Applications and characterization of anti-browning enzymatically modified potato starch (EPS) film associated with chitosan (CTS)/L-Cys/citric acid (CA) on fresh-cut potato slices.

This study explores the influence of incorporating L-cysteine (L-Cys), chitosan (CTS), and citric acid (CA) on the enzymatic modification of potato starch (EPS) films to enhance anti-browning properties. Four types of EPS composite films were evaluated for preserving fresh-cut potato slices at low temperatures to inhibit browning. Their thermal, physiochemical, mechanical, and digestibility properties were assessed. Results indicate that the addition of CTS, CA, and L-Cys improved the anti-browning activity of the EPS films by increasing film thickness and reducing water vapor permeability (WVP), oxygen transmission rate (OTR), ultraviolet (UV) transmittance, and tensile strength (TS). Furthermore, these additives improved the film's microstructure, resulting in reinforced intermolecular interactions, increased elongation at break, heightened crystallinity, enhanced thermal stability, and favorable gastrointestinal digestibility. Overall, EPS/CTS/L-Cys/CA composite films show promise as edible packaging materials with effective anti-browning properties.

Detection of glutathione in dairy products based on surface-enhanced infrared absorption spectroscopy of silver nanoparticles.

In this paper, silver nanoparticles (AgNPs) were prepared as enhanced substrates for the detection of glutathione in dairy products by polyol reduction of silver nitrate. The infrared spectra were collected and analyzed by surface-enhanced infrared absorption spectroscopy (SEIRA) method of transmission mode using a cell of calcium fluoride window sheet immobilization solution for the study. The disappearance of the thiol (-SH) absorption peak in the infrared spectrum, and the shift of its characteristic absorption peak when glutathione was bound to AgNPs solvate indicated the Ag-S bond interaction and the aggregation of AgNPS. AgNPs accumulate to form "hot spots", resulting in enhanced electromagnetic fields and thus enhanced infrared signals of glutathione. The intensity of the characteristic absorption peak at 1,654 cm-1 (carbonyl C=O bond stretching) was used for the quantitative analysis of glutathione. After optimizing the conditions, glutathione content in pretreated pure milk and pure ewe's milk was determined using AgNPs in combination with SEIRA. Good linearity was obtained in the range of 0.02-0.12 mg/mL with correlation coefficients (R 2) of 0.9879 and 0.9833, respectively, and LOD of 0.02 mg/mL with average spiked recoveries of 101.3 and 92.5%, respectively. The results show that the method can be used for accurate determination of glutathione content in common dairy products.

Research Progress of Applying Infrared Spectroscopy Technology for Detection of Toxic and Harmful Substances in Food.

In recent years, food safety incidents have been frequently reported. Food or raw materials themselves contain substances that may endanger human health and are called toxic and harmful substances in food, which can be divided into endogenous, exogenous toxic, and harmful substances and biological toxins. Therefore, realizing the rapid, efficient, and nondestructive testing of toxic and harmful substances in food is of great significance to ensure food safety and improve the ability of food safety supervision. Among the nondestructive detection methods, infrared spectroscopy technology has become a powerful solution for detecting toxic and harmful substances in food with its high efficiency, speed, easy operation, and low costs, while requiring less sample size and is nondestructive, and has been widely used in many fields. In this review, the concept and principle of IR spectroscopy in food are briefly introduced, including NIR and FTIR. Then, the main progress and contribution of IR spectroscopy are summarized, including the model's establishment, technical application, and spectral optimization in grain, fruits, vegetables, and beverages. Moreover, the limitations and development prospects of detection are discussed. It is anticipated that infrared spectroscopy technology, in combination with other advanced technologies, will be widely used in the whole food safety field.

Advances in differentiation and identification of foodborne bacteria using near infrared spectroscopy.

Rapid and sensitive detection of foodborne bacteria is a growing concern for ensuring safe food supply and preventing human foodborne infections. It is difficult for conventional methods to meet these detection requirements because they are often tedious and time-consuming. In the recent years, near infrared (NIR) spectroscopy has been found to be a promising method for all sorts of analyses in microbiology due to its highly specific absorption signature and non-destructive measurements. In this review, we first briefly introduce the fundamental and basic operational procedure of NIR spectroscopy for foodborne bacteria detection. Then we summarize the main advances and contributions of this technique in the study of foodborne bacteria. Finally, we conclude that much work still remains to be done before NIR spectroscopy really becomes a viable alternative in the field of microbiological characterization.

Evaporation of Sessile Water Droplets on Horizontal and Vertical Biphobic Patterned Surfaces.

This paper presents an experimental study on thermal transport to single water droplets evaporating on heated biphobic surfaces consisting of a superhydrophobic matrix with a circular hydrophobic pattern with strong contact line pinning. A single water droplet of 8 µL volume is placed on a preheated surface and allowed to evaporate in an open laboratory environment. We investigate the influence of substrate orientation (horizontal and vertical) on evaporation dynamics. Using optical and infrared imaging, we report droplet fluid dynamics and heat transfer characteristics of the evaporating droplet. Overall, evaporation is more efficient on the vertical surface, exhibiting higher total heat transfer rates and up to 10% shorter evaporation times. Counterintuitively, on the vertical surface, the substrate-droplet interfacial heat flux was higher near the lower contact line than in the upper region, despite a high contact angle and an expected wedge effect at the bottom. At the same time, the temperature is colder in the lower part of the droplet. We attribute this apparent anomaly to the competition between sensible heating and evaporation, and a modified convective flow signature (both within the droplet and the gas phase) compared to a horizontal surface. We also show that the thermal signature becomes uniform once the contact angles at the upper and lower contact lines become equal toward the end of the evaporation process. Insights from this work can guide the design of spray cooling devices or be used to alter particle deposition patterns during evaporation-based fabrication techniques and ink-jet printing.

Hollow core anti-resonant fiber with split cladding.

An improved design for hollow core anti-resonant fibers (HAFs) is presented. A split cladding structure is introduced to reduce the fabrication distortion within design tolerance. We use numerical simulations to compare the Kagome fibers (KFs) and the proposed split cladding fibers (SCFs) over two normalized transmission bands. It reveals that SCFs are able to maintain the desired round shape of silica cladding walls, hence improving the confinement loss (CL) compared to the KF and is comparable to that of the nested antiresonant nodeless fiber (NANF) with the same core size. In addition, the SCF allows stacking multiple layers of cladding rings to control the CL. The influences of the number of cladding layers and the cladding gap width on the CL of the SCFs have been studied. SCF with three cladding rings is fabricated by the stack-and-draw technique. A measured attenuation spectrum matches well with the calculation prediction. The measured near field mode patterns also prove the feasibility of our fiber design.

Reflective liquid level sensor based on modes conversion in thin-core fiber incorporating titled fiber Bragg grating.

A simple and compact reflective liquid level sensor based on modes conversion in the thin-core fiber incorporating one tilted fiber Bragg grating (TFBG) is proposed and experimentally demonstrated. A piece of thin-core fiber containing one TFBG ensures the modes conversion between the core mode and cladding modes. The external liquid can induce the cladding modes covert to the radiation modes and lead to the decrement of the collected cladding modes power, then the liquid level can be measured from the collected cladding modes power. The modes conversion in the proposed structure is theoretically analyzed. The experimental results show the high liquid level sensitivity and temperature immunity of the proposed sensor, and its significant advantage is that the measurement range is not limited to the length of the TFBG itself.

Simple and compact reflective refractometer based on tilted fiber Bragg grating inscribed in thin-core fiber.

A simple and compact reflective refractometer based on a tilted fiber Bragg grating (TFBG) inscribed in an ultra-high photon-sensitive thin-core fiber is proposed and experimentally demonstrated. The reflective refractometer utilizes a short piece of thin-core fiber containing one TFBG to ensure the recoupling of cladding modes. The reflection spectra occur in two well-defined wavelength bands that correspond to the Bragg core mode and cladding modes, respectively. It is found that the power of the collected cladding modes changes with the external refractive index (RI), while that of the Bragg core mode remains unaffected and can be used as the temperature reference. High RI sensitivity and temperature immunity of the proposed reflective refractometer are experimentally achieved.

catena-Poly[[[triaqua-(4,5-diaza-fluorene-9-one)cadmium]-µ-benzene-1,3-dicarboxyl-ato] dihydrate].

In the title compound, {[Cd(C(8)H(4)O(4))(C(11)H(6)N(2)O)(H(2)O)(3)]·2H(2)O}(n), the Cd(II) atom is seven-coordinated by two N atoms from the phenanthroline-derived 4,5-diaza-fluorene-9-one ligand, two O atoms from one bidentate benzene-1,3-dicarboxyl-ate ligand and three O atoms from the three water mol-ecules in a distorted penta-gonal-bipyramidal arrangement. Moreover, there are two dissociative water mol-ecules in each unit. Neighbouring units inter-act through π-π inter-actions [centroid-centroid distances = 3.325 (3) and 3.358 (4) Å] and O-H⋯O hydrogen-bonding, resulting in a two-dimensional network extending parallel to (001).