ascorbic-acid and 5-hydroxymethylfurfural

A non-enzymatic browning reaction occurs easily in Dongbei Suancai (DS) during storage. Using the method of path analysis, the changes in contents of VC (ascorbic acid), polyphenol, reducing sugar, amino nitrogen, and 5-HMF (5-hydroxymethyl furfural) were investigated to analyze the direct pathways and determinants of browning caused by pre-production blanching at 100 °C (R-100), salt-addition increased from 2% to 6% (Y-6) and fermentation time extended from 30 d to 40 d (T-40), respectively. The results showed that R-100 could delay the browning by inhibiting two direct pathways of oxidative decomposition of VC and oxidation-polymerization of polyphenols, but T-40 could lead to an increase in degree of browning for which primary determinant was the interaction between polyphenol and reducing sugar, while Y-6 had no obvious effect on browning pathway and determinants. R-100 was thus deemed to be a good measure with inhibiting non-enzymatic browning in DS during storage.

Topics: Ascorbic Acid; Carbohydrates; Fermentation; Furaldehyde; Maillard Reaction; Nitrogen; Oxidation-Reduction; Polyphenols; Vegetables

As a flavor and quality parameter, furfural has potential undesirable effects. This study aimed to elucidate furfural formation, including generation, pathways, and possible precursors during the production of Zhenjiang aromatic vinegar. A cereal vinegar model, rich in saccharides, amino acids, and organic acids, was used to explore the potential precursors. Furfural and 5-hydroxymethylfurfural (HMF) mainly generated during the decoction process, but the HMF also increased during the aging process. Three pathways were found to coexist for the formation of furfural: (i) the Maillard reaction induced by saccharides and nitrogenous compounds, (ii) the direct cleavage of pentose, and (iii) indirect conversion from pentosan, which only made a minor contribution. Furfural was not formed from HMF or l-ascorbic acid in vinegar. Instead, ribose, xylose, arabinose, galacturonic acid, glucuronic acid, and pentosan were the main precursors. These insights may be useful for the risk/benefit balance and improve the flavor quality and safety.

Topics: Acetic Acid; Amino Acids; Ascorbic Acid; Chromatography, High Pressure Liquid; Furaldehyde; Spectrophotometry, Ultraviolet; Sugars; Uronic Acids

Among popular crops, plum (

Topics: Anthocyanins; Antioxidants; Ascorbic Acid; Chromatography, Liquid; Desiccation; Flavonols; Fruit; Fruit and Vegetable Juices; Furaldehyde; Mass Spectrometry; Phenols; Plant Extracts; Polyphenols; Powders; Prunus domestica; Quality Control

Papaya has been identified as a valuable source of nutrients and antioxidants, which are beneficial for human health. To preserve the nutritional properties after drying, appropriate storage specifications should be considered. This study aimed to investigate the quality and stability of air-dried papaya in terms of quality dynamics and behavior of bio-active compounds during storage for up to 9 months in two packaging materials: aluminum laminated polyethylene and polyamide/polyethylene. Samples with moisture content (MC) of 0.1328 g g(-1) and water activity (aw) of 0.5 were stored at 30 °C and relative humidity (RH) of 40-50%. The MC, aw, degree of browning (DB) and 5-hydroxymethylfurfural (HMF) content were found to notably increase as storage progressed. On the contrary, there was a significant decrease in antioxidant capacity (DPPH, FRAP and ABTS), total phenolic (TP) and ascorbic acid (AA) contents. Packaging in aluminum laminated polyethylene under ambient conditions was found to better preserve bio-active compounds and retard increases in MC, aw and DB, when compared to polyamide/polyethylene.

Topics: Antioxidants; Ascorbic Acid; Carica; Desiccation; Food Packaging; Food Preservation; Food Storage; Furaldehyde; Phenols; Plant Extracts

In this study, samples of coffee honey produced in Espírito Santo State, Brazil, were characterized based on their melissopalynology, physicochemical and nutritional properties, and mineral and caffeine contents. The caffeine content in the nectar from coffee flowers was measured by high performance liquid chromatography (HPLC). Blends of honey were obtained from three Coffea arabica crops, each with 10 colonies of Africanized Apis mellifera. All honey samples contained monofloral (75-78%) pollen belonging to C. arabica. Physicochemical parameters (total acidity, pH, moisture, dry matter, ash, and qualitative hydroxymethylfurfural) were within the approved limits established by EU legislation. Coffee honey contains high levels of ascorbic acid (294.68 mg kg(-1)) and low amounts of total flavonoids (3.51 ± 0.18 mg QE kg(-1)). The most abundant minerals were potassium and calcium (962.59 ± 154.3 and 343.75 ± 25.56 mg kg(-1), respectively). The caffeine content in coffee nectar (1.64 mg kg(-1)) was approximately 8-fold lower than that in honey (12.02 ± 0.81 mg kg(-1)).

Topics: Animals; Ascorbic Acid; Bees; Brazil; Caffeine; Coffea; Flavonoids; Flowers; Furaldehyde; Honey; Pollen

We first reported the role of 5-hydroxymethyl-2-furfural (5-HMF) against hypoxia. Here, we studied the mechanism by using oxygen-dependent degradation domain (ODD)-Luc mice, which are a useful model to probe the stabilization of hypoxia-inducible factor 1α (HIF-1α). Compared with three other compounds that have been reported to have a role in stabilizing HIF-1α, 5-HMF caused stronger bioluminescence, which is indicative of HIF-1α stability in the brain and kidney of ODD-Luc mice. We further demonstrated that the HIF-1α protein accumulated in response to 5-HMF in the brains and kidneys of these mice, as well as in PC12 cells. Additionally, 5-HMF promoted the nuclear translocation of HIF-1α and the transcriptional activity of HIF-1, which was evaluated by detecting vascular endothelial growth factor (VEGF ) mRNA expression. These results suggest that 5-HMF stabilized HIF-1α and increased its activity. Considering the role of proline hydroxylases (PHDs) in negatively regulating HIF-1α stability, we explored whether 5-HMF interacts with the substrates and cofactors of PHDs, such as 2-oxoglutarate (2-OG), Fe(2+) and vitamin C (VC), which affects the activity of PHDs. The result revealed that 5-HMF did not interact with Fe(2+) or 2-OG but interacted with VC. This interaction was confirmed by subsequent experiments, in which 5-HMF entered into cells and reduced the VC content. The enhanced stability of HIF-1α by 5-HMF was reversed by VC supplementation, and the improved survival of mice caused by 5-HMF under hypoxia was abrogated by VC supplementation. Thus, we demonstrated for the first time that 5-HMF increases HIF-1α stability by reducing the VC content, which mediates the protection against hypoxia.

Topics: Animals; Ascorbic Acid; Brain; Furaldehyde; Hypoxia; Hypoxia-Inducible Factor 1, alpha Subunit; Ketoglutaric Acids; Kidney; Luciferases, Firefly; Mice, Inbred C57BL; Mice, Transgenic; PC12 Cells; Protective Agents; Protein Structure, Tertiary; Rats

In view of understanding colour instability of pasteurised orange juice during storage, to the best of our knowledge, this study reports for the first time in a systematic and quantitative way on a range of changes in specific quality parameters as a function of time and as well as temperature (20-42 °C). A zero-order (°Brix, fructose, glucose), a first-order (vitamin C), a second-order (sucrose) and a fractional conversion model (oxygen) were selected to model the evolution of the parameters between parentheses. Activation energies ranged from 22 to 136 kJ mol(-1), HMF formation being the most temperature sensitive. High correlations were found between sugars, ascorbic acid, their degradation products (furfural and HMF) and total colour difference (ΔE(∗)). Based on PLS regression, the importance of the quality parameters for colour degradation was ranked relatively among each other: the acid-catalysed degradation of sugars and ascorbic acid degradation reactions appeared to be important for browning development in pasteurised orange juice during ambient storage.

Topics: Ascorbic Acid; Carbohydrates; Citrus sinensis; Color; Food Storage; Fruit and Vegetable Juices; Furaldehyde; Kinetics; Pasteurization; Temperature

Antioxidant activity, colour and some nutritional properties of hot air and freeze-dried strawberry tree (Arbutus unedo L.) fruits were investigated. Additionally, the effects of two pre-treatments, namely ethyl oleate and water blanching, were compared in terms of drying characteristics. For determination of antioxidant activities in ethanol extracts, two different analytical methods were used: 1,1-diphenyl-2-picrylhydrazyl scavenging activity and β-carotene bleaching activity. As a result, the ethyl oleate pre-treatment shortened the drying time by hot air method and gave a higher 1,1-diphenyl-2-picrylhydrazyl scavenging activity (82.16 ± 0.34%), total phenolic content (7.62 ± 1.09 µg GAE/g extract), ascorbic acid content (236.93 ± 20.14 mg/100 g), besides hydromethylfurfural was not observed. Freeze-dried fruits exhibited higher ascorbic acid content (368.63 ± 17.16 mg/100 g) than those fresh fruits (231.33 ± 19.51 mg/100 g) and nearly 1,1-diphenyl-2-picrylhydrazyl activity (93.52 ± 0.41 %) to fresh fruits (94.03 ± 1.18%). Colour characteristics, sugar content and mineral contents of fruits were significantly affected by pre-treatments and drying methods (p < 0.05). It is concluded that the drying of strawberry tree fruits should bring a valuable and attractive foodstuff to food industry due to the rich nutritional components, antioxidant activity and colour. Another conclusion from this study is that the freeze-drying is the best drying method to keep the nutritional value, antioxidant activity and sensory properties of fruits.

Topics: Antioxidants; Ascorbic Acid; Dietary Carbohydrates; Ericaceae; Food Preservation; Freeze Drying; Fruit; Furaldehyde; Hot Temperature; Kinetics; Minerals; Nutritive Value; Oleic Acids; Pigmentation; Plant Extracts; Sensation; Trace Elements; Turkey

This article reports the characterization of a wild strain of Alicyclobacillus acidoterrestris and describes the implications of the heat resistance of this microorganism in tomato juice. The strain (labeled as A. acidoterrestrisγ4) showed pH and temperature ranges for growth typical of the species (3.0 to 6.0 for the pH and 35 to 60 °C for the temperature); heat resistance in tomato juice was as follows: D(T) values of 40.65, 9.47, and 1.5 min (at 85, 90, and 95 °C, respectively) and z-value of 7 °C. A treatment at 70 °C for 15 min was found to be optimal for spore activation, whereas Malt Extract Agar, acidified to pH 4.5, showed good results for spore recovery. Concerning the implications of heat resistance of A. acidoterrestris on tomato juice, high temperatures required for spore inactivation determined a general decrease of the antioxidant activity (increase of the redox potential and reduction of the chain-breaking activity), but not the formation of brown compounds (namely, hydroxymethylfurfural), thus suggesting an effect on the secondary antioxidants (carotenoids and ascorbic acid) rather than on lycopene.. Alicyclobacillus acidoterrestris is an emerging spore-forming microorganism, capable of causing spoilage in tomato juice. Due to their high thermal resistance, spores could be used as targets for the optimization of heat processing; this article reports on the assessment of thermal resistance of a wild strain of A. acidoterrestris, then focusing on the effect of the thermal treatment necessary to inactivate spores on the quality of tomato juice.

Topics: Alicyclobacillus; Antioxidants; Ascorbic Acid; Beverages; Carotenoids; Colony Count, Microbial; Color; Food Handling; Food Microbiology; Furaldehyde; Hot Temperature; Hydrogen-Ion Concentration; Solanum lycopersicum; Spores, Bacterial

In this work, 7 Spanish honeys with different botanical origins were studied. The honey origins were rosemary, chestnut, lavender, echium, thyme, multifloral, and honeydew. The chemical compounds determined were ascorbic acid (vitamin C), hydroxymethylfurfural, and major sugar contents (glucose and fructose). The physicochemical parameters, pH, conductivity, moisture, free acidity, and color, were also measured. Vitamin C is an important antioxidant in food, and the possibility to use it as discriminate parameter among different honeys was studied. The determination of vitamin C in honey samples was carried out by 2 different methods, volumetric and chromatographic comparing the results by both statistically. Vitamin C content was higher in thyme honeys than in the other types; however a wide dispersion in the values was found. Through a linear discriminant analysis (LDA), conductivity, glucose, fructose, and vitamin C content were the most important discriminant parameters.. Vitamin C content in different honey sources has been determined by a simple and rapid chromatographic method (less than 3 min) in honeys from 6 botanical origins. The results together with glucose and fructose content and some physicochemical parameters have been studied in order to discriminate the botanical origin of honeys and in the future certified their quality. A statistical LDA was applied to the data, and differentiation of honey sources was possible with very good agreement. The vitamin C content found in thymus honeys was significantly higher than in other types. This fact makes vitamin C a special marker for thymus honeys that have a higher antioxidant effect than the others giving it special properties. The identification of honey sources is essential for beekeepers in order to certify honeys for consumers.

Topics: Antioxidants; Ascorbic Acid; Chemical Phenomena; Chromatography, High Pressure Liquid; Discriminant Analysis; Electric Conductivity; Fructose; Furaldehyde; Glucose; Hexoses; Honey; Hydrogen-Ion Concentration; Quality Control; Spain; Thymus Plant; Water

Jams and marmalades are often wrongly believed to be stable products, as the degradation of pigments such as anthocyanins, browning reactions, and the formation of sugar degradation products may occur during storage. The paper aims at studying some of the degradation reactions occurring in blood orange marmalade stored at 20 °C and 35 °C. The addition of natural (tea extract) and naturally occurring (ascorbic acid, cysteine, gallic acid) compounds to marmalade was addressed at investigating the possible effect on retarding such phenomena. Results highlight the dependence of anthocyans and 5-hydroxymethyl-2-furaldehyde (HMF) levels on the storage temperature. Marmalades added with cysteine, unlike the samples added with phenol compounds, showed higher anthocyans and lower HMF levels just after processing, together with a reduced anthocyan loss kinetics and a slowdown of HMF formation during storage at both temperatures.. Transformation of blood oranges into marmalade represents an alternative to fresh market in periods when the high availability of the citrus causes the collapse of prices. Blood orange marmalade is characterized by a high nutritional value, however, it is not widely distributed yet. Its storability is limited by color and organoleptic changes that influence consumers' acceptance. The optimization of blood orange marmalade preparation could help producers improve storability and widen distribution.

Topics: Anthocyanins; Ascorbic Acid; Citrus sinensis; Color; Cysteine; Food Additives; Food Handling; Food Preservation; Fruit; Furaldehyde; Gallic Acid; Maillard Reaction; Tea; Temperature

The presence of ascorbic acid (AA), vitamin C (AA + dehydroascorbic acid (DHAA)) and furfural as potential precursors of furan in commercial fruit and vegetable jarred baby food was studied. Hydroxymethylfurfural (HMF) was also determined and used, together with furfural levels, as markers of thermal damage. AA, calculated DHAA and vitamin C values ranged between 22.4 and 103, 2.9 and 13.8, and 32.1 and 113.2 mg/100 g, respectively, in fruit-based baby food. However, no trace of AA was found in the vegetable-based baby food samples tested, probably because these samples are not enriched in vitamin C and the content of this vitamin in fresh vegetables is destroyed during processing. Furfural values ranged from not detected to 236 microg/100 g, being higher in vegetable samples than in fruit samples possibly because of greater AA degradation favored by a higher pH in the vegetable samples. HMF values (range: not detected-959 microg/100 g), however, were higher in the fruit samples, probably due to greater carbohydrate content degradation and as a consequence of the Maillard reaction, favored by a lower pH in these samples. According to these results, HMF would be the optimum indicator of thermal treatment for fruits, and furfural for vegetables. The higher furfural content of vegetable baby food could be considered an index of greater AA degradation and, therefore, the furan content might be higher in this kind of sample than in fruit-based baby food.

Topics: Ascorbic Acid; Chromatography, High Pressure Liquid; Dehydroascorbic Acid; Food Handling; Fruit; Furaldehyde; Furans; Hot Temperature; Infant Food; Vegetables

The effects of the physicochemical and quality characteristics of various minimally pasteurized refrigerated orange Spanish juices and their changes with storage time and temperature were investigated. Essential oils, acidity, conductivity, diacetyl index, hydroxymethylfurfural, formol index, viscosity and ascorbic acid varied with storage time more significantly at 10 degrees C than at 4 degrees C. Density, colour and pectinmethylesterase did not vary at 4 degrees C. Some of the parameters could be used as indicators of quality loss or spoilage of the juices. The degradation kinetics of the concentration of remaining ascorbic acid against time follows a straight line whose slope indicates the degradation rate. A period of at least 42 days at 4 degrees C and 35 days at 10 degrees C was established as the shelf life of the juices.

Topics: Amino Acids; Ascorbic Acid; Beverages; Chemical Phenomena; Chemistry, Physical; Citrus; Color; Electric Conductivity; Food Microbiology; Food Preservation; Furaldehyde; Hydrogen-Ion Concentration; Nutritive Value; Oils, Volatile; Refrigeration; Spain; Sterilization; Temperature; Time Factors; Viscosity

Little is known about the individual components of honey that are responsible for its antioxidant activity. The present study was carried out to characterize the phenolics and other antioxidants present in honeys from seven floral sources. Chromatograms of the phenolic nonpolar fraction of the honeys indicated that most honeys have similar but quantitatively different phenolic profiles. Many of the flavonoids and phenolic acids identified have been previously described as potent antioxidants. A linear correlation between phenolic content and ORAC activity was demonstrated (R(2) = 0.963, p < 0.0001). Honeys were separated by solid-phase extraction into four fractions for sugar removal and separation based on solubility to identify the relative contribution of each fraction to the antioxidant activity of honey. Antioxidant analysis of the different honey fractions suggested that the water-soluble fraction contained most of the antioxidant components. Specific water-soluble antioxidant components were quantified, including protein; gluconic acid; ascorbic acid; hydroxymethylfuraldehyde; and the combined activities of the enzymes glucose oxidase, catalase and peroxidase. Of these components, a significant correlation could be established only between protein content and ORAC activity (R(2) = 0.674, p = 0.024). In general, the antioxidant capacity of honey appeared to be a result of the combined activity of a wide range of compounds including phenolics, peptides, organic acids, enzymes, Maillard reaction products, and possibly other minor components. The phenolic compounds contributed significantly to the antioxidant capacity of honey but were not solely responsible for it.

Topics: Antioxidants; Ascorbic Acid; Catalase; Chemical Fractionation; Chromatography, High Pressure Liquid; Chromatography, Liquid; Furaldehyde; Gluconates; Glucose Oxidase; Honey; Mass Spectrometry; Peroxidase; Phenols; Solubility; Water

An HPLC method using a reversed-phase macroreticular PLRP-S column and phosphate buffer as eluent is described for the analysis of L-ascorbic acid degradation products, 5-hydroxymethyl furfuraldehyde and furfuraldehyde, in processed fruit juices. Measurement of the levels of 5-HMF and furfuraldehyde in citrus juices against time showed the presence of 5-HMF (0.45 mg l-1) even at zero time. An assessment on the effect of the additives on the formation of 5-HMF of reconstituted single-strength orange juice showed virtually the same results for all the samples stored at 4 degrees C and 20 degrees C, irrespective of the additive. For citrus juice samples which had been subjected to accelerated degradation, those that showed the highest decomposition of L-ascorbic acid, produced the highest level of 5-HMF. The presence of furfuraldehyde in any of the samples was not detected, probably due to the fact that furfuraldehyde was formed in such small amounts which are below the minimum detectability limit of the method (0.050 mg l-1).

Topics: Acetates; Ascorbic Acid; Beverages; Biotechnology; Chromatography, High Pressure Liquid; Citrus; Furaldehyde