Development of amine-sensitive intelligent film with MIL-100(Fe) as function filler based on anthocyanins/pectin for monitoring chilled meat freshness.

To enhance the amine-sensitivity of intelligent films for accurate monitoring of chilled meat freshness, different additions (0, 1, 2, 3 wt%) of MIL-100(Fe) were incorporated into the matrix composed of anthocyanins (ANs) and pectin (P). Results indicated that the tensile strength, thermal stability, barrier performance and absorption capacity of the films with MIL-100(Fe) were improved significantly (p < 0.05). Especially, the film with 2 % MIL-100(Fe) exhibited the best performance due to its compact structure and the highest crystallinity. Additionally, adsorption isotherms of the films with MIL-100(Fe) were fitted on the Langmuir and the Freundlich isotherm, and adsorption kinetics were fitted on the pseudo-second-order model and Elovich model, respectively (R2 > 0.96), suggesting a combined mechanism of chemisorption and intraparticle diffusion. Besides, when the films were exposed in ammonia environment, they changed color from purple to blue-violet, finally to green. Ultimately, film with 2 % MIL-100(Fe) was used to monitor the chilled meat freshness, as expected, similar color variation was observed at three stages of meat freshness (fresh, sub-fresh, and spoiled), which enabled the accurate differentiation of meat freshness. Thus, films with MIL-100(Fe) demonstrated the potential to be amine-sensitive intelligent packaging for monitoring chilled meat freshness in real time.

Isolation, structural, biological activity and application of Gleditsia species seeds galactomannans.

Gleditsia fruits have been known as a valuable traditional Chinese herb for tens of centuries. Previous studies showed that the galactomannans are considered as one of the major bioactive components in Gleditsia fruits seeds (GSGs). Here, we systematically review the major studies of GSGs in recent years to promote their better understanding. The extraction methods of GSGs mainly include hot water extraction, microwave-assisted extraction, ultrasonic extraction, acid extraction, and alkali extraction. The analysis revealed that GGSs exhibited in the form of semi-flexible coils, and its molecular weight ranged from 0.018 × 103 to 2.778 × 103 KDa. GSGs are composed of various monosaccharide constituents such as mannose, galactose, glucose, and arabinose. In terms of pharmacological effects, GSGs exhibit excellent activity in antioxidation, hypoglycemic, hypolipidemic, anti-inflammation. Moreover, GSGs have excellent bioavailability, biocompatibility, and biodegradability, which make them used in food additives, food packaging, pharmaceutical field, industry and agriculture. Of cause, the shortcomings of the current research and the potential development and future research are also highlighted. We believe our work provides comprehensive knowledge and underpinnings for further research and development of GSGs.

Freeze-drying pretreatment of watermelon peel to improve the efficiency of pectin extraction: RSM optimization, extraction mechanism, and characterization.

This study assessed the processing parameters and mechanism of pectin extraction and pectin qualities from freeze-dried (FD) pretreatment watermelon peel. The optimal extraction conditions for the highest pectin yield (21.83 %) were a liquid/solid ratio (w/w) of 29, pH of 1.8, ultrasonic power of 573 W, and ultrasonic time of 43 min. Compared to hot-air dried (HD) method, the extraction of pectin from FD watermelon peel was facilitated by the increased cross-sectional areas of cells, transfer rate of extracting solution, mass transfer rate, and reduced rehydration time during the extraction. HD pectin (HDP) exhibited browning, whereas FD pectin (FDP) displayed bright brownish-yellow coloration. Furthermore, the L* value of pectin from FDP was significantly higher and a* and b* values were significantly lower than pectin from HDP (P < 0.05). Additionally, the moisture, ash and protein contents of FDP were significantly higher than those in HDP (P < 0.05). Structural characterization demonstrated FDP as a low-methoxy acetylated pectin, with significantly lower degree of methoxylation and molecular weight compared to that of HDP (P < 0.05). Besides, FDP demonstrated significantly superior emulsification performance compared to HDP (P < 0.05). These findings suggest FD as a potent, efficient, and time-saving technology for drying fresh watermelon peel for pectin preparation.

Active film preparation using pectin and polyphenols of watermelon peel and its applications for super-chilled storage of chilled mutton.

We investigated the effect of active packaging films prepared by pectin (WMP) and polyphenols (WME) obtained from watermelon peel on the quality of chilled mutton during super-chilled storage. The addition of WME created new chemical and hydrogen bonds in film. Furthermore, an appropriate amount of WME (≤1.5%) was evenly distributed throughout the film matrix, improving barrier properties, mechanical properties, thermal stability, and light transmittance of the film. An assessment of the meat quality showed that the pH, L*, b*, thiobarbituric acid reactive substances (TBARs), total volatile basic nitrogen (TVB-N), and total bacterial count (TCA) of super-chilled + film group were significantly lower, whereas shear force and a* value were significantly higher (P < 0.05) than other groups. The WMP/WME film has dense microstructure and excellent mechanical properties after storage. Pectin and polyphenols obtained from watermelon peel have good potential as a novel packaging material for chilled mutton during super-chilled storage.

Impact of Nitrite Supplementation on Bioactive Peptides during Sausage Processing.

The goal of this investigation was to examine the impact of nitrite supplementation on the concentration, antioxidant properties, and species of antioxidant peptides in fermented sausages. The polypeptide concentration in nitrite-supplemented sausages was markedly elevated during sausage processing compared to the blank control (p < 0.05). Moreover, nitrite supplementation in fermented sausages markedly enhanced the DPPH, as well as the ABTS, hydroxyl radical, and superoxide anion free radical scavenging abilities (FRSA) of polypeptides (p < 0.05). The ferrous ion chelating ability was also significantly enhanced (p < 0.05). Based on the liquid chromatograph-mass spectrometer (LC-MS) analysis of the sausage, LPGGGHGDL, TKYRVP, FLKMN, SAGNPN, GLAGA, LPGGGT, DLEE, GKFNV, GLAGA, AEEEYPDL, HCNKKYRSEM, TSNRYHSYPWG, and other polypeptides exhibited antioxidant properties. Moreover, the number of species of antioxidant polypeptides in the nitrite-supplemented sausage was greater in comparison to the controls. Based on this evidence, it may be concluded that nitrite supplementation positively modulated antioxidant polypeptide formation in fermented sausages, thereby providing strong evidence that nitrite supplementation significantly enhances sausage quality.

Spectrum modulation-based field of view extension in Airy-beam tomographic microscopy.

We reveal the self-accelerating performance of an Airy beam under space-variable spectrum modulation, which corresponds to the extension of the field of view (FOV) and imaging depth in Airy-beam tomographic microscopy (ATM), resulting in the decline of fidelity and resolution of a reconstructed image with an increased FOV and depth of field (DOF). A strategy of spectrum modulation is proposed, and high-fidelity, high-resolution 3D imaging is realized in a 150 µm × 50 µm × 12 µm volume. This study offers a paradigm to improve the quality of reconstructed 3D images based on spectrum modulation for other light fields.

A novel colorimetric indicator film based on watermelon peel pectin and anthocyanins from purple cabbage for monitoring mutton freshness.

Novel films based on watermelon peel pectin (WMP) incorporated with purple cabbage extract (PCE) were developed for monitoring the freshness of mutton. The FTIR result showed that WMP and PCE interacted through hydrogen bonds. Low PCE content (≤1.5%) could be well dispersed in the film matrix, resulting in an enhancement in light transmittance, mechanical properties, barrier properties, and thermal stability. Excessive addition of PCE destroyed the compact structure of the film and decreased the comprehensive properties. The antioxidant and antimicrobial activity of WMP/PCE films were proportional to the amount of incorporated PCE. Moreover, the color of the film deepened as the PCE content increased. The film had excellent color stability and pH response properties. The WMP/PCE1.5 film color varied from mauve to baby blue according to the quality of mutton (fresh to spoiled). Our results suggested that the WMP/PCE film might have great potential for monitoring the freshness of mutton.

Metabolites Analysis on Water-Holding Capacity in Beef Longissimus lumborum Muscle during Postmortem Aging.

Currently, the metabolomic research on water-holding capacity (WHC) of beef during postmortem aging is still insufficient. In this paper, the kit method was adopted for energy metabolites testing, the ultra-high-performance liquid chromatography (UHPLC) system was used for sample separation, and the mass spectrometer was applied to collect the primary and secondary spectra of the samples. The results showed that lactic acid reached saturation at day 2 postmortem, while energy metabolites changed significantly within day 2 postmortem (p < 0.05). Based on these findings, it was suggested that the energy metabolism qualities of the beef had already achieved a largely stable state at around day 2 postmortem. Then, through metabolomic analysis, 25 compounds were differentially abundant at days 0, 0.5, 1, and 2 during postmortem aging. Within the period of day 0−2 postmortem, the purine metabolism in beef was relatively active until 0.5 d postmortem, while glycolysis metabolism remained active until day 2 postmortem. The functions of the identified metabolites contribute to a more detailed molecular view of the processes behind WHC and are a valuable resource for future investigations into the flavor of postmortem beef.

Dielectric barrier discharge plasma: A green method to change structure of potato starch and improve physicochemical properties of potato starch films.

The effects of dielectric barrier discharge (DBD) plasma treatment on the physicochemical properties of potato starch and its films were studied. The results showed that the plasma species caused etching lead to small cracks and pores in potato starch particles and that oxidation, de-polymerization, and crosslinking were the main mechanisms underlying the effects of DBD plasma treatment. As the treatment time extended, starch hydrolysis, turbidity, syneresis, and gelatinization temperatures increased first and then decreased, whereas the solubility, swelling power, and water absorption significantly increased (P < 0.05). There was a decrease in the retrogradation tendency of the starch gels. The surfaces of the DBD plasma-modified potato starch-based films were relatively flat. After a 9-min treatment, the films exhibited the lowest water vapor permeability and highest tensile strength. In conclusion, the use of DBD plasma is a simple and green method to enhance the properties of potato starch and its film.

Changes in chilled beef packaged in starch film containing sea buckthorn pomace extract and quality changes in the film during super-chilled storage.

This study aimed to evaluate the effects of super-chilled storage (-1.3 °C) combined with starch film packaging containing different contents of sea buckthorn pomace extract (SSF, 0, 1, 2, and 3%, w/w) on the quality of chilled beef. The release kinetics, microstructure, and mechanical properties of the film were also measured to investigate its suitability for super-chilled storage. The results of the meat quality assessment showed that the L*, a*, and sensory evaluation values of the SSF-3% samples were significantly higher (P < 0.05), and the pH, b*, thiobarbituric acid reactive substance (TBARS), total volatile basic nitrogen (TVB-N), and total viable count (TCA) were significantly lower (P < 0.05) than the SSF-0%. The release of SBP from the SSF film was controlled by diffusion. Furthermore, SSF-3% was found to have a compact microstructure and good mechanical properties at the end of the super-chilled storage. The results demonstrated that SSF is an effective packaging material for beef at super-chilling temperatures.

A Digital Microscreen for the Enhanced Appearance of Ocular Prosthetic Motility (an American Ophthalmological Society Thesis).

PURPOSE: This study aims to improve the apparent motility of ocular prosthetic devices using technology. Prevailing ocular prostheses are acrylic shells with a static eye image rendered on the convex surface. A limited range of ocular prosthetic movement and lack of natural saccadic movements commonly causes the appearance of eye misalignment that may be disfiguring. Digital screens and computational systems may obviate current limitations in eye prosthetic motility and help prosthetic wearers feel less self-conscious about their appearance. METHODS: We applied convoluted neural networks (CNNs) to track pupil location in various conditions. These algorithms were coupled to a microscreen digital prosthetic eye (DPE) prototype to assess the ability of the system to capture full ocular ductions and saccadic movements in a miniaturized, portable, and wearable system. RESULTS: The CNNs captured pupil location with high accuracy. Pupil location data were transmitted to a miniature screen ocular prosthetic prototype that displayed a dynamic contralateral eye image. The transmission achieved a full range of ocular ductions and with grossly undetectable latency. Lack of iris and sclera color and detail, as well as constraints in luminosity, dimensionality and image stability limited the real eye appearance. Yet, the digitally rendered eye moved in the same amplitude and velocity as the native, tracked eye. CONCLUSIONS: Real-time image processing using CNNs coupled to microcameras and a miniscreen DPE may offer improvements in amplitude and velocity of apparent prosthetic eye movement. These developments, along with ocular image precision, may offer a next-generation eye prosthesis. NOTE: Publication of this article is sponsored by the American Ophthalmological Society.

Ultrasound-assisted thawing of frozen white yak meat: Effects on thawing rate, meat quality, nutrients, and microstructure.

The objective of this study was to assess the effects of ultrasound-assisted thawing (UAT) on the quality of longissimus dorsi muscles from white yak meat (WYM). Ultrasonic power levels of 0, 200, 400, and 600 W (frequency of 20 kHz) were used to assist thawing. The thawing rate, meat quality, nutrient substances, volatile compounds, and microstructure of the WYM were determined. The results showed that ultrasonic thawing treatment reduced thawing times by 30.95-64.28% compared to control. The meat quality results revealed that the thawing loss, cooking loss, L* and b* values, and pH values decreased significantly while the a* value and cutting force increased significantly (P < 0.05) at the lower 400 W power level compared with the control. In addition, the free amino acid (FAA), mineral, and vitamin (especially water-soluble vitamins) contents were significantly (P < 0.05) increased with the ultrasound treatment. UAT significantly (P < 0.05) increased the content of volatile compounds, an effect that was highest in the UAT-400 W group. Partial least squares discrimination analysis (PLS-DA) showed that 2,4-heptadienal was critical in distinguishing the UAT groups from the control. When the ultrasonic power was lower than 400 W, the muscle cell area was significantly (P < 0.05) increased but decreased when higher power was used. Therefore, UAT improves the thawing efficiency and quality of frozen WYM, particularly at a power level of 400 W, and these findings have potential applications in the meat industry.

Effect of a sea buckthorn pomace extract-esterified potato starch film on the quality and spoilage bacteria of beef jerky sold in supermarket.

A new food packaging material was developed for beef jerky. The material consists of an esterified potato starch film with 3 different concentrations (2%, 4%, and 6%, w/w) of sea buckthorn pomace extract. The packaged beef jerky was kept in supermarket. The sea buckthorn pomace extract-esterified potato starch film (SPF) packaging significantly reduces the water loss, L*, a*, thiobarbituric acid reactive substances (TBARS) and the total volatile basic nitrogen (TVB-N) of beef jerky during storage (p < 0.05), demonstrating a protective effect to reduce the deterioration of the quality. However, a high content of sea buckthorn pomace extract in film (6%) also affects the smell of beef jerky. Moreover, SPF effectively inhibits the growth of common spoilage bacteria in beef jerky. These results demonstrated that SPF reduces the deterioration rate of the beef jerky and the decreases the spoilage by bacteria, which both gives SPE a high potential as a new packaging material.

Imbalance of Th22/Treg cells causes microinflammation in uremic patients undergoing hemodialysis.

BACKGROUND: Regulatory T (Treg) cells are of critical functionality in immune activation and inflammation in uremic patients undergoing hemodialysis (HD). A disruption in balance of Treg cells has potency to elicit infectious disease progression. Here, we examined possible association between ratio imbalance of Th22/Treg cells and microinflammation in uremic patients undergoing HD. METHODS: Peripheral blood mononuclear cells (PBMCs) were isolated to allow measurement of the percentage of Th22 cells and Treg cells using flow cytometry. Subsequently, serum levels of related cytokines, interleukin (IL) 22 (IL-22) and IL-10 and inflammatory factors, C-reactive protein (CRP), (TNF-α), IL-6 were determined via enzyme-linked immunosorbent assay (ELISA). Then relationships among dialysis time, microinflammation status (CRP) and dialysis adequacy (immunoreactive parathyroid hormone (iPTH), urea clearance index (Kt/V), ß2-MG, serum calcium, and serum phosphorus) were evaluated. Finally, correlation between microinflammation status and dialysis adequacy was analyzed with Pearson's correlation coefficient. RESULTS: An increased percentage of Th22 and a decreased percentage of Treg cells were evident in uremic patients undergoing HD. Serum levels of IL-22, CRP, TNF-α, and IL-6 were increased, while IL-10 serum level was reduced. An imbalance of Th22/Treg cells was associated with microinflammation status in uremic patients undergoing HD. Furthermore, prolongation of the dialysis time, the microinflammation status and dialysis adequacy were changed. Increased dialysis adequacy was observed to correlate with alleviated microinflammation of uremic patients undergoing HD. CONCLUSIONS: Conjointly, an imbalance of Th22/Treg cells may be a potential cause responsible for uremia occurrence, which in turn indicates that uremia could be effectively alleviated by altering the ratio of Th22/Treg cells.