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We outline techniques for the control and measurement of the nucleation of crystalline materials. Small angle x-ray scattering/wide angle x-ray scattering x-ray diffraction measurements are presented that demonstrate the impact of low power, continuous, non-cavitational ultrasound on the nucleation and crystallization of a wax—n-eicosane dissolved in a heptane/toluene solvent. A mathematical-physical approach based on the rectification of heat and mass transport by such a low power oscillating pressure field is outlined, and it is suggested that this approach be combined with dissipative particle dynamics computational modeling to develop a predictive method capable of modeling the impact of low power oscillating pressure fields (acoustics and ultrasonics) on a wide range of nucleating systems. Combining the ultrasound pitch and catch speed of sound measurements with low power harmonically oscillating pressure fields to monitor and control nucleation presents the prospect of entirely new industrially significant methods of process control in crystallization. It also offers new insights into nucleation processes in general. However, for the acoustic control technique to be widely applied , further theoretical and modeling work will be necessary since, at present, we are unable to predict the precise effect of low power ultrasound in any given situation. [ABSTRACT FROM AUTHOR]

High-stability bi-layer films were prepared by incorporating anthocyanin-loaded liposomes into carrageenan and agar (A-CBAL) for non-destructive shrimp freshness monitoring. The encapsulation efficiency of the anthocyanin-loaded liposomes increased from 36.06% to 46.99% with an increasing ratio of lecithin. The water vapor transmission (WVP) of the A-CBAL films, with a value of 2.32 × 10−7 g · m−1 · h−1 · pa−1, was lower than that of the film with free anthocyanins (A-CBA). The exudation rate of the A-CBA film reached 100% at pH 7 and pH 9 after 50 min, while the A-CBAL films slowed down to a value lower than 45%. The encapsulation of anthocyanins slightly decreased the ammonia sensitivity. Finally, the bi-layer films with liposomes successfully monitored shrimp freshness with visible color changes to the naked eye. These results indicated that films with anthocyanin-loaded liposomes have potential applications in high-humidity environments. [ABSTRACT FROM AUTHOR]

Low‐field time‐domain nuclear magnetic resonance (NMR; 20 MHz) is commonly used in the studies of fats in the form of solid fat content (SFC) measurements. However, it has the disadvantage of low sensitivity to small amounts of crystalline material (0.5%), thus often incorrectly determining crystallisation induction times. From spin–lattice relaxation rate measurements (R1) during the isothermal crystallisation measurements of cocoa butter between 0.01 and 10 MHz using fast field cycling NMR, we learnt previously that the most sensitive frequency region is below 1 MHz. Thus, we focused on analysing our 10‐kHz data in detail, by observing the time dependence of R1 and comparing it with standard SFCNMR and SFC determinations from small‐angle X‐ray scattering (SFCSAXS). Although not reflecting directly the SFC, the R1 at this low frequency is very sensitive to changes in molecular aggregation and hence potentially serving as an alternative for determination of crystallisation induction times. Alongside R1, we also show that SFCSAXS is more sensitive to early stages of crystallisation, that is, standard SFCNMR determinations become more relevant when crystal growth starts to dominate the crystallisation process but fail to pick up earlier crystallisation steps. This paper thus demonstrates the potential of studying triacylglycerols at frequencies below 1 MHz for obtaining further understanding of the early crystallisation stages of fats and presents an alternative and complementary method to estimate SFC by SAXS. [ABSTRACT FROM AUTHOR]

Due to its relevance in the confectionery industry, cocoa butter (CB) has been extensively studied. However, most studies focus on its crystallisation properties, whilst studies of its liquid state are lacking. Here, and for the first time, a study of the self-diffusion of CB at different temperatures is presented, using fast field cycling (FFC) nuclear magnetic resonance (NMR) further validated using pulsed field gradient stimulated echo (PGSTE) NMR. Measurements were performed upon heating CB to either 50°C or 100°C and cooling it to 22°C. No hysteresis was found between the different thermal treatments. However, the activation energy (28.7 kJ/mol) estimated from the cooling protocol of the 100°C treatment, was the closest to that reported in the literature for similar systems. This suggests that measurements using a wider range of temperatures, and starting with a liquid material are advisable. Additionally, samples were measured during isothermal crystallisation at 22°C, showing that the region below 1 MHz is the most sensitive to phase changes. [ABSTRACT FROM AUTHOR]

[Display omitted] • Baobab seed oil Pickering emulsion (BOPE) was optimized using Box–Behnken design. • Films consist of sodium alginate, guar gum, Lycium ruthenicum extract, AgNPS and BOPE. • BOPE improved the water-resistance and mechanical properties of the films. • Lycium ruthenicum extract/AgNPS improved the biological properties of the films. • The 2.0%BOPE-loaded films exhibited the optimal preservation effect on mushroom. The poor biological, mechanical and water-resistance properties of sodium alginate/guar gum film (SG) limit its application in food preservation. To overcome this disadvantage, we added β-Cyclodextrin/persimmon pectin-stabilized baobab seed oil Pickering emulsion (BOPE) to enhance the mechanical and water resistance properties of SG film, and added green synthesized silver nanoparticles (AgNPS) and Lycium ruthenicum extract (LA) to improve the biological properties of the film. The properties of BOPE was optimized using Box–Behnken design (BBD). Scanning electron microscope and Fourier transform infrared results revealed the change of structure and molecular interaction in the SG film after the addition of AgNPS, LA, and optimized BOPE. The 2.0%BOPE-loaded film containing AgNPS/LA with the enhanced mechanical, barrier, BO retention, and biological properties not only improved the preservation effect on mushroom (A. bisporus), but also maintained structural stability. Thus, the 2.0%BOPE-loaded SG/LA/AgNPS film has considerable potential in active packaging applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • Dual-emission carbon quantum dot (CQD) was successfully synthesized. • Hydrophobic electrospun films were developed using CQD and PVDF for the first times. • The films showed yellow green-to-blue color changes in response to amines. • The films had good fluorescence color stabilities during storage. • The films can be used to monitor the freshness of beef, pork and shrimp at 4 °C. A ratiometric fluorescence sensor based on dual-emission carbon quantum dots (CQD) was developed to real time monitor food spoilage. Two hydrophobic electrospun fluorescent films were developed using polyvinylidene fluoride (PVDF) as the film-forming polymer in combination with CQD as the fluorescent probe. The CQD/PVDF film and CQD@PVDF film enabled the analysis of TMA with limits of detection (LODs) of 1.04 μM and 2.1 μM, respectively, and they exhibited excellent stability at 4 °C. By these virtues, the CQD@PVDF film exhibited visible fluorescence color changes from yellow green to blue by real time and nondestructively sensing volatile amines generated from beef, pork and shrimp in a packaging system with high humidity. This strategy provided a simple but useful, non-destructive, robust, and platform to real time monitor food spoilage for intelligent food packaging. [ABSTRACT FROM AUTHOR]

• Ag nanoparticles (AgNPs) were green synthesized by using gellan gum (GG). • GG-AgNPs show good sensitivity and selectivity towards H 2 S. • GG-AgNPs presented visible color changes when used to monitor meat spoilage. • GG-AgNPs should have great potential for application in intelligent packaging. A colorimetric hydrogen sulfide (H 2 S) sensor based on gellan gum capped silver nanoparticles was developed to real-time monitor meat spoilage. The colorimetric sensor strategy was attributed to the ultrastrong binding ability of Ag with H 2 S to form Ag 2 S. The sensor enables the analysis of H 2 S with a limit of detection (LOD) of 0.81 μM, and it exhibited excellent selectivity toward H 2 S against other volatile components generated from chicken breast and silver carp during spoilage. By these virtues, the sensor presented visible color changes from yellow to colorless by in situ and nondestructively sensing H 2 S generated from chicken breast and silver carp in a packaging system. This strategy provided a simple but useful, non-destructive, robust, cost-effective, and user-friendly platform to real time monitor meat spoilage for intelligent food packaging. [ABSTRACT FROM AUTHOR]

[Display omitted] • Gelatin/gellan gum bilayer film was prepared as a novel probiotic carrier material. • Blueberry anthocyanin extract (BE) improved the probiotic viability in the film. • Baobab seed oil (BO) improved water and oxygen barrier properties of the stored film. • BO/BE loaded-bilayer film obtained the greatest Bifidobacterium longum viability. • BO/BE loaded-bilayer film maintain satisfactory B. longum viability in steamed bread. The gelatin/gellan gum based-bilayer emulsion film was developed in this work to improve the survivability of Bifidobacterium longum during the storage process. The baobab seed oil (BO) was added to the gelatin (GE) matrix to develop emulsion film as the barrier outer layer. The blueberry anthocyanin extract (BE) was incorporated into the gellan gum (GG)-based inner layer to enhance the viability of B. longum. The SEM and FTIR results revealed that the probiotics were successfully entrapped in BO/BE-loaded bilayer film. The greatest survivability and viable cell numbers of the B. longum during the storage period were observed in the BO/BE loaded bilayer film. Furthermore, the stability of the colorful patterns by electrochemical writing was also evaluated in this work. Finally, the GE/BO-GG/BE/BM maintain satisfactory probiotic viability in steamed bread coating application. Hence, the GE/BO-GG/BE/BM bilayer film could be considered a novel material to deliver and protect the probiotics in food applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • A pH-triggered mechanism of active film was prepared by incorporated Eudragit L100. • The LCC100 film was dissolved then the CEO released quickly when pH above 6. • The core–shell structure of LCC100 nanofiber was verified by morphology structure. • The active film can effectively prolong the shelf-life of griskin by 3 days at 4 °C. The regular release kinetics of active ingredients is inconsistent with the demand of meat preservation. Herein, the pH-triggered dynamic mechanism of packaging film was developed based on L100 polymer incorporated with Cinnamon essential oil (CEO) by coaxial electrospinning. The acquired results revealed that UV–vis and fluorescence spectra confirmed the pH release behavior. The fabricated film was quickly dissolved and transformed from solid to liquid phase, resulting in a faster release rate of CEO from 68.9 % to 98.2 % with the pH increasing. The morphological structure verified the core–shell structure formation with a specific surface area value of 7.22 m2/g. The live/dead results of bacteria indicated good antibacterial efficacy against E. coli and S. aureus. The pH-sensitive film successfully extends the shelf-life of griskin by 3 days. In conclusion, this work will aid in optimizing durability of active ingredients in packaging. [ABSTRACT FROM AUTHOR]

• ZnO nanoparticles improved the UV-blocking property and color stability of the bilayer film. • Different patterns could be printed on the bilayer colorimetric film by electrochemical writing. • The bilayer colorimetric film showed a limit of detection of 0.01 mM to NH 3. • The bilayer colorimetric film with written patterns can monitor crucian freshness in real-time. Bilayer colorimetric films were developed for monitoring fish spoilage by using gelatin (GN) incorporated with ZnO nanoparticles as the upper layer (GN-ZnO), and gellan gum (GG) incorporated with mulberry anthocyanins (MBA) as the lower layer (GG-MBA). The color stability of the bilayer colorimetric films under visible and ultraviolet light was improved with the increase of ZnO nanoparticles content. Meanwhile, the bilayer films had good NH 3 sensitivity. The limit of detection of the GG-MBA/GN-2.0% ZnO film to NH 3 was 0.01 mM. The electrochemical writing ability of the bilayer films was also identified, indicating the feasibility of inks-free printing on biopolymer films. Finally, the GG-MBA/GN-2.0% ZnO film with an electrochemical writing pattern was used to monitor crucian spoilage. The GG-MBA/GN-2.0% ZnO film with electrochemical writing pattern showed visible color changes with the crucian spoilage. In conclusion, the bilayer colorimetric film was expected to be a good fish spoilage indicator in smart packaging. [ABSTRACT FROM AUTHOR]

An edible and pH-sensitive film combined with electrochemical writing was developed by using gelatin, gellan gum, and red radish anthocyanins extract for intelligent food packaging. The composite film showed an orange red-to-yellow color change in the pH range of 2-12. The tensile strength, ductility, and barrier abilities to ultraviolet (UV) light and oxygen of the films were improved as the concentration of red radish anthocyanins increased. Multicolor patterns were successfully drawn on the films by using the electrochemical writing method. The composite films, which acted as gas sensors, presented visible color changes in the presence of milk and fish spoilage, while the written patterns were well-preserved. Accordingly, this composite film with written patterns could be an easy-to-use indicator with great potential for monitoring food spoilage as a part of an intelligent packaging system.