首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 31 毫秒
1.
The phenolic compounds hydroxycinnamates, anthocyanins, flavonols, and flavan-3-ols of sweet cherry cultivars Burlat, Saco, Summit, and Van harvested in 2001 and 2002 were quantified by HPLC-DAD. Phenolics were analyzed at partially ripe and ripe stages and during storage at 15 +/- 5 degrees C (room temperature) and 1-2 degrees C (cool temperature). Neochlorogenic and p-coumaroylquinic acids were the main hydroxycinnamic acid derivatives, but chlorogenic acid was also identified in all cultivars. The 3-glucoside and 3-rutinoside of cyanidin were the major anthocyanins. Peonidin and pelargonidin 3-rutinosides were the minor anthocyanins, and peonidin 3-glucoside was also present in cvs. Burlat and Van. Epicatechin was the main monomeric flavan-3-ol with catechin present in smaller amounts in all cultivars. The flavonol rutin was also detected. Cultivar Saco contained the highest amounts of phenolics [227 mg/100 g of fresh weight (fw)] and cv. Van the lowest (124 mg/100 g of fw). Phenolic acid contents generally decreased with storage at 1-2 degrees C and increased with storage at 15 +/- 5 degrees C. Anthocyanin levels increased at both storage temperatures. In cv. Van the anthocyanins increased up to 5-fold during storage at 15 +/- 5 degrees C (from 47 to 230 mg/100 g of fw). Flavonol and flavan-3-ol contents remained quite constant. For all cultivars the levels of phenolic acids were higher in 2001 and the anthocyanin levels were higher in 2002, which suggest a significant influence of climatic conditions on these compounds.  相似文献   

2.
Ten cranberry (Vaccinium macrocarpon Aiton) cultivars were evaluated for oxygen radical absorbance capacity (ORAC), anthocyanins, and total phenolics contents after three months of storage at 0, 5, 10, 15, and 20 degrees C. The antioxidant capacity of cranberry was affected by cultivars and storage temperatures. Among the 10 cranberry cultivars used in this study, Early Black, Crowley, and Franklin had higher antioxidant capacities than the other cultivars. ORAC values, anthocyanins, and total phenolics contents increased during storage. The highest increases in antioxidant activity, anthocyanin, and phenolics contents occurred at 15 degrees C storage. Fruit stored at 20 degrees C had lower ORAC values than those stored at 15 degrees C. A positive relationship existed between ORAC values and anthocyanin or phenolic content in all 10 cranberry cultivars at different storage temperatures.  相似文献   

3.
Ellagic acid and flavonoid antioxidant content of muscadine wine and juice   总被引：5，自引：0，他引：5  
Antioxidant properties of flavonoids and ellagic acid were characterized in eight wines and juices produced by various processing methodologies from red and white muscadine grape cultivars (Vitis rotundifolia). Juices and wines were produced by hot- and cold-pressed techniques, and additional wine was produced following on-hull fermentation for 3, 5, and 7 days. Chromatographic conditions were developed to simultaneously separate anthocyanins, ellagic acid, and flavonols and correlated to a measurement of overall antioxidant capacity (AOX), and their changes were monitored after storage for 60 days at 20 and 37 degrees C. Regression coefficients between concentrations of individual polyphenolics and AOX ranged from 0.55 for ellagic acid to 0.90 for kaempferol. Both red and white wines had higher AOX values after storage than juices made from an identical grape press, despite lower concentrations of individual polyphenolic compounds. Red wines fermented on-hull had higher initial concentrations of antioxidant polyphenolics as compared to a corresponding hot-pressed juice, but changes in AOX during storage were more affected by time than by storage temperature despite lower concentrations of flavonoids and ellagic acid present at 37 degrees C as compared to 20 degrees C. Oxidative or polymerization reactions significantly decreased levels of monomeric anthocyanins during storage with the greatest losses observed for delphinidin and petunidin 3,5-diglucosides. Processing methods for muscadine wine and juice production were important factors influencing concentrations of antioxidant flavonoids and ellagic acid, while the role of fermentation and time had the greatest influence on retention of AOX properties during storage.  相似文献   

4.
This research characterized flour and raw starches isolated from red and white sweet potato cultivars. Their composition, determined by proximate analysis, is typical of sweet potato cultivars. These cultivars have high amylose content (32-34%) and exhibit a Ca-type X-ray diffraction pattern. Similar gelatinization characteristics were detected for both starches with onset temperature of 67 degrees C and enthalpy of 10.5-11.0 J/g. Starches of both red and white cultivars had well-correlated (r (2) = 0.982) and high solubilization and swelling temperatures, starting at 80 degrees C. Pasting properties of the white cultivar exhibit lower tendency for retrogradation. Water and oil absorption capacities were low for both red and white flours. When parboiled, both cultivars showed improved water absorption capacity and decreased least gelation concentration. It is concluded that the white cultivar should be preferred when low retrogradation tendency is required.  相似文献   

5.
The caffeic acid content of storage root periderm and cortex tissues of genetically diverse sweet potato [Ipomoea batatas (L.) Lam.] cultivars and breeding clones was quantified by high-performance liquid chromatography. Periderm caffeic acid content of the clones ranged from 0.008 to 7.97 mg/g dry weight, whereas the highest cortex content was 0.047 mg/g. Clones varied greatly in periderm caffeic acid content in all experiments, but there were also differences between experiments in content averaged for all clones. This indicates that periderm caffeic acid content is subject to genetic and environmental influences. Caffeic acid inhibited the growth of four sweet potato pathogenic fungi and germination of proso millet seeds in bioassays. Inhibitory activity in the bioassays suggests that high periderm caffeic acid levels contribute to the storage root defense chemistry of some sweet potato genotypes.  相似文献   

6.
In this study the main chemical parameters, ascorbic acid and polyphenol content, and antioxidant activity of two varieties of prunes, dried by high-temperature (85 + 70 degrees C) and low-temperature (60 degrees C) procedures, were monitored during storage. Ascorbic acid content was higher in the prunes dried at 60 degrees C but significantly decreased in both varieties during storage. The different classes of polyphenols analyzed (cinnamates, anthocyanins, flavonols) showed different stabilities during storage. Neochlorogenic acid decreased only in the President variety, whereas chlorogenic acid increased in both varieties; anthocyanins, present only in the President prunes, disappeared in the first months of storage, and the flavonol content fell significantly in both cultivars during the year of the study. Drying temperature significantly affected the polyphenol content, with different effects according to the class of polyphenols. Antioxidant activity showed a significant increase at the end of the storage period and in the President variety was higher in the sample dried at the higher temperature.  相似文献   

7.
钾素对食用型甘薯糖代谢相关酶活性的影响   总被引：10，自引：6，他引：4  
为了探讨钾素提高甘薯块根可溶性糖含量的生理基础。选用典型的食用型甘薯品种北京553,设置不同施钾处理,于2009～2010年2个生长季在山东农业大学农学试验站进行试验。采用甘薯块根膨大过程中定期取样的方法,测定块根可溶性糖和淀粉含量及相关酶活性、功能叶蔗糖含量及相关酶活性。结果表明,与对照比较,施用钾肥能显著提高块根产量、可溶性糖及各糖组分含量,其中K2O用量为24 g/m2处理增幅最大,为最适用量。进一步研究发现,适宜供钾处理显著提高了功能叶磷酸蔗糖合成酶活性和蔗糖含量,生育期内平均增幅分别为10.31%和34.13%,同时提高了块根中蔗糖合成酶、不溶性酸性转化酶的活性,生育期内平均增幅为16.47%和3.66%,在提高源端光合产物供应的同时促进蔗糖在库端的卸载,促进块根中淀粉和可溶性糖的积累;适宜供钾处理还提高了块根中-和-淀粉酶的活性,生育期内平均增幅分别为26.06%和14.64%,促进淀粉向可溶性糖转化。此外,适宜供钾处理还显著提高了生长前期和后期块根中可溶性酸性转化酶活性、以及生长后期块根中蔗糖-蔗糖果糖基转移酶活性,促进了葡萄糖、果糖和果聚糖在块根中的积累。在甘薯收获期,块根可溶性糖和淀粉含量分别提高了13.52%和3.02%。即钾肥能够增加块根中蔗糖的供应量、促进块根对蔗糖的吸收、促进淀粉水解,是其提高块根可溶性糖含量的生理原因。  相似文献   

8.
甘薯抗疮痂病多胺与吲哚乙酸代谢的研究   总被引：1，自引：2，他引：1       下载免费PDF全文
研究不同抗性甘薯品种受疮痂病菌侵染前后多胺和吲哚乙酸代谢变化结果表明 ,感染疮痂病菌后抗病与感病品种甘薯叶片中吲哚乙酸含量和多胺氧化酶活性降低 ,多胺总量及腐胺含量增加 ,腐胺 / (精胺 亚精胺 )比值升高 ,感病品种变化幅度高于抗病品种。疮痂病菌侵入后感病品种甘薯叶片中绿原酸含量下降 ,吲哚乙酸氧化酶和过氧化物酶活性升高 ,而抗病品种则相反。  相似文献   

9.
Orange fruits of two blood varieties (Tarocco and Moro) were stored at 8 degrees C and 22 degrees C for 85 and 106 days, respectively, and analyzed periodically for standard quality parameters (total soluble solids, total acidity, ascorbic acid, juice yield, and rind color) and sensory influencing parameters (anthocyanins, and total and free hydroxycinnamic acids). A decrease in total acidity (TA) and juice yield during storage was observed for both cultivars; total soluble solids (TSS) increased only in the Tarocco oranges stored at 8 degrees C. The increase in TSS observed for Tarocco and the simultaneous decrease in TA in both varieties resulted in a higher maturity index (TSS/TA) for the two cultivars. No loss of vitamin C was noted in Tarocco orange at either temperature, whereas a sharp reduction in vitamin C occurred in the first 50 days of storage for Moro. A significant increase in anthocyanin content was observed in Tarocco and Moro stored at 8 degrees C. Overlong storage induces extensive hydrolysis of hydroxycinnamic derivatives to free acids in Moro orange and these, in turn, could develop the malodorous vinylphenols.  相似文献   

10.
The influence of 2 weeks and 3 months of dark storage upon light-induced chlorogenic acid accumulation within tuber tissue of four potato cultivars and upon 5-, 4-, and 3-caffeoylquinic acid concentrations within cv. King Edward was determined. Storage period significantly affected (P < 0.05) the magnitude of the light-induced chlorogenic acid response with accumulation rates 3-4 times higher in tubers exposed to light after 2 weeks compared with those placed under light after 3 months. Comparison of chlorogenic acid concentrations in controls after 2 and 3 months of dark storage indicated that tuber chlorogenic concentrations decline during prolonged cold store at 5 degrees C. Rates of accumulation in response to light were cultivar-dependent with cv. Fianna the most light-sensitive and cv. Maris Piper relatively light-insensitive. In virtually all cases exposure to sodium and fluorescent light promoted higher rates of accumulation than did exposure to high-pressure mercury light sources. Chlorogenic acid values steadily increased over 15 days of illumination with, in the majority of cases, no indication of cessation. Light exposure increased 5-, 4-, and 3-caffeoylquinic acid accumulation rates in cv. King Edward. Irrespective of storage period and light source, ratios of 5-:4-:3-caffeoylquinic acid were ca. 85:15:0 at day 0 and 52:42:6 by day 15.  相似文献   

11.
选用徐薯 18号为材料 ,通过大田试验研究了供钾水平对甘薯块根薄壁细胞显微和超微结构、块根呼吸速率和ATP含量、14C同化物分配和产量等的影响。结果表明 ,施用适量钾肥 ,甘薯块根薄壁细胞膜结构完整、清晰 ,内含较多的线粒体和质体 ,胞质较丰富 ;块根的呼吸速率和ATP含量较高 ,有利于提高块根“库”的活性。适量供钾 ,增加单位体积块根内的淀粉粒数 ,提高块根淀粉含量 ;促进光合产物由叶片向块根的运输 ,提高了14C同化物在块根中的分配比例 ;促进块根迅速膨大 ,增加单薯重 ;提高块根产量  相似文献   

12.
In this work a study of critical storage temperatures on pigment degradation of green beans (Phaseolus vulgaris, cvs. Perona and Boby) was conducted. In this way, green beans kept better quality at 4 degrees C than either 8 or 12 degrees C, maintaining a bright green color and good texture. Nevertheless, temperatures of 4 degrees C induced chilling injury (CI) after eight days of storage, which became evident when the pods were transferred to 20 degrees C. Cold storage temperatures, 12, 8, and 4 degrees C, produced different changes on the green beans chlorophyll profile. Green beans of both cultivars, Perona and Boby, stored at 4 and 12 degrees C showed a continuous degradation of chlorophyll pigments during storage, while samples stored at 8 degrees C showed an increase of chlorophyll content at the first 15 days. Carotenoid pigments also suffered different changes during cold storage. Perona was the green beans cultivar which maintained the higher level of lutein, mainly when samples were stored at the most suitable temperature (8 degrees C).  相似文献   

13.
Protein hydrolysates were prepared by limited alcalase hydrolysis (0.5, 1, and 6 h, corresponding to degrees of hydrolysis of 0.72, 1.9, and 2.3, respectively) of heat-coagulated potato protein. The hydrolysates were characterized for peptide composition, ferric reducing/antioxidant power (FRAP), 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical-scavenging activity, and Fe2+- and Cu2+-chelation capacity. Hydrolyzed and intact proteins were formulated (4%, w/w) into beef patties to determine in situ antioxidant efficacy. Thiobarbituric acid-reactive substances (TBARS) and peroxide value (PV) formed in cooked and PVC-packaged patties during storage (4 degrees C, 0-7 days) were analyzed. Hydrolysis increased the protein solubility by 14-19-fold and produced numerous short peptides (< 6 kDa). The FRAP values of the protein sample (23 micromol/g) increased markedly after hydrolysis but were similar between the three hydrolysates (597-643 micromol/g). Similarly, the ABTS radical-scavenging activity also was increased by hydrolysis and was the greatest for the 1-h hydrolysate. Hydrolysis increased the Cu2+-chelation activity but decreased the Fe2+-chelation ability of the protein. The production of PV in patties after 7 days of storage was lowered 44.9% and 74.5% (P < 0.05), and that of TBARS was reduced 40.9% and 50.3% (P < 0.05), by intact and hydrolyzed proteins, respectively.  相似文献   

14.
氮肥施用量对甘薯产量和品质性状的影响   总被引：6，自引：1，他引：5  
【目的】氮是影响作物产量和品质性状的重要因素,合理施氮是提高作物产量和改善品质的主要途径。研究施氮量对甘薯块根产量形成、营养品质和淀粉糊化特性的影响,对于明确江苏徐淮地区甘薯种植的适宜施氮量具有重要意义。【方法】本文选用淀粉型甘薯品种徐薯22和兼用型甘薯品种徐薯28为试验材料,设置5个施氮水平0、60、120、180、240 kg/hm2。调查了甘薯不同生育期的叶面积指数、光合势、干物质积累和产量构成要素,采用分光光度法测定了块根主要营养品质指标,利用Tech-master型RVA快速测定淀粉谱粘滞特性,分析明确施氮量对块根主要品质指标和淀粉糊化特征值的影响。【结果】施氮N 60 kg/hm2增加了各生育期甘薯的叶面积,提高了甘薯的光合势,显著增加了块根产量(徐薯28增产16.38%,徐薯22增产9.31%),过量施氮(N 240 kg/hm2)则产量降低。施氮并未显著降低块根中的淀粉和直链淀粉含量,但明显增加了可溶性糖和蔗糖含量。施氮显著提高最高粘度、最低粘度、最终粘度和消减值。相关分析显示,直链淀粉含量与最高粘度值和崩解值呈极显著或显著负相关(相关系数分别为-0.90**和-0.71*);直链淀粉含量与消减值呈显著正相关(相关系数为0.73*)。【结论】综合考虑甘薯的产量和品质,在本实验条件下甘薯较为适宜的氮肥用量约为60 kg/hm2。  相似文献   

15.
L-galactono-gamma-lactone dehydrogenase (GLDH) activity and vitamin C content as ascorbic acid (AA) plus dehydroascorbic acid (DHA) were evaluated in five potato tuber cultivars (Agata, Altesse, Franceline, Manon, and Monalisa). The effect of fresh-cutting and subsequent refrigerated storage of Manon potato under different atmospheres (air, 20% CO(2) + air, 100% N(2), and vacuum packaging) on GLDH activity and vitamin C content was also determined. GLDH from the five potato tuber cultivars showed typical inhibition kinetics by high substrate concentration in the synthesis of AA from its physiological precursor L-galactonic acid-gamma-lactone (GL). GLDH activity was not correlated with the corresponding vitamin C content in any potato tuber cultivar. GLDH from all the cultivars presented a major isoform with isoelectric point (IEP) 5, which changed to IEP = 4.3 after minimal processing. In addition, the GLDH-catalyzed synthesis of AA by the new isoform showed typical Michaelis kinetics, in which the enzyme became more efficient to catalyze the reaction. Whether the change in the isoform pattern was due to either post-translational modifications or de novo synthesis of a new isoenzyme remains unanswered. Fresh-cutting increased GLDH activity from 4.7-fold (vacuum packaging) to 11-fold (air) after 6 days. In addition, 100% of vitamin C content was retained in air and decreased in the rest of atmospheres after this storage period, following the sequence vacuum packaging (89%) > 100% N(2) (78%) > 20% CO(2) + air (63%). This tendency was correlated with the corresponding GLDH activity detected in each storage atmosphere, except in the case of 20% CO(2) + air. Vacuum packaging proved to be the best storage condition, because fresh-cut potatoes did not turn brown and retained 89% of initial vitamin C content.  相似文献   

16.
The stability of red grape anthocyanins (Vitis vinifera) was evaluated in a model juice system during normal (25 degrees C) and accelerated storage (35 degrees C) in the presence of ascorbic acid. Rosemary polyphenolic cofactors (0, 0.2, and 0.4% v/v) were evaluated as anthocyanin stabilizing agents. Cofactor addition resulted in concentration-dependent hyperchromic (up to 178%) and bathochromic (up to 23 nm) shifts, indicating a more intense red coloration of the models. Anthocyanin and ascorbic acid degradation followed first-order kinetics during storage. Results showed that copigmented treatments underwent a lower conversion of L-ascorbic acid into dehydroascorbic acid during storage when compared to the control, favorably impacting the vitamin retention of these models. Copigmentation did not affect anthocyanin degradation in the absence of ascorbic acid but in its presence aided to retain a higher anthocyanin content than the control. This study indicated that the addition of anthocyanin cofactors could be used to reduce the pigment and vitamin degradation while masking detrimental color changes in anthocyanin containing products.  相似文献   

17.
Caffeoyl quinic acid (CQA) derivatives in ku-ding-cha, mate, coffee, and related plants were determined by HPLC. One ku-ding-cha contained a large amount of 3,5-dicaffeoylquinic acid (3,5-diCQA, 10.6% in dry weight) as well as 3-CQA (1.7%), 4-CQA (1.1%), 5-CQA (6.3%), 3,4-diCQA (1.8%), and 4,5-diCQA (4.3%). In this ku-ding-cha, the total caffeic acid moiety was 90.3 mmol/100 g of dry weight. The leaves of Ilex latifolia, which is one original species of ku-ding-cha, and another plant of the same genus, I. rotunda, also contained 3,5-diCQA (9.5 and 14.6%), 3-CQA (4.3 and 1.9%), and 5-CQA (4.8 and 3.8%), respectively, whereas raw coffee bean contained 5.5% 5-CQA and other low CQA derivatives. 3,5-DiCQA and 5-CQA with an apple acetone powder (AP) containing polyphenol oxidase showed high capturing activities toward thiols, and two addition compounds between 3,5-diCQA and methane thiol were also identified. Ku-ding-cha indicated extremely strong capturing activities toward methanethiol, propanethiol, and 2-propenethiol in the presence of apple AP. Furthermore, drinking ku-ding-cha reduced the amount of allyl methyl sulfide gas, well-known to persist as malodorous breath long after the ingestion of garlic.  相似文献   

18.
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   

19.
A number of parameters linked to storage of potatoes were evaluated with regard to their potential to influence the acrylamide formation in French fries. Acrylamide, which is a potential human carcinogen, is reported to be formed during the frying of potatoes as a result of the reactions between asparagine and reducing sugars. This study was conducted using three potato varieties (Bintje, Ramos, and Saturna) typically used in Belgium, The Netherlands, and the northern part of France for French fry and crisp production. Saturna, mainly used in crisp production, appeared to be the least susceptible for acrylamide formation during frying. Especially storage at low temperatures (4 degrees C) compared to storage at 8 degrees C seemed to enhance acrylamide formation due to a strong increase in reducing sugars caused by low-temperature storage. Because of the reversible nature of this physiological reaction, it was possible to achieve a significant reduction of the reducing sugars after a reconditioning of the cold-stored potatoes for 3 weeks at 15 degrees C. All changes in acrylamide concentrations could mainly be explained by the reducing sugar content of the potato (R2 = 0.84, n = 160). This means that, by ensuring a low reducing sugar content of the potato tuber, the risk for acrylamide formation will largely be reduced. Finally the use of a sprout inhibitor did not influence the composition of the potato, and thus acrylamide formation was not susceptible to this treatment.  相似文献   

20.
甘薯抗薯瘟病的苯丙烷类代谢研究   总被引：1，自引：0，他引：1  
甘薯瘟病是甘薯的重要病害, 严重影响甘薯的品质和产量.本试验在甘薯苗期, 通过剪叶法接菌研究甘薯抗感病品种苯丙烷类代谢的变化规律.结果表明: 甘薯抗感病品种接菌后PAL、POD活性均有所提高, 且提高速度与品种抗性呈正相关; 抗病品种接菌后木质素和绿原酸含量显著增加, 感病品种接菌后绿原酸、总酚和类黄酮含量波动较大, 木质素含量降低.相关性分析表明, 接菌后木质素和绿原酸的积累与甘薯品种抗病性密切相关.接菌后PAL、POD活性迅速提高并积累木质素和绿原酸等抗病物质是甘薯抗薯瘟病的苯丙烷类代谢基础, 在抗病品种鉴定方面有一定的参考价值.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号