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1.
Phytochemical levels in fruits and vegetables can be affected by several postharvest factors. In the present study, the effect of electron-beam (E-beam) irradiation was studied on grapefruit bioactive compounds. 'Rio Red' and 'Marsh White' grapefruits were irradiated with E-beam at 0, 1.0, 2.5, 5.0, and 10.0 kGy. Changes of various bioactive compounds, such as vitamin C, flavonoids, carotenoids, furocoumarins, and limonoids, were measured. The acidity decreased slightly with an increasing E-beam dose, whereas the total soluble solids were increased. Irradiation did not affect the vitamin C content at 1 kGy; however, doses beyond 1 kGy significantly reduced the vitamin C content. Lycopene and beta-carotene did not change significantly from the irradiation. Lycopene levels decreased as the E-beam dose increased, while the beta-carotene content slightly increased. Dihydroxybergamottin levels exhibited a decreasing trend, while the bergamottin content did not change. Naringin, a major flavonoid of grapefruit, showed a significant increase over the control at 10 kGy in both 'Rio Red' and 'Marsh White'. Nomilin continued to decrease with an increasing dose of E-beam irradiation, while limonin levels remained the same at all of the doses. Low-dose E-beam irradiation has very little effect on the bioactive compounds and offers a safe alternative to existing postharvest treatments for the disinfection and decontamination of grapefruits.  相似文献   

2.
The effect of electron-beam ionizing radiation stress and storage on mango fruit antioxidant compounds was evaluated in a dose range of 1-3.1 kGy. Phenolic high-performance liquid chromatography (HPLC) profiles were not affected right after the irradiation process; however, an increase in flavonol constituents was observed after 18 days in storage (3.1 kGy). Total phenolics by the Folin Ciocalteu method and antioxidant capacity (ORAC) were not affected, while reduced ascorbic acid decreased approximately 50-54% during storage (>/=1.5 kGy). No major changes in carotenoid HPLC profiles indicated a delay in ripening of irradiated mangoes (1-3.1 kGy) compared to nonirradiated fruits. However, irradiation dose >/=1.5 kGy induced flesh pitting due to localized tissue death. A summary of the potential roles of reactive oxygen species generated by the irradiation stress on different antioxidant constituents of mango fruits is presented.  相似文献   

3.
The fruit ripening traits of pawpaw [ Asimina triloba (L.) Dunal] were examined after harvest and after cold storage at -2, 2, 4, and 6 degrees C for up to 12 weeks. Generally, fruits stored at 2-4 degrees C for 4 weeks ripened normally, but those stored at -2 degrees C did not ripen normally, those stored at 6 degrees C were overripe, and by 6-8 weeks those stored at 2-4 degrees C had a lower respiration rate and ethylene production, lower firmness, and lower pH than fruit cold-stored for 4 weeks or less. These changes, and the occasional development of brown discoloration in the pulp once the fruits were moved back to room temperature, were evidence of chilling injury by 6 weeks. After harvest and through 4 weeks of cold storage, the main volatile compounds produced by fruit were methyl and ethyl octanoates and hexanoates. Volatile production significantly increased >5-fold in fruit ripened for 72 h after harvest or after removal from up to 4 weeks of cold storage. Fruit cold-stored for 6 weeks or more produced fewer total volatiles and esters but increased levels of such off-flavor compounds as ethyl acetate, ethyl propionate, and hexanoic and decanoic acids. Alcohol acyltransferase (AAT) activity declined in cold-stored fruit but was not correlated with either total volatile production or total ester production. Alcohol dehydrogenase activity did not change during ripening after harvest or cold storage. Lipoxygenase activity was highest just after harvest or after 2 weeks of cold storage, but was low by 4 weeks. Thus, ripening of pawpaw fruit seems to be limited to 4 weeks at 2-4 degrees C with loss of ability to continue ripening and chilling injury symptoms evident at colder temperatures and after longer periods of cold storage.  相似文献   

4.
Sweet cherry cultivars ('Cristalina' and 'Prime Giant') harvested at commercial ripening stage were treated with salicylic acid (SA), acetylsalicylic acid (ASA) or oxalic acid (OA) at 1 mM and then stored for 20 days under cold temperature. Results showed that all treatments delayed the postharvest ripening process, manifested by lower acidity, color changes and firmness losses, and maintained quality attributes for longer periods than controls. In addition, total phenolics, anthocyanins and antioxidant activity increased in untreated fruit during the first 10 days of storage and then decreased, while in fruits of all treatments, these parameters increased continuously during storage without significant differences among treatments. Thus, postharvest treatments with natural compounds, such as SA, ASA or OA, could be innovative tools to extend the storability of sweet cherry with higher content of bioactive compounds and antioxidant activity as compared with control fruits.  相似文献   

5.
The effect of preharvest calcium (Ca) foliar application on ethylene (C2H4) production, respiratory rate, soluble polyuronides, and fruit firmness of ‘Bebekou’ apricot fruits was determined. The study was carried out in two experimental years, 1991 and 1992. Calcium was applied 21, 17, and 13 days before harvest for 1991 at the concentration of 0.5% calcium chloride (CaCl2) each time and 16 and 12 days before harvest for 1992 at the concentrations of 0.8 and 0.7% CaCl2, respectively. Calcium treatment resulted in a 30–76% increase in the Ca content of fruit flesh. Treated fruits had significantly lower C2H4 production rates than control during (i) four (1991) or five days (1992) at 21°C out of the 7‐day period examined immediately after harvest, and (ii) one (1991) or two days (1992) at 21°C out of the seven‐day period examined immediately after a 3rd‐ (1991) or 4th‐week (1992) storage period at 0°C. After harvest, Ca‐treated fruits displayed one day delay to reach the peak rate of C2H4 production. Respiratory rate was significantly suppressed over a five‐day period at 21°C out of the seven‐day period examined immediately after harvesting. However, after four weeks of storage at 0°C, there was not any significant effect of Ca on the respiratory rate. The respiratory peak rate occurred earlier in the control fruits compared to that of the Ca‐treated fruits at harvest time. Calcium‐treated fruits were about 70% firmer than the untreated ones at harvest time. Furthermore, this difference persisted after four weeks of storage at 0°C. Foliar‐applied Ca produced a 29% decrease in the soluble polyuronide content of the fruits at harvest time, but not after four weeks of storage. Fruit firmness was positively correlated to the Ca content of fruits while the soluble polyuronide content of the fruit was negatively correlated to fruit Ca.  相似文献   

6.
采前苯丙噻重氮处理抑制厚皮甜瓜采后挥发性物质的释放   总被引:4,自引:1,他引:4  
用50 mg/L苯丙噻重氮(BTH)于采前1周喷洒“银帝”甜瓜植株和果实,采收后采用固相微萃取(SPME)结合气-质联用(GC-MS)技术分析果实常温贮藏期间挥发性物质的释放变化。结果表明:BTH处理可明显抑制果实挥发性物质的释放,处理者挥发性物质的释放随贮藏时间的延长而逐渐增加,而对照果实挥发性物质的释放呈单峰形变化,至采后第7 d达到高峰。BTH处理者挥发性物质的释放总量也明显低于对照。此外,BTH处理对10种甜瓜特征成分的释放也存在不同程度的影响。  相似文献   

7.
The effect of the harvest time on oil-based bioactive compounds in sea buckthorn berries ( Hippophae rhamnoides L. ssp. sinensis) was investigated. Sea buckthorn berries were collected at early maturity (September), maturity (November), and postmaturity (January) during the 2003-2004 harvest year. Whole berries were analyzed for physical characteristics, and fruit and seed fractions were analyzed for bioactive content. November-harvested berries yielded the highest values for berry sizes, CIELab factor a*, and total carotenoid content in the fruit fraction ( p < 0.05). September yielded significantly higher ( p < 0.05) levels of major compounds, alpha-tocopherol and beta-sitosterol, in the fruit fraction. Seed characteristics and bioactive compounds did not vary significantly with respect to the harvest time ( p > 0.05). These results have identified the most suitable level of maturity for the optimization of certain compounds and the losses that may occur with winter harvest, commonly practiced in cold climates.  相似文献   

8.
Antioxidant activity, total phenolic content, anthocyanin content, and six other fruit characters including titratable acid concentration, soluble solids, firmness, and percentage of bruised berries were determined for nine blueberry (Vaccinium L. sp.) cultivars at harvest and at various postharvest intervals after storage at 5 degrees C. Berries from MSU-58, Brigitta, and Legacy stored successfully for 7 weeks, Bluegold stored for 3-5 weeks, Bluecrop, Elliott, and Nelson stored for 3 weeks, and Jersey and Little Giant stored for fewer than 3 weeks. During the time they retained marketable quality, one cultivar (MSU-58) demonstrated a 29% increase in antioxidant activity. None of the cultivars showed a significant decrease from the harvest antioxidant activity value during storage. Antioxidant activity, total phenolic content, and anthocyanin content were strongly correlated with each other (r = 0.87-0.99, P < 0.01). All three parameters were moderately correlated with soluble solids (r = 0.47, P < or =0.05; r = 0.44, P < or = 0.05; and r = 0.64, P < or = 0.01, respectively), and antioxidant activity and total phenolic content were both moderately correlated with pH (r = 0.53 and 0.49, respectively; P < or = 0.05). However, antioxidant activity, total phenolic content, and anthocyanin content showed no correlation with firmness, percent severely bruised berries, or weight loss. Antioxidant activity and total phenolic content at harvest both correlated with titratable acidity at harvest (r = 0.68, P < or = 0.05 and r = 0.70, P < or = 0.05, respectively) on a cultivar mean basis. Berries from Elliott were also harvested from plants at two levels of bush ripeness (30-50% and 60-80% ripe berries on plants) and separated into three fruit maturity classes on the basis of percent blue color. The level of bush ripeness had no significant effect on antioxidant activity, total phenolic content, or anthocyanin content; however, fruit maturity had a significant effect on antioxidant activity, total phenolic content, and anthocyanin content, and bush ripeness x fruit maturity interactions were significant for these three traits. Berries with 50-75% blue coloration harvested from bushes with 60-80% mature fruit showed a significant increase in antioxidant activity, total phenolic content, and anthocyanin content during the first 3 weeks in storage. Our results demonstrate that increases in antioxidant activity, total phenolic content, and anthocyanin content may occur in the blueberry during cold storage and are cultivar-dependent. The increases that occur in immature fruit, such as in Elliott, may be advantageous for producers who wish to delay marketing of the fruit.  相似文献   

9.
To enhance the shelf life of a late variety of Moroccan Citrus clementina (Nour), ionizing treatments were applied at 0.3 kGy, as well as washing (cold water) and waxing treatments. It has been found that, despite the irradiation treatment, the washing and waxing treatment do not improve the quality of C. clementina, but rather result in yellower peels, peel injury, and reductions of vitamin C content, acidity, and soluble solids. However, gamma-irradiation alone enhanced significantly (p 相似文献   

10.
Star Ruby grapefruit [Citrus paradisi (Macf.)] were harvested in November, February, and May, treated with ultraviolet C (UV-C) light at 0.5, 1.5, or 3.0 kJ.m(-)(2), and then stored at 7 degrees C and 90-95% relative humidity (RH) for 4 weeks with 1 additional week at 20 degrees C and approximately 80% RH. Untreated fruits were used as control. UV-C irradiation at 0.5 kJ.m(-)(2) effectively reduced decay development as compared to nontreated fruit without causing damage. Irradiation at dosages >0.5 kJ.m(-)(2) did not further improve decay control and caused rind browning and necrotic peel, the extent of damage depending on treatment dosage and harvest date. The percentage of damaged fruit after irradiation at the higher UV-C dosages was significantly higher in fruit harvested in November; differences between fruits harvested in February and May were negligible. After UV-C irradiation, the phytoalexins scoparone and scopoletin accumulated in flavedo tissue, their amounts depending on harvest date and UV-C dosage. Both phytoalexins showed similar accumulation patterns, although the concentrations of scoparone were much lower than those of scopoletin. Phytoalexin levels increased in most samples as the treatment dosage increased. No detectable levels of scoparone and scopoletin could be found in nonirradiated fruit. The influence of UV-C treatments on soluble solids concentration and titratable acidity of juice was negligible.  相似文献   

11.
The influence of gamma-irradiation on the content of phenolic compounds was evaluated on Moroccan Citrus fruits (Citrus clementina Hort. ex. Tanaka) treated at a mean dose of 0.3 kGy and stored for 49 days at 3 degrees C. The results show that irradiation has enhanced the synthesis of total phenolic compounds and is correlated with phenylalanine ammonia-lyase activity (PAL) during storage. Accumulation of phenolic compounds in cells is demonstrated and may be explained by the enhancement of PAL activity. HPLC/UV (diode array detector) analysis demonstrated that hesperidin was the major flavanone and nobiletin and heptamethoxyflavone were the major polymethoxylated flavones. Hesperidin is also the major phenolic compound in clementines. Irradiation stimulates the biosynthesis of hesperidin after 14 days of storage, corresponding to the maximum of PAL activity. p-Coumaric acid was also identified, and its content was particularly high in irradiated fruits after 49 days of storage. Accumulation of flavonoids and p-coumaric acid could be related to a better resistance. The percentage of losses due to peel injury "pitting" during storage was between 1 and 5% after 49 days of storage. The connections between irradiation, enzyme activity, phenolic content, and peel injury are briefly discussed.  相似文献   

12.
~(60)Co辐照对白灵菇采后低温贮藏的影响   总被引:3,自引:0,他引:3  
以0.8、1.2、1.6和2.0kGy60Coγ射线辐照白灵菇,在4℃下贮藏保鲜。结果表明,经过1.2kGy辐照处理的白灵菇维持了最高的可溶性蛋白质含量和最大的硬度,贮藏保鲜时间最长。白灵菇在贮藏期间的硬度越大,其可溶性蛋白的含量也越高,且二者之间存在显著的相关性。辐照会加大白灵菇的细胞膜透性,破坏细胞膜结构,剂量过大反而会加速营养成分降解和腐烂。  相似文献   

13.
Fruit pulp and seeds from the jujube plant possess nutritional and medicinal properties. The bioactive components have been shown to vary both with cultivar and with growing conditions. Most studies report the components of varieties from China. We measured free amino acid, individual phenolic, and total phenolic content, and antioxidative activities in three jujube fruit pulp extracts from Boeun-deachu, Mechu, and Sanzoin cultivars and two seed extracts (Mechu and Sanzoin) from plants grown in Korea. In g/100 g dry weight, total free amino acid content measured by ion-exchange chromatography ranged from 5.2 to 9.8 in the pulp and from 4.0 to 5.3 in the seed. Total phenolic content measured by Folin-Ciocalteu ranged from 1.1 to 2.4 in the pulp and from 3.6 to 4.6 in the seed. Flavonoids were measured by HPLC and ranged from 0.7 to 1.8 in the pulp and from 3.2 to 4.0 in the seed. Flavonoids were identified by HPLC elution position and UV/vis and mass spectra. Fruits contained the following flavonoids: procyanidin B2, epicatechin, quercetin-3-O-rutinoside (Q-3-R), quercetin-3-O-galactoside (Q-3-G), kaempferol-glucosyl-rhamnoside (K-G-R), and two unidentified compounds. Seeds contained the following flavonoids: saponarin, spinosin, vitexin, swertish, 6'-hydroxybenzoylspinosin (6'-HBS), 6'-feruloylspinosin (6'-FS), and one unidentified substance. Dimensions and weights of the fresh fruit samples affected phenolic content. The distribution of the individual flavonoids among the different samples varied widely. Data determined by the FRAP antioxidative assay were well correlated with total phenolic content. In a departure from other studies, data from the DPPH free radical assay were not correlated with FRAP or with any of the measured compositional parameters. Because individual jujube flavonoids are reported to exhibit different health-promoting effects, knowledge of the composition and concentration of bioactive compounds of jujube products can benefit consumers.  相似文献   

14.
【目的】研究采前、 采后钙处理对葡萄柚果实细胞壁组分、 细胞壁降解酶活性变化及其相关基因表达的影响,可为了解钙与果实细胞壁物质代谢之间的关系,揭示钙对果实软化的作用机理,为调控葡萄柚果实膳食纤维含量,提高果实质地品质提供理论依据。【方法】试验于2011年2月至11月在云南省玉溪市葡萄柚果园进行,供试品种为‘里约红’葡萄柚,该品种于2005年嫁接于当地砧木,株行距为3 m×3 m。试验由采前和采后钙处理两部分组成。采前钙处理在幼果初期、 幼果末期、 膨大初期、 膨大末期、 转色期,叶面喷施2% CaCl2; 采后钙处理在果实成熟采后浸于2% CaCl2溶液5 min, 室温贮藏。之后每15天取样一次,每次取10个果实,测定葡萄柚果肉细胞壁组分、 细胞壁降解酶活性及其基因表达量。【结果】随葡萄柚果实后熟软化,紧密结合型果胶(共价结合型果胶)解聚为松散结合型果胶(水溶性果胶、 离子结合型果胶),紧密结合型半纤维素(24% KOH可溶性半纤维素)解聚使其含量下降,而松散结合型半纤维素含量增加(4%KOH可溶性半纤维素)。果实PG、 PME、 Cx、 α-L-Af和β-Gal酶活性及其基因表达量均随果实软化呈不同程度增加。PME活性在果实采收后表现出较高含量,而PG活性在果实贮藏前期急剧增加,其酶基因的表达量与酶活性变化趋势基本一致。Cx、 α-L-Af和β-Gal活性在贮藏中、 后期上升较快,相关酶基因的表达量亦明显增加。钙处理显著地降低果实细胞壁降解酶活性和基因表达水平,其中采后钙处理对α-L-Af和β-Gal活性和基因表达在贮藏中、 后期的调控作用较显著,酶活性和基因表达均维持在较低水平。【结论】外源钙处理降低细胞壁降解酶活性及其基因表达,抑制了细胞壁物质的解聚,采后钙处理对细胞壁物质代谢的调控效果优于采前钙处理。外源钙处理抑制了细胞壁降解酶基因表达水平,降低了细胞壁降解酶活性,减缓了果胶、 半纤维素的解聚,从而达到调控果实膳食纤维含量、 维持果实质地品质、 延长果实货架期寿命的目的。  相似文献   

15.
Accumulation of bioactive compounds and storage components during developmental stages of mango ginger ( Curcuma amada Roxb.) rhizome was investigated from 60 to 240 days, as a function of physiological maturity. Four distinct developmental phases were defined, namely, vegetative phase (up to 60 days from planting), initiation and development phase (60-150 days), maturation phase (150-180 days), and senescence phase (180 days). Difurocumenonol, a bioactive terpenoid compound and phenolics were identified as biomarkers, to determine the optimum physiological maturity to harvest mango ginger rhizome. Accumulation of phenolics was observed in newly initiated rhizomes (after 60 days from planting). The phenolic content was high in mango ginger pulp compared to its juice. Newly initiated rhizome contained no difurocumenonol, and it was observed after 120 days after planting. Peak accumulation of phenolics, difurocumenonol, and total protein were noticed in 180 day old rhizome. Accordingly, the abundance of these components on 180 days was set as an optimum maturity standard for harvest of mango ginger rhizome, compared with a conventional harvest period that ranges from 200 to 240 days.  相似文献   

16.
不同采收期对苹果常温贮藏品质和衰老的影响   总被引:2,自引:2,他引:0  
以通辽地区的‘塞外红’苹果为试材,研究了生长发育期在116~134 d内的3个采收期果实常温(20±1)℃贮藏品质和软化衰老的变化,以确定‘塞外红’苹果的最佳采收成熟度和适宜采收期。结果表明,随着采收期的推迟,果实硬度逐渐降低,可溶性固形物和可滴定酸含量逐渐升高,种子颜色逐渐变褐到全褐。随着贮藏时间的延长,3个采收期果实的硬度、维生素C和可滴定酸含量均逐渐下降,从采收到贮藏结束,采期Ⅰ果实的硬度一直保持最高,采期Ⅱ保持了果实较高的维生素C和可滴定酸含量,采期Ⅲ果实的可溶性固形物含量SSC一直保持最高。结果还表明,采期Ⅰ的果实常温贮藏期间虽然具有较高的原果胶和纤维素含量,而且抑制了可溶性果胶的生成,推迟了果实多聚半乳糖醛酸酶PG活性和纤维素酶活性高峰,延缓了果实呼吸高峰和乙烯释放高峰的出现时间,但果实的外观色泽、口感和风味相对较差;采期Ⅲ的果实丙二醛和乙醇含量积累较多,果实衰老快。综合分析,采期Ⅱ的‘塞外红’苹果具有良好的内在品质、外观色泽和贮运性能。因此,建议通辽地区‘塞外红’苹果的采收期以9月5—10日为宜(可适当晚采1~2 d),采收成熟度参考标准为:果实生长发育天数123~128 d、果肉硬度11.0~11.5 kg/cm^2、SSC≥16.5%、种子的颜色3/4左右变褐、淀粉染色为4.5级左右。  相似文献   

17.
Sodium orthophenylphenate (SOPP) has been used extensively for >40 years to control postharvest diseases of citrus fruits. Studies of the metabolism of [(14)C]SOPP have identified orthophenylphenol (OPP) as the major metabolite with phenylhydroquinone (PHQ) as a minor metabolite. The whole-fruit tolerance in the United States for OPP is 10 ppm. This study was conducted to quantify terminal OPP and PHQ residues in whole Navel oranges, grapefruit, and lemons following SOPP applications at maximum application rates and following commercial application and fruit storage practices. OPP and PHQ residues also were determined in products processed from treated Navel oranges. OPP residues in lemons, Navel oranges, and grapefruit treated with SOPP using foamer wash and shipping wax applications remained below the 10 ppm tolerance, and PHQ residues were all < or =0.439 ppm. PHQ residues in whole fruit increased with time in commercial storage. OPP residues in all Navel orange matrices except oil remained relatively stable with time in commercial storage; residues in oil declined substantially while in storage.  相似文献   

18.
19.
The effect of wax application, storage temperature (4 or 21 degrees C), and storage time (14 or 28 days after wax application) on grapefruit gland oil composition was examined by capillary gas chromatography. Wax application decreases nonanal and nootkatone levels. beta-Pinene, alpha-phellandrene, 3-carene, ocimene, octanol, trans-linalool oxide, and cis-p-mentha-2,8-dien-1-ol levels increase, but limonene levels decrease, with temperature. Levels of alpha-pinene, limonene, linalool, citronellal, alpha-terpineol, neral, dodecanal, and alpha-humulene decrease with time. Levels of alpha-phellandrene, 3-carene, ocimene, and trans-linalool oxide increase with time. No compound level was affected by the interactive action of temperature and wax application, suggesting that these two factors cause grapefruit oil gland collapse (postharvest pitting) through means other than changing gland oil composition. Compounds that are toxic to the Caribbean fruit fly (alpha-pinene, limonene, alpha-terpineol, and some aldehydes) decrease with time, thus suggesting grapefruit becomes increasingly susceptible to the fly during storage.  相似文献   

20.
硅酸钠处理对杏品质和风味物质的影响(英)   总被引:1,自引:0,他引:1  
硅酸盐作为一种安全有效的物质,已被广泛用于果蔬等采后病害的控制,为了研究其处理对园艺产品品质的影响,该文以兰州“大接杏”(Armeniaca vulgaris Lam. cv. Lanzhou Dajie)为试验对象,在室温(22±2℃)下使用硅酸钠(10 mmol/L)化学诱抗处理,探讨硅酸盐对杏果实品质,特别是挥发性风味物质的影响。结果表明,硅酸钠处理可延缓果实硬度的下降和腐烂率的升高,在贮藏结束后,其分别是对照组的1.95倍和58%。并能够减少贮藏过程中可滴定酸、可溶性固形物及Vc含量的下降,但对果实总糖含量的影响不显著。采用固相微萃取(SPME)结合气相色谱质谱联用(GC-MS)的方法分离鉴定了“大接杏”果实的香气成分,共分离鉴定出超过100多种挥发性成分。硅酸钠处理样挥发性物质的释放总量低于对照。同时,处理后的杏果还表现出醛类物质、萜类物质和β-紫罗兰酮的释放增大和酯类物质的释放减少的现象。与对照相比,该处理能够更好地保持杏果实良好的品质,是一种可行的杏果保鲜处理方法。  相似文献   

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