Improvement in the quality of frozen dough for fried flour products by electrostatic field-assisted freezing.

BACKGROUND: With the development of the food industry, frozen dough technology has gradually become an indispensable part of dough processing but its quality is often reduced due to freezing during the production process. Electrostatic field-assisted freezing (EF) technology, a key research project in recent years, reduces the physical damage to food materials by reducing or changing the size of ice crystals in frozen products. RESULTS: In this study, different intensities of electrostatic fields were used to assist in the repeated freezing and thawing of dough. The effects of electrostatic fields on the freezing nucleation process were evaluated by measuring dough freezing curves, low field nuclear magnetic resonance, and melting enthalpy. It was found that the freezing time of frozen dough added with electrostatic field-assisted freezing processing was shortened, the rate at which hardness, viscosity, and elasticity decreased was reduced, and the indicators of water distribution and protein secondary structure components were closer to those of fresh dough. CONCLUSION: This experiment used electrostatic field-assisted freezing to reduce the damage to the dough structure during the freezing process, improve the quality of frozen dough and fried products, and improve the freezing efficiency of frozen dough. It provides a new idea for the study of frozen dough. © 2023 Society of Chemical Industry.

Application of physical field-assisted freezing and thawing to mitigate damage to frozen food.

Freezing is an effective technique to prolong the storage life of food. However, the freeze-thaw process also brings challenges to the quality of food, such as mechanical damage and freeze cracks. Increasingly, physical fields have been preferred as a means of assisting the freezing and thawing (F/T) processes to improve the quality of frozen food because of their high efficiency and simplicity of application. This article systematically reviews the application of high-efficiency physical field techniques in the F/T of food. These include ultrasound, microwave, radio frequency, electric fields, magnetic fields, and high pressure. The mechanisms, application effects, advantages and disadvantages of these physical fields are discussed. To better understand the role of various physical fields, the damage to food caused by the F/T process and traditional freezing is discussed. The evidence shows that the physical fields of ultrasound, electric field and high pressure have positive effects on the F/T of food. Proper application can control the size and distribution of ice crystals effectively, shorten the freezing time, and maintain the quality of food. Microwave and radio frequency exhibit positive effects on the thawing of food. Dipole rotation and ion oscillation caused by electromagnetic waves can generate heat inside the product and accelerate thawing. The effects of magnetic field on F/T are controversial. Although some physical field techniques are effective in assisting F/T of food, negative phenomena such as uneven temperature distribution and local overheating often occur at the same time. The generation of hotspots during thawing can damage the product and limit application of these techniques in industry. © 2022 Society of Chemical Industry.

Novel evaluation technology for the demand characteristics of 3D food printing materials: a review.

As a recently developed way of food manufacturing - 3D printing - is bringing about a revolution in the food industry. Rheological and mechanical properties of food material being printed are the determinants of their printability. Therefore, it is important to analyze the requirements of different 3D printing technologies on material properties and to evaluate the performance of the printed materials. In this review, the printing characteristics and classification of food materials are discussed. The four commonly used 3D printing techniques e.g. extrusion-based printing, selective sintering printing (SLS), binder jetting, and inkjet printing, are outlined along with suitable material characteristics required for each printing technique. Finally, recent technologies for evaluation of 3D printed products including low field nuclear magnetic resonance (LF-NMR), computer numerical simulation, applied reference material, morphological identification, and some novel instrumental analysis techniques are highlighted.

UV induced conversion during drying of ergosterol to vitamin D in various mushrooms: Effect of different drying conditions.

BACKGROUND: Mushrooms are increasingly popular around the world as a nutritional food which is an excellent source of vitamin D2. Although natural mushrooms often contain very little vitamin D2 as many are grown in the dark, they are rich in ergosterol, a precursor to vitamin D2. Ergosterol can be converted to vitamin D2 under ultraviolet radiation. Due to the high water content of fresh mushroom, its quality deteriorates rapidly after harvest, and drying is the most commonly used technology to extend the shelf life. The vitamin D2 content of dried mushrooms depends on the drying conditions used. SCOPE AND APPROACH: In this review, the chemistry of the photo-conversion process of ergosterol to vitamin D2 under ultraviolet radiation is introduced. The ergosterol and vitamin D contents in different mushroom varieties are discussed. The effects of several drying methods and the influence of different drying conditions are reviewed.Key findings and conclusions: Thermal drying in the presence of UV has been proven to convert ergosterol into vitamin D and enhance the nutritional content of all types of edible mushrooms. Solar drying, hot air drying, freeze drying, microwave drying and infrared drying can be used for mushrooms drying under selected operating conditions. A critical evaluation of published literature demonstrates the importance of applying appropriate drying methodology to maximize the nutritional value of various types of edible mushrooms.

Intelligent System/Equipment for Quality Deterioration Detection of Fresh Food: Recent Advances and Application.

The quality of fresh foods tends to deteriorate rapidly during harvesting, storage, and transportation. Intelligent detection equipment is designed to monitor and ensure product quality in the supply chain, measure appropriate food quality parameters in real time, and thus minimize quality degradation and potential financial losses. Through various available tracking devices, consumers can obtain actionable information about fresh food products. This paper reviews the recent progress in intelligent detection equipment for sensing the quality deterioration of fresh foods, including computer vision equipment, electronic nose, smart colorimetric films, hyperspectral imaging (HSI), near-infrared spectroscopy (NIR), nuclear magnetic resonance (NMR), ultrasonic non-destructive testing, and intelligent tracing equipment. These devices offer the advantages of high speed, non-destructive operation, precision, and high sensitivity.

A novel infrared and microwave alternate thawing method for frozen pork: Effect on thawing rate and products quality.

The effect of infrared and microwave alternate thawing (IR + MWT) on frozen pork were compared to fresh, air thawing (AT), infrared thawing (IRT), microwave thawing (MWT). The IR + MWT took only about 11.81 min of the thawing time compared to AT 66.5 min, and the Raman spectroscopy and Low-field nuclear magnetic resonance (LF-NMR) results showed that the IR + MWT maintained better protein secondary structure composition and moisture state compared to MWT and IRT. In terms of thawing losses, IR + MWT had the lowest loss 1.92%. In terms of texture, IR + MWT had the least effect on the post-thawing textural properties and increased the springiness of the meat. Scanning electron microscopy results also showed that there was reduced damage to the muscle structure with IR + MWT. Regarding the odor of the meat after thawing, IR + MWT retained the odor better and was closer to the fresh sample. Therefore, IR + MWT can be used to enhance the thawing rate to protect the quality of the thawed pork.

Effects of magnetic field-assisted liquid carbon dioxide spray freezing on the quality of honeydew melon.

The effectiveness of static magnetic fields with different intensities (5, 10, 15 mT) combined with liquid carbon dioxide spray freezing (LCSF) technique in improving the quality of frozen honeydew melon was investigated. The results showed that LCSF with magnetic fields above 10 mT significantly improved ice nucleation and quality of frozen melons compared to conventional -20 °C freezing, -80 °C freezing and LCSF method without magnetic field assistance (P < 0.05). 15 mT strength static magnetic field assistance suggested the best results, with a 15.0% reduction in total freezing time, 17.7% increase in average freezing rate, 26.6% reduction in drip loss, and better maintenance of sample quality compared to LCSF. These findings demonstrate that LCSF with static magnetic field assistance is promising in improving the quality of frozen foods.

Effects of electric and magnetic field on freezing characteristics of gel model food.

The novel freezing technologies including electrostatic field assisted freezing (EF), static magnetic field assisted freezing (MF), electrostatic field combined with static magnetic field assisted freezing (EMF) were conducted on model food to facilitate comparing their application effect. The results show that the effect of EMF treatment was best, which significantly changed the freezing parameters of the sample. Compared with the control, the phase transition time and total freezing time were shortened by 17.2% and 10.5%, respectively; the proportion of the sample free water content detected by low-field nuclear magnetic resonance was significantly decreased; the gel strength and hardness were significantly improved; the protein secondary and tertiary structures were better maintained; the ice crystal area was reduced by 49.28%. Inverted fluorescence and scanning electron microscopic results indicated that the gel structure of EMF treatment samples was better than MF and EF. MF was less effective in maintaining the quality of frozen gel model.

Comparative freezing study of broccoli and cauliflower: Effects of electrostatic field and static magnetic field.

The effects of 1, 3, 5 kV/cm electrostatic field (EF) and 2, 5, 8 mT static magnetic field (MF) on the quality of frozen broccoli and cauliflower (B and C) were studied. The freezing parameters were significantly improved by 3, 5 kV/cm EF or 8 mT MF treatment (P < 0.05), a maximum reduction of nucleation time and phase transition time by 20.14 % and 32.09 % was found in 5 kV/cm EF treated cauliflower. EF or MF treatment improved sample quality to some extent, the overall effect of 3 kV/cm EF was the best, which led to a maximum drip loss reduction of 64.3 % in cauliflower, accompanied by lower relative conductivity, higher ascorbic acid and less cell rupture. EF or MF did not significantly reduce the damage of the flavor. MF was less effective than EF in improving the quality of frozen B and C.

Combination strategy of CO2 pressurization and ultrasound: To improve the freezing quality of fresh-cut honeydew melon.

The effects of CO2 pressurization combined with ultrasound-assisted immersion freezing (CO2USIF) on improving the freezing quality of honeydew melon were studied. The cut melon samples were first subjected to 0.2, 0.5 and 0.8 MPa CO2 pressure for 2 h respectively, and then frozen by an ultrasound-assisted freezing device. The results indicated that the CO2 pressurization affected the water state and reduced the freezable water content. Cryo-observed results showed the ice crystal area of the 0.5CO2USIF sample was 66.6% smaller than that of the SF, and 60.8% smaller than that of the IF. The drip loss of 0.5CO2USIF sample was 58.2% lower than that of SF. The indexes of vitamin C, flavor, texture and color of CO2USIF samples were kept better. The SEM results showed that the cell structures of CO2USIF samples were better maintained. These demonstrated that CO2USIF technology has application potential in improving the quality of frozen food.

miR-24 protects against ischemia-induced brain damage in rats via regulating microglia polarization by targeting Clcn3.

Microglia and macrophages play important roles in ischemic brain injury. Changes in their M1/M2 polarization phenotypes significantly impact disease progression. The M2 microglia/macrophages are anti-inflammatory and have a protective effect against ischemic injury. The microRNA 24 (miR-24) promotes M2 macrophage polarization and suppresses inflammation. We tested the hypothesis that miR-24 is protective in ischemic brain injury by regulating microglia polarization. We treated rats with miR-24 inhibitor or mimic and subsequently subjected the rats to middle cerebral artery occlusion (MCAO) to induce ischemic brain injury. Neurological deficit and infarct volume were analyzed. Microglia and macrophages were assessed by fluorescence-activated cell sorting. Microglia polarization was determined by genes specific for M1 and M2 both in vivo and in BV-2 cells. The effect of miR-24 target Clcn3 on microglia polarization was examined. We found that miR-24 inhibition aggravated MCAO induced damage, while miR-24 overexpression alleviated brain injury by suppressing microglia/macrophage infiltration. miR-24 suppressed M1 and promoted M2 microglia polarization both in vivo and in vitro. Finally, we showed that miR-24 targeted Clcn3 to regulate microglia polarization. Our study indicates that miR-24 plays a neuroprotective role by promoting anti-proinflammatory microglia polarization during ischemic brain injury.

Application of ultrasonic technology in postharvested fruits and vegetables storage: A review.

It has been an important research topic and a serious applicable issue to extend storage time of fruits and vegetables using advanced scientific and effective technology. Among various approaches, ultrasound has been regarded as one of the most pollution-free and effective technical means to significantly improve the preservation of fruits and vegetables. This paper summarizes the application of ultrasonic technology in fruits and vegetables storage in recent years, including removal of pesticide residues and cleaning, sterilization, enzyme inactivation, effect on physico-chemical indexes. Additionally, we also discussed limitations and negative effects of ultrasonic treatment on fruits and vegetables such as damages to tissues and cells. Furthermore, a proper application of ultrasonic technology has been proven to effectively extend the storage period of postharvest fruits and vegetables and maintain the quality. Moreover, the combination of ultrasound and other conventional preservation technologies can further improve the preservation in a coordinate manner and even have a broader application prospect.

miR-24 Reduces Serum Lipid Levels and Inhibits Brain Tissue Cells Apoptosis of Rats with Cerebral Infarction.

AIM: To study miR-24 effects on cerebral infarction in rats. MATERIAL AND METHODS: A rat middle cerebral artery occlusion model (MCAO) was constructed. Intracerebroventricular stereotactic injection of miR-24 agomir/antagomir was performed in the rat MCAO model. According to different experiences, rats were divided into normal, sham, MCAO, miR-24 agomir and miR-24 antagomir groups. Serum TCH, HDL and TG levels were detected. RESULTS: Comparingthe normal and sham groups, we observed decreased relative miR-24 expression (p < 0.05) and increased cerebral infarction area percentage, apoptotic cells and relative caspase-3 protein expression (p < 0.05) in theMCAO, miR-24 agomirand miR-24 antagomir groups. TC, TG and HDL-C levels of the MCAO and miR-24 antagomir groups were higher than those of normal and sham groups (p < 0.05).Compared with the MCAO group, increased relative miR-24 expression (p < 0.05) and decreased TC, TG and HDL-C levels,cerebral infarction area percentage, number of apoptotic cells and caspase-3 expression (p < 0.05) were found in themiR-24 agomir group, contrasting with theobservations from the miR-24 antagomir group. CONCLUSION: miR-24 reduced serum TCH, HDL and TG levels and inhibited brain tissue cell apoptosis in rats with cerebral infarction.

miR-24 reduces serum lipid levels and inhibits brain tissue cells apoptosis of rats with cerebral infarction.

AIM: To study miR-24 effects on cerebral infarction in rats. MATERIAL AND METHODS: A rat middle cerebral artery occlusion model (MCAO) was constructed. Intracerebroventricular stereotactic injection of miR-24 agomir/antagomir was performed in the rat MCAO model. According to different experiences, rats were divided into normal, sham, MCAO, miR-24 agomir and miR-24 antagomir groups. Serum TCH, HDL and TG levels were detected. RESULTS: Comparing the normal and sham groups, we observed decreased relative miR-24 expression (P 0.05) and increased cerebral infarction area percentage, apoptotic cells and relative caspase-3 protein expression (P 0.05) in the MCAO, miR-24 agomir and miR-24 antagomir groups. TC, TG and HDL-C levels of the MCAO and miR-24 antagomir groups were higher than those of normal and sham groups (P 0.05). Compared with the MCAO group, increased relative miR-24 expression (P 0.05) and decreased TC, TG and HDL-C levels, cerebral infarction area percentage, number of apoptotic cells and caspase-3 expression (P 0.05) were found in the miR-24 agomir group, contrasting with the observations from the miR-24 antagomir group. CONCLUSION: miR-24 reduced serum TCH, HDL and TG levels and inhibited brain tissue cell apoptosis in rats with cerebral infarction.