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1.
5-Hydroxymethylfurfural (HMF) is generated during food and beverage heating processes and/or storage. Its daily intake, estimated as 4–10 mg day?1, is several orders of magnitude higher than other process contaminants. Beer can be of relevance to the evaluation of HMF exposure; however, the information concerning its occurrence in different types of beer and during product storage is scarce. Therefore, the major goal of this work was to assess the amounts of HMF in different commercial beers, as well as the impact of storage, to deepen knowledge about the contribution of beer to HMF exposure. Blonde beers presented a mean content of 4.29 ± 1.05 mg L?1, which was significantly lower (P ≤ 0.05) than those obtained for amber (6.84 ± 0.75 mg L?1) and dark beers (6.99 ± 0.52 mg L?1). Additionally, to study kinetic of HMF formation, fresh pilsner beers were stored at 30, 40 and 50°C during 40 days; a zero-order reaction was observed. The dependence of the rate constant on temperature was described by the Arrhenius equation and calculated activation energy was 101.85 kJ mol?1. Storage can increase drastically HMF content, which means higher exposure for consumers. Thus, beer contribution to HMF exposure should not be neglected, since the intake of 1 L of beer entails a consumption of 4–7 mg of HMF or even more, depending on storage time and temperature.  相似文献   

2.
Anthocyanins present in fruits and vegetables are receiving increased attention because of their potential antioxidant activity but are very susceptible to degradation during processing and storage. Effect of storage on kinetics of anthocyanin degradation and hydroxymethylfurfural (HMF) formation in black mulberry juice and concentrate was determined during 8 months of storage at temperatures of 5°, 20°, 30°, and 40 °C. The monomeric anthocyanin degradation was in accordance with the first-order reaction kinetics and the activation energies of anthocyanin degradation in black mulberry juice and concentrate were found as 56.48 and 49.75 kJ mol?1, respectively. HMF formation in black mulberry juice and concentrate increased linearly with storage time and temperature and followed zero-order reactions. The activation energies of HMF formation in black mulberry juice and concentrate were found as 75.70 and 104.11 kJ mol?1, respectively. The losses of antioxidant activity for black mulberry juice and concentrate during storage at different temperatures were in the ranges of 4.87–16.01 and 4.47–33.57 %, respectively. Antioxidant activity in black mulberry juice and concentrate was correlated with total monomeric anthocyanins.  相似文献   

3.
The effects of high-pressure (HP) treatment (400?MPa at 42 °C for 5 min) and pulsed electric field (PEF) processing (25 kV/cm at 57 °C for 280 μs) on ascorbic acid, total carotenoids, total phenolic compounds and total antioxidant capacity (TEAC and ORAC) of an orange juice–milk (OJ-M) beverage along the storage time at 4 °C were compared with a conventional heat preservation technology used in industry (90 °C for 15 s). During storage, ascorbic acid, total carotenoids and antioxidant capacity (TEAC) depleted with time regardless of the treatment applied. Instead, total phenolic content and antioxidant capacity measured by the ORAC method increased at the end of the storage. Non-thermal-treated beverage had less non-enzymatic browning than the thermally pasteurized one. There were no significant variations in the hidroxymethylfurfural (HMF) content of the HP- and PEF-treated OJ-M, whilst a significant increase was obtained after thermal treatment. During refrigerated storage, HMF was always below the maximum values established. The HP treatments reduced the L* value of the treated beverages immediately after processing and during refrigerated storage and induced an increase in total colour differences of beverages treated by HP compared with PEF and thermally processed orange juice–milk. Hence, alternative methods such as HP and PEF may give new opportunities to develop orange juice–milk with an equivalent shelf life to that of thermally treated orange juice mixed with milk in terms of microbial, physicochemical and nutritional characteristics.  相似文献   

4.
In this study, reaction kinetics of ascorbic acid degradation and hydroxymethylfurfural (HMF) formation in glass-bottled and cardboard-packaged rosehip nectars stored at 25, 35 and 45 °C were evaluated. Variations of total phenolics, total carotenoids, and antioxidant activity of samples were also evaluated. HMF formation followed a zero-order reaction, while a first-order reaction model was fitted to ascorbic acid degradation. The activation energies for ascorbic acid degradation and HMF formation were found as 56–63.9 and 42.9–53.0 kJ mol?1, respectively. During storage, total phenolics content of rosehip nectars were decreased significantly. However, changes in the total carotenoids of rosehip nectars during storage were not statistically significant. Decreases in the antioxidant activity of glass-bottled rosehip nectars during storage at all applied temperatures were found statistically significant, whereas no significant variations were observed in the antioxidant activities of cardboard-packaged rosehip nectars.  相似文献   

5.
To establish the storage conditions for asparagus preparation before ascorbic acid determination, samples were ground, the mass was divided into three aliquots that were, respectively, stored at 4°C, – 18°C, or extracted with 1% oxalic acid. The extract was further split into aliquots and stored at 25°, 4°, –18° and -75°C. Ascorbic acid content was measured at different times of storage by a polarographic method. The rate of degradation increased with storage temperature; the degradation rate was higher in ground samples than in extracts; no significant changes in ascorbic acid content were observed in extracts stored for 7 days at -18° or for 90 days at -75°C.  相似文献   

6.
The influence of temperature (25, 30, 35 and 40 °C) and storage time (up to 62 or 104 days) on colour; hydroxymethyl furfural (HMF) content; and diastase index (ID) of citrus, rosemary, eucalyptus, polyfloral and honeydew honey was evaluated. Decreases in luminosity, whiteness index, hue and chroma with the increase in temperature and storage time were observed to different extents depending on the botanical origin of the honey. At all temperatures, the highest values of chromatic parameters throughout the whole period of storage corresponded to citrus honey. Honeydew honey showed the lowest values and the fewest colour differences. Principal component analysis explained 89% of the variations. PC1 (73%) separated honey types at lower temperatures in terms of colour parameters. PC2 (16%) described variations in HMF and ID in relation to storage conditions. Honey type had a much greater influence on HMF, ID and colour than storage conditions. The evaluated postharvest treatments did not alter the characteristic colour of each type of honey as long as the commercial requirements for freshness parameters were met.  相似文献   

7.
Furfural, hydroxymethylfurfural (HMF), furosine, lactulose, ascorbic acid and absorbance at 284 and 420 nm (A284 and A420) were all determined in two types of liquid infant formula prepared with different processing protocols. These browning indicators were used to assess the effects of storage and modified atmosphere on the shelf‐life of infant formulae. The study was carried out at 20 and 55 °C for 15, 30 and 90 days. At 20 °C, slight browning was observed and could be evaluated by furosine, furfural and total HMF indicators. At 55 °C, formula type A (pasteurised, spray‐dried and reconstituted) showed more browning in nitrogen storage conditions than did type B. Furfural, HMF, lactulose, A284 and A420 are useful indicators to control the extent of browning reactions in adverse storage conditions. © 2002 Society of Chemical Industry  相似文献   

8.
Packaging Effects on Applesauce in Multilayer Polymeric Films and Glass   总被引:1,自引:0,他引:1  
Four different multilayer polymeric films were assessed for suitability as packaging materials for hot-filled fruit products, by determining the effect of storage time and temperature on applesauce packaged in each film type, as compared to glass. Applesauce from each package type was assessed at S wk intervals for changes in sensory and analytical characteristics during 15 wks storage at 20°, 30°, 37° and 43°C. Films containing an ethylene vinyl alcohol or polyvinylidine chloride layer performed similarly to glass. Applesauce packaged in a nylon/ linear low density polyethylene film was less acceptable and had significantly greater browning at all temperatures.  相似文献   

9.
In this paper, the 5-hydroxymethylfurfural (HMF) contents of the acacia honeys after heat treatment were determined by HPLC; the kinetics of HMF formation was also investigated. The HMF content of acacia honey was 0.38±0.01mg/kg, but rapidly increased to the maximum of 18,320.07±14.29 mg/kg at 190°C and decreased to 1,180.24±6.54 mg/kg at 230°C after heating. The HMF content increased gradually in honey samples heated in 12 h at the temperature of 80, 100, and 120°C. The apparent frequency constant was k f =3.91×1025/h, and the apparent activation energy was E a=173.10 kJ/mol. The HMF content in the acacia honey was related to honey composition, heating temperature, and time, and the HMF formation could also be related to the initial honey pH.  相似文献   

10.
Oxidative rancidity in fresh and stored ground beef samples was measured using a thiobarbituric acid (TBA) assay with antioxidant protection. The independent variables were fat concentration (15 or 30%), package type (polyethylene or vacuum-packaged), freezer storage temperature (-12.2°, -23.3° or -34.4°C) and storage time (4, 8, 12, 16, or 20 weeks). At the end of each storage time samples were thawed and TBA values were determined on the samples before and after cooking. TBA values increased during the first 12 to 16 weeks after which time it decreased for both the cooked and uncooked samples. The higher fat samples, packaged in polyethylene, had higher TBA values for both cooked and uncooked patties. Uncooked patties stored at - 12.2°C had higher TBA values than those stored at -23.3°C or -34.4°C but cooked sample TBA values showed no dependence on storage temperature.  相似文献   

11.
The purpose of this research was to determine the effects of the packaging materials and size on the stability of monomeric anthocyanins, polyphenols, antioxidant activity, ascorbic acid, colour index and hydroxyl methyl furfural (HMF) during the 12‐month shelf life of sour cherry nectars at 4 °C and 20 °C. Sour cherry nectars were aseptically filled out into packaging of different sizes and materials. The packaging included cartons of two different sizes (200 and 1000 mL) and aluminium cans (330 mL). Results showed that the nectars were of better quality when stored at lower temperatures. HMF generally increased significantly for all nectars during storage. Conversely, the total polyphenol content and the antioxidant activity of the nectars stored in aluminium cans and the larger‐sized carton packaging decreased during storage. Lower anthocyanin loss and colour change were found in the nectars stored in aluminium cans. However, the better packaging material was found to be the large‐sized carton package when HMF was analysed.  相似文献   

12.
In this study, the effects of storage temperature (10, 20, and 37°C) and time (0, 2, 4, and 6 months) on the HMF and color values in strawberry, cherry and apricot jams were studied. Results showed that the HMF and total color difference (ΔE) values of all jams were increased linearly with storage time and higher values were found at higher storage temperature. Kinetic model was applied to changes in HMF and ΔE. Changes in HMF and ΔE were explained using zero-order reaction kinetics and the dependence of the rate constant on temperature was described by the Arrhenius equation  相似文献   

13.
Aging of cream is an important process to manage production time and to produce butter with consistent quality. The objective of this study was to evaluate the combined effect of temperature (5, 10, and 15°C) and agitation rate (0, 40, and 240 rpm) during aging of cream on the physical properties of cream and butter in a model system. Cream's solid fat content (SFC), melting behavior, and droplet size distribution were measured during and after 90 min of aging. Butter physical properties such as melting behavior, water content, and hardness were measured. The effects of agitation on SFC and droplet size are dependent on aging and churning temperature. Solid fat content increased faster at 5°C, and the maximum SFC was the highest at this temperature. An effect of agitation on SFC was observed only when cream was aged at 15°C. Agitating cream at 40 rpm increased the droplet size regardless of aging temperature. Two melting peaks, medium melting fraction (MMF) and high melting fraction (HMF), were found in cream samples aged at 5 and 10°C, but only a HMF melting peak was seen in the cream aged at 15°C. The enthalpy of MMF in the cream aged at 10°C with 40 rpm and without agitation was significantly lower than that in samples aged at 5°C regardless of agitation rate. Butter can be formed only from cream aged under certain conditions during 14.5 min of churning, which are 5°C with high agitation and 10°C regardless of agitation level. Butter produced with cream aged at 5°C with high agitation showed significantly higher MMF and total enthalpy values. However, no significant difference in enthalpy values was observed among the butter samples made from the cream aged at 10°C. Further crystallization of MMF occurred in the butter produced with cream aged at 10°C during 24 h of storage at 5°C, whereas no further crystallization occurred in the butter made with the cream aged at 5°C with high agitation. The hardest butter was obtained when cream was aged at 5°C with 240 rpm and at 10°C with 40 rpm. Softer butter was obtained when cream aged at 10°C with 240 rpm was used. This butter also had the highest water content. This study shows that butter hardness can be tailored by changing the aging conditions of the cream. Cream can be aged at higher temperature with low agitation without altering the hardness of butter. These results will help dairy producers to optimize butter making processes to obtain desired properties in the final product.  相似文献   

14.
The quality and biochemical properties of honey are affected by heating or during storage period. The most important biochemical reaction that occurs in this process is the Maillard reaction. HMF (5-hydroxymethylfurfural) is one of the major intermediate products in the Maillard reaction that can lead to quality reduction in heated honey. In this study, the effect of heating on the antioxidant activity, and colour values as Maillard reaction indicators of three different botanical honeys were investigated; the HMF formation was also determined. Temperatures of 50, 70 and 80 °C were applied on the honeys between 0 and 48 h. Total phenolic content, ferric reducing/antioxidant power and scavenging of 2,2-diphenyl-1-picrylhydrazyl free radical assays are used to determine the antioxidant capacity. Results showed that the formation of HMF and the antioxidant properties of honeys were significantly increased during the heating process. Pure HMF compound also showed lower antioxidant activity. The formation of HMF has higher degree of linearity in the fit of the zero order reaction and also it was the highest in the chestnut honey. Furthermore, it was found that as the biochemical value of the honeys increased, the HMF formation decelerated.  相似文献   

15.
Fresh ginseng (Panax ginseng) was packaged with LDPE and PVC films. The respiration rates of fresh ginseng were determined in modified atmosphere packaging (MAP) at 0, 10 and 20 °C. The changes in chemical compositions were also measured before and after storage. The results showed that respiration rates of fresh ginseng were suppressed more effectively in MAP, especially in a poly(vinyl chloride) (PVC) package. The storage life of fresh ginseng was significantly extended with better appearance and firmness for 210 days. The decay rate was only 1.3% and 1.0% in both low density polyethylene (LDPE) and PVC film package after 210 days of storage at 0 °C, respectively. The results of saponin analysis indicated that the contents of total saponin were not changed much in all treatments. Reducing sugar was increased by 2.7 to 5.3 times, while pectin decreased by 1.1 to 1.4 times after 210 days of storage at the range of 0–20 °C. Total sugar content also increased during storage, especially in LDPE packages and high temperature. It was considered that MAP was very effective storage method for keeping quality better with minimal quality loss and lower decay rate at lower temperature. Copyright © 2005 Society of Chemical Industry  相似文献   

16.
BACKGROUND: The quality of honey can be affected by practices such as adulteration, inadequate storage or the application of severe heat treatments. Because hydroxymehylfurfural (HMF) is an indicator of honey freshness and furosine (ε‐2‐furoylmethyl lysine) has proved to be a useful chemical indicator of the progress of the Maillard reaction in foods, the aim of this work was to assess their usefulness as indicators of fresh honey quality. The effect of heat treatment, storage and adulteration with different types of syrups on HMF and furosine content has been studied. RESULTS: In fresh honey, HMF and furosine values ranged from 0.9 to 14.6 mg kg?1 of product and from 3.06 to 12.06 g kg?1 of protein, respectively. Heating of honey samples with different pH (3.76 and 5.14) produced slight increases in HMF content and negligible changes were detected in furosine values. The storage of fresh honey for 2 years caused a high increase in the HMF level, reaching values above EU limits. However, furosine showed a different behavior depending on the type of honey sample. Adulteration assays using different syrups produced an increase in HMF and a decrease of furosine values by dilution effect. HMF content of adulterated honey samples with syrup of known origin did not exceed EU limits. CONCLUSION: These results show the influence of long periods of storage or adulteration, using different percentages of corn or invert sugar syrups, on HMF and furosine content of fresh honey. This seems to indicate that the combination of HMF and furosine may be useful for evaluating the quality of fresh honey. Copyright © 2009 Society of Chemical Industry  相似文献   

17.
《Food chemistry》2004,85(4):605-609
Simultaneous formation of hydroxymethylfurfural (HMF) and furosine (Fu) during the storage of three batches of jam samples (one commercial and two laboratory prepared) and one of fruit-based infant food (commercial), at 20 and 35 °C during 12 months, was investigated to evaluate the reliability of the combination of both parameters as quality indicators. In general, the concentration of both indicators increased with time and temperature of storage, formation of furosine being less temperature dependent than that of HMF. HMF was proved to be a good indicator of the severity of heating during manufacture and/or inadequate temperature during prolonged storage, whereas furosine may be a useful indicator of the storage conditions. The combination of both indicators can afford important information on the quality of jams and fruit-based infant foods during processing and storage.  相似文献   

18.
《Food chemistry》1999,67(4):389-397
A comparison between physico-chemical, enzymatic activities and rheological properties of Helianthus annuus and Eucalyptus lanceolatus honey was made. Eucalyptus lanceolatus honey showed higher protein, diastase and catalase activity than Helianthus annuus honey, while proline, conductivity, total acidity, free acids and lactone content were higher in Helianthus annuus honey. Consistency coefficient and activation energy for flow were lower for Helianthus annuus than Eucalyptus lanceolatus honey. Confirmation of monofloral origin of honey types was accomplished through microscopic examination. The effects of convective and microwave heating on hydroxymethylfurfural (HMF) formation in both honey types were also investigated. Total acidity, free acids and lactone content increased in both honey types during heating. HMF formation varied linearly with temperature and time of heating in both honey types. Microwave heating of both honey types also caused an increase in HMF formation. Effect of storage of honey, heated under different conditions, on HMF content was also investigated. Statistical analysis revealed that storage duration had the greatest effect on HMF formation, followed by heating duration and heating temperature, in Helianthus annuus honey, while heating duration showed the most pronounced effect, followed by heating temperature and duration, in Eucalyptus lanceolatus honey.  相似文献   

19.
HPLC-DAD was used to monitor the evolution of potential and free furfural compounds (5-hydroxymethyl-2-furaldehyde, HMF; 2-furaldehyde, F; 2-furyl methyl ketone, FMC; and 5-methyl-2-furaldehyde, MF) over the shelf life of two types of infant powder formula: one supplemented with long-chain polyunsaturated fatty acids (LC-PUFA) in the form of microencapsulated fish oil (MFO), the other not supplemented with LC-PUFA. Following production, the formulae were stored at 25 and 37 °C. The initial furfural content in the supplemented formula was as follows: potential HMF (485.88 μg/100 g), potential F (167.13 μg/100 g), and free HMF (58.23 μg/100 g), while free F was not detected. In the unsupplemented formula, the following values were recorded: potential HMF (515.85 μg/100 g), potential F (170.29 μg/100 g), free HMF (84.92 μg/100 g), and free F (1.19 μg/100 g). In general, increased furfural content was observed during storage, an increase more pronounced in formula stored at 37 °C. Hardly any differences in furfural evolution during storage were observed between supplemented and unsupplemented infant formulae. The results suggest that the uses of MFO material for supplement formula not affected furfural formation. Neither FMC nor MF was formed in the formulae studied.  相似文献   

20.
The present study aimed to investigate the effect of recipe and temperature–time on the formation of acrylamide and 5-hydroxymethylfurfural (HMF) during biscuit baking. Baking experiments were performed with biscuits of two different recipes, with and without NaCl, at 180 °C, 190 °C and 200 °C. Acrylamide and HMF reached highest concentrations at 200 °C for both recipes. The presence of NaCl in the biscuit formulation lowered acrylamide concentrations at 180 °C and 190 °C but not at 200 °C, and led to higher concentrations of HMF at all the tested temperatures. Sucrose hydrolysis was a key step in acrylamide and HMF formation during biscuit baking, even though a significant amount of acrylamide already had formed before the onset of sucrose hydrolysis. A lag phase was observed before sucrose hydrolysis occurred, which might depend on the melting of crystalline sucrose occurring at approximately 180 °C.A mathematical model based on the chemical reaction pathways was developed for the recipe with NaCl baked at 200 °C. The model described the chemical evolution during the last part of biscuit baking, and accurately predicted acrylamide and HMF content at the end of baking. The model showed the significant contribution of the reducing sugars to the formation of both acrylamide and HMF. The model could not be extended to the entire baking period because it was not possible to incorporate the lag phase observed before sucrose hydrolysis. The results reported in this study confirm that the kinetics of acrylamide and HMF formation in real food and dry systems may depend on the physical state of their precursors.  相似文献   

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