Magnetic resonance imaging (MRI) and pulsed nuclear magnetic resonance techniques were used to study the water mobility in sweet rolls during storage. Different fractions of water with distinguishable molecular mobility were identified. MRI provided information on the spatial distribution of water content and of water mobility. During storage, moisture migrated from the crumb to the crust, which was associated with the firming of the crumb. A spatial redistribution of water mobility within the sample was also observed. As storage time increased, the mobility of the less mobile water fraction decreased; whereas the mobility of the more mobile water fraction increased upon staling, suggesting a redistribution of water mobility within the water molecules in the samples. A relationship between water mobility and staling was discussed.

Overreporting of dietary intake in infants is a problem when using food records (FR), distorting possible relationships between diet and health outcomes. Image-assisted dietary assessment may improve the accuracy, but to date, evaluation in the pediatric setting is limited. The aim of the study was to compare macronutrient and energy intake by using an active image-assisted five-day FR against a regular five-day FR, and to validate image-assistance with total energy expenditure (TEE), was measured using doubly labeled water. Participants in this validation study were 22 healthy infants randomly selected from the control group of a larger, randomized intervention trial. The parents reported the infants’ dietary intake, and supplied images of main course meals taken from standardized flat-surfaced plates before and after eating episodes. Energy and nutrient intakes were calculated separately using regular FR and image-assisted FRs. The mean (± standard deviations) energy intake (EI) was 3902 ± 476 kJ/day from the regular FR, and 3905 ± 476 kJ/day from the FR using active image-assistance. The mean EI from main-course meals when image-assistance was used did not differ (1.7 ± 55 kJ, p = 0.89) compared to regular FRs nor did the intake of macronutrients. Compared to TEE, image-assisted FR overestimated EI by 10%. Without validation, commercially available software to aid in the volume estimations, food item identification, and automation of the image processing, image-assisted methods remain a more costly and burdensome alternative to regular FRs in infants. The image-assisted method did, however, identify leftovers better than did regular FR, where such information is usually not readily available.

Recently, food-grade Pickering particles, particularly plant proteins, have attracted tremendous attention because they are biobased, environmentally-friendly and edible. To explore the potential of tea water-insoluble protein (TWIP) nanoparticles from tea residues for stabilizing Pickering emulsions, the average hydrodynamic diameter (DH), zeta potential and morphologic profiles of TWIP nanoparticles were characterized using dynamic light scattering (DLS), laser Doppler velocimetry (LDV) and atomic force microscopy (AFM), respectively. The results indicated that TWIP nanoparticles were irregular colloidal particles with a DH greater than 300 nm and a negative charge of more than −30 mV at ionic strengths of 0–400 mM and a fixed TWIP nanoparticle concentration (2.0%). Furthermore, the effect of the TWIP nanoparticle concentration (0.5–4.0%, w/v) and oil-water ratio (2:8–6:4) on the characteristics of the Pickering emulsions stabilized via TWIP nanoparticles was investigated. Increasing the TWIP nanoparticle concentration generated a firm and thick TWIP nanoparticle-based interfacial layer, as verified by Cryo-scanning electron microscopy imaging, and decreased the droplet size of Pickering emulsions at an oil-water ratio of 4:6. Additionally, an increase of the oil-water ratio to 6:4 favored the formation of emulsions with extraordinary creaming stability at the fixed TWIP nanoparticle concentration of 2.0%. The present study is the first to suggest TWIP nanoparticles as a type of food-grade Pickering particle.

A simple and low cost assay for total iron in various samples based on dispersive liquid-liquid microextraction (DLLME) coupled with digital scanning image analysis was proposed. Orthogonal experiment design was utilized to optimize the amount of extraction solvent and disperser solvent, O-phenanthroline concentration and buffer pH. Under the optimum conditions, the calibration curve was linear over the range of 0.047–1.0μgmL−1 (R2>0.99) of iron. The limit of detection (LOD) for iron was 14.1μgL−1 and limit of quantification (LOQ) was 46.5μgL−1. The relative standard deviations for seven replicate determinations of 0.5μgmL−1 of iron was 3.75%. The method was successfully applied for analysis of total iron in water and food samples without using any spectral instrument and it could have a potential industrial impact in developing fast and portable devices to analyze the iron content in water and certain foods.

In this work, we present a low-field magnetic resonance imaging (LF-MRI) aptasensor based on the difference in magnetic behavior of two magnetic nanoparticles with diameters of 10 (MN₁₀) and 400 nm (MN₄₀₀) for the rapid detection of Pseudomonas aeruginosa (P. aeruginosa). First, specific anti-P. aeruginosa aptamers were covalently immobilized onto magnetic nanoparticles via 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide/N-hydroxysuccinimide chemistry for the capture of the target bacteria. In the presence of P. aeruginosa, an MN₁₀–bacteria–MN₄₀₀ (MBM) complex was formed after binding between the aptamers on magnetic nanoparticles and P. aeruginosa cells. When a magnetic field was applied, the MBM complex and free MN₄₀₀ were rapidly magnetically separated, and free MN₁₀ left in the solution worked as a T₂ (transverse relaxation time) single readout in MRI measurement. Under optimum conditions, the LF-MRI platform provides both image analysis and quantitative detection of P. aeruginosa, with a detection limit of 100 cfu/mL. The feasibility and specificity of the aptasensor were demonstrated in detecting real food, orange juice, and drinking water samples and validated using plate counting methods.

The identification of CN– in water, seeds, and biological systems has, because of its high toxicity, attracted the increasing attention of many chemical industry researchers. In the work, a novel highly selective and reversible sensor, MMY, was shown to recognize CN– effectively. The color and fluorescent changes verified the interaction of MMY with CN–, and the fluorescence lifetime of MMY was also changed upon addition of CN–. A mode of interaction of MMY with CN– based on the results of various experiments was speculated. The LOD of MMY toward CN– was 9.4 × 10–¹⁰ M, lower than the concentration of CN– deemed acceptable by the WHO (World Health Organization) and the U.S. EPA (United States Environmental Protection Agency). MMY showed good reversibility and reusability for detecting CN–. In addition, test slips and silica plates were both earned by ourselves, which were able to recognize CN– qualitatively. Additionally, MMY could recognize CN– in tap water quantitatively with the use of a smartphone APP. Interestingly, MMY was also used to detect CN– in seeds. It was valid to image CN– in Caenorhabditis elegans and mice with a vivid “turn-on” fluorescence. MMY thus can circulate in the bloodstream.