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1.
The antibrowning and antimicrobial activities of the water-soluble extract from pine needles of Cedrus deodara (CDE), a traditional Chinese medicine and raw materials of pine needle tea, was investigated. Total phenols of CDE were 31.4 ± 0.53 mg gallic acid equivalent/g, and total flavonoids were 23.1 ± 0.79 mg rutin equivalent/g. CDE showed a strong antioxidant activity against ABTS free radicals with IC(50) (the half-inhibitory concentration) of 25.5 ± 0.64 μg/mL. In mushroom tyrosinase inhibitory assay, IC(50) values were 2.1 ± 0.98 and 2.27 ± 0.93 mg/mL for monophenolase and diphenolase, respectively. Evaluated by detecting changes of L* (indicated the darkness of sample), a* (indicated the redness of sample), and b* (indicated the yellowness of sample) values in fresh-cut apple slices model, CDE showed a significant antibrowning effect when compared with ascorbic acid. In addition, it was discovered that CDE in combination with 0.5% ascorbic acid exhibited a synergistic antibrowning effect. Meanwhile, CDE was observed to show a potent antimicrobial effect on all of the tested Gram-positive and Gram-negative bacteria. In conclusion, the results of the present research suggested that pine needles of C. deodara could be used as a natural resource of antibrowning and antimicrobial agents in food preservation. PRACTICAL APPLICATION: The present study provides a theoretical basis for the potential application of pine needles of C. deodara to be used as a natural resource of antibrowning and antimicrobial agents in food industry.  相似文献   

2.
ABSTRACT:  Polyphenoloxidase (PPO) and peroxidase (POD) were evaluated in fresh-cut Fuji apple slices and the effect of the individual or combined use of ascorbic acid, 4-hexylresorcinol, N-acetylcysteine, and glutathione on their respective activities was determined. Additionally, color changes during storage at 4 °C were measured throughout 14 d of storage. PPO activity increased with storage time and was inhibited by the individual use of N-acetylcysteine and glutathione. POD activity in the apple slices was effectively inhibited by the combined use of ascorbic acid with any of the other antibrowning agents. On the other hand, an individual treatment with 1% N-acetylcysteine helped in maintaining the color of fresh-cut apples during 14 d of storage, whereas the use of ascorbic acid was not enough to prevent color deterioration of the apple slices from the 1st day of storage. The results obtained corroborated the effectiveness of other natural antibrowning agents over the traditional use of ascorbic acid in the control of the enzymatic browning in the fresh-cut fruit industry.  相似文献   

3.
可食性复合涂膜保鲜剂对延长鲜切苹果货架期的研究   总被引:3,自引:0,他引:3  
曾文兵 《食品科学》2006,27(2):262-265
本文主要研究了可食性涂膜剂与抗褐变剂复配后对鲜切苹果的保鲜效果。研究表明:25℃条件下,苹果切块经卡拉胶(0.5%)涂膜剂和乳清浓缩蛋白WPC(5%)涂膜剂处理后,其呼吸强度可分别降低5%和20%。在可食性涂膜剂中添加不同的抗褐变剂对苹果切块有良好的护色效果,添加1%CaCl2可增加产品的硬度,同时这些复合保鲜剂可提高苹果切块的感官指标和抑制微生物繁殖,而5%WPC涂膜液+1%CaCl2+1%抗坏血酸复合液浸泡苹果切块,3℃条件下贮藏2w后保鲜效果最佳。  相似文献   

4.
The present study examined various types of Maillard reaction products (MRPs) for their inhibitory effect on mushroom tyrosinase. Results showed that monosaccharide–GSH (glutathione) but not polysaccharide–GSH derived MRPs were more active than GSH in inhibiting mushroom tyrosinase. However, in fresh-cut apple slice model, surprisingly GSH performed much better than sucrose–GSH derived MRPs when the apple slices were stored at room temperature for 24 h. Further time-course study did find deterioration in tyrosinase mushroom inhibitory activity of sugar–GSH derived MRPs over time, suggesting the formed tyrosinase inhibitors in MRPs are unstable. Different combinations of chemical agents with sucrose–GSH derived MRPs were also investigated on apple slices. A synergistic effect was observed when sucrose–GSH derived MRPs (3.125 mM) were applied in combination with 0.5% ascorbic acid. Apart from instability of principal inhibitors, observation of an unpleasant odor from apple slices treated with MRPs raised another concern about the probable negative impact of these inhibitors on the sensory quality of food products. Our research indicates the limited application of MRPs as antibrowning agents for food products.  相似文献   

5.
This article focuses on finding the novel antibrowning agents from the pine needles of Cedrus deodara and studying its antibrowning effect. By bioassay guide of tyrosinase inhibitory activity, the main active compound was isolated and purified from 50% methanol extract of pine needles of C. deodara through macroporous resin Diaion HP‐20 column chromatography and high‐performance liquid chromatography. Based on mass and nuclear magnetic resonance data, the active compound was identified as 2R,3R‐dihydromyricetin, which showed the potent monophenolase and diphenolase inhibitory activities. Moreover, 2R,3R‐dihydromyricetin exhibited a strong ABTS radical scavenging activity with a dose‐dependent manner. The antibrowning efficacy of 2R,3R‐dihydromyricetin was evaluated by monitoring the changes of L*, a*, and b* values and total color difference (△E) on fresh‐cut apple slices. It was found that 2R,3R‐dihydromyricetin was effective in inhibiting the browning of apple slices treated with a concentration as low as 0.05% at 25 °C for 24 h. Its antibrowning effect was significantly better than ascorbic acid (0.5%) alone. Furthermore, 2R,3R‐dihydromyricetin showed a good synergistic antibrowning effect with ascorbic acid. This is the first report that 2R,3R‐dihydromyricetin from pine needles of C. deodara may be used as a potential antibrowning agent in protecting against food browning.  相似文献   

6.
This research studied the influence of treatment with ascorbic acid, citric acid, and calcium lactate dipping and cassava starch edible coatings on quality parameters and shelf life of fresh-cut pineapple in slices during 12 d at 5 °C. After previous tests, the treatments selected for this study were samples dipped into antibrowning solution with 0.5% of ascorbic acid and 1% of citric acid, with and without 2% of calcium lactate and coated with 2% of cassava starch suspensions. Changes in weight loss, juice leakage, mechanical properties (stress at failure), color parameters (L* and H*), ascorbic acid content, sensory acceptance, and microbial growth of fruits were evaluated. Samples only treated with antibrowning agents were used as control. Edible coatings with and without calcium lactate were efficient in reducing weight loss, juice leakage, and maintaining firmness during storage. However, these samples showed more browning and the ascorbic acid content was reduced. All treatments presented good sensory acceptance (scores above 6). The determining factor of shelf life of pineapple slices was the microbial spoilage. A shelf life of 8 d was obtained for pineapple slices only treated with antibrowning agents. On the other hand, coated samples showed a reduced shelf life of 7 d and higher yeast and mold growth. Thus, although cassava starch coatings were efficient in reducing respiration rate, weight loss, and juice leakage and maintained mechanical properties, these treatments were not able to increase the shelf life of minimally processed pineapple. Practical Application: Pineapple fruit is highly appreciated for its aroma, flavor, and juiciness, but its immediate consumption is difficult. Therefore, pineapple is a potential fruit for minimal processing. However, shelf life of fresh-cut pineapple is very limited by changes in color, texture, appearance, off-flavors, and microbial growth. The use of edible coatings as gas and water vapor barrier and antibrowning agents can extend the storage time and maintain the quality of fresh-cut produce. Cassava starch and alginate coatings are alternative to preserve minimally processed pineapples without changing the quality parameters of fresh fruit. Thus, this study is useful for consumers and fresh-cut industry interested in knowing factors affecting shelf life and quality of fresh-cut pineapple.  相似文献   

7.
ABSTRACT:  The effect of ripening state, modified atmosphere, and the use of antibrowning agents was investigated in an attempt to determine optimum ripeness and processing conditions for extending the shelf-life of fresh-cut Fuji apple. Apples were classified in 3 groups: mature-green, partially ripe, and ripe; after peeling and slicing, fruits were treated with 1% (w/v) N -acetylcysteine, or 1% (w/v) ascorbic acid (control), and then packed into polypropylene trays with air or a gas mixture (2.5% O2+ 7% CO2+ 90.5% N2) and sealed. Trays containing the apple slices were stored in darkness at 4 °C ± 1 °C and analyzed periodically during 43 d. Changes in atmosphere composition, color, and firmness were examined. Partially ripe apples, based on their lower ethanol production and maintenance of their original color and firmness, were the most suitable to prepare the fresh-cut commodities. A postcutting dip in 1% (w/v) N -acetylcysteine was the most effective treatment to prevent cut surface browning and preserve the initial appearance of Fuji apple slices during more than 1 mo at 4 °C. Low O2 and elevated CO2 (2.5% O2+ 7% CO2) atmosphere extended the shelf life of apple slices because of a significant inhibition of ethylene production.  相似文献   

8.
R. Yoruk    S. Yoruk    M.O. Balaban    M.R. Marshall 《Journal of food science》2004,69(6):E281-E289
ABSTRACT: Relative antibrowning potency of oxalic acid on banana and apple slices was investigated using a machine vision system. Degree of browning on fresh-cut surfaces was evaluated visually and quantitatively by observing changes of CIE L * values and evaluating temporal changes in color spectra based on experimental variables, oxalic acid concentration, and storage time. Browning inhibition was most prominent on banana and apple slices treated with oxalic acid solutions at concentrations of 60 and 5 m M , respectively. Oxalic acid was a more potent antibrowning agent compared with other structurally related acids. Average residual oxalic acid levels in the tissues for an effective antibrowning activity were measured.  相似文献   

9.
壳聚糖涂膜对鲜切苹果品质的影响   总被引:1,自引:0,他引:1  
以山东红富士苹果为原材料,研究了不同浓度复合的壳聚糖、抗坏血酸及柠檬酸对鲜切苹果的外观和内部品质的影响。采用L9(34)正交实验设计,测定了贮藏过程中各组鲜切苹果的腐烂率、色泽、pH、可滴定酸、还原性糖等指标的变化情况。根据模糊权重法对贮藏4d的鲜切苹果外观和内部品质进行了综合评定。结果表明:选用2.0%柠檬酸、1.0%壳聚糖配制涂膜液和0.5%抗坏血酸溶液作为护色液,对鲜切苹果具有良好的保鲜效果。  相似文献   

10.
ABSTRACT: Although ionizing radiation effectively inactivates food-borne bacterial pathogens in fresh-cut fruits and vegetables, it may adversely affect product quality. In this study, the effects of calcium ascorbate (CaA) and ionizing radiation on quality of 'Gala' apple slices under modified atmosphere packaging were investigated. 'Gala' apple slices, treated with water or 7% CaA followed by either nonirradiation (0 kGy) or irradiation at 0.5 and 1.0 kGy, were stored at 10°C for up to 3 wk. The titratable acidity, pH, firmness, ascorbic acid content, color, and microflora population were measured weekly throughout storage. Irradiation did not affect titratable acidity and pH of sliced apples. Fruit slices softened during irradiation and storage, but this decrease in firmness during storage was reduced by the CaA treatment. Although the ascorbic acid content of apple slices treated with CaA decreased rapidly during storage, the ascorbic acid content was always higher in those treated samples than in the apple slices treated with water. Irradiation decreased both L * and hue values of apple slices. Hue values decreased during the entire storage period while L * increased during the 1st wk of storage, then decreased between 1 to 3 wk of storage. CaA increased L * and hue values of apple slices, suggesting CaA reduced browning, even in irradiated samples. The microflora population of apples slices was not affected by CaA, and CaA treatment did not alter the reduction in microflora by irradiation. The combination of CaA and irradiation enhanced microbial food safety while maintaining quality of fresh-cut apple slices.  相似文献   

11.
《Food chemistry》2001,73(1):23-30
A comprehensive study to evaluate the relative antibrowning activity of 36 known compounds was conducted. Five chemical groups, including carboxylic acids, ascorbic acid derivatives, sulfur containing amino acids, phenolic acids and other miscellaneous compounds, were tested on apple slices under the same conditions. Among the compounds tested, oxalic acid, oxalacetic acid, ascorbic acid-2-phosphate, cysteine, glutathione, N-acetylcysteine, kojic acid and 4-hexyl resorcinol belonged to a group that showed the highest inhibitory activity on apple browning. The minimal concentrations of oxalacetic acid, oxalic acid, cysteine and kojic acid, for an effective antibrowning activity, were 0.25, 0.05, 0.05 and 0.05%, respectively. Oxalic acid showed a synergistic effect when 0.02% oxalic acid was used with 1% ascorbic acid or its derivatives.  相似文献   

12.
Cedrus deodara is a large evergreen tree of the family Pinaceae and widely distributed to the west of Himalayas. Its pine needles are consumed as a traditional food and perceived as a valuable source for bioactive compounds. A recent study has demonstrated Cedrus deodara pine needle extract (CDE) can inactivate tyrosinase. However, possible action mechanism and application of the extract have not been elucidated. In the present study, the application of CDE in food industry was explored using a fresh-cut apple slice model. Through evaluating the variation in a*, b* and L* values, the browning extent of apple slices was found to be inhibited by CDE. Moreover, in order to explore the antibrowning mechanism, we investigated the antioxidant and antibrowning capacities, total phenolic and flavonoid contents and the major bioactive constituents of the extract. It was found CDE showed strong antioxidant activity to scavenge ABTS (SC50, 24.33 μg/mL) and DPPH (SC50, 35.94 μg/mL) radicals, inhibited monophenolase (IC50, 0.76 ± 0.08 mg/mL) and diphenolase (IC50, 1.01 ± 0.09 mg/mL) activities and contained high content of phenolics (76.39 ± 2.27 mg gallic acid equivalent/g extract) and flavonoids (33.23 ± 3.25 mg rutin equivalent/g extract). Furthermore, according to the bioassay-guided isolation and the analysis of high-performance liquid chromatography–mass spectrometry and nuclear magnetic resonance, methylconiferin and ferulic acid-β-d-glucoside were determined to be the main active compounds. The current results provided the possible antibrowning mechanism of CDE and confirmed C. deodara pine needles might be a natural resource for preparing antibrowning agents of vegetables and fruits in food industry.  相似文献   

13.
ABSTRACT: There are few available compounds that can both control browning and enhance microbial safety of fresh‐cut fruits. In the present study, the antibrowning ability of sodium acid sulfate (SAS) on “Granny Smith” apple slices was first investigated in terms of optimum concentration and treatment time. In a separate experiment, the apple slices were treated with water or 3% of SAS, calcium ascorbate, citric acid, or acidified calcium sulfate for 5 min. Total plate count, color, firmness, and tissue damage were assessed during a 21‐d storage at 4 °C. Results showed that the efficacy of SAS in inhibiting browning of apple slices increased with increasing concentration. A minimum 3% of SAS was needed to achieve 14 d of shelf life. Firmness was not significantly affected by SAS at 3% or lower concentrations. Antibrowning potential of SAS was similar for all treatment times ranging from 2 to 10 min. However, SAS caused some skin discoloration of apple slices. When cut surface of apple slices were stained with a fluorescein diacetate solution, tissue damage could be observed under a microscope even though visual damage was not evident. Among the antibrowning agents tested, SAS was the most effective in inhibiting browning and microbial growth for the first 14 d. Total plate count of samples treated with 3% SAS was significantly lower than those treated with calcium ascorbate, a commonly used antibrowning agent. Our results suggested that it is possible to use SAS to control browning while inhibiting the growth of microorganisms on the apple slices if the skin damage can be minimized. Practical Application: Fresh‐cut apples have emerged as one of the popular products in restaurants, schools, and food service establishments as more consumers demand fresh, convenient, and nutritious foods. Processing of fresh‐cut apples induces mechanical damage to the fruit and exposes apple tissue to air, resulting in the development of undesirable tissue browning. The fresh‐cut industry currently uses antibrowning agents to prevent discoloration. However, the antibrowning solutions can become contaminated with human pathogens such as Listeria monocytogenes, and washing of apple slices with the contaminated solutions can result in the transfer of pathogens to the product. It would be ideal if an antibrowning compound prevented the proliferation of human pathogens in solutions and minimized the growth of pathogens during storage. The study was conducted to investigate antibrowning and antimicrobial properties of sodium acid sulfate (SAS) in comparison with other common antibrowning agents on Granny Smith apples. Results showed that among the antimicrobial agents we tested, SAS was the most effective in inhibiting browning and microbial growth for 14 d at 4 °C. However, SAS caused some skin discoloration of apple slices. Overall, SAS can potentially be used to inhibit tissue browning while reducing the microbial growth on apple slices. The information is useful for the fresh‐cut produce industry to enhance microbial safety of fresh‐cut apples while minimizing browning, thus increasing the consumption of the health benefiting fresh fruit.  相似文献   

14.
Sulfite replacement was investigated in a commercial apple freezing operation: Jonathan and Spy apple slices were vacuum-impregnated in 0.5% or 1% ascorbic acid (LAA) or D-araboascorbic acid (DAA). 0.25% or 0.5% citric acid (CA), 2h NaCl, and 0.25% CaCl2 Treatments with DAA gave color and sensory properties equal to LAA treatments. Slice color was not significantly different between 0.5% and 1.0% ascorbic acid isomers and 0.25% or 0.5% CA. Shear measurements of Jonathan slices were significantly influenced by DAA and citric acid concentrations. Texture of Spy slices was not affected by treatment or storage. This study indicates that DAA may be substituted for more expensive LAA for treating Spy and Jonathan slices prior to freezing.  相似文献   

15.
《LWT》2003,36(3):323-329
Effect of edible coatings in combination with antibrowning agents on minimally processed apple slices was studied during storage at 3°C for 2 week. To control initial respiration rate of apple slices, edible coatings were applied to cut apples as semipermeable barriers against air. Initial respiration rate showed a decrease by 5% and 20% in carrageenan (0.5 g/100 mL)-coated and whey protein concentrate (5 g/100 mL)-coated apples, respectively, at 25°C. Edible coatings in combination with antibrowning agents effectively prolonged the shelf-life of minimally processed apple slices by 2 week when stored in packed trays at 3°C. Addition of various antibrowning agents to these coating solutions was advantageous in maintaining color during storage. Addition of CaCl2 (1 g/100 mL) significantly inhibited the loss of firmness. These edible coatings in combination with antibrowning agents also showed positive sensory analysis results and beneficial reduction of microbial levels. WPC (5 g/100 mL) containing ascorbic acid (1 g/100 mL) plus CaCl2 (1 g/100 mL) was the most effective preservation treatment in terms of sensory quality after 2 week.  相似文献   

16.
研究红花黄酮对鲜切苹果片的保鲜及其保鲜机理.以不同浓度的红花黄酮处理鲜切苹果片,考察对苹果片褐变度、TSS含量和VC 含量的影响,并通过对酪氨酸酶的抑制和清除自由基实验探讨其保鲜机理.结果表明,3.0mg/mL红花黄酮对酪氨酸酶的抑制率为78.03%,同时对DPPH·、O2-·和·OH有较强的清除力.研究说明,红花黄酮对苹果片具有保鲜作用,并推断其可能是通过抑制酪氨酸酶活和抗氧化途径达到保鲜目的.  相似文献   

17.
The effect of antibrowning compounds on the color and firmness of fresh-cut avocado treated with intense light pulses (ILP), as well as their impact on the survival of Listeria innocua, was investigated in this study. Dipping solutions containing 2% (w/v) L-cysteine without ascorbic acid and combined with 1% (w/v) citric acid and 1% w/v calcium lactate most effectively preserved the initial color and texture of ILP-treated fresh-cut avocado. On the other hand, ILP treatments caused a reduction of more than 3 log cycles in the populations of L. innocua inoculated on fresh-cut avocado. Log reduction levels increased when antibrowning agents were combined with ILP treatments. In conclusion, the use of quality-stabilizing agents is a good option to guarantee both the microbiological safety of fresh-cut avocado treated with ILP as well as to improve its physical and chemical quality. PRACTICAL APPLICATION: Intense light pulses (ILP) have received considerable attention during the last years after its approval by the U.S. Food and Drug Administration (FDA) in 1996 as a decontamination method for food or food surfaces. This article presents relevant information regarding the effect of ILP treatments combined with quality-stabilizing compounds as a feasible alternative to improve the physical and chemical quality of fresh-cut avocado as well as to guarantee its microbiological safety.  相似文献   

18.
柠檬酸处理对鲜切苹果的保鲜效果   总被引:3,自引:0,他引:3  
为研究柠檬酸处理对鲜切苹果品质的影响,将鲜切‘寒富’苹果分别放入0.5%、1.0%、1.5%柠檬酸溶液中浸泡2 min后沥干,用0.11 mm厚度的聚乙烯保鲜膜包装后置于4 ℃冷库中贮藏,每2 d检测与成熟衰老相关生理生化指标。结果表明,适当质量分数的柠檬酸处理可保持苹果切块的感官品质,延缓营养物质的下降,抑制微生物的繁殖,对鲜切苹果有较好的护色效果;1.5%柠檬酸溶液浸泡处理能在8 d贮藏期内4 ℃冷藏条件下保持着鲜切苹果的良好品质,能有效延迟果肉褐化进程,降低褐变程度,抑制硬度和可溶性固形物、可滴定酸及抗坏血酸含量的下降,并能延缓相对电导率和丙二醛含量的上升,降低多酚氧化酶、过氧化物酶的活性。  相似文献   

19.
Custard apple pulp treated with 100 ppm ascorbic acid as antibrowning agent and packed in 200 gauge polyethylene was frozen at −25 °C in an alcohol bath and stored at −18 °C in a deep‐freeze. The effect of three cryoprotectants (w/w), namely 0.5% propylene glycol (I), 0.5% glycerol (II) and 2% glycerol + 1% propylene glycol + 10% glucose syrup + 10% maltodextrin (III), on the thawing time of this pulp was studied for a period of 3 months. A control sample without any cryoprotectant was included for comparison. The half‐life for ascorbic acid degradation was monitored in the control pulp and that containing the cryoprotectants. It was found that formulation (III) gave a product that was pourable even on frozen storage and also had the highest half‐life of 75.33 days for ascorbic acid degradation as compared to 34.82 days for the control. © 2000 Society of Chemical Industry  相似文献   

20.
ABSTRACT: Tissue browning and microbial growth are the main concerns associated with fresh-cut apples. In this study, effects of sodium chlorite (SC) and calcium propionate (CP), individually and combined, on quality and microbial population of apple slices were investigated. “Granny Smith” apple slices, dipped for 5 min in CP solutions at 0%, 0.5%, 1%, and 2% (w/v) either alone or in combination with 0.05% (w/v) SC, were stored at 3 and 10 °C for up to 14 d. Color, firmness, and microflora population were measured at 1, 7, and 14 d of storage. Results showed that CP alone had no significant effect on the browning of cut apples. Even though SC significantly inhibited tissue browning initially, the apple slices turned brown during storage at 10 °C. The combination of CP and SC was able to inhibit apple browning during storage. Samples treated with the combination of SC with CP did not show any detectable yeast and mold growth during the entire storage period at 3 °C. At 10 °C, yeast and mold count increased on apple slices during storage while CP reduced the increase. However, high concentrations of CP reduced the efficacy of SC in inactivating E. coli inoculated on apples. Overall, our results suggested that combination of SC with 0.5% and 1% CP could be used to inhibit tissue browning and maintain firmness while reducing microbial population. Practical Application: Apple slices, which contain antioxidants and other nutrient components, have emerged as popular snacks in food service establishments, school lunch programs, and for family consumption. However, the further growth of the industry is limited by product quality deterioration caused by tissue browning, short shelf-life due to microbial growth, and possible contamination with human pathogens during processing. Therefore, this study was conducted to develop treatments to reduce microbial population and tissue browning of “Granny Smith” apple slices. Results showed that an antimicrobial compound, sodium chlorite, is effective in not only eliminating microbes but also inhibiting tissue browning of apple slices. However, the compound caused tissue softening and its antibrowning effect was short-lived, lasting only for a few days. Combination of the compound with a calcium-containing food additive was able to improve firmness and freshness of apple slices while reducing population of Escherichia coli artificially inoculated on samples and inhibiting the growth of yeast and mold during storage.  相似文献   

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