Inactivation mechanisms on pectin methylesterase by high pressure processing combined with its recombinant inhibitor.

High pressure processing (HPP) juice often experiences cloud loss during storage, caused by the activity of pectin methylesterase (PME). The combination of HPP with natural pectin methylesterase inhibitor (PMEI) could improve juice stability. However, extracting natural PMEI is challenging. Gene recombination technology offers a solution by efficiently expressing recombinant PMEI from Escherichia coli and Pichia pastoris. Experimental and molecular dynamics simulation were conducted to investigate changes in activity, structure, and interaction of PME and recombinant PMEI during HPP. The results showed PME retained high residual activity, while PMEI demonstrated superior pressure resistance. Under HPP, PMEI's structure remained stable, while the N-terminus of PME's α-helix became unstable. Additionally, the helix at the junction with the PME/PMEI complex changed, thereby affecting its binding. Furthermore, PMEI competed with pectin for active sites on PME, elucidating. The potential mechanism of PME inactivation through the synergistic effects of HPP and PMEI.

Antioxidant Activities of Konjac Glucomannan Hydrolysates of Different Molecular Weights at Different Values of pH.

Konjac glucomannan (KGM) is a high-molecular-weight polysaccharide that was originally extracted from the corms (underground storage organs) of Amorphophallus konjac. KGM and its oligomers have been reported as dietary fibers that exhibit an array of health benefits. The depolymerization of KGM via enzymatic hydrolysis at different conditions gives products of low viscosity and can be used for coating materials in microencapsulation. In the present study, konjac glucomannan hydrolysates (KGMHs) were produced by enzymatic hydrolysis using commercial mannanase at pH 4.5 at 70 °C for 5-120 min, then KGMHs' molecular weight (Mw), Degree of Polymerization (DP) and their bioactivities were determined. A longer hydrolysis time resulted in KGMH of a lower DP. Oligoglucomannans (Mw < 10,000) could be obtained after hydrolysis for 20 min. The DP of KGMH rapidly decreased during an early stage of the hydrolysis (first 40 min); DP reached around 7 at the end of the hydrolysis. Antioxidant activities were determined by the DPPH radical scavenging and FRAP assays of KGMHs prepared at pH 4.5 and evaluated at pH 2.0-8.0 depending on pH. KGMH having lower Mw exhibited higher antioxidant activities. KGMHs having the smallest molecular weight (Mw = 419) exhibited the highest DPPH radical scavenging activity. Mw and pH have a greater impact on KGMHs' bioactivities which can be useful information for KGMHs as functional ingredients.

Effect of the Structure of Highly Porous Silica Extracted from Sugarcane Bagasse Fly Ash on Aflatoxin B1 Adsorption.

Sugarcane bagasse fly ash is industrial waste produced by incinerating biomass to generate power and steam. The fly ash contains SiO2 and Al2O3, which can be used to prepare aluminosilicate. This latter material exhibits high potential as an adsorbent in various applications, including the livestock industry where issues related to contamination of aflatoxins in animal feeds need to be addressed; addition of adsorbents can help decrease the concentration of aflatoxins during feed digestion. In this study, the effect of the structure of silica prepared from sugarcane bagasse fly ash on physicochemical properties and aflatoxin B1 (AFB1) adsorption capability compared with that of bentonite was investigated. BPS-5, Xerogel-5, MCM-41, and SBA-15 mesoporous silica supports were synthesized using sodium silicate hydrate (Na2SiO3) from sugarcane bagasse fly ash as a silica source. BPS-5, Xerogel-5, MCM-41, and SBA-15 exhibited amorphous structures, while sodium silicate possessed a crystalline structure. BPS-5 possessed larger pore size, pore volume, and pore size distribution with a bimodal mesoporous structure, while Xerogel-5 exhibited lower pore size and pore size distribution with a unimodal mesoporous structure. BPS-5 with a negatively charged surface exhibited the highest AFB1 adsorption capability compared with other porous silica. However, the AFB1 adsorption capability of bentonite was superior to those of all porous silica. Sufficient pore diameter with high total pore volume as well as high intensity of acid sites and negative charge on the surface of the adsorbent is required to increase AFB1 adsorption in the in vitro gastrointestinal tract of animals.

Production and characterization of nanofibrillated cellulose gels simultaneously exhibiting thermally stable green color and oil-in-water emulsion stabilizing capability from Centella asiatica.

Nanofibrillated cellulose (NFC) gels simultaneously exhibiting Pickering stabilizing capability and thermally stable green color were developed for use as food additive in thermally processed food emulsion requiring the expression of color. Chopped Centella asiatica plant was mixed with zinc amino acid chelate solution and subject to autoclaving at 130°C for 2 h to form zinc-chlorophylls complex and to remove noncellulosic components. Autoclaved sample was high-shear homogenized at 26,000 rpm for 15 min and microfluidized at either 80, 120, or 160 MPa for 5 passes. An increase in microfluidization pressure resulted in a decrease in NFC diameters; microfluidization at 160 MPa did not nevertheless yield any further reduction in the diameters when compared with that at 120 MPa. From energy consumption point of view, microfluidization at 120 MPa for 5 passes was then noted as optimal condition for preparation of NFC coloring gel; NFC with diameters of 8-42 nm and crystallinity index of 35% was obtained. Freshly prepared gel exhibited gel-like behavior and dark green color. Heating at 121°C for 1 h did not affect diameters, viscoelasticity, and color of the gel. Addition of the gel at 0.9% or 1.2% (w/w) into soybean oil-in-water emulsion, in combination with high-shear homogenization at 18,000 rpm for 5 min, resulted in adequate emulsion stability. The emulsion exhibited stable dark green color and no phase separation after heating at 121°C for 1 h and during storage for 8 weeks. PRACTICAL APPLICATIONS: Information presented here can serve as a guideline for further development of a multifunctional food ingredient exhibiting thermally stable green color and oil-in-water emulsion stabilizing capability. In other words, one simple ingredient can serve at the same time as both natural food colorant and emulsion stabilizer.

Protocols for extraction and purification of rutin from leafy by-products of asparagus (Asparagus officinalis) and characterization of the purified product.

Valorization of asparagus leafy by-products as a potential source of rutin through selected extraction and purification protocols was investigated. Protocol resulting in the highest extraction yield was first selected. Crude extract was subject to purification via multiple liquid-liquid back extraction using ethanol, methanol or water as a solvent; selection of the most appropriate purification solvent was made based on rutin solubility. The proposed purification protocol yielded yellow-color crystals, which were characterized by fluorescence microscopy, Fourier-transform infrared spectroscopy and liquid chromatography-mass spectrometry to confirm them as rutin. Purity of rutin was confirmed by ultra-performance liquid chromatography at 97.6%; yield of the purified rutin was determined to be 78.2%. The remaining rutin (21.8%) was found in the liquids collected at various stages of purification; such liquids could be recycled using the same purification process. The proposed protocols are simple, yet effective for rutin extraction and purification from asparagus leafy by-products.

Rapid smartphone-based assays for pesticides inspection in foods: current status, limitations, and future directions.

Smartphone-based assays to inspect pesticides in foods have attracted much attention as such assays can transform tedious laboratory-based assays into real-time, on-site, or even home-based assay and hence overcoming the limitations of conventional assays. Although an array of smartphone-based assays is available, information on the use of these assays for pesticides inspection is scattered. The purposes of this review are therefore to compile, summarize and discuss state-of-the-art as well as advantages and limitations of the relevant technologies. Suggestions are provided for further development of smartphone-based assays for rapid inspection of pesticides in foods. Smartphone-based assays relying on enzyme inhibitions are noted to be nonselective qualitative, capable of reporting results in a quantitative manner only when a sample contains an individual pesticide. Smartphone-based assays relying on chemical reactions also target only individual pesticides. Smartphone-based visible spectroscopy can, on the other hand, inspect individual and multiple pesticides with the aid of appropriate colorimetry-, luminescence-, or fluorescence-based assay. Smartphone-based visible-near infrared and Raman spectroscopies are suitable for simultaneous multiple pesticides inspection. Raman spectroscopy is of particular interest as it can detect pesticides even at lower concentrations. This spectroscopic technique can also serve as a real-time assay with the aid of cloud network computations.

Production of salad dressings via the use of economically prepared cellulose nanofiber from lime residue as a functional ingredient.

Production of cellulose nanofiber (CNF) via the use of a more economical and less energy-intensive means is desirable. Once formed, it is necessary to determine whether or not the prepared CNF would be capable of forming a Pickering emulsion as in the case of traditionally prepared nanofiber. In the present study, oil-in-water emulsions, namely, salad dressings, with CNF as a functional ingredient, were prepared. Lime residue powder as the source of dietary fiber was subject to high-shear homogenization to form CNF suspension, which was then mixed with other ingredients. Different contents of fat (20%-40%), egg yolk (0%-4%), and lime residue powder (0%-4%) were tested. The formed CNF successfully acted as a Pickering emulsifier and allowed the production of salad dressings with desirable characteristics at 30%-40% fat, 2% egg yolk, and 2% lime residue powder. The dressings exhibited adequate physicochemical properties and remained stable throughout the storage period of 28 days. PRACTICAL APPLICATION: The presently proposed means would allow the industry to produce cellulose nanofiber (CNF) in a more economical and less energy-intensive manner. The so-produced CNF exhibits comparable properties as traditionally prepared nanofiber and can be used as a stabilizer in food emulsions.

Brazilein as an alternative pigment: Isolation, characterization, stability enhancement and food applications.

This review gives, for the first time, a systematic presentation and discussion on the chemistry and use of brazilein in foods. Processes of isolation, purification and quantification of this alternative pigment are firstly reviewed. Molecular structure and color stabilities as well as ways to enhance stability of the pigment are then discussed. Selected applications of the pigment in foods are given. Based on the review of the literature, future studies should focus on the isolation and purification of the pigment prior to its use in foods. Extraction yield and purity of brazilein obtained from the different methods should also be compared. Since the pigment is very sensitive to pH change, its stability should be enhanced prior to its use. Co-pigmentation is among the methods that exhibits potential for stability enhancement of the pigment.

Effects of Texture Modifiers on Physicochemical Properties of 3D-Printed Meat Mimics from Pea Protein Isolate-Alginate Gel Mixture.

Meat mimics were prepared from pea protein isolate-alginate gel via 3D printing. The texture of 3D-printed meat mimics was modified by incorporating transglutaminase (TGase) or κ-carrageenan (κc) at 0.3, 0.6 or 0.9% (w/w) into printing material prior to 3D printing. Rheological properties of modified printing material were measured; results were used to support 3D printing results. Textural properties of raw and cooked meat mimics were determined and compared with those of selected animal meats, namely, pork tenderloin, chicken breast, salmon meat and Spanish mackerel. Cooking losses of meat mimics were also determined. G', G″ and tan δ of TGase-modified material were not significantly different from those of the control. In contrast, increasing κc content resulted in increased G' and G″; tan δ of all κc-modified samples decreased from that of the control. Addition of TGase at 0.9% into printing material increased the hardness of raw meat mimics, while κc at 0.9% increased hardness of cooked meat mimics. Raw meat mimics treated with 0.9% TGase exhibited texture closest to raw salmon. Texture of cooked meat mimics treated with 0.9% κc was closest to that of cooked salmon. TGase-treated meat mimics tended to experience lower cooking losses, while κc-treated meat mimics exhibited an opposite trend.

Improvement of Moist Heat Resistance of Ascorbic Acid through Encapsulation in Egg Yolk-Chitosan Composite: Application for Production of Highly Nutritious Shrimp Feed Pellets.

Egg yolk (EY) is an excellent supplement for aquatic animals and has good technofunctionality. Ascorbic acid (AA) is a potent bioactive substance and is essentially added to shrimp feed; however, it is drastically lost in both feed processing and in rearing environments. In this study, AA was microencapsulated in an EY-chitosan (CS) composite. The encapsulated vitamin was then mixed into a shrimp feed mixture to form pelleted feed via twin-screw extrusion. The effects of the EY/AA ratio and the amount of CS on moist heat resistance, production yield, encapsulation efficiency (EE), and morphology of microcapsules were investigated. The molecular interaction of the microcapsule components was analyzed by FTIR. The size and size distribution of the microcapsules were determined using a laser diffraction analyzer. The microstructure was evaluated by SEM. The physical properties of the microcapsule-fortified pelleted feed were determined. The AA retention at each step of feed processing and during exposure to seawater was evaluated. The results showed that the microcapsules had a spherical shape with an average diameter of ~6.0 µm. Decreasing the EY/AA ratio significantly improved the production yield, EE, and morphology of the microcapsules. EY proved to be the key component for moist heat resistance, while CS majorly improved the production yield, EE, and morphology of the microcapsules. The microcapsules showed no adverse impact on feed properties. The loss of AA in food processing and seawater was remarkably improved. The final content of the encapsulated AA remaining in shrimp feed was 16-fold higher than that of the unencapsulated AA.

Increased plasma trimethylamine-N-oxide levels are associated with mild cognitive impairment in high cardiovascular risk elderly population.

Trimethylamine-N-oxide (TMAO) has been shown to be associated with cardiovascular (CV) disease and cognitive impairment. The association between early stages of cognitive impairment and TMAO in a high CV risk population has not been previously investigated. This study aimed to investigate the association between the plasma TMAO level and cognitive function in a population with a high risk of CV disease. Participants at a high risk of CV were included. The cognition was evaluated using the Montreal Cognitive Assessment. A score lower than 25 out of 30 was used to indicate mild cognitive impairment (MCI). Blood samples of all participants (n = 233) were collected to measure the plasma levels of TMAO and other metabolic parameters, including fasting blood sugar and lipid profiles. Logistic regression was used to evaluate the association between MCI and high plasma TMAO levels, adjusted for confounding factors. Of 233 patients, the mean age of patients in this study was 64 years old (SD 8.4). The median TMAO level was 4.31 µM (IQR 3.95). The high TMAO level was an independent risk factor of MCI (aOR 2.36, 95% CI 1.02 to 5.47; p 0.046), when adjusted for age, gender, health care service scheme, smoking history, metabolic syndrome, and history of established CV events. The high TMAO level was associated with MCI, after adjustment for potential confounding factors. These findings demonstrate that plasma TMAO levels can serve for target prediction as an independent risk factor for MCI in this population.

Defects in 3D/4D food printing and their possible solutions: A comprehensive review.

3D food printing has recently attracted significant attention, both from academic and industrial researchers, due to its ability to manufacture customized products in such terms as size, shape, texture, color, and nutrition to meet demands of individual consumers. 4D printing, which is a technique that allows evolution of various characteristics/properties of 3D printed objects over time through external stimulation, has also been gaining more attention. In order to produce defect-free printed objects via both 3D and 4D printing, it is necessary to first identify the causes of defects and then their mitigation strategies. Comprehensive review on these important issues is nevertheless missing. The purpose of this review is to investigate causes and characteristics of defects occurring during and/or after 3D food printing, with a focus on how different factors affect the printing accuracy. Various techniques that can potentially minimize or eliminate printing defects and produce high-quality 3D/4D printed food products without the need for time-consuming trial and error printing experiments are critically discussed. Guidelines to avoid defects to improve the efficiency of future 3D/4D printed food production are given.

Investigation on simultaneous change of deformation, color and aroma of 4D printed starch-based pastes from fruit and vegetable as induced by microwave.

Conventional 3D printing exhibits serious limitation for it requires a support layer upon which more layers can be formed. A designed structure that lacks such a layer is therefore very difficult, if not impossible, to be printed. A novel means to allow 4D deformation of simple 3D-printed object into complex suspended structure is therefore proposed; microwave irradiation was used to induce the desired directed deformation. In this study, yellow flesh peach-buckwheat paste was used to study the effects of model structure and microwave power on directed 4D deformation behavior. Then, finite-element based simulation was conducted to investigate interactions between the printed object and microwave irradiation. Experiments and simulations showed that local high temperature generated by microwave (200 W) caused directional micro puffing at resulting hot spots, forming a driving force to allow 3D-printed objects to rapidly undergo 4D deformation (within 90 s). The verification test also proved that puffing was the main factor driving 4D deformation. This strategy could combine with color and flavor changing microcapsules to realize the synchronous 4D printing process of deformation, color changing, and aroma changing within 15 s, induced by a household microwave oven (700 W). The purpose of this study is to provide a new 4D printing method interacting with consumers in a short time, which could be applied to children's food.

Spray drying of non-chemically prepared nanofibrillated cellulose: Improving water redispersibility of the dried product.

Despite increasing interest in using nanofibrillated cellulose (NFC) as food thickener and emulsifier, poor water redispersibility of dried NFC, which is form suitable for practical utilization, significantly limits such applications. Studies are lacking on preparation of dried NFC with superior redispersibility. The present study therefore proposed and examined strategies to improve water redispersibility of spray dried NFC via the use of selected co-carriers, i.e., gum Arabic with/without xanthan gum, carboxymethyl cellulose or pectin. Synergistic interactions between NFC and co-carriers, as confirmed by X-ray diffraction (XRD) patterns and Fourier transform infrared (FTIR) spectra, helped prevent NFC agglomeration during spray drying. All reconstituted spray-dried NFC/co-carriers suspensions exhibited shear-thinning and gel-like behaviors, thus supporting the use of such suspensions as thickener and emulsifier. Spray-dried NFC with 80% gum Arabic and 20% xanthan gum (SD-NFC/GA20XG) resulted in suspension with highest viscosity; the suspension also performed best at recovering viscous characteristics of NFC. Water thickened by SD-NFC/GA20XG had strongest shear-thinning behavior, indicating that SD-NFC/GA20XG suspension resulted in smoothest mouth feel and easiest swallowing. Such observations were supported by XRD patterns of SD-NFC/GA20XG, which suggested that its relative crystallinity was the lowest. Its FTIR spectra also showed the highest intensity of -OH bending and carbonyl bands, which are directly related to water adsorption capability of NFC. Use of reconstituted SD-NFC/GA20XG as emulsifier also resulted in highest stability for oil-in-water (O/W) Pickering emulsion during storage for up to 30 days.

Progresses in processing technologies for special foods with ultra-long shelf life.

Foods for special applications have recently received much attention due to rapid development of space and military industries as well as to frequent occurrence of natural and man-made disasters. Since the way such foods are processed clearly and directly affects their consumer's acceptability and shelf life, it is of interest to explore in detail how these special foods can be processed. This article presents a review on the difficulties in the processing, application and storage as well as on how to ensure the shelf life and acceptability of special foods through the use of efficient processing technologies. Emphasis is made on the use of both conventional and alternative thermal processing and irradiation technologies. Appropriate packaging technologies for each of the discussed special foods are also mentioned along with the way to overcome the problem of product quality degradation. Through comparison and analysis, it is found that foods with different attributes require different technologies and processes to achieve desirable results. Combined use of multiple technologies has also noted to be advantageous.

Effect of addition of carbon dots to the frying oils on oxidative stabilities and quality changes of fried meatballs during refrigerated storage.

Carbon dots (CDs) were prepared and noted to exhibit potent scavenging activities against DPPH·, ·OH, and O2·- radicals. Addition of CDs to frying oil as a means to improve oxidative stability and minimize quality changes of fried meatballs during refrigerated storage was investigated in comparison with the use of tert-butylhydroquinone (TBHQ) and carnosic acid (CA). Compared with the control sample, 0.05% CDs significantly reduced thiobarbituric acid reactive substances value, carbonyl and total volatile basic nitrogen contents of fried meatballs. Both lipid and protein oxidation inhibition capabilities of CDs were higher than those of 0.05% CA but lower than those of 0.02% TBHQ. Total sensory score of sample with CDs (7.1 ± 0.06) was significantly higher than those of the control (4.7 ± 0.03) and sample with TBHQ (6.4 ± 0.04). CDs could delay oxidation of fried meatballs during refrigerated storage and can well serve as an alternative antioxidant.

Development and testing of a novel image analysis algorithm for descriptive evaluation of shape change of a shrinkable soft material.

Soft material can undergo non-uniform deformation or change of shape upon processing. Identifying shape and its change is nevertheless not straightforward. In this study, novel image-based algorithm that can be used to identify shapes of input images and at the same time classify non-uniform deformation into various patterns, i.e., swelling/shrinkage, horizontal and vertical elongations/contractions as well as convexity and concavity, is proposed. The algorithm was first tested with computer-generated images and later applied to agar cubes, which were used as model shrinkable soft material, undergoing drying at different temperatures. Shape parameters and shape-parameter based algorithm as well as convolutional neural networks (CNNs) either incorrectly identified some complicated shapes or could only identify the point where non-uniform deformation started to take place; CNNs lacked ability to describe non-uniform deformation evolution. Shape identification accuracy of the newly developed algorithm against computer-generated images was 65.88%, while those of the other tested algorithms ranged from 34.76 to 97.88%. However, when being applied to the deformation of agar cubes, the developed algorithm performed superiorly to the others. The proposed algorithm could both identify the shapes and describe their changes. The interpretation agreed well with that via visual observation.

Textural properties and muscle activities during mastication of normal and ultrasonically softened sticky rice aimed for consumers with swallowing disorder: A pilot study.

Ultrasonication was used to develop softer sticky rice for elder adults. Textural properties of original sticky rice (oSR) and ultrasonically modified sticky rice (mSR) were determined. In addition, jaw muscle activities during mastication of both oSR and mSR were investigated. Twenty-seven healthy elderly subjects, age 68.9 ± 7.6 years, were asked to masticate both types of sticky rice in random sequence for three times with a 5-min rest between each test. Activities of bilateral masseter and suprahyoid muscles were recorded. Root mean square (RMS) and mastication duration were analyzed. After mastication trials, subjects were asked to rate preference and softness of the samples. mSR exhibited significantly lower hardness than oSR, while cohesiveness and adhesiveness values of the two samples were not significantly different. Interestingly, all the muscle activities were not significantly different between masticating oSR and mSR, whereas the number of chewing cycles while chewing the mSR was larger. However, 92% of the subjects preferred mSR and felt that it was softer. mSR may therefore be regarded as having potential for elder people who have difficulty masticating hard solid foods based on its lower hardness and higher level of preference compared to oSR.

Microstructures of encapsulates and their relations with encapsulation efficiency and controlled release of bioactive constituents: A review.

Vitamins, peptides, essential oils, and probiotics are examples of health beneficial constituents, which are nevertheless heat-sensitive and possess poor chemical stability. Various encapsulation methods have been applied to protect these constituents against thermal and chemical degradations. Encapsulates prepared by different methods and/or at different conditions exhibit different microstructures, which in turn differently influence the encapsulation efficiency as well as retention of encapsulated core materials. This review provides a summary of various microstructures resulted from the use of selected encapsulation methods or systems, namely, spray coating; co-extrusion; emulsion-, micelle-, and liposome-based; coacervation; and ionic gelation encapsulation, at different conditions. Subsequent effects of the different microstructures on encapsulation efficiency and retention of encapsulated core materials are mentioned and discussed. Encapsulates having compact microstructures resulted from the use of low-surface tension and low-viscosity encapsulants, high-stability encapsulation systems, lower loads of core materials to total solids of encapsulants and appropriate solidification conditions have proved to exhibit higher encapsulation efficiencies and better retention of encapsulated core materials. Encapsulates with hollow, dent, shrunken microstructures or thinner walls resulted from inappropriate solidification conditions and higher loads of core materials, on the other hand, possess lower encapsulation efficiencies and protection capabilities. Encapsulates having crack, blow-hole or porous microstructures resulted from the use of high-viscosity encapsulants and inappropriate solidification conditions exhibit the lowest encapsulation efficiencies and poorest protection capabilities. Compact microstructures and structures formed between ionic biopolymers could be used to regulate the release of encapsulated cores.

Comparative evaluation of acrylamide and polycyclic aromatic hydrocarbons contents in Robusta coffee beans roasted by hot air and superheated steam.

Although hot air (HA) is a conventional roasting medium for coffee beans, HA roasting is known to result in possible formation of toxic compounds, including acrolein, acrylamide and polycyclic aromatic hydrocarbons (PAHs). Superheated steam (SHS) roasting is therefore proposed as an alternative means to alleviate the formation of these toxic compounds in roasted coffee beans. Robusta coffee beans were roasted either with HA or SHS in a fluidized bed roaster at 210-250 °C until the bean color reached the targeted roast levels. The contents of acrolein, acrylamide and 16 PAHs in the roasted beans were determined; only acrylamide and 5 PAHs were nevertheless found. SHS roasting interestingly resulted in lower acrylamide contents in dark-roasted beans; similar trend was noted in the beans medium-roasted at 250 °C. The contents of three-ring PAHs, namely fluorene, phenanthrene and anthracene, in dark-roasted beans were significantly lower upon SHS roasting at 250 °C.