Characterization and quantitation of antioxidant constituents of sweet pepper (Capsicum annuum L.)

Sweet peppers (Capsicum annuum L.) cv. Vergasa have been studied at four maturity stages (immature green, green, immature red, and red). The individual phenolics (hydroxycinnamic acids and flavonoids), vitamin C (ascorbic acid and dehydroascorbic acid), and individual carotenoids were characterized and quantified. Five hydroxycinnamic derivatives and 23 flavonoids were characterized and quantified from the pericarp of sweet pepper by high-performance liquid chromatography-diode array detection-electrospray ionization-mass spectrometry. Identification was carried out by their UV spectra, chromatographic comparisons with authentic markers, identification of hydrolysis products, and tandem mass spectrometry analysis. Hydroxycinnamic derivatives, O-glycosides of quercetin, luteolin, and chrysoeriol, and a large number of C-glycosyl flavones have been characterized. Some of these compounds were found for the first time in nature. Clear differences in the individual and total phenolic content were detected between the different maturity stages. Immature green pepper had a very high phenolic content while green, immature red, and red ripe peppers showed a 4-5-fold reduction. Ascorbic acid was the main form of vitamin C, and its content increased as the pepper reached maturity. The red ripe stage had a relevant impact on the carotenoids content. Thus, immature green peppers showed the highest content of polyphenols, while red ripe fruits had the highest content of vitamin C and provitamin A.     

Firmness and phytochemical losses in pasteurized yellow banana peppers (Capsicum annuum) as affected by calcium chloride and storage

The effect of calcium chloride brine treatment on firmness and retention of phytochemicals in pastuerized yellow banana peppers was studied. Shear force values declined during processing and storage, but CaCl(2) treatment resulted in greater firmness retention. Processing reduced ascorbic acid content by 63%, and after 124 days, <10% of ascorbic acid remained. Quercetin and luteolin contents declined 45% during processing, but levels stabilized during storage. Capsaicinoid content was stable during processing and storage. CaCl(2) treatment did not affect ascorbic acid, flavonoid, or capsaicinoid retention during pasteurization and storage. Retention of phytochemicals appeared to be related to their solubility and structural properties.     

Low-density lipoprotein antioxidant activity of phenolic compounds and polyphenol oxidase activity in selected clingstone peach cultivars

The antioxidant potential of eight clingstone peach cultivars was investigated by determining phenolic compounds and inhibition of low-density lipoprotein (LDL) oxidation. Cultivars low in polyphenol oxidase (PPO) were also selected to minimize enzymatic browning. Inhibition of LDL oxidation varied from 17.0 to 37.1% in peach flesh extract, from 15.2 to 49.8% in whole peach extract, and from 18.2 to 48.1% in peel extract. Total phenols were 432.8-768.1 mg/kg in flesh extract, 483.3-803.0 mg/kg in whole extract, and 910.9-1922.9 mg/kg in peel extract. The correlation coefficient between relative LDL antioxidant activity and concentration of total phenols was 0.76. Peel PPO activity was higher than flesh activity in most cultivars. The lowest PPO and specific activities were found in the Walgant cultivar, followed by Kakamas and 18-8-23. These three cultivars combine the desirable characteristics of strong antioxidant activity, low PPO activity, and lower susceptibility to browning reactions.     

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.     

Antioxidant activity of the main phenolic compounds isolated from hot pepper fruit (Capsicum annuum L)

Four cultivars (Bronowicka Ostra, Cyklon, Tornado, and Tajfun) of pepper fruit Capsicum annuum L. were studied for phenolics contents and antioxidant activity. Two fractions of phenolics, flavonoids (with phenolic acids) and capsaicinoids, were isolated from the pericarp of pepper fruit at two growth stages (green and red) and were studied for their antioxidant capacity. Both fractions from red fruits had higher activities than those from green fruits. A comparison of the capsaicinoid fraction with the flavonoid and phenolic acid fraction from red fruit with respect to their antioxidant activity gave similar results. Phenolic compounds were separated and quantified by LC and HPLC. Contents of nine compounds were determined in the flavonoid and phenolic acid fraction: trans-p-feruloyl-beta-d-glucopyranoside, trans-p-sinapoyl-beta-d-glucopyranoside, quercetin 3-O-alpha-l-rhamnopyranoside-7-O-beta-d-glucopyranoside, trans-p-ferulyl alcohol-4-O-[6-(2-methyl-3-hydroxypropionyl] glucopyranoside, luteolin 6-C-beta-d-glucopyranoside-8-C-alpha-l-arabinopyranoside, apigenin 6-C-beta-d-glucopyranoside-8-C-alpha-l-arabinopyranoside, lutoeolin 7-O-[2-(beta-d-apiofuranosyl)-beta-d-glucopyranoside], quercetin 3-O-alpha-l-rhamnopyranoside, and luteolin 7-O-[2-(beta-d-apiofuranosyl)-4-(beta-d-glucopyranosyl)-6-malonyl]-beta-d-glucopyranoside. The main compounds of this fraction isolated from red pepper were sinapoyl and feruloyl glycosides, and the main compound from green pepper was quercetin-3-O-l-rhamnoside. Capsaicin and dihydrocapsaicin were the main components of the capsaicinoid fraction. A high correlation was found between the content of these compounds and the antioxidant activity of both fractions. Their antioxidant activities were elucidated by heat-induced oxidation in the beta-carotene-linoleic acid system and the antiradical activity by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) decoloration test. The highest antioxidant activity in the beta-carotene-linoleic acid system was found for trans-p-sinapoyl-beta-d-glucopyranoside, which was lower than the activity of free sinapic acid. Quercetin 3-O-alpha-l-rhamnopyranoside had the highest antiradical activity in the DPPH system, which was comparable to the activity of quercetin. The activities of capsaicin and dihydrocapsaicin were similar to that of trans-p-feruloyl-beta-d-glucopyranoside in the DPPH model system.     

Adsorption,activity, and kinetics of acid phosphatase as influenced by selected oxides and clay minerals

Abstrac

The effects of 3 oxides (Fe, Al, and Mn oxides) and 3 clay minerals (kaolin, montmorillonite, and allophane) on the adsorption and subsequent kinetic properties of acid phosphatase were compared. The amount of enzyme adsorbed by the oxides and clay minerals followed the order: montmorillonite ? kaolin > Mn oxide > Fe oxide > Al oxide ? allophane. The adsorption isotherms of the enzyme on the oxides and clay minerals, except for montmorillonite and allophane, fitted the Langmuir equation. The activity of the enzyme immobilized by the inorganic components studied was in the order of allophane > kaolin > Fe oxide > montmorillonite > Al oxide ≒ Mn oxide. Compared to the free enzyme, the V _max, K_m, and V _max / K _m values of the immobilized enzyme decreased, increased, and decreased, respectively. Among the oxides or clay minerals, the higher the ability of the inorganic components to adsorb the enzyme, the lower the value of the V _max / K _m ratio of the immobilized enzyme. These findings suggest that the catalytic efficiency of the enzyme complexes formed is determined by the adsorbability of the inorganic components for the enzyme.     

Activity and process stability of purified green pepper (Capsicum annuum) pectin methylesterase

Pectin methylesterase (PME) from green bell peppers (Capsicum annuum) was extracted and purified by affinity chromatography on a CNBr-Sepharose-PMEI column. A single protein peak with pectin methylesterase activity was observed. For the pepper PME, a biochemical characterization in terms of molar mass (MM), isoelectric points (pI), and kinetic parameters for activity and thermostability was performed. The optimum pH for PME activity at 22 degrees C was 7.5, and its optimum temperature at neutral pH was between 52.5 and 55.0 degrees C. The purified pepper PME required the presence of 0.13 M NaCl for optimum activity. Isothermal inactivation of purified pepper PME in 20 mM Tris buffer (pH 7.5) could be described by a fractional conversion model for lower temperatures (55-57 degrees C) and a biphasic model for higher temperatures (58-70 degrees C). The enzyme showed a stable behavior toward high-pressure/temperature treatments.     

Carotenoid biosynthesis changes in five red pepper (Capsicum annuum L.) cultivars during ripening. Cultivar selection for breeding

Changes in the biosynthesis of individual carotenoid pigments have been investigated during fruit ripening of five cultivars of red pepper (Capsicum annuum L.): Mana, Numex, Belrubi, Delfin, and Negral (a chlorophyll-retaining mutant when ripe). The study was carried out throughout the ripening process, and with special emphasis on the ripe stage, to discover possible differences between cultivars and to characterize these by their carotenoid pattern and content for selecting the best varieties for breeding programs. Ripening fruit of the five cultivars showed the typical and characteristic pattern of carotenoid biosynthesis for the Capsicum genus. In the five cultivars, lutein and neoxanthin, both characteristic chloroplast pigments, decreased in concentration with ripening and eventually disappeared. beta-Carotene, antheraxanthin, and violaxanthin increased in concentration, and other pigments were biosynthesized de novo: zeaxanthin, beta-cryptoxanthin, capsanthin, capsorubin, capsanthin-5,6-epoxide, and cucurbitaxanthin A. A pool of zeaxanthin stands out of the rest of pigment during ripening, which reveals the importance of this pigment as a branching point in the carotenoid biosynthesis in Capsicum. Quantitatively, Negral cultivar showed the highest increase in total carotenoid content (48. 39-fold), followed by Mana and Delfin with 38.03- and 36.8-fold, respectively, and by Belrubi and Numex with 28.03- and 23.48-fold, respectively. In all the red varieties, there was an inverse relationship between total carotenoid content and the red to yellow isochromic pigment fraction ratio (R/Y) and the capsanthin-to-zeaxanthin ratio (Caps/Zeax). This seems to be related to the carotenogenic capacity of the cultivar, and thus selection and breeding should not only seek a higher total carotenoid content but also attempt to increase these ratios. In the present study, the cultivar Mana had the highest total carotenoid content (13 208 mg/kg dwt), but the lowest R/Y (1.25) and Caps/Zeax (3.38) ratios, which are therefore the parameters to improve. The cultivar Negral had a high carotenoid content (8797 mg/kg dwt) and high R/Y and Caps/Zeax ratios and could be used for transfer of these characters in direct crosses with the cultivar Mana. The cultivar Numex had the highest Caps/Zeax ratio (7.17) and is thus an ideal progenitor for this character.     

Interactions of soil microorganisms on growth and disease incidence of pepper (Capsicum annum)

The effect of interactions between soil borne pathogen, Phytophthora infestans the antagonistic organism Trichoderma viride and Arbuscular mycorrhizal Glomus etunicatum on growth and disease severity of pepper Capsicum annum was investigated in a greenhouse experiment. Pepper seedlings inoculated with the pathogen alone had sever disease symptoms. While those inoculated with mycorrhizal alone had the highest flowering and fruiting values, followed by the pepper seedlings inoculated with Trichoderma viride. But pepper seedlings simultaneously or dually inoculated with the three microorganisms also had good growth parameters, such as early and high flowering incidence, fruit maturity increase in leaf number, height and growth, while the effect of the pathogen was highly suppressed.     

Mineral composition of bermudagrass as influenced by maturity and nitrogen in a cool,temperate environment

Abstract

Warm‐season grasses contribute substantially to herbage supply during summer in cool‐temperate environments, when the productivity of cool‐season grasses declines. Herbage digestibility as well as mineral concentration may limit the amount of essential nutrients available to meet grazing animal requirements. A field study was conducted to determine the productivity and quality of a new selection of bermudagrass [Cynodon dactylon (L) Pers.], RSl, which is capable of growth and persistence in areas where other cultivars of bermudagrass are likely to winterkill. Concentrations and uptake of mineral nutrients in RSl bermudagrass were determined in response to N levels (0, 120, 240, and 360 kg N/ha) and delayed initial harvest (advancing maturity) at 2, 4, and 6 weeks after active growth began. Concentrations of P, Ca, K, Mg, and S in early season growth generally declined with advancing maturity. Concentrations of elements showed mixed response to N levels, and generally were not affected by treatments late in the growing season. Early in the growing season, mineral uptakes increased with advancing maturity. Increasing N levels early and late in the growing season enhanced mineral uptake. Mineral ratios, such as N:S and K (Ca + Mg), were within critical limits for adequate animal nutrition, but the Ca:P ratio was less than 2:1 and could contribute to known mineral‐related disorders in male sheep. Herbage mineral concentrations of RSl generally met or exceeded mineral nutrient requirements for sheep and cattle in growing or lactating physiological states.     

辣椒果实钙吸收累积的基因型差异及其生理特征

采用砂培试验研究了 16个辣椒品种对Ca吸收累积的基因型差异和产生差异的生理特征。结果表明 ,在不同供Ca水平下 ,辣椒果实Ca含量的品种间差异明显 ,按供Ca水平与果实Ca累积关系 ,将其分为 :不敏感型 (低Ca时果实Ca降幅 10 % ,高Ca时降幅 >10 % )和增Ca潜力型 (果实Ca随供Ca水平提高而提高 ,增幅 >10 % )三个基因型。比较讨论了三类基因型品种在根系形态特征、叶片蒸腾速率和CAT活性的差异 ,说明辣椒吸收养分及适应能力、蒸腾速率、生物膜的自我保护或修复能力与Ca营养基因型密切相关     

Calcium uptake and concentration in bell pepper plants as influenced by nitrogen form and stages of development

Calcium uptake by bell pepper (Capsicum annuum L. cv. ‘California Wonder') varied by stage of plant development and N form supplied (NO₃ ^‐NH₄ ⁺ ratios: 1:0, 3:1, 1:1, 1:3, and 0:1) in a hydroponic study. Uptake of Ca⁺⁺ was highest at bloom and during fruit expansion, making the fruit development stage the highest demand period. Calcium uptake declined with each increasing increment of NH₄ ⁺ relative to NO₃ ^‐ supplied, although fruit yield was not significantly reduced until the ratio of NH₄ ⁺ to NO₃ ^‐ exceeded 50%. Tissue Ca⁺⁺ levels in the blossom‐end of the fruit were reduced whenever NH₄ ⁺ was included with N supplied. Vegetative yield of plants followed the same trend as that observed for total fruit dry weights. Our results indicate that pepper yields are higher when NO₃ ^‐ is the predominant form of N. Also, these results strongly suggest that Ca⁺⁺ fertilizer applications should precede the bloom period and continue during fruit development to ensure adequate Ca⁺⁺ availability for fruit development.     

Microbial biomass phosphorus and alkaline phosphomonoesterase activity in the rhizosphere of different wheat cultivars as influenced by inorganic phosphorus and farmyard manure

Wheat cultivars C 306, PBW 175, HD 1553, and HD 2329 were grown in an alkaline soil with and without inorganic P fertilizer and/or farmyard manure in a pot culture experiment. Microbial biomass P (MBP) and alkaline phosphomonoesterase (APM) activities were studied in rhizosphere soils of the above wheat cultivars at different physiological stages. Root weight and P uptake were also estimated simultaneously. Higher microbial biomass P was observed at crown root initiation (CRI) stage while APM activities were higher at panicle initiation (PI) stage. The HD cultivars showed higher MBP and APM activities at PI stage, while at CRI stage, the reverse was true. Though the application of inorganic P apparently showed higher APM activity, the ratio of APM activity and microbial biomass P (APM to MBP) decreased in the presence of inorganic fertilizer P. Inorganic P compared to FYM was the more dominant factor in reducing the APM to MBP ratio. Root weight did not correlate with grain yield. From step-wise regression analysis, it was revealed that microbial biomass P at both CRI and PI stages was a significant factor in influencing the P uptake in relation to grain yield of wheat.     

Analysis of molecular species of glycolipids in fruit pastes of red bell pepper (Capsicum annuum L.) by high-performance liquid chromatography-mass spectrometry

Five major glycolipid classes (acylated steryl glucoside, steryl glucoside, monogalactosyldiacylglycerol, digalactosyldiacylglycerol, and glucocerebroside) from fruit pastes of red bell pepper were separated by silica gel column chromatography. The molecular species of each glycolipid were separated and characterized by reversed-phase high-performance liquid chromatography coupled with on-line mass spectrometry using atmospheric pressure chemical ionization. The molecular species of steryl glucoside were beta-sitosteryl and campesteryl glucosides, and those of the acylated steryl glucoside were their fatty acid esters. The dilinolenoyl species was predominant in monogalactosyldiacylglycerol in addition to small amounts of another five molecular species, whereas digalactosyldiacylglycerol consisted of seven molecular species varying in their degree of unsaturation. The glucocerebroside class contained at least seven molecular species, which were characterized by proton nuclear magnetic resonance spectroscopy.     

Essential oil of Valeriana officinalis L. cultivars and their antimicrobial activity as influenced by harvesting time under commercial organic cultivation

The essential oil content and the composition of subterranean parts of two valerian (Valeriana officinalis, L.) cultivars Select and Anthose, from certified commercial organic fields, were determined by hydrodistillation, followed by gas chromatography (GC) and GC/mass spectrometry analysis. Eight and fourteen month old cv. Select had 0.67 and 0.87% essential oil, while similar aged cv. Anthose contained 0.97 and 1.1% essential oil. Forty-three and fifty-three components from cv. Select and cv. Anthose oils were detected, respectively. The oil composition significantly varied due to the cultivar type, plant age, and/or harvesting time. The major components for cv. Select were valerenal, bornyl acetate, 15-acetoxy valeranone, valerenic acid, and camphene, while cv. Anthose had valerenal, (-)-bornyl acetate, alpha-humulene, camphene, 15-acetoxy valeranone, and valerenic acid. With further aging of the plants, the valerenal, valerenic acid, and alpha-humulene contents increased. The oil of cv. Select had a strong antimicrobial effect against Aspergillus niger, Escherichia coli, Staphylococcus aureus, and Saccharomyces cerevisiae, while cv. Anthose showed low or no activity against all test microbes, including Pseudomonas aeruginosa, suggesting that the inhibitory activity of valerian oil depends on the cultivar and its developmental stage. The oil profile of our cultivars did not match the literature proposed chemotype profiles.     

Soil organic matter distribution as influenced by enchytraeid and earthworm activity

Loam and sandy soils, and the earthworm casts produced with ¹⁴C-labelled plant material in both soils, were incubated in airtight glass vessels with and without enchytraeids to evaluate the effects of soil fauna on the distribution and fragmentation of organic matter. After 1, 3, and 6 weeks, the amount of C mineralised was determined in soils and earthworm casts, and the soil was fractionated into particulate organic matter (POM), the most active pool of soil organic matter, after complete physical dispersion in water. The percentage weight of fine fractions (0-50 µm) was 67.4% in the loam soil. Sand (coarse, i.e. 150-2,000 µm and fine 50-150 µm) represented 87.2% of total weight in sandy soil, while the percentages of C (PC) were 23.2% in coarse POM (2,000-150 µm) and 11.9% in fine POM (150-50 µm). These percentages were higher than those in loam soil, i.e. 3.4% (coarse POM) and 5.4% (fine POM). The PC in coarse POM (9.50%) and fine POM (16.4%) remained higher in casts from sandy soil than in casts from loam soil (4.7% in coarse and 14.3% in fine POM). The highest percentages of ¹⁴C-labelled leaves were found in fine fractions, 55.9% in casts from loam soil and 48.8% in casts from sandy soil. The C mineralisation of the added plant material was higher in casts from the sandy soil (20.3%) than from the loam soil (13.5%). Enchytraeids enhanced C mineralisation in the bulk sandy soil, but did not affect the mineralisation of added plant material in either soil. The main enchytraeid effect was enhancement of the humification process in the bulk sandy soil, the casts from this soil, and the bulk loam soil.     

Kinetics of the desorption of mercury from selected freshwater sediments as influenced by chloride

The kinetics of Hg desorption from selected freshwater sediments in the Canadian Prairies as influenced by a range of chloride concentrations (0, 10⁻⁴, 10⁻³, 10⁻², 2×10⁻², 4×10⁻², 6×10⁻², 8×10⁻², 10⁻¹ M) were studied. The extent of the influence of Cl⁻ concentrations on the increase of the rate of Hg release from the sediments in the fast desorption and slow desorption processes varied from 2.5 to 10.5 times and 2.0 to 8.5 times, respectively. An abrupt increase in the Hg release from the sediments was observed when the Cl⁻ concentration was 2×10⁻² M and higher. The increase of Hg release with increasing Cl⁻ concentrations was attributed to the dissolution of the adsorbed Hg through its complexation with Cl⁻. The release of Hg was not affected by the ionic strength and the Na concentrations in the systems studied. The influence of Cl- concentrations on the kinetics of the release of the sediment-bound Hg varied with the nature and properties of the sediments. The data indicate that short-range ordered oxides of Al, Fe, and Mn and their complexes with organic components merit close attention in studying the influence of Cl⁻, whose sources include deicing salts, fertilizers, animal wastes, and sewage effluents, on the rate of the dispersion of Hg from freshwater sediments.     

Variation in major antioxidants and total antioxidant activity of Yuzu (Citrus junos Sieb ex Tanaka) during maturation and between cultivars

Epidemiological studies suggest that a high consumption of fruits can reduce the risk of some cancers and cardiovascular disease, and this may be attributable to the antioxidant activity of vitamins and phenolic compounds. The present study investigated the variations in vitamin C, total phenolic, hesperidin, and naringin contents, and total antioxidant activity of yuzu (Citrus junos Sieb ex Tanaka)-which is a popular citrus fruit in Korea and Japan-between cultivars and during maturity. The amounts of phenolics and vitamin C and the antioxidant activity in all tested yuzu cultivars were higher in peel than in flesh. Ripening increased the total antioxidant activity and vitamin C content in both peel and flesh of yuzu. However, the amounts of all total phenolics, hesperidin, and naringin in peel increased with ripening, whereas they decreased slightly in flesh. There was a highly linear relationship between the vitamin C content and the total antioxidant activity in both peel (r(2) = 1.000) and flesh (r(2) =0.998), suggesting that vitamin C plays a key role in the antioxidant activity of yuzu. In addition, the contribution of each antioxidant to the total antioxidant activity of yuzu was determined using a 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging assay and is expressed here in terms of the vitamin C equivalent antioxidant capacity (VCEAC). The means of vitamin C, naringin, and hesperidin in yuzu were 90.4, 63.8, and 65.7 mg/100 g fresh yuzu, respectively. The relative VCEAC values of these compounds were in the following order: vitamin C (1.00) > naringin (0.195) > hesperidin (0.162). Therefore, the estimated contribution of each antioxidant to the total antioxidant capacity of 100 g of fresh yuzus is as follows (in mg of VCEAC): vitamin C (90.36 mg) > naringin (12.44 mg) > hesperidin (10.64 mg). Our results indicate that mature yuzu contains higher amounts of vitamin C and phenolics than other citrus fruits and could therefore be used as a significant dietary source of antioxidants.     

Change in the carotenoid and antioxidant content of spice red pepper (paprika) as a function of ripening and some technological factors

A study was conducted to investigate the change in quality attributes of red pepper (paprika) (Capsicum annuum L. var. Km-622) as a function of ripening and some technological factors. Of quality attributes, carotenoids and bioantioxidants (ascorbic acid and tocopherols) have been studied. It was found that the dynamics of fruit ripening with regard to carotenoids and bioantioxidants was influenced to a considerable extent by weather conditions of the production season. A rainy and cool season yielded fruits with more beta-carotene but less diesters of red xanthophylls as compared to those produced in a relatively dry and warm season. The ripening stage at harvest was found to affect the quality of paprika. Harvest at unripe stages (color break or faint red) resulted in a high accumulation of dehydroascorbic acid in the overripe fruits, whereas de novo biosynthesis of carotenoids and tocopherols was partially retarded. Application of pre-drying centrifugation resulted in a marked loss of ascorbic acid, and as a consequence, carotenoid stability was impaired during the storage of ground paprika. Sugar caramelization caused dry pods and ground paprika to retain more pigments and tocopherol as compared to those from control or centrifuged red pepper samples. During the storage of ground paprika, color stability was improved by grinding the seeds with the pericarp.