivate E. coli and S. aureus both in vitro and in situ, highlighting the promising utilization of this formulation for antimicrobial purposes in the area of food safety and public health.

Cinnamaldehyde microcapsules enhance bioavailability and regulate intestinal flora in mice.

The effects of cinnamaldehyde microcapsules on the concentration of cinnamaldehyde and its metabolites in plasma, urine, and feces, the antioxidant capacity, and the intestinal flora in male C57/BL6 mice were evaluated by oral administration for 7 weeks. Microencapsulation significantly increased the contents of cinnamaldehyde, cinnamyl alcohol, and methyl cinnamate in plasma and decreased those in urine and feces excretion (p < 0.05). In addition, microencapsulated cinnamaldehyde improved antioxidant capacity in liver, duodenum, and colon. Furthermore, 16S rRNA gene sequencing data suggested that microencapsulated cinnamaldehyde significantly improved the gut microbial richness and diversity, increased  the abundance of Bacteroides, Bacteroidetes/Firmicutes, unclassified_f_Lachnospiraceae, Lactobacillus, and Blautia genera, and decreased in Ruminococcaceae_UCG-014, Faecalibaculum, norank_f_Muribaculaceae, and Gordonibacter genera, which was accompanied by the increased contents of butyric acid in feces. Therefore, microencapsulated cinnamaldehyde may increase its bioavailability and regulate the balance of intestinal flora.

Formation of sacha inchi oil microemulsion systems: effects of non-ionic surfactants, short-chain alcohols, straight-chain esters and essential oils.

BACKGROUND: This study reports the formation of sacha inchi oil (SIO) microemulsions for food and cosmetic applications. Effects of non-ionic surfactants, short-chain alcohols, essential oil and straight-chain esters on the phase behavior and formulation of U-type microemulsion were investigated. Pseudo ternary phase diagrams were constructed to assess the influence of these factors using water titration method. Structural transitions were measured along several water dilution lines using conductivity and viscosity tools. RESULTS: Among four different surfactants, Tween 80 solubilized the maximum oil and induced the formation of a U-type microemulsion system. Oil solubilization was decreased in the presence of short-chain alcohols. In addition, the system containing straight-chain esters as the cosolvent showed a higher expansion effect in the U-type areas than that containing essential oils. Finally, upon water dilution of three systems with SIO/ethyl acetate of 1:1, 1:2 and 1:3, microstructural transition from W/O to bicontinuous occurred at 200 g kg-1 (w/w) water content, and then to O/W structure at 650 g kg-1 (w/w) water content. CONCLUSION: Straight-chain esters as cosolvent is a potential strategy to extend the dilutability of SIO microemulsions. © 2021 Society of Chemical Industry.

Preservation of traditional Chinese pork balls supplemented with essential oil microemulsion in a phase-change material package.

BACKGROUND: In this study, we evaluated the combined effect of cinnamon essential oil (CEO) microemulsions, and a temperature buffering package using phase-change material (PCM) microcapsules on the physicochemical property, lipid oxidation, and bacterial load of traditional Chinese pork balls (shi zi tou) during temperature fluctuation storage for 9 days. RESULTS: Transmission electron microscope characterization revealed that n-tetradecane microcapsules possessed a core-shell spherical shape with a size ranging from 300 to 600 nm. The use of n-tetradecane microcapsule packaging was found to maintain cold storage temperature efficiently. After 9 days of storage, the combination of CEO microemulsions with n-tetradecane microcapsules did not lead to changes in the color parameters of pork balls. At day 9, n-tetradecane microcapsules, used alone or in combination with CEO microemulsions, showed lower thiobarbituric acid reactive substances (TBARS) values than the control group, while their combination exhibited the lowest pH and 1,1-diphenyl-2-picrylhydrazyl (DPPH) values. Furthermore, the combination treatment retarded the growth of total plate count, lactic acid bacteria, Enterobacteriaceae, and Staphylococcus spp. after 4 and 9 days. CONCLUSIONS: The combinations of CEO microemulsions and PCM microcapsules could extend the shelf-life of cooked pork products, suggesting a feasible strategy for meat preservation. © 2020 Society of Chemical Industry.

Failure of Staphylococcus aureus to Acquire Direct and Cross Tolerance after Habituation to Cinnamon Essential Oil.

Utilization of sublethal concentrations of cinnamon essential oil (CEO) for food preservation has been proposed. However, exposure to stressful, sublethal growth conditions may induce bacterial tolerance to homologous or heterologous stressing agents. Hence, the ability of CEO to stimulate bacterial stress response was evaluated in the current work. Staphylococcus aureus was exposed to 1/4 and 1/2 of the minimum inhibitory concentration (MIC, 500 µL/L) of CEO for 18 h. It was found that overnight habituation to CEO failed to induce direct tolerance and cross-tolerance to lactic acid (pH 4.5), NaCl (10 g/100 mL) and high temperature (45 °C) in S. aureus. Likewise, S. aureus cells subjected to successive habituation with increasing amounts (1/16 MIC to 2× MIC) of CEO developed no direct tolerance. Taken together, CEO has no inductive effect on the acquisition of stress tolerance in S. aureus.

The stability and controlled release of I-ascorbic acid encapsulated in poly (ethyl-2-cyanoacrylate) nanocapsules prepared by interfacial polymerization of water-in-oil microemulsions.

The L-ascorbic acid (AA) was encapsulated into biodegradable and biocompatible poly(ethyl-2-cyanoacrylate) (PECA) nanocapsules by interfacial polymerization of water-in-oil (W/O) microemulsions. The influences of surfactant concentration, pH value of the dispersed aqueous phase, and W/O ratio on nanocapsule size were discussed. The stability and in vitro release of encapsulated AA were also investigated. The results show that nanocapsules could be obtained under the conditions with low pH value, high fraction of aqueous phase, and appropriate surfactant concentration. The encapsulated AA was protected by nanocapsules from oxidation and presented superior storage stability in aqueous medium than pure AA. Releasing AA from the inner core of nanocapsules could be controlled by adjusting the enzyme hydrolysis extent of the PECA wall.

On weak exponential expansiveness of evolution families in Banach spaces.

The aim of this paper is to give several characterizations for the property of weak exponential expansiveness for evolution families in Banach spaces. Variants for weak exponential expansiveness of some well-known results in stability theory (Datko (1973), Rolewicz (1986), Ichikawa (1984), and Megan et al. (2003)) are obtained.

4-Amino-1-(2-benzoyl-1-phenyl-eth-yl)-3-phenyl-1H-1,2,4-triazol-5(4H)-thione.

In the title compound, C(23)H(20)N(4)OS, the two phenyl rings of the diphenyl-propanone fragment form a dihedral angle of 86.8 (1)°, and the third phenyl ring attached to the triazole ring is twisted from the latter at 40.1 (1)°. In the crystal, mol-ecules are paired into centrosymmetric dimers via pairs of inter-molecular N-H⋯O and N-H⋯S hydrogen bonds.