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Non-enzymatic browning is a severe problem in juice industry. Here, polyphenol mediated non-enzymatic browning and its inhibition in apple juice were investigated. Epicatechin (R = -0.83), catechin (CAT, R = -0.79), chlorogenic acid (CGA, R = 0.65) and caffeic acid (CAF, R = 0.65) were strongly correlated with browning. CAT and chlorogenic acid quinone (CGAQ) decreased during storage with the fastest CAT degradation rate (k

Thiabendazole (TBZ), a benzimidazole fungicide used for post-harvest treatment, may be a trace contaminant of food matrices. In this work, we report the first EC-SERS (electrochemical-surface enhanced Raman spectroscopy) detection of TBZ in spiked apple juice using electrochemically (EC) roughened, gold-based screen-printed electrodes (AuSPEs) and portable instrumentation. Polarizing the substrate (−0.8 V vs Ag/AgCl) improves the recorded SERS signal of TBZ, allowing to reach a limit of detection (LOD) in juice of 0.061 ppm with a relatively wide linear range (0.5–10 μM) and good intermediate precision (%RSD < 10). The recovery of TBZ from unprocessed juice was found to be more than 82 %. Furthermore, a proof-of-concept integration of AuSPEs with a miniaturized flow cell for the preconcentration of TBZ and the controlled delivery of sample and reagents has been demonstrated. This approach paves the way for integrated, portable analytical systems applicable for on-site sample collection, processing, and analysis.

The quality of postharvest apples is greatly affected by storage temperatures. In this paper, the sensory qualities, such as flavor, texture, color, and taste change of apples during storage at 4 °C and 20 °C were investigated. After correlation analysis, the partial least squares (PLS) and artificial neural network (ANN) techniques were used to build a shelf-life prediction model. The results showed that lower temperature storage can better maintain the color, flesh hardness, and release of volatile compounds of apples. The acidity of apples stored at 20 °C decreased much faster than that at 4 °C. The PLS models were successful in predicting the apple shelf life. When modeling using PLS with a single type index, the order of accuracy of the prediction model was texture, color, and flavor. As a nonlinear algorithm, the ANN model was also an effective predictive tool of apple shelf life at both temperatures.

In order to develop environmentally friendly, economical and facile preparation method of carbon aerogels (CAs), the waste printing paper as the raw material was combined with graphene oxide and carboxylic multi-walled carbon nanotubes to produce CAs (ρ = 44 mg cm

Plasma activated water (PAW) is a new approach to disinfecting surfaces including fresh-cut foods while maintaining their quality attributes. The aim of this study was to evaluate the effect of PAW on enzyme activity, microbial and physicochemical quality of fresh-cut apples. PAW was produced at different production activation times of 10 min, 20 min, 30 min, 45 min and 60 min and the fresh-cut apple slices were washed with PAW for 5 min and stored at 4 °C for 12 days. Results showed that PAW treatments reduced the polyphenol oxidase activity immediately after treatment and the lowest activity was recorded in PAW-20 min (5.10 ± 0.16 U/g FW) after 12 days. Conversely, peroxidase activity of the samples increased immediately after PAW treatment and the samples treated with PAW activated for 30 min had the lowest peroxidase activity at the end of 12 days of storage. No significant changes in the total phenolic content and FRAP antioxidant activity of the fresh-cut apple samples after PAW treatments. The results from firmness, membrane permeability, respiration rate and microstructural imaging showed that at higher PAW activation times (45 min and 60 min) had adverse effects on the quality of fresh-cut apples. Significant reductions in the total aerobic bacteria and total yeast and molds were observed in all PAW treatments except PAW activated for 10 min. The results suggests that plasma activated water could maintain the quality of the fresh-cut apples during storage for plasma activation times of 20 min and 30 min for up to 12 days of storage.

Transit vibration is a potential risk that may cause fruit deterioration. Regulating energy metabolism is recognized for attenuating fruit abiotic/abiotic stresses. To explore the role of energy metabolism in the response of fruit to vibration stress, this research investigated the effects of exogenous treatment with adenosine triphosphate (ATP) and 2,4-dinitrophenol (DNP) on fruit after simulated vibration stress. The results demonstrated that DNP treatment induced significant energy depletion, which exacerbated the adverse physiological responses induced by vibration stress. In contrast, ATP regulated higher fruit energy levels and significantly alleviated fruit quality deterioration. This is achieved by supplying direct energy substances, maintaining higher energy charges, inhibiting ethylene biosynthesis, elevating the antioxidant system, and suppressing cell oxidative damage. The results demonstrated the positive role of fruit energy metabolism response to vibration stress. Ensuring sufficient energy level may be a promising strategy for controlling vibration-induced adverse physiological responses and a potential method to maintain fruit quality.

It was assumed that, high purity endo-arabinanase and endo-mannanase could be useful in the isolation of pectin of enhanced health-promoting potential. Extraction was carried out with 50 U of enzymes per gram of apple pomace at 40 °C, obtaining up to 22% increase in effectiveness, as compared to the acid extraction. The pectins, despite their high M

Different technologies commonly employed by the fruit processing industry affect the phenolic content. This study aimed to establish the extent to which different processing techniques and conditions, tested at an industrial scale, affect phenolics, color, and sensory attributes of fresh strawberries and apples. The effects of freezing, thermal treatments, and high-pressure processing were investigated. In strawberries, mild and standard thermal treatments showed similar patterns for most phenolic groups; an increase in proanthocyanidins, no change in ellagic acid conjugates, and a major decrease in flavonols and anthocyanins. In apples, mild treatments and high-pressure processing had similar effects in all phenolic groups, with increases in dihydrochalcones, hydroxycinnamics, and proanthocyanidins and decreases in flavonols. However, the standard thermal treatment increased flavonols and dihydrochalcones concentrations. This study shows that each fruit behaves differently, and both technology and processing conditions should be customized accordingly to preserve or even increase the phenolic content.

The presence of watercored fruit with translucent mesocarp has attracted immense attention due to its unique morphology and taste, however, the metabolic reconstruction between watercored and non-watercored tissues remain elusive. Herein, the combined proteomic and metabolomic approach was carried out to characterize the protein abundance and metabolic profile in watercored apple. Results demonstrated that carbohydrate metabolism was prioritized enriched in watercored apple, including highly accumulated sucrose and sugar alcohols, and the increased level of transcription factor WHIRLY2 (WHY2), which is required in sugar reallocation. More than 50% overlap of differently abundant proteins involved in calcium ion binding, starch and sucrose metabolism implied the involvement of calcium signaling in watercore development. Moreover, significantly lower calcium content was detected in watercored apples. Sucrose synthase (SUSY) protein, which is involved both in calcium ion binding and sugar metabolism, was the potential basis of apple watercore development, which provided a likely candidate in regulation of apparent quality.

A comprehensive UHPLC-QTOF-IMS based metabolomics investigation in skin and pulp of Malus domestica and Malus baccata was performed. M. domestica fruit parts had higher phenolic contents (25.75-43.05 mg GAE/g) as compared to M. baccata (18.10-28.37 mg GAE/g) and flavonoid content (1.34-9.59 mg RE/g) followed by promising antioxidant activity (MD_Skin

In this study, the use of co-immobilized amylase, pectinase and cellulase enzymes for clarification of apple, grape and pear juices were investigated. Four different co-immobilization method was applied and the highest activity was observed for co-immobilized enzymes onto silica gel. The effect of the enzyme units used in the co-immobilization, reaction temperature and time on turbidity and reducing sugar concentration were optimized by Response Surface Methodology (RSM) via Design Expert Software 8.0.7.1. applying 3-factor Box-Behnken design. Co-immobilized samples were reacted with the substrate solution in batch type and feedback packed bed column reactors and according to turbidity and reducing sugar concentration values, batch reactor efficiency was found to be higher. Finally, freshly squeezed apple, pear and grape juices were interacted with co-immobilized enzymes in the batch reactor system, and turbidity and reducing sugar concentrations were monitored over time. Changes were also observed in antioxidant activities depending on the enzyme treatment.

Natural deep eutectic solvents (NADES) coupled with ultrasound assisted extraction (UAE) was evaluated as extraction techniques for bioactive compounds from apple pomace. Seven natural deep eutectic solvents (NADES) with different molar ratios were explored as green extraction solvents to evaluate extraction efficiency in terms of total flavonoid content (TFC), total phenolic content (TPC), lipid peroxidation inhibition (LBI) and antioxidant potential. The solvents which performed better than conventional solvent were DES1 (Choline chloride: glycerol (1:2)), DES2 (Choline chloride: lactic acid (1:3)) and DES5 ((Choline chloride: citric acid (1:1)). These solvents were further evaluated for optimisation of processing parameters in UAE-DES. The maximum TPC value was achieved using sonication time 40 min, water 30 %, solid/liquid ratio 1:30, temperature 40 °C, acoustic intensity 83.2 W/cm

In this work, a colorimetric sensor array (CSA) for quantitative determination of total acids in apple vinegar during fermentation was constructed. The sensor array was properly designed based on indicators displacement assay (IDA) using three metal ions (Cu

The impacts of ethanol pretreatment and blanching on moisture transfer, microstructure, and nanostructure of cell-wall polysaccharides of apple slices were studied. The physicochemical properties, namely, color, rehydration, and antioxidant capacity were also evaluated. The results corroborated that the use of ethanol and blanching reduced drying time 45-60% and 21-42% at various drying temperatures (50, 60, 70, and 80 °C), respectively, compared to controls. Ethanol loosened the cell wall structure, thereby reducing the internal resistance of moisture diffusion, and the changes in cell wall structure caused by blanching were mainly due to the β-elimination degradation of pectins. Both samples of ethanol pretreatment and blanching possessed lower browning index and higher antioxidant capacity compared with the untreated ones. Overall, ethanol pretreated products exhibited the shortest drying time, less color change and higher antioxidant capacity. These results provide new insights on possible mechanisms about ethanol pretreatment and blanching to improve drying.

We evaluated the in vitro digestibility of apple polyphenols mimicking elderly and adult digestion models (dynamic and static systems). The digestibility of total apple polyphenols in small intestine was much higher in the adult dynamic system (62 μg/100 g fresh apple) compared to the static system (20 μg/100 g fresh apple) and elderly dynamic digestion conditions (33 μg/100 g fresh apple). Elderly in vitro static digestion showed better antioxidant activity than the adult system (OH and ABTS

In order to develop the tyrosinase inhibitors with potential application in food industry, a series of stilbene-hydroxypyridinone hybrids were prepared. Among these compounds, 1h was found to possess the most potent tyrosinase inhibitory effect on both monophenolase and diphenolase activities, with IC

In situ recording of the voltammetric profile of different apple (Malus domestica Borkh.) varieties (Golden, Granny Smith, Reineta, Red delicious, Fuji, and Braeburn) without and with ROS generation is reported. The voltammetric response associated to the oxidation of ascorbic acid (AA) and polyphenolic (PPs) components was recorded. The obtained voltammetric profiles were satisfactorily fitted to a theoretical kinetic model consisting of the competing, dual activation pathways of AA and PPs followed by a degradative step. The rate constants for these processes were calculated from voltammetric data revealing significant differences between varieties. The activation pathways as well as the influence of electrochemical ROS generation on it were variety-sensitive while the degradative step was almost variety insensitive and lightly sensitive to ROS generation.

In this work, we report a simple and rapid surface-enhanced Raman scattering (SERS) method for the screening of pesticide residues on fruit peels using a portable Raman spectrometer. Adhesive tapes were used as the sampling media; the effectiveness of different tape brands was examined. Collection efficiencies were found to be 60.2 ± 7.6%, 54.3 ± 5.0%, and 52.3 ± 9.0% on glass, aluminum foil, and fruit peels, respectively. SERS was achieved by applying silver nanoparticles (Ag NPs) to the surface of the tape after analyte collection. Preparation of the Ag NPs was optimized for pesticide detection. The limit of detection of triazophos on apple peels was 25 ng/cm2 with the portable Raman spectrometer. Considering the least favorable conditions, the calculated detection limit was 0.0225 mg/kg, which is an order of magnitude less than the maximum residue limit (MRL, 0.2 mg/kg) in China. The method is sufficiently sensitive for use in field analysis.

Ancient apple cultivars are known for their organoleptic properties over a small geographic area, but little is known of their nutraceutical properties, which might be useful in large-scale breeding programmes. Nine ancient apple cultivars from Tuscany (Italy) were characterized for their organoleptic properties, phenolic profiles, and antioxidant activity. These cultivars had high polyphenol concentrations (principally flavanols and phenolic acids) and high total antioxidant capacity compared with most commercial apple cultivars. Fruits from the cultivars 'San Michele' and 'Del Debbio' showed a good compromise between fruit size and solid soluble content, and might be suitable for fresh consumption, while fruit from 'Benito', 'Della Piastra', 'Lugliese Grisanti', 'Del Sangue' and 'Ruggine' had high polyphenol contents and excellent antioxidant capacity, and may be suitable for breeding programmes. 'Ruggine' fruit could also be used for sweet juices with good nutraceutical properties due to their high soluble solid content and high flavanol concentration.

Blue mould caused by Penicillium expansum is one of the important diseases of apple fruit during storage. Phenylpropanoid pathway is an important induction mechanism that can utilize downstream metabolites of shikimate pathway to synthesize a series of secondary metabolites. Apple fruit (cv. Fuji) were treated with sodium nitroprusside (SNP) to study its effect on blue mould, shikimate and phenylpropanoid pathways. The results showed that 1.0 mmol L−1 SNP significantly inhibited lesion development of apple fruit inoculated with P. expansum. The results also indicated that SNP enhanced MdDHQS, MdSKDH, MdSK and MdEPSPS genes expressions, increased shikimic acid, tryptophan, tyrosine and phenylalanine contents in apple fruit. The activities of phenylalanine ammonialyase, 4-coumarate: coenzyme A, ligase, cinnamate 4-hydroxylase, lignin, total phenolic compounds and flavonoids contents in apple fruit were also increased by SNP treatment. These results suggest that SNP might modulate shikimate and phenylpropanoid pathways to enhance disease resistance of apple fruit.

Iron oxide nanoparticles (IONPs) modified with polydopamine were covalently immobilized with nisin to inhibit the growth of Alicyclobacillus acidoterrestris in apple juice. The minimum bactericidal concentration (MBC) of IONPs @ pDA-nisin composites against Alicyclobacillus acidoterrestris cells and spores in three kinds of apple juice were 1.25 mg/mL and 2.5 mg/mL, respectively. The concentration of cells and spores decreased from 106 to 10 CFU/mL in apple juice after pretreatment with the composites at the concentration of 20 mg/mL for 10 min. Meanwhile, the investigation of the content of polyphenols, organic acids, volatile compounds and sugars indicated that there was no significant influence of the composites on the apple juices. The results of cytotoxicity (HepG2, Caco 2, SH-SY5Y, and BV2 cells) and acute toxicity test demonstrated the biosecurity and nontoxicity of the composites, which suggested that it was promising to apply the proposed composites to apple juice industry for the control of Alicyclobacillus acidoterrestris pollution.

The adsorption capacity of principal phenolic compounds onto cell walls from three apple varieties was investigated. Isothermal adsorption modelled with Langmuir, Freundlich and Redlich-Peterson equations were carried out over a range of concentrations from 0.5 to 30 mM before and after cell walls were subjected to boiling, oven-drying or freeze-drying. The isotherm data were best fitted by the Langmuir model in all cases. Polyphenols selectively adsorbed onto cell walls with maximum binding capacities ranging from 140 to 580 µg/mg cell walls depending on surface charge. Increased pectin in apple cell walls caused a 129%–311% decrease in the adsorption of negatively charged polyphenols, presumably due to electrostatic repulsive forces. Boiling had limited effect on cell wall polysaccharides and polyphenol-cell wall interactions. However, more than twofold reduction in binding capacities of polyphenols was induced after drying by altering the structural (i.e. binding sites) and compositional (i.e. pectin degradation) characteristics of cell walls.

A package was created that extends apple shelf-life by slowing Penicillium expansum growth. The package consisted of a peelable lid and a tray with a double bottom with inclusion complexes (ICs) of s-cyclodextrin (s-CD) containing the essential oils of palmarosa (ICp) or of star anise (ICsa). Oil amounts required for antimicrobial activity were obtained from in vitro assays. After 12 days at 23 °C, P. expansum-inoculated apples in both of the double-bottom antimicrobial packages (DBAP) had 1/3 less fungal growth, less than 50% weight loss and ethylene and CO2 production, and less than 25% firmness loss, TA and SSC increase, and pH decrease compared to controls. The DBAP with ICsa performed better than with ICp in reducing ethylene production, respiration rate, firmness loss, TA increase, and pH decrease. This demonstrates DBAP containing ICp or ICsa can maximize the shelf-life of apples injured by P. expansum, validating a novel type of antimicrobial packaging.

Gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) for the analysis of key volatile compounds sampled using headspace solid phase microextraction (HS-SPME) is an appropriate tool for authenticity assessment of apple aromas. The current research characterises 18 laboratory produced and 15 commercial apple recovery aroma samples, establishes a database of δ13C values of 16 aroma compounds with respect to their origin (synthetic and natural), and assesses the authenticity of commercially available aroma compounds. Analysis of so-called natural aroma products, revealed δ13C values that were within the expected authentic range although the data did reveal possible falsifications. The sensitivity of the method was evaluated through simple isotope mass balance calculation. Falsification identification is possible for most aromatic substances when the amount of added synthetic compound is in tens of percent.

In this work, a novel knitting aromatic polymer (KAP) was fabricated for the first time by knitting ferrocene with 1,3,5-tris(bromomethyl)-2,4,6-trimethylbenzene via Friedel-Crafts reaction, and then the KAP was magnetically functionalized with Fe

Food traceability is an important component of food safety and quality. Currently, there is no authentic established technique to identify the origin of concentrated apple juice (CAJ) in China. In this study, the isotopes of δ

Patulin is a toxic secondary metabolite produced by several moulds, which contaminates fruits and their products posing serious threats to human health. Though several microorganisms and enzymes have been reported to effectively degrade patulin, separation of them from fruit juice challenges the commercial applications. Here, a Pseudomonas aeruginosa strain TF-06 was isolated, its patulin degradation mechanism and optimum conditions for enzyme immobilization were investigated. The results indicated that TF-06 could degrade patulin into non-cytotoxic E/Z-ascladiol mainly by the activity of intracellular enzymes. For easy separation of enzymes, calcium alginate was selected for immobilization of intracellular enzymes from TF-06. The immobilized enzyme beads were effective in detoxification of patulin in apple juice. The mitigation rate was reached 95%, while there was no negative effect on juice quality. The study provides a promising way to resolve the issue of enzyme separation during mycotoxin biological detoxification in fruit juice.

The present study aimed to evaluate the metabolism and bioavailability of anthocyanins (ACN) and other phenolics from red-fleshed apple (RFA) and to define the intake biomarkers compared to common white-fleshed apple (WFA). Acute and sustained (6-week) interventions were combined in a randomized, controlled and parallel study with 121 hypercholesterolemic subjects. Another arm consuming ACN-rich infusion from aronia fruit (ARO) provided matched content and profile of ACN. Plasma, urine and faeces samples were analyzed using UPLC-MS/MS. Results showed higher bioavailability of ACN after ARO compared to RFA, showing a clear apple matrix effect. The dihydrochalcone phloretin-2¿ -O-glucuronide was the most discriminant intake biomarker of both apples. The urinary peonidin-3-O-galactoside was a good biomarker after both ARO and RFA intakes, whereas peonidin-O-arabinoside was reported to be specific from ARO. The elucidation of the phenolic metabolism and the selection of intake biomarkers is a promising approach to relate phenolic compounds and human health., This study was supported by the Spanish Ministry of Industry, Economy and Competitiveness through the AGL2016-76943-C2-1-R and AGL2016-76943-C2-2-R projects (co-funded by the European Social Fund, European Union); M.J. Motilva thanks to Consejo Superior de Investigaciones Científicas-CSIC for partial funding throught the “Ayudas incorporacion ´ a escalas científicas CSIC, 2018” (Reference 201870I129). L.R. was Sara Borrell postdoctoral contract and she is a Serra Húnter Fellow. I.A.L. enjoys a post-doctoral contract (2017PMFPOST2-19) from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement and from the Universitat Rovira i Virgili (URV). S.Y. was supported by a pre-doctoral grant from the University of Lleida. The authors are grateful to CALIDAD PASCUAL (Aranda de Duero, Burgos, Spain) for generously providing the Bezoya mineral water to prepare daily Aronia infusion.

The purpose of the study was to assess the effect of static and multi-pulsed high pressure processing (HPP) (300-600 MPa, 5-15 min) on the changes in the polyphenolic profile, polyphenoloxidase (PPO) and peroxidise (POD) activities and colour of apple juice. Content of (-)-epicatechin, procyanidin B2, phloretin isomers and phloridzin was detected using Triple-TOF-LC-MS/MS analysis. After HPP treatment, 1,2- disinapoyl-2-feruloylgentiobiose was detected, whereas sinapoyl glucose was degraded after applying 450 MPa and 600 MPa in single pulse, therefore indicating sensitivity of this compound to high pressure and/or polymerization caused by enzymatic reactions. The highest inactivation of PPO (95%) and POD (26%) was observed at 600 MPa. The multi-pulsed HPP (300 MPa × 3 pulses) resulted in higher reduction in oxidoreductive enzyme activity than higher pressure in single pulse (450 MPa). Statistical changes in the colour parameters were observed in pressurized samples, with the lowest ΔE values for 300 MPa × 3 pulses.

This study reports a facile sonohydrolysis synthesis route to prepare the iron antimony oxide (FeSbO4) nanoparticles for the trace level electrochemical sensing of fungicide carbendazim (CRBZ). As prepared FeSbO4 nanoparticles show a nano-cubes-like morphology with uniform distributions that crystallized in the tetragonal phase. The diffraction studies reveal that the FeSbO4 nanoparticles have high crystallinity and high purity. Furthermore, the other structural properties and morphology are characterized by XRD, Raman, XPS, HRTEM, and FESEM analysis. The electrochemical characterizations of FeSbO4 modified GCE towards the detection of CRBZ are performed by cyclic voltammetry and chronoamperometry techniques. The FeSbO4/GCE exhibits a linear range from 0.01 µmol L−1 to 64.3 µmol L−1, the sensitivity of 0.68 µA cm−2 µM−1, and the LOD of 5.4 nmol L−1. Moreover, the FeSbO4/GCE delivered high selectivity among the possibly interfering compounds. Also, our projected FeSbO4/GCE electrode material shows good recoveries in apple juice and paddy water real samples.

Malus micromalus Makino has great commercial and nutritional value. The regression and classification models were investigated by using near-infrared hyperspectral imaging (NIR-HSI) combined with chemometrics to improve the efficiency of non-destructive detection. The successive projections algorithm (SPA), interval random frog, and competitive adaptive reweighted sampling were employed to extract effective wavelengths sensitive to changes of soluble solid content (SSC) and firmness index (FI) information. Two types of assessment models based on full spectrum and effective wavelengths, namely partial least squares regression and extreme learning machine, were established to predict SSC and FI. In addition, the classification models based on the support vector machine improved by the grey wolf optimizer (GWO-SVM) and partial least squares discrimination analysis were constructed to differentiate maturity stage. The SPA-ELM and SPA-GWO-SVM models achieved satisfactory performance. The results illustrate that NIR-HSI is feasible for evaluation of the quality of Malus micromalus Makino.

Chinese Tibetan tea made from the tender leaves of Malus transitoria is a widely consumed health drink, but there are few reports on its chemical composition and biological activity. In this study, we found that a 50% ethanol extract of M. transitoria had good antioxidant and α-glucosidase inhibitory activities in vitro. Guided by in vitro bioassays, chromatographic separation and purification were conducted, and the most active fraction in M. transitoria was determined. UPLC-Orbitrap-MS/MS was used to further quickly and comprehensively characterize the chemical composition. Library searches, MS/MS fragmentation patterns of two isolated reference compounds, and bibliography were used to annotate 81 compounds, of which 2 were new compounds, and 79 were identified from M. transitoria for the first time. This study provides a scientific basis for the development of antioxidant and anti-diabetic functional foods from M. transitoria.