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Chrysanthemum is among the oldest plants cultivated by man, being widely cultivated in Brazil. In view of its economic importance and use in breeding, the present study aims to characterize mini chrysanthemum varieties, focusing on morphological and physiological parameters. Therefore, four varieties of mini chrysanthemums, in pots, were acquired in the local market: V1 - ‘Swifty Light Pink’ (purple), V2 - ‘Diablo Time’ (red), V3 - ‘White Cherie’ (white); V4 - ‘Giovanni’ (yellow), from which they were taken leaves and inflorescences samples for measurement of height, diameter and fresh mass, as well as to quantify the total soluble sugar (TSS, %), reducing sugar (RS, %), non-reducing sugar (NRS, %), anthocyanin and chlorophyll contents. Regarding the characterization of inflorescences, it was found that ‘Diablo Time’ had the largest diameter, height and fresh weight, in these last two cases not differing from ‘Giovanni’, which had lower anthocyanin content; while the highest values of carbohydrate content were found in ‘White Cherie’. In relation to the characterization of the leaves, ‘Giovanni’ had the largest dimensions, fresh mass and chlorophyll content. Already ‘Swifty Light Pink’ stood as to the sugar contents. Thus, it is clear that there are morphophysiological differences between the chrysanthemum mini varieties, which can contribute to breeding programs. Resumo O crisântemo faz parte do conjunto de plantas mais antigas a serem cultivadas pelo homem, possuindo grande área de produção de flores no Brasil. Diante de sua importância econômica e uso em melhoramento genético, o presente trabalho tem como objetivo caracterizar variedades de minicrisântemos, com ênfase em parâmetros morfológicos e fisiológicos. Para tanto, foram adquiridas no comércio local, quatro variedades de minicrisântemos em vaso: V1 - ‘Swifty Light Pink’ (lilás), V2 - ‘Diablo Time’ (vermelho), V3 - ‘White Cherie’ (branco); V4 - ‘Giovanni’ (amarelo), das quais foram retiradas amostras de folhas e inflorescências para a mensuração de altura; diâmetro; massa fresca, bem como quantificação do teor de açúcares solúveis totais (AST%), açúcares redutores (AR%) e açúcares não redutores (ANR%); teor de antocianina e clorofila. Quanto à caracterização das inflorescências, constatou-se que a ‘Diablo Time’ apresentou o maior diâmetro, altura e massa fresca, nestes dois últimos casos não diferindo de ‘Giovanni’, que apresentaram menor teor de antocianina; enquanto que os maiores valores de teor de carboidrato foram verificados em ‘White Cherie’. No que se refere à caracterização das folhas, ‘Giovanni’ apresentou as maiores dimensões, massa fresca e teor de clorofila. Enquanto ‘Swifty Light Pink’ se destacou quanto aos teores de açúcares. Assim, percebe-se que há diferenças morfofisiológicas entre as variedades de minicrisântemo, o que pode contribuir em programas de melhoramento genético.

Cycnoches haagii Barb. Rodr. is an epiphytic orchid very targeted by collectors, but no reference was found in the literature about its reproductive biology. Thus, the purpose of this study was to obtain initial information regarding pollination types and its influence on seed viability of this native orchid of the Brazilian Cerrado, in order to enable future propagation and preservation programs. Pollination among flowers of the same plant (geitonogamy) or different plants (xenogamy) were carried out. Seeds extracted from the capsules were sown in B&G medium, with full and half strength. Seeds from geitonogamic resulted in 25% of albino protocorms and consequently in albino seedlings. This phenomenon did not occur in seedlings derived from xenogamic pollination. Pigment analysis showed that even the albino seedlings presented chlorophylls and carotenoids, however, in significantly minor concentrations, 16% and 37% respectively, in relation to green seedlings. Geitonogamic and xenogamic pollinations resulted in C. haagii viable seeds with high germination percentage (90%) under in vitro conditions. The germination of seeds from xenogamic pollination resulted in chlorophyll or normal seedlings only, and can be recommended at conservation programs. On the other hand, although geitonogamic pollination should be avoided at conservation programs of this orchid species as it leads to albino seedlings, it showed a very interesting system to obtain seedlings with this phenotype, an interesting plant material to future investigation. Resumo Cycnoches haagii é uma orquídea epífita alvo de muitos coletores, mas nenhuma referência foi encontrada na literatura sobre sua biologia reprodutiva. Assim, o objetivo deste estudo foi obter informações preliminares sobre os tipos de polinização e sua influência na viabilidade das sementes desta orquídea nativa do Cerrado brasileiro, a fim de viabilizar futuros programas de multiplicação e preservação. Foram realizadas polinizações entre flores da mesma planta (geitonogamia) ou plantas diferentes (xenogamia). As sementes obtidas das cápsulas foram semeadas em meio B&G, com concentração total e parcial de sais. Sementes de geitonogamia resultaram em 25% dos protocormos albinos e consequentemente em plântulas albinas. Este fenômeno não ocorreu em sementes oriundas de polinização xenogâmica. A análise de pigmentos mostrou que mesmo as plântulas albinas apresentaram clorofilas e carotenoides, porém em concentrações significativamente menores, 16% e 37% respectivamente, em relação às plântulas pigmentadas. A polinização geitonogâmica deve ser evitada em programas de propagação da orquídea C. haagii devido à origem de plântulas albinas. Além disso, a polinização xenogâmica mostrou-se um método muito interessante para a obtenção de mudas com fenótipo albino, material vegetal muito intrigante para futuras investigações.

The two hydroxyl groups of the 4′,7-dihydroxyfurano-3,2′-flavylium cation (1), a synthetic analog of the aurone pigments of plants, have been shown to have different relative acidities in the ground state (S0) and the lowest excited singlet state (S1). In the ground state, the 4′-OH group is slightly more acidic, while in the excited state, the molecule is strongly photoacidic and deprotonation occurs preferentially from the 7-OH group. In order to compare the relative acidities of these two OH groups via quantum chemical methodology, a common reference state was employed in which an explicit water molecule was hydrogen-bonded to each of the OH groups of 1. The relative acidities of the two OH groups were then inferred from the differential change in energy along the coordinate for proton transfer to the explicit water molecule via time-dependent density functional calculations (B3-LYP with Grimme’s D3 dispersion correction; TZVP basis set; and PCM to simulate an aqueous environment). The calculated acidity changes confirm the experimentally observed inversion in the relative acidities between S0 and S1. The enhanced photoacidity of S1 was also mirrored in the natural transition orbitals and the decrease in the negative change on the oxygen atoms of the OH groups. Employing a common reference state with an explicit water as the proton acceptor should thus serve as a convenient strategy for exploring the relative ground- and excited-state acidities of the OH groups of natural or synthetic dyes, especially when the values are not readily accessible through experiment.

Submitted by Gilmar Da Silveira Sousa Júnior (gilmar.sousa@unesp.br) on 2021-02-01T17:36:17Z No. of bitstreams: 1 Gilmar_da_Silveira_Sousa_Junior_TESE.pdf: 2402121 bytes, checksum: c3789374956b197e3206124a25687bb8 (MD5) Approved for entry into archive by Laudicélia Martins Arantes (lm.arantes@unesp.br) on 2021-02-01T20:32:06Z (GMT) No. of bitstreams: 1 sousajunior_gs_dr_jabo.pdf: 2447272 bytes, checksum: 78a339db6e2c45f6787a0f9aa7c14a4c (MD5) Made available in DSpace on 2021-02-01T20:32:06Z (GMT). No. of bitstreams: 1 sousajunior_gs_dr_jabo.pdf: 2447272 bytes, checksum: 78a339db6e2c45f6787a0f9aa7c14a4c (MD5) Previous issue date: 2020-12-04 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) O excesso de alumínio (Al), é considerado um dos principais fatores limitantes do crescimento e desenvolvimento das plantas, devido à toxicidade do metal. Atualmente, o cultivo de cana-de-açúcar se faz presente em, aproximadamente, 50% das terras que apresentam toxicidade por Al. Nesse sentido, estudos anteriores com indutores de tolerância, como o Silício (S), mostraram atenuar os efeitos deletérios de vários estresses. Porém, ainda são escassas as pesquisas do Si como um atenuador da toxicidade de Al em cana de açúcar. O objetivo desse estudo foi verificar o efeito atenuador da aplicação de Si em plantas jovens de cana-de-açúcar sob toxicidade de Al em sistema hidropônico. Para tanto, em casa de vegetação foi conduzido um sistema hidropônico, com delineamento experimental em blocos casualizados (2x4x2): com duas cultivares de cana de açúcar (CTC9003 e CTC9002) e os tratamentos formados pela ausência e presença de Si (0 e Si 2,0 mmol L-1 K2SiO3); e com quatro concentrações de Al (0, 10, 15 e 20mg L-1 Al2(SO4)3.18H2O). Foram realizadas as avaliações de acúmulo de lignina, pigmentos vegetais, trocas gasosas, densidade estomática, peróxido de hidrogênio (H2O2), peroxidação lipídica (malondialdeído [MDA]), atividade de enzimas antioxidantes (superóxido dismutase, SOD; ascorbato peroxidase, APX; guaiacol peroxidase, GPOX), bem como a eficiência de uso e acúmulo de nutrientes e crescimento (área foliar e massa seca). Nossos resultados demonstraram que, nas plantas estressadas com Al, o Si proporcionou aumento no teor de lignina, aumento do número de estômatos e das trocas gasosas, menor redução dos pigmentos fotossintéticos e da peroxidação lipídica, aumento da atividade das enzimas antioxidantes, maior acúmulo e eficiência nutricional e maior crescimento de plantas em comparação a aquelas com Al e sem Si. A cv. CTC9003 apresentou melhor resposta de atenuação pelo Si na toxicidade de alumínio. The excess of aluminum (Al) is considered one of the major factors limiting plant growth and development, due the metal toxicity. Currently, about 50% of the land with Al toxicity cultivates sugarcane. In this regard, previous studies of tolerance inducers, such Silicon (Si), have been shown to attenuate the deleterious effects of several stresses. However, research on Si as an attenuator of aluminum toxicity in sugar cane remain unclear. The aim of this study was to verify attenuate effect of applying Si in young sugarcane plants under Al toxicity on hydroponic system. A hydroponic experiment was conducted under greenhouse conditions using a randomized block design (2x4x2): with two sugarcane cultivars (CTC9003 and CTC9002) and treatments were formed by absence and presence of Si application (0 and Si 2,0 mmol L-1 K2SiO3); and with four concentrations of Al (0, 10, 15 e 20mg L-1 Al2(SO4)3.18H2O). Lignin content, pigments, gas exchange, stomatal density, hydrogen peroxide, (H2O2), lipid peroxidation (malondialdehyde [MDA]), antioxidant enzymes activities (superoxide dismutase, SOD; ascorbate peroxidase, APX; guaiacol peroxidase, GPOX), as well efficiency of use and nutrient accumulation and growth (leaf area and dry biomass) were determined. Our results demonstrated that plants stressed with Al, the Si provided an increase in lignin content, number of stomata and gas exchange, lower reduction in photosynthetic pigments and lipid peroxidation, an increased activity of antioxidant enzymes, greater accumulation and efficiency nutritional and plant growth when compared to plants with Al and without Si. The CTC9003 showed a greater Si attenuation response in Al toxicity. 001

Submitted by MOIS??S AM??NCIO (marancio13@gmail.com) on 2021-03-18T03:40:18Z No. of bitstreams: 4 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Diserta????o_final.pdf: 3209935 bytes, checksum: 9b89e1e7321c5c3300bdf085ad575d16 (MD5) CartaEncaminhamentoTCC-TESE-DISSERTA????O-1.pdf: 104750 bytes, checksum: a8ed58b945b886a6c5bb6c4e33eca9b2 (MD5) Folha_de_Aprova????o.pdf: 267763 bytes, checksum: 08f3d412597b5facccf929b9cdefd67a (MD5) Approved for entry into archive by PPGQ Qu??mica (ppgqsecretaria@gmail.com) on 2021-03-23T13:38:01Z (GMT) No. of bitstreams: 4 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Diserta????o_final.pdf: 3209935 bytes, checksum: 9b89e1e7321c5c3300bdf085ad575d16 (MD5) CartaEncaminhamentoTCC-TESE-DISSERTA????O-1.pdf: 104750 bytes, checksum: a8ed58b945b886a6c5bb6c4e33eca9b2 (MD5) Folha_de_Aprova????o.pdf: 267763 bytes, checksum: 08f3d412597b5facccf929b9cdefd67a (MD5) Approved for entry into archive by Divis??o de Documenta????o/BC Biblioteca Central (ddbc@ufam.edu.br) on 2021-03-23T14:26:01Z (GMT) No. of bitstreams: 4 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Diserta????o_final.pdf: 3209935 bytes, checksum: 9b89e1e7321c5c3300bdf085ad575d16 (MD5) CartaEncaminhamentoTCC-TESE-DISSERTA????O-1.pdf: 104750 bytes, checksum: a8ed58b945b886a6c5bb6c4e33eca9b2 (MD5) Folha_de_Aprova????o.pdf: 267763 bytes, checksum: 08f3d412597b5facccf929b9cdefd67a (MD5) Made available in DSpace on 2021-03-23T14:26:01Z (GMT). No. of bitstreams: 4 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Diserta????o_final.pdf: 3209935 bytes, checksum: 9b89e1e7321c5c3300bdf085ad575d16 (MD5) CartaEncaminhamentoTCC-TESE-DISSERTA????O-1.pdf: 104750 bytes, checksum: a8ed58b945b886a6c5bb6c4e33eca9b2 (MD5) Folha_de_Aprova????o.pdf: 267763 bytes, checksum: 08f3d412597b5facccf929b9cdefd67a (MD5) Previous issue date: 2020-11-09 Environmental issues have driven research in alternative energy, especially concerning solar energy, since this energy source has a high potential and an expressive abundance. It is estimated that the Earth is irradiated daily by an amount of energy greater than the global daily consumption. However, without correspondence from the dominant photovoltaic sector in the market (Si-m and Si-p cells), the emerging cells (DSSC's; CSSPQ's; PSC's, among others) are introduced in an encouraging perspective, with very low cost of manufacture, in addition to a simple configuration. In this perspective, the present work was set out to develop photosensitized solar cells (emerging). In this work, plant dyes from Amazon Florest region were extracted, in addition, were synthetized quantum dots of CdS (PQ???s) and the most recent MAPbI3 perovskite for application as a photosensitive material solar cell. Morphological (SEM), structural (DRX), topographic (AFM) and absorption regions in UV-vis were also applied. All cells were evaluated according to the open circuit potential (Voc), photocurrent density (Jsc), curve filling factor (FF) and efficiency (??). The results revealed promising parameters for CdS and MAPbI3 solar cells, which showed the best energy conversion efficiency among the manufactured devices. The studies carried out from the modification of the preparation of the semiconductor layer, by electrodeposition of np-TiO2, showed progressive results, both in obtaining these films and in the photoelectric performances presented by the cells, explained by the roughness factor. In summary, the study focused on the photoelectrochemical performances of different photosensitive compounds when applied in photosensitized solar cells. In this sense, we seek to optimize these performances by modifying the deposition mode of the semiconductor layer, in addition to the synthesis of compounds with high photoactive potential. As quest??es ambientais t??m impulsionado as pesquisas na ??rea de energia alternativa, sobretudo com rela????o a energia solar, uma vez que essa fonte energ??tica apresenta um elevado potencial e uma expressiva abund??ncia. Estima-se que terra chega a ser irradiada diariamente por um quantitativo energ??tico maior que o consumo di??rio global; todavia, sem a correspond??ncia do setor fotovoltaico dominante do mercado (c??lulas Si-m e Si-p), as c??lulas emergentes (DSSC???s; CSSPQ???s; PSC???s entre outras) s??o introduzidas numa perspectiva animadora, com baix??ssimo custo de confec????o, al??m de uma configura????o simples. Nessa perspectiva, o presente trabalho disp??s-se ao desenvolvimento de c??lulas solares fotossensibilizadas (emergentes). Na ocasi??o foram extra??dos pigmentos vegetais de plantas encontrada na regi??o amaz??nica, al??m da s??ntese de pontos qu??nticos de CdS (PQ???s) e das mais recentes perovskita de MAPbI3 para aplica????o como material fotossens??vel nas c??lulas. Caracteriza????es morfol??gicas (MEV), estruturais (DRX), topogr??fica (AFM) e regi??es de absor????o no UV-vis tamb??m foram aplicadas. Todas as c??lulas foram avaliadas de acordo com o potencial de circuito aberto (Voc), densidade de fotocorrente (Jsc), fator de preenchimento da curva (FF) e efici??ncia (??). Os resultados revelaram par??metros promissores para as c??lulas de CdS, e MAPbI3, as quais chegaram apresentar as melhores efici??ncia de convers??o energ??tica entre as c??lulas confeccionadas. Os estudos realizados a partir da modifica????o da prepara????o da camada semicondutora, por eletrodeposi????o de np-TiO2, mostraram resultados progressivos, tanto na obten????o desses filmes quanto nos desempenhos fotoel??tricos apresentados pelas c??lulas, explicados pelo fator rugosidade. Em resumo, o estudo focou nos desempenhos fotoeletroqu??micos de distintos compostos fotossens??veis quando aplicados em c??lulas solares fotossensibilizadas. Neste sentido, buscamos otimizar estes desempenhos modificando o modo de deposi????o da camada semicondutora, al??m da s??ntese de compostos de elevada potencialidade fotoativa.

Flavylium cations are synthetic analogues of anthocyanins, the natural plant pigments that are responsible for the majority of the red, blue, and purple colors of flowers, fruits, and leaves. Unlike anthocyanins, the properties and reactivity of flavylium cations can be manipulated by the nature and position of substituents on the flavylium cation chromophore. Currently, the most promising strategies for stabilizing the color of anthocyanins and flavylium cations appear to be to intercalate and/or adsorb them on solid surfaces and/or in confined spaces. We report here that hybrid pigments with improved thermal stability, fluorescence, and attractive colors are produced by the cation-exchange-mediated adsorption of flavylium cations (FL) on two synthetic clays, the mica-montmorillonite SYn-1, and the laponite SYnL-1. Compared to the FL/SYn-1 hybrid pigments, the FL/SYnL-1 pigments exhibited improved thermal stability as judged by color retention, better preferential adsorption of the cationic form of FL1 at neutral to mildly basic pH (pH 7-8), and lower susceptibility to color changes at pH 10. Although both clays adsorb the cationic form on their external surfaces, SYnL-1 gave more evidence of adsorption in the interlayer regions of the clay. This interlayer adsorption appears to be the contributing factor to the better properties of the FL/SYnL-1 hybrid pigments, pointing to this clay to be a promising inorganic matrix for the development of brightly colored, thermally more stable hybrid pigments based on cationic analogues of natural plant pigments.

Betalains are phytochemicals of nutraceutical importance that emerged as potent antioxidants, preventing radical chain propagation and the deleterious health effects of oxidative stress. However, despite the wide application of betalains as color additives in products for human consumption, little is known about the relationship between their structure and antioxidant potential. Here we investigate the mechanism of antioxidant action of three regioisomeric phenolic betalains and show that the meta isomer has higher antiradical capacity than most natural betalains, anthocyanins and flavonoids. Structural and pH effects on redox and antiradical properties were investigated and the results are rationalized in light of quantum chemical calculations. Our results demonstrate that hydrogen atom transfer/proton-coupled electron transfer or sequential proton loss electron transfer mechanisms are plausible to explain the radical chain breaking properties of phenolic betalains in water. Furthermore, mesomeric effects are responsible for the stabilization of the resulting radical phenolic betalains. These findings are useful for the design of biocompatible antioxidants and for the development of novel additives for functional foods and cosmetics with high antioxidant potential.

The feasibility of producing proliposomes containing curcumin, as well as liposome dispersions, using different mixtures of purified and nonpurified soybean phospholipids was studied. Proliposomes were produced through coating of micronized sucrose and physicochemically characterized over 30 days of storage. In addition, the possible interactions among the components were investigated using X-ray powder diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). The proliposomes demonstrated a low propensity of water adsorption and low hygroscopicity. In addition, the curcumin content retained in the powders ranged from 67 to 92%. The liposomes were produced following proliposome hydration. Atomic force microscopy indicated the vesicles presented spherical shapes and photon correlation spectroscopy detected that their hydrodynamic diameters ranged from 207 to 222 nm. Finally, the curcumin-loaded liposomes preserved up to 63% of the bioactive compound but remained stable for only 15 days of storage.

Betanin (betanidin 5-O-β-D-glucoside) is a water-soluble plant pigment used as a color additive in food, drugs and cosmetic products. Despite its sensitivity to light and heat, betanin maintains appreciable tinctorial strength in low acidic and neutral conditions, where the color of other plant pigments, such as anthocyanins, quickly fades. However, betanin is an iminium natural product that experiences acid- and base-catalyzed hydrolysis to form the fairly stable betalamic acid and cyclo-DOPA-5-O-β-D-glucoside. Here, we show that the decomposition of betanin in aqueous phosphate solution pH 2-11 is subject to general base catalysis by hydrogen phosphate ion and intramolecular general acid and base catalysis, providing new insights on the mechanism of betanin hydrolysis. UV/Vis absorption spectrophotometry, 1 H NMR spectroscopy and mass spectrometry were used to investigate product formation. Furthermore, theoretical calculations support the hypothesis that the nitrogen atom of the tetrahydropyridine ring of betanin is doubly protonated, as observed for structurally simpler amino dicarboxylic acids. Our results contribute to the study of betanin and other pigments belonging to the class of betalains and to deepen the knowledge on the chemical properties of imino acids as well as on iminium-catalyzed modifications of carbonyl compounds in water.

The effects of solar UV radiation on mycosporine-like amino acids (MAAs), growth, photosynthetic pigments (Chl a, phycobiliproteins), soluble proteins (SP), and C and N content of Mazzaella laminarioides tetrasporophytes and gametophytes were investigated. Apical segments of tetrasporophytes and gametophytes were exposed to solar radiation under three treatments (PAR [P], PAR+UVA [PA], and PAR+UVA+UVB [PAB]) during 18 d in spring 2009, Punta Arenas, Chile. Samples were taken after 2, 6, 12, and 18 d of solar radiation exposure. Most of the parameters assessed on M. laminarioides were significantly influenced by the radiation treatment, and both gametophytes and tetrasporophytes seemed to respond differently when exposed to high UV radiation. The two main effects promoted by UV radiation were: (i) higher synthesis of MAAs in gametophytes than tetrasporophytes at 2 d, and (ii) a decrease in phycoerythrin, phycocyanin, and SPs, but an increase in MAA content in tetrasporophytes at 6 and 12 d of culture. Despite some changes that were observed in biochemical parameters in both tetrasporophytes and gametophytes of M. laminarioides when exposed to UVB radiation, these changes did not promote deleterious effects that might interfere with the growth in the long term (18 d). The tolerance and resistance of M. laminarioides to higher UV irradiance were expected, as this intertidal species is exposed to variation in solar radiation, especially during low tide.

As clorofilas são pigmentos verdes, comuns em todas as células fotossintéticas. Por sua estrutura química ser instável, são facilmente degradadas, resultando em produtos de decomposição que modificam a percepção e qualidade dos alimentos. Esta revisão trata dos vários fatores que interferem na degradação das clorofilas, como a luz, radiação, calor, ácidos, oxigênio, alteração enzimática e interação com outros pigmentos. Também, outro aspecto a ser abordado é a utilização das clorofilas como corantes, através da formação de complexos que tornam esses pigmentos mais estáveis à decomposição.The Chlorophylls are a common green pigment to all photosynthetic cells. They are easily degraded, because of their unstable chemical structure. Degradation results in products alter the perception and quality of foods. This review discusses the various factors, that interfere on chlorophyll degradation such as light, irradiation, heat, acids, oxygen, enzymatical alteration and the interaction with other pigments. Also, the other topic that was mentioned the utilization of the chlorophylls as dyes through a complex formation that make this pigment more stable to degradation.

As clorofilas são pigmentos verdes, comuns em todas as células fotossintéticas. Por sua estrutura química ser instável, são facilmente degradadas, resultando em produtos de decomposição que modificam a percepção e qualidade dos alimentos. Esta revisão trata dos vários fatores que interferem na degradação das clorofilas, como a luz, radiação, calor, ácidos, oxigênio, alteração enzimática e interação com outros pigmentos. Também, outro aspecto a ser abordado é a utilização das clorofilas como corantes, através da formação de complexos que tornam esses pigmentos mais estáveis à decomposição.

This work evaluated the effects of Tris (hydroxymethyl)-aminomethane (TRIS) buffer and its interaction with nutrient concentration on the development of Gracilaria birdie, a common species on the Brazilian coast that has been exploited for agar production. Responses to different conditions were assessed through growth rates and pigment content (chlorophyll a, phycoerythrin, phycocyanin and allophycocyanin). Provasoli's nutrient solution with and without TRIS addition was tested at concentrations of 12.5, 25 and 50%. The pH was also monitored. G. birdiae grew better in the absence of TRIS and at low nutrient concentrations, 12.5 and 25% (growth rates of 10.8-11.3%.day-1). Higher contents of phycoerythrin and chlorophyll a were observed without TRIS at 12.5 and 25% (Phycoerythrin, 649.6-698.0 μg g-1 fresh biomass; Chlorophyll a, 156.0-168.6 μg g-1 fresh biomass). These findings highlight the deleterious effect of TRIS on growth and phycoerythrin and chlorophyll a content. They also demonstrate the importance of appropriate nutrient concentration for laboratory cultures, depending on the intrinsic characteristics of each species.

As clorofilas são pigmentos verdes, comuns em todas as células fotossintéticas. Por sua estrutura química ser instável, são facilmente degradadas, resultando em produtos de decomposição que modificam a percepção e qualidade dos alimentos. Esta revisão trata dos vários fatores que interferem na degradação das clorofilas, como a luz, radiação, calor, ácidos, oxigênio, alteração enzimática e interação com outros pigmentos. Também, outro aspecto a ser abordado é a utilização das clorofilas como corantes, através da formação de complexos que tornam esses pigmentos mais estáveis à decomposição. The Chlorophylls are a common green pigment to all photosynthetic cells. They are easily degraded, because of their unstable chemical structure. Degradation results in products alter the perception and quality of foods. This review discusses the various factors, that interfere on chlorophyll degradation such as light, irradiation, heat, acids, oxygen, enzymatical alteration and the interaction with other pigments. Also, the other topic that was mentioned the utilization of the chlorophylls as dyes through a complex formation that make this pigment more stable to degradation.

As clorofilas são pigmentos verdes, comuns em todas as células fotossintéticas. Por sua estrutura química ser instável, são facilmente degradadas, resultando em produtos de decomposição que modificam a percepção e qualidade dos alimentos. Esta revisão trata dos vários fatores que interferem na degradação das clorofilas, como a luz, radiação, calor, ácidos, oxigênio, alteração enzimática e interação com outros pigmentos. Também, outro aspecto a ser abordado é a utilização das clorofilas como corantes, através da formação de complexos que tornam esses pigmentos mais estáveis à decomposição.

An overview is provided of the status of research at the frontiers of investigation of the chemistry and photochemistry of two classes of natural plant pigments, the anthocyanins and the betalains, as well as of the pyranoanthocyanin pigments formed from anthocyanins during the maturation of red wine. Together, anthocyanins and betalains are responsible for almost all of the red, purple and blue colors of fruits and flowers and anthocyanins and pyranoanthocyanins are major contributors to the color of red wines. All three types of pigments are cationic below about pH 3, highly colored, non-toxic, reasonably soluble in water or alcohol and fairly stable to light. They exhibit good antioxidant or antiradical activity and, as part of our diet, confer a number of important health benefits. Systematic studies of model compounds containing the basic chromophoric groups of these three types of pigments are providing a deeper understanding of the often complex chemistry and photochemistry of these pigments and their relationship to the roles in vivo of these pigments in plants. These natural pigments are currently being exploited as starting materials for the preparation of novel semi-synthetic dyes, pigments and fluorescence probes.