Flexible dynamic quantitative phase imaging based on division of focal plane polarization imaging technique.

This paper proposes a flexible and accurate dynamic quantitative phase imaging (QPI) method using single-shot transport of intensity equation (TIE) phase retrieval achieved by division of focal plane (DoFP) polarization imaging technique. By exploiting the polarization property of the liquid crystal spatial light modulator (LC-SLM), two intensity images of different defocus distances contained in orthogonal polarization directions can be generated simultaneously. Then, with the help of the DoFP polarization imaging, these images can be captured with single exposure, enabling accurate dynamic QPI by solving the TIE. In addition, our approach gains great flexibility in defocus distance adjustment by adjusting the pattern loaded on the LC-SLM. Experiments on microlens array, phase plate, and living human gastric cancer cells demonstrate the accuracy, flexibility, and dynamic measurement performance for various objects. The proposed method provides a simple, flexible, and accurate approach for real-time QPI without sacrificing the field of view.

Recent development in evaluation methods, influencing factors and control measures for freeze denaturation of food protein.

Frozen storage is most widely adopted preservation method to maintain food freshness and nutritional attributes. However, at low temperature, food is prone to chemical changes such as protein denaturation and lipid oxidation. In this review, we discussed the reasons and influencing factors that cause protein denaturation during freezing, such as freezing rate, freezing temperature, freezing method, etc. From the previous literatures, it was found that frozen storage is commonly used to prevent freeze induced protein denaturation by adding cryoprotectants to food. Some widely used cryoprotectants (for example, sucrose and sorbitol) have been reported with higher sweetness and weaker cryoprotective abilities. Therefore, this article comprehensively discusses the new cryopreservation methods and providing comparative study to the conventional frozen storage. Meanwhile, this article sheds light on the freeze induced alterations, such as change in functional and gelling properties. In addition, this article could be helpful for the prolonged frozen storage of food with minimum quality related changes. Meanwhile, it could also improve the commercial values and consumer satisfaction of frozen food as well.

Recent advance in technological innovations of sugar-reduced products.

Sugar is crucial as an essential nutrient for humans as well as for providing texture, sweetness and so on to food. But with the rise in people's pursuit of health, it is becoming increasingly clear that excessive consumption of sugar can locate a load on the body. It has been that excessive sugar is associated with many diseases, such as dental caries, obesity, diabetes, and coronary heart disease. Therefore, researchers and industries are trying to reduce or substitute sugar in food without affecting the sensory evaluation. Substituting sugar with sweeteners is alternatively becoming the most traditional way to minimize its use. So far, the sweeteners such as stevia and xylitol have been are commercially applied. Several studies have shown that technological innovation can partially compensate for the loss in sweetness as a result of sugar reduction, such as cross-modal interactions that stimulate sweetness with aroma, nanofiltration that filters disaccharides and above, enzyme-catalyzed sugar hydrolysis, and microbial fermentation that turns sugar into sugar alcohol. This review summarizes these studies to enhance the safety and quality of sugar-reduced products, and will provide some theoretical frameworks for the food industry to reduce sugar in foods, meet consumers' needs, and promote human health.

Development of point diffraction interferometer by a dimension-reduction-based phase-shifting algorithm.

To avoid exhaustive calibration of the shifter device in point diffraction interferometers, we present a dimension-reduction-based method to reconstruct the phase map from more phase-shifting fringe patterns with three or more frames. The proposed method assumes that the intensity space can be described adequately by the sine and cosine of multiple phase shifts introduced, which are the basis of the intensity space. Then, low-dimensional approximations of high-dimensional intensity spaces are determined by the newly developed reduced basis decomposition technique. Finally, the phase is reconstructed using the low-dimensional surrogates of the intensity spaces without the knowledge of accurate phase steps. Numerical and experimental studies demonstrated that the proposed method outperforms the existing popular phase reconstruction techniques in terms of accuracy and efficiency. Moreover, the performance of the proposed method is not limited by variations in the background and modulation, unlike the existing phase-shifting-algorithm-based approaches.

Real-time infrared image detail enhancement based on fast guided image filter and plateau equalization.

Image detail enhancement is critical to the performance of infrared imaging systems because the original images generally suffer from low contrast and a low signal-to-noise ratio. Although conventional decomposition-based methods have advantages in enhancing image details, they also have clear disadvantages, which include intensive computations, over-enhanced noise, and gradient reversal artifacts. In this paper, we propose to accelerate enhancement processing by using a fast guided filter and plateau equalization. Our method consists of image decomposition, base and detail layers processing, and projection of the enhanced image to an 8-bit dynamic range. Experimental results demonstrated that our proposed method achieves a good balance among detail enhancement performance, noise and gradient reversal artifacts suppression, and computational cost, with a frame rate around 30 fps for 640×512 infrared images.

High-performance concealment of defective pixel clusters in infrared imagers.

Defective pixel concealment is a necessary procedure in infrared image processing and is widely used. However, current approaches are mainly focused on the concealment of isolated pixels and small defective pixel clusters. Consequently, these approaches cannot meet the requirements when applied to infrared detectors with large defective pixel clusters. In this paper, we present a novel and comprehensive approach to processing the image data acquired from infrared imagers with large and small defective pixel clusters. Our approach consists of preprocessing, coarse concealment, high dynamic range enhancement, and fine concealment by generative adversarial networks. Experiments using mid-wave infrared and long-wave infrared images demonstrated that the proposed approach achieves better results than the best conventional approach, known as transforming image completion, with the peak signal-to-noise ratio and structural similarity metrics improved by 2.7063 dB (16.3%) and 0.1951 dB (34.1%), respectively.

Robust and flexible method for calibrating the focal length of on-orbit space zoom camera.

For the on-orbit space zoom camera, the camera focal length is in a constant process of change; accordingly, compared with calibrating other camera intrinsic parameters, calibrating the focal length has a practical significance for the space zoom camera. With the vanishing points obtained from the solar panel of human-made space satellites, this paper introduces a focal length self-calibration method for the on-orbit space zoom camera. First, the geometrical relationship and infinite homography of vanishing points at various camera positions are used to derive the method. To improve the accuracy and robustness performance of this approach, an optimization method is then proposed to nonlinearly optimize the camera focal length. Finally, simulation and real physical experiments demonstrate that the proposed method is flexible and accurate with good anti-noise interference and real-time capacity. The method proposed in this paper makes more realistic sense for a number of important space tasks.

A comprehensive review of the application of ultrasonication in the production and processing of edible mushrooms: Drying, extraction of bioactive compounds, and post-harvest preservation.

Edible mushrooms are high in nutrients, low in calories, and contain bioactive substances; thus, they are a valuable food source. However, the high moisture content of edible mushrooms not only restricts their storage and transportation after harvesting, but also leads to a shorter processable cycle, production and processing limitations, and a high risk of deterioration. In recent years, ultrasonic technology has been widely applied to various food production operations, including product cleaning, post-harvest preservation, freezing and thawing, emulsifying, and drying. This paper reviews applications of ultrasonic technology in the production and processing of edible mushrooms in recent years. The effects of ultrasonic technology on the drying, extraction of bioactive substances, post-harvest preservation, shelf life/preservation, freezing and thawing, and frying of edible mushrooms are discussed. In summary, the application of ultrasonic technology in the edible mushroom industry has a positive effect and promotes the development of this industry.

Effect of guar gum on the physicochemical properties and in vitro digestive characteristics of extruded starches.

The present study assessed the impact of guar gum (GG) on the physical and chemical attributes and the in vitro digestibility of maize starch (MS), pea starch (PS), and sweet potato starch (SPS) subjected to extrusion treatment. Starch with 25 % moisture content and combined with GG in a 9:1 ratio was selected for extrusion. Scanning electron microscopy and differential scanning calorimetry reveal that extrusion disrupts the ordered structure of starch and induces aggregation of starch granules, resulting in a more cohesive structure, and GG addition led to the further evolution of this structure into a more intricate and irregular form. Rheological assessments demonstrated a remarkable enhancement in the gelatinization characteristics of starch with GG addition, which led to elevated flow resistance and increased viscosity. On evaluating the in vitro digestive characteristics, we noted that adding GG to starch augmented the levels of slow-digestible starch and resistant starch. Consequently, this resulted in diminished digestibility and a lowered glycemic index. In summary, GG synergistically interacts with starch, forming intricately assimilable components. Moreover, the effects of extrusion vary across different starches, which proves advantageous for SPS and GG amalgamation, thereby enhancing their resistant components. Conversely, extrusion manifests contrasting outcomes for MS and PS.

Influence of gelatinized octenyl succinic anhydride-modified waxy adlay seed starch on the properties of astaxanthin-loaded emulsions: Emulsion properties, stability and in vitro digestion properties.

Octenyl succinic anhydride (OSA)-modified starch is a commonly used food emulsifier and its emulsifying properties are positively correlated with the degree of substitution (DS). However, the maximum concentration of OSA in starch approved by the FDA and the China National Food Safety Standards is 3%. This study aims to enhance the emulsifying properties of OSA-modified waxy adlay seed starch by gelatinization under a limited DS and investigate its use in preparing delivery systems. The gelatinized OSA starch exhibited a more flexible macromolecular structure and better emulsifying activity (20.19 m2/g). The gelatinized OSA starch-stabilized astaxanthin-loaded emulsions showed high retention of astaxanthin (>50%) and long-term stability (56 days). In vitro digestion, the emulsion system showed a protective effect on astaxanthin, and the bioaccessibility of astaxanthin was increased to 16.32%. This study indicated that gelatinization could enhance the emulsifying properties of OSA starch, and this starch-stabilized emulsion was an effective system for astaxanthin.

Indazolin-3-ylidenes (Indy*): easily accessible, sterically-hindered indazole-derived N-heterocyclic carbenes and their application in gold catalysis.

Sterically-hindered N-heterocyclic carbenes (NHCs) with functionalized N-wingtips are a pivotal class of ligands in organic synthesis. Herein, we report the first class of sterically-hindered N-heterocyclic carbenes based on the indazole framework. These ligands combine the strong σ-donation of the carbene center due to the carbene placement at the C3-indazole position with the sterically-hindered and flexible N-substitution with the versatile 2,6-bis(diphenylmethyl)aryl moiety that extends beyond the metal centre for the first time in non-classical N-heterocyclic carbenes. The ligands are readily accessible by the rare Cadogan indazole synthesis of sterically-hindered N-aryl-1-(2-nitrophenyl)methanimines. Steric and electronic characterization as well as catalytic studies in the synthesis of oxazolines are described. Considering the unique properties of indazole-derived carbenes, we anticipate that this class of compounds will find broad application in organic synthesis and catalysis.

Microstructural, physicochemical properties and starch digestibility of brown rice flour treated with extrusion and heat moisture.

Effects of heat moisture treatment (HMT), extrusion treatment (ET), and the combination treatment (HMT-ET) on microstructural, physicochemical properties, and starch digestibility of brown rice flour (BRF) were investigated. With a rise in resistant starch (RS), melting temperature, and a decrease in swelling capacity (SC), peak viscosity, and apparent amylose content (AAC), the HMT-ET BRF showed a significant lower expected glycemic index (eGI) than HMT and ET. XRD and FTIR results showed ET, HMT-ET caused the transition of starch crystals from amorphous to crystalline region, suggesting the formation of the starch-lipid complex. The analysis of DSC and RVA proved HMT-ET flours induced starch gelatinization and inhibited the starch retrogradation of BRF compared with the other three flours. Correlation analysis suggested that the combined effect of HMT and ET was response for the changes in physicochemical properties and reduction of in vitro starch digestibility. Overall, the BRF after HMT-ET with improved physicochemical properties and starch digestibility could be better utilized as a good substitute for carbohydrate sources.

Structural, physicochemical, and functional properties of insoluble dietary fiber derived from okara by Viscozyme® L.

The endogenous components of okara can affect the extraction and modification of insoluble dietary fiber (IDF). This study was intended to investigate the effect of extraction and purification of IDFs from okara affected by the endogenous components and composite enzyme Viscozyme® L. After that, the physicochemical, functional, and structural characteristics of IDFs were analyzed. The results showed that with the purification of degreasing, deproteinizing and destarching, Viscozyme® L can accurately act on the cell wall of okara, leading to the increase in specific surface area of IDF and the formation of honeycomb-like structure. In accordance with the X-ray diffraction and Fourier-transform infrared spectrum investigations, relative crystallinity decreased and certain cellulose components were reallocated and changed into soluble dietary fiber. Moreover, the modified IDF showed improved water-holding capacity (10.73-11.59 g/g), oil-holding capacity (5.37-6.60 g/g), and swelling capacity (8.99-12.37 mL/g), leading to improved adsorption capacities of glucose (maximum: 39.60 mg/g), cholesterol (14.54-33.56 mg/g at pH 7; 10.94-19.37 mg/g at pH 2), and cholate and better cation-exchange capacity. The outcomes demonstrated the potential for the acquired IDFs, particularly the high-purity modified-IDFs T3 and T4 , to be exploited as functional fiber components in the food sector. PRACTICAL APPLICATION: This study advances the understanding of the internal mechanism of modified insoluble dietary fiber (IDF) with different purities in okara. The obtained high-purity modified IDF can be employed as a functional fiber raw material in the manufacture of functional foods, and can also be utilized to assist in the treatment of some illnesses due to its well-established in vivo function.

Higher visceral adiposity index was associated with an elevated prevalence of gallstones and an earlier age at first gallstone surgery in US adults: the results are based on a cross-sectional study.

Objective: We sought to evaluate the association between visceral adiposity index (VAI) and the incidence of gallstones and the age at first gallstone surgery in adults in the United States. Methods: We selected individuals from the National Health and Nutrition Examination Survey (NHANES) database from 2017 to 2020 and evaluated the association between VAI and gallstone incidence and age at first gallstone surgery using logistic regression analysis, subgroup analysis, and dose-response curves. Results: A total of 7,409 participants aged >20 years were included in our study; 767 had a self-reported history of gallstones. After adjustment for all confounding factors, for each unit of VAI after Ln conversion, gallstone prevalence increased by 31% (OR = 1.31, 95% CI: 1.17, 1.48), while the first gallstone surgery was 1.97 years earlier (ß = -1.97, 95% CI: -3.35, -0.42). The dose-response curves showed a positive correlation between VAI and gallstone prevalence. There was a negative correlation between increased VAI and age at first gallstone surgery. Conclusion: A higher VAI is positively associated with the prevalence of gallstones and may lead to an earlier age at first gallstone surgery. This is worthy of attention, although causality cannot be established.

High Oxygen Shocking Reduces Postharvest Disease and Maintains Satisfying Quality in Fresh Goji Berries during Cold Storage by Affecting Fungi Community Composition.

Fresh goji (Lycium barbarum L.) berries were treated with high-concentration (50% and 90%) oxygen shocking for 30 min and then stored at 0 ± 0.5 °C for 30 d. Decay, aerobic plate count, firmness, weight loss, total soluble solid (TSS), and titratable acidity (TA) were evaluated during storage. A total of 90% O2 shocking more effectively reduced decay and maintained the weight loss and firmness of goji berries. Subsequently, changes in fungi communities were analyzed using high-throughput sequencing (HTS) in the 90% O2-shocking and control groups. The results showed that 90% O2 shocking retained the richness and diversity of fungi communities and the microbiome was related to the quality properties of the fruit. Thus, we inferred that high oxygen shocking inhibited the development of natural decay and maintained the satisfying quality of goji berries by affecting the fungi community composition, which reduced the growth of pathogenic fungi and harmful saprotrophic fungi in the genera, such as Filobasidium sp., Alternaria sp., and Cladosporium sp. We provide a new insight into the disease development and quality changes during the storage of postharvest goji berries.

Optimization of Microwave Pre-Cooked Conditions for Gelatinization of Adzuki Bean.

Pre-cooked adzuki beans (Vigna angularis), which looks like dried adzuki bean, is easily cooked and preserved. This study aimed to optimize the microwave pre-cooked conditions on adzuki beans by applying the response surface methodology. The results showed that soaking time has a significant effect on the gelatinization degree of adzuki beans according to microwave time. The most suitable gelatinization and the sensory scores were obtained with a soaking time of 7.8 h, a microwave power of 830 W, and microwave time of 92 s. The pre-cooked treatment had no significant effect (p > 0.05) on the protein, free amino acid, fat and starch content of adzuki bean products. The results of SEM and polarized light microscopy showed that the surface and center of starch were damaged after microwave treatment. XRD showed that microwave pre-cooking did not change the crystal structure of starch and maintained the original order of type A structure while reducing the relative starch crystallinity. FT-IR showed that the pre-cooked treatment did not produce new structure in adzuki bean starch, but the ratio of 1047/1022 cm-1 was slightly decreased, indicating that the starch crystallization area decreased relative to the amorphous area and the relative crystallinity decreased. The results of FTIR were consistent with X-ray diffraction results. Therefore, microwaves improved the gelatinization of adzuki beans and made the pre-cooked adzuki beans more suitable.

An air-stable, well-defined palladium-BIAN-NHC chloro dimer: a fast-activating, highly efficient catalyst for cross-coupling.

We report the synthesis, characterization and reactivity of an air-stable, well-defined acenaphthoimidazolylidene palladium-BIAN-NHC chloro dimer complex, [Pd(BIAN-IPr)(µ-Cl)Cl]2. This rapidly activating catalyst merges the reactive properties of palladium chloro dimers, [Pd(NHC)(µ-Cl)Cl]2, with the attractive structural features of the BIAN framework. [Pd(BIAN-IPr)(µ-Cl)Cl]2 is the most reactive Pd(II)-NHC precatalyst discovered to date undergoing fast activation under both an inert atmosphere and aerobic conditions. The catalyst features bulky-yet-flexible sterics that render the C-H substituents closer to the metal center in combination with rapid dissociation to monomers and strong σ-donor properties. [Pd(BIAN-IPr)(µ-Cl)Cl]2 should be considered as a catalyst for reactions using well-defined Pd(II)-NHCs.

Hot extrusion 3D printing technologies based on starchy food: A review.

Three-dimensional (3D) printing is a new technique used to construct complex geometric forms for personalized nutrition and customization. With good rheological and gelling properties, starch materials have great potential in the 3D printed food industry. The successful printing of materials depends on various aspects, and current researches have focused on discussing the influence of the rheological properties of starch materials on printing, while the researches on the printing characteristics with other starch properties, material processing methods, printing process parameters are still insufficient. This review mainly focuses on the relationship between the material properties of starch foods and hot extrusion 3D printing, discussing the influence of material properties (rheology, adhesiveness, thermal properties, microstructure and component interaction) on the feasibility of printing. In addition, the effects of additives (hydrocolloids, lipids, fiber, protein, salt and other), processing methods, and process parameters (nozzle diameter, print height, print speed, and throughput) on printing are reviewed.

Pd-Catalyzed umpolung asymmetric allylic alkylation of hydrazones to vicinal tertiary and quaternary chiral carbon centers.

Diastereo- and enantioselective construction of vicinal tertiary and quaternary carbon centers is a great challenge in synthetic chemistry. Herein, we report a facile and efficient protocol to construct vicinal tertiary and quaternary chiral carbon centers in high yields with high regio-, diastereo- and enantioselectivities via Pd-catalyzed umpolung asymmetric allylic alkylation of hydrazones with monosubstituted allyl reagents by using Kündig-type chiral N-heterocyclic carbene as the ligand. The control experiments revealed that the reaction proceeds via the inner-sphere mechanism.

Regio- and enantioselective umpolung gem-difluoroallylation of hydrazones via palladium catalysis enabled by N-heterocyclic carbene ligand.

The enantioselective construction of C-CF2R (R: alkyl or fluoroalkyl) bonds has attracted the attention of synthetic chemists because of the importance of chiral fluorinated compounds in life and materials sciences. Catalytic asymmetric fluoroalkylation has mainly been realized under organocatalysis and Lewis acid catalysis, with substrates limited to carbonyl compounds. Few examples using transition-metal catalysis exist, owing to side reactions including decomposition and isomerization of fluoroalkylating reagents. Herein we report umpolung asymmetric difluoroallylation of hydrazones with 3-bromo-3,3-difluoropropene (BDFP) under palladium catalysis. Difluoroallylation products having quaternary chiral carbon centers are afforded in good yields with high α/γ- and enantioselectivities. The usefulness of the reaction products is demonstrated and an inner-sphere mechanism of the reaction is proposed. The use of chiral N-heterocyclic carbene as ligand is the key for the selectivities as well as the productivity of the reaction.