Changes in carotenoid and ascorbic acid contents in fruits of different tomato genotypes related to the depletion of UV-B radiation

The aim of the present study was to investigate if the depletion of UV-B radiation affected the most representative carotenoids as well as the ascorbic acid content in tomato fruits, harvested at both breaker and firm red stages. To do this, three tomato genotypes, DRW 5981, HP 1, and Esperanza, were grown inside a greenhouse either covered with polyethylene transparent to UV-B or depleted of UV-B by a special covering film. The antioxidant properties of the fruits were evaluated on the water-insoluble fractions according to the ABTS method. UV-B effect on antioxidant activity was negligible in DRW and HP 1 genotypes, whereas it was detrimental in Esperanza at both ripening stages. This genotype seems to have a negligible capability of accumulating carotenoids and a great susceptibility to detrimental effects of UV-B; conversely, the DRW genotype shows high carotenoid levels under sunlight conditions and a further promotion by UV-B. On the other hand, the HP 1 mutant displays an intermediate behavior and represents the only genotype favored by UV-B with respect to ascorbic acid accumulation.     

Antioxidants, low molecular weight carbohydrates, and total antioxidant capacity in strawberries (Fragaria x ananassa): effects of cultivar, ripening, and storage

Four cultivars of strawberries (Senga Sengana, BFr77111, Elsanta, and Honeoye) were studied for their content of antioxidants, total antioxidant capacity, and low molecular weight carbohydrates in relation to harvest year, ripening stage, and cold storage. For ascorbic acid, chlorogenic acid, ellagic acid, and total antioxidative capacity, measured in both water-soluble and water-insoluble extracts, there was a 2-5-fold variation among cultivars. Unripe berries contained lower concentrations of chlorogenic acid and p-coumaric acid and also quercetin and kaempferol compared with riper berries. During cold storage for up to 3 days, relatively few changes in the concentration of the different antioxidants occurred. The concentrations of several investigated parameters were interrelated, for example, for ascorbic acid and water-soluble antioxidant capacity and for ellagic acid and water-insoluble antioxidant capacity. The dominating sugars in strawberries were fructose and glucose, but considerable amounts of sucrose were also present, and their contents varied among cultivars, giving a predicted glycemic index of approximately 81. Verbascose, raffinose, and stachyose were found in only minor amounts. The study shows that the concentration of a number of bioactive compounds in strawberries varied according to cultivar, ripening stage, and storage. This information should make it possible to select strawberries with an optimal content of bioactive compounds.     

Antioxidant composition in cherry and high-pigment tomato cultivars

Fourteen cultivars of cherry tomatoes and four cultivars of high-pigment tomato hybrids were cultivated in southern Italy, and the red-ripe fruits were analyzed for their content in different classes of antioxidants and for their antioxidant activity. Among the different cultivars, significant differences were found between lycopene, beta-carotene, alpha-tocopherol, vitamin C (ascorbic acid and dehydroascorbic acid), and total phenolic and flavonoid contents. LS203 and Corbus appear to be the cultivars with the highest content of lipophilic and hydrophilic antioxidants among cherry tomatoes, respectively. All cultivars of high-pigment tomato hybrids showed an expected exceptionally high lycopene content. Among them, the highest content of lipophilic and hydrophilic antioxidants was found in cv. HLY 13. Hydrophilic and lipophilic antioxidant activities were both significantly influenced by genotype. Such results highlight an existing unexploited variability in tomato germplasm and stress the need to evaluate the biodiversity and to support conventional breeding programs to improve tomato nutritional value.     

Content of chalconaringenin and chlorogenic acid in cherry tomatoes is strongly reduced during postharvest ripening

The contents of chalconaringenin, chlorogenic acid, rutin, ascorbic acid, lycopene, and beta-carotene were analyzed during postharvest and vine ripening of cherry tomatoes (Lycopersicon esculentumMill.) (cv. Jennita) produced in a greenhouse. A remarkable decrease in the content of chalconaringenin took place during postharvest ripening. The tomatoes were found to contain 15.26 mg 100 g(-1) fresh weight (FW) at harvest but held only 0.41 mg after 3 weeks at 20 degrees C in darkness. Chalconaringenin did not convert into naringenin. The content of chlorogenic acid fell from 0.51 to 0.06 mg 100 g(-1) FW at the same conditions. The content of rutin and that of total phenolics remained stable during postharvest ripening. The amounts of lycopene as well as beta-carotene and ascorbic acid increased during postharvest ripening. No significant change in the amount of methanol soluble antioxidants or total soluble solids was found during postharvest ripening of the tomato fruits. During vine ripening, the total amount of phenolics and that of soluble solids (% Brix) increased. The content of phenolics correlated well with the content of methanol soluble antioxidants (p < 0.001). The amount of ascorbic acid increased from 9.7 mg in green-yellow tomatoes to 17.1 mg 100 g(-1) FW in red tomatoes. The amount of chalconaringenin decreased to 8.16 mg 100 g(-1) FW, whereas no significant change was observed for chlorogenic acid or rutin. Possible causes for the decrease in chalconaringenin are discussed.     

The influence of diluted seawater and ripening stage on the content of antioxidants in fruits of different tomato genotypes

The aim of this study was to investigate if the combined effect of diluted seawater and ripening can improve the beneficial nutritional properties of tomato fruits from an antioxidant point of view. To reach the goal, different tomato cultivars and breeding lines, genetically modified for ripening, were investigated, and analysis of NADPH and NADP+ as well as of the main antioxidants such as ascorbic acid, lipoic acid, and tocopherols was performed at two ripening stages. The research was conducted on berries of the following genotypes of tomato: cv. Jama, Gimar wild type, Gimar gf, and Gimar nor. The mutant gf is a typical "stay green" mutant, characterized by an incomplete loss of chlorophyll; the nor mutation is characterized by a reduced biosynthesis of ethylene and carotenoids. Both ripening and salinity induced an oxidative stress, and the sensitivity to salt treatment was genotype-dependent. The genotypes cv. Jama and Gimar gf line showed increases in ascorbic acid, lipoic acid, and alpha-tocopherol during both ripening and salt treatment whereas total ascorbate and tocopherols decreased in the berries from salt-treated plants of Gimar wild type. Ripening also determined decreases in ascorbate and tocopherol amounts in the Gimar nor line where a positive effect of ripening and salinity was observed.     

Antioxidative activity and carotenoid and tomatine contents in different typologies of fresh consumption tomatoes

The phytonutrient intake associated with tomato consumption depends also on cultivar and fruit ripening stage. This work associates the antioxidative ability, the level of carotenoids, and the amount of glycoalkaloids to the main carpometric characteristics of four different typologies of tomatoes: "cherry", "cluster", "elongated," and "salad". These typologies have different weights and shapes, and they are usually consumed in the Mediterranean area at different ripening stages. Results showed that the considered tomato typologies also differ in their antioxidative ability and their carotenoid and glycoalkaloid contents. Growing conditions are also important in determining fruit characteristics: the analysis of the same cultivar of cherry tomato produced under the influence of moderate salt stress showed increases in the lipophilic antioxidative ability and the amount of carotenoid, whereas the level of glycoalkaloid decreased.     

Processing effects on lycopene content and antioxidant activity of tomatoes

Consumption of tomato products has been associated with decreased risk of some cancer types, and the tomato antioxidant, lycopene, is thought to play an important role in the observed health effects. In this study, four carotenoids, trans-lycopene, phytofluene, phytoene, and zeta-carotene, were quantified in tomato products. Samples of raw tomatoes, tomato juice after hot break scalder, and final paste were obtained from two different processing plants over two years. Comparison of carotenoid levels throughout processing indicated that lycopene losses during processing of tomatoes into final paste (25-30 degrees Brix) ranged from 9 to 28%. The initial Brix level of the raw tomatoes appeared to influence the amount of lycopene loss that occurred, possibly due to the differences in processing time required to achieve the final desired Brix level of the paste. In general, no consistent changes in the other carotenoids were observed as a function of processing. The antioxidant activity of fresh tomatoes, tomato paste, and three fractions obtained from these products (i.e., aqueous, methanol, and hexane fractions) was also determined. In both a free radical quenching assay and a singlet oxygen quenching assay, significant antioxidant activity was found in both the hexane fraction (containing lycopene) and the methanol fraction, which contained the phenolic antioxidants caffeic and chlorogenic acid. The results suggest that in addition to lycopene, polyphenols in tomatoes may also be important in conferring protective antioxidative effects.     

猪血蛋白水解物对盆栽樱桃番茄生长和品质的影响

  【目的】  研究外源喷施不同浓度猪血蛋白水解物 (PP)对樱桃番茄植株生长和品质的影响,以期为高产优质樱桃番茄生产提供理论参考。  【方法】  以樱桃番茄品种“盆栽红”为试验材料,采用基质栽培,设置3个PP浓度:0 g/L (CK)、1 g/L (PP1)、2 g/L (PP2),在开花期进行叶面喷施,整个生育期共喷施6次。樱桃番茄在第三穗果实完全成熟后收获,分析外源PP对樱桃番茄植株生长、光合作用、养分吸收以及果实品质的影响。  【结果】  PP1和PP2处理不同程度地增加了番茄地上部、根部以及果实中氮、磷、钾含量,显著提高了叶片叶绿素含量、净光合速率 (Pn)、蒸腾速率 (Tr)和气孔导度 (Gs),植株地上部鲜重比CK处理分别增加了18.2%和40.6%,干重分别增加了42.3%和57.4%,且PP2处理的效果好于PP1处理。与CK处理相比,PP2处理番茄的产量、单果重、横径、纵径和硬度分别增加了37.4%、26.6%、16.3%、10.3%和30.8%,并有效改善了果实色泽,提高了樱桃番茄的外观品质。PP2处理有利于樱桃番茄果实中可溶性糖、可溶性蛋白、抗坏血酸和谷胱甘肽的积累,较CK分别增加了24.2%、25.5%、96.6%和30.9%;番茄果实中的总酚、类黄酮和花色素苷含量分别增加18.7%、33.3%和56.2%,DPPH自由基清除能力和铁还原抗氧化能力分别增加了27.7%和29.4%,显著提高了番茄果实的抗氧化活性。  【结论】  外源喷施2 g/L的猪血蛋白水解物能有效改善番茄植株的养分吸收和光合作用,促进植株生长和番茄品质的提升,是一种提高樱桃番茄产量、改善营养和功能性品质的高效有机措施。     

LED红蓝弱光照射保持樱桃番茄冷库贮藏品质

为了探究单色光对番茄冷藏过程中品质的影响,开发樱桃番茄保鲜新技术,以绿熟期樱桃番茄(Lycopersicon esculentum Mill.)为试材,在4℃条件下分别采用发光二极管(LED,light emitting diode)红蓝单色弱光(30 lx)持续照射,研究LED红蓝单色弱光对樱桃番茄采后贮藏过程中感官和主要营养品质指标的影响。结果表明:研制的LED试验装置稳定可靠,红蓝单色光的发射光谱稳定,不因光照强度的变化而发生偏移。贮藏10 d以后LED红蓝光处理的樱桃番茄感官品质显著优于无光对照(P0.05),且LED红光处理好于蓝光处理(P0.05)。LED蓝光照射能较好地保持樱桃番茄维生素C含量(P0.05),但LED红光照射不利于维生素C含量的保持。LED红蓝单色弱光照射有利于促进樱桃番茄早期贮藏过程中的还原糖和可溶性总糖积累,显著抑制贮藏后期糖含量的下降(P0.05)。LED红蓝单色弱光照射处理还能显著延缓樱桃番茄贮藏过程中可溶性固形物下降(P0.05),提高樱桃番茄果实可滴定酸的含量,其中LED红光处理显著高于蓝光处理(P0.05)。贮藏20 d时,红光照射可显著促进番茄红素的合成,但贮藏过程中LED蓝光照射与对照差异不显著(P0.05)。综合来看,与对照(CK)相比,LED红蓝弱光(30 lx)照射有利于樱桃番茄4℃贮藏过程中感官和营养价值的保持,其中LED红色弱光照射处理效果较好。作为一种简便可行的物理保鲜方法,LED红蓝弱光持续照射处理在樱桃番茄采后营养品质调控方面具有应用潜力。     

Irrigation with diluted seawater improves the nutritional value of cherry tomatoes

The aim of this study was to assess whether the nutritional value of cherry tomato can be improved by irrigating plants with diluted seawater (12%; EC = 10 mS/cm in comparison with a control at EC = 4 mS/cm). Berries of cherry tomato cv. Naomi were analyzed at the red-ripe stage for the contents of NADPH and NADP+ as well as for the amounts of the main antioxidants, such as ascorbic acid, lipoic acid, tocopherols, and phenolic acids. As compared to the controls, the fruits of salt-treated plants showed a higher titratable acidity and a higher concentration of reducing sugars. The fruits picked from tomato plants irrigated with diluted seawater produced berries characterized by a higher nutritional value. Following salinity, berries showed higher amounts of vitamin C, vitamin E, dihydrolipoic acid, and chlorogenic acid. It was hypothesized that protocatechuic, vanillic, caffeic, and ferulic acids were utilized to counteract the damaging effects of salinity-induced oxidative stress, allowing tomato fruits to maintain a high reduced status even following salinization.     

Chemical constituents and antioxidant activity of sweet cherry at different ripening stages

The development and ripening process of sweet cherry (Prunus avium L. cv. 4-70) on the tree was evaluated. For this purpose, 14 different stages were selected in accordance with homogeneous size and color. Some parameters related to fruit quality, such as color, texture, sugars, organic acids, total antioxidant activity, total phenolic compounds, anthocyanins, and ascorbic acid were analyzed. The results revealed that in sweet cherry, the changes in skin color, glucose and fructose accumulation, and softening process are initiated at early developmental stages, coinciding with the fast increase in fruit size. Also, the decrease in color parameter a was correlated with the greatest accumulation of total anthocyanins. Ascorbic acid, total antioxidant activity (TAA), and total phenolic compounds decreased during the early stages of sweet cherry development but exponentially increased from stage 8, which coincided with the anthocyanin accumulation and fruit darkening. TAA showed positive correlations (r(2) = 0.99) with both ascorbic acid and total phenolic compounds and also with the anthocyanin concentration from stage 8. Taking into account the reduced shelf life of sweet cherry and to ensure that these fruits reach consumers with the maximum organoleptic, nutritional, and functional properties, it is advisable to harvest sweet cherries at stage 12 of ripening.     

Influence of organic versus conventional agricultural practice on the antioxidant microconstituent content of tomatoes and derived purees; consequences on antioxidant plasma status in humans

The present study aims first to compare the antioxidant microconstituent contents between organically and conventionally grown tomatoes and, second, to evaluate whether the consumption of purees made of these tomatoes can differently affect the plasma levels of antioxidant microconstituents in humans. When results were expressed as fresh matter, organic tomatoes had higher vitamin C, carotenoids, and polyphenol contents (except for chlorogenic acid) than conventional tomatoes. When results were expressed as dry matter, no significant difference was found for lycopene and naringenin. In tomato purees, no difference in carotenoid content was found between the two modes of culture, whereas the concentrations of vitamin C and polyphenols remained higher in purees made out of organic tomatoes. For the nutritional intervention, no significant difference (after 3 weeks of consumption of 96 g/day of tomato puree) was found between the two purees with regard to their ability to affect the plasma levels of the two major antioxidants, vitamin C and lycopene.     

Changes in fruit antioxidant activity among blueberry cultivars during cold-temperature storage

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.     

Change in carotenoids and antioxidant vitamins in tomato as a function of varietal and technological factors

The change in the carotenoid and bioantioxidant content of tomato as a function of varietal and technological factors was investigated in the present work. No great differences were found between cultivars for fresh consumption (salad tomatoes) and those for processing in ascorbic acid content. The concentration of ascorbic acid ranged between 14.6 and 21.7 mg/100 g fresh weight of ripe tomato fruit. Processing cultivars contained higher amounts of tocopherols, particularly alpha-tocopherol than tomatoes for fresh consumption. Significant differences could be obtained between the examined varieties with regard to carotenoid concentration. The different tomatoes varied not only in the total carotenoid content but also in the qualitative distribution of some pigments such as lycopene, beta-carotene and lutein. During heat-based processing, ascorbic acid, tocopherols, and carotenoids showed different role and response. Ascorbic acid, alpha-tocopherol quinone, and beta-carotene were the most susceptible components toward thermal degradation.     

Evaluation of radical scavenging activity of fresh and air-dried tomatoes by three model reactions.

The radical scavenging activity and the antioxidant content of fresh and air-dried tomatoes were investigated. Tomato halves were dried in a pilot-scale dryer under the following conditions: air temperature, 80 degrees C; air flow rate, 1.5 m/s; drying time, 400 min; final moisture, 25%. Carotenoid (lycopene, beta-carotene, lutein) and ascorbic acid were analyzed by HPLC with a spectrophotometric and an electrochemical detector, respectively. Total phenolics were determined by using the Folin-Ciocalteu reagent. The radical scavenging activity was studied in three model systems: (a) the xanthine oxidase and xanthine system, which generates superoxide radical and hydrogen peroxide; (b) the 3-morpholinosydnonimine system, which releases spontaneously superoxide radical and nitrogen monoxide, forming peroxynitrite; (c) the linoleic acid and CuSO(4) system, which promotes lipid peroxidation. These model systems allow the simulation of key reactions involved in the pathogenesis of certain chronic diseases and may be related to the in vivo activity of tomato antioxidants. Hence, these measurements can be used for optimizing tomato processing and storage. The drying process resulted in a decrease of ascorbic acid content, whereas phenol reagent reducing compounds increased. Carotenoid levels were substantially unchanged upon drying. Fresh and air-dried tomato extracts could act as radical scavengers both in the reactive oxygen species-mediated reactions and in lipid peroxidation. Drying affected the antioxidant effectiveness as measured in the xanthine/xanthine oxidase system, which was found to be the most sensitive method for the measurement of tomato antioxidant activity (lower I(50)) but retained the antioxidant effectiveness in the other two systems.     

Antioxidant activity and general fruit characteristics in different ecotypes of Corbarini small tomatoes

Sixteen ecotypes of Corbarini small tomatoes were studied. The antioxidant activity was evaluated with the DMPD (N, N-dimethyl-p-phenylenediamine) method in the water-soluble fraction (S-AA) and with the ABTS [2, 2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid)] method in the water-insoluble fraction (I-AA). S-AA and I-AA were strongly related to each other, varying to a large extent between the ecotypes considered. They were also significantly correlated with fruit weight, total solids, and refractive index. The combination of the latter variables (by multiple regression analysis) accounted for 36% and 44% of the total variability of S-AA and I-AA, respectively. Moreover, when the ecotypes were subdivided according to their shape (round, pear-shaped, oval, and long), S-AA and I-AA were both significantly higher in round tomatoes and lower in the long ones. In conclusion, the antioxidant activity varies to a considerable extent between different ecotypes of Corbarini small tomatoes. These differences are related to shape and some other fruit characteristics.     

Identification and quantification of antioxidant components of honeys from various floral sources

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

Chlorophyll and carotenoid patterns in olive fruits, Olea europaea Cv. arbequina

In olive fruits of the cultivar Arbequina, the chlorophyll pigments decrease significantly throughout ripening, while the carotenoids decrease more gradually and discontinuously. There is no degradation of the carotenoid fraction in stages before complete ripeness. The presence of esterified xanthophylls exclusively in this variety suggests that the chloroplast pigment metabolism is different from that in other olive varieties studied previously. There are increases of specific carotenoids, violaxanthin, neoxanthin, antheraxanthin, lutein epoxide, and esterified xanthophylls between the light green and yellowish green ripening stages. Such increases are related to the detection of precursor carotenoids (phytofluene and xi-carotene) in the yellowish green stage. Chlorophyllides (a and b) and alpha-carotene have also been detected exclusively in this variety. Quantitatively, the drastic change in color between light green and yellowish green ripening stages characteristic of this variety can be explained by the considerable reduction found in the chlorophylls/carotenoids ratio. The study of the pigments present in skin and pulp has shown that the pattern of carotenoid distribution differs depending on the fruit part concerned.     

Postharvest treatments with salicylic acid, acetylsalicylic acid or oxalic acid delayed ripening and enhanced bioactive compounds and antioxidant capacity in sweet cherry

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.