Brazilian Archives of Biology and Technology
URI permanente para esta coleçãohttps://thoth.dti.ufv.br/handle/123456789/12090
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Item Stability of phenolic compounds and antioxidant capacity of regular and decaffeinated coffees(Instituto de Tecnologia do Paraná - Tecpar, 2014-01) Vicente, Silvio José Valadão; Queiroz, Yara Severino; Gotlieb, Sabina Léa Davidson; Torres, Elizabeth Aparecida Ferraz da SilvaThis study compared the regular and decaffeinated coffees in relation to antioxidant capacity, levels of some antioxidant molecules and stability of these parameters over a six-month period under different storage conditions. The regular coffee samples analyzed right after the industrial production showed higher antioxidant capacity (ORAC and DPPH), the same levels of phenolic compounds and higher levels of phenolic acids than decaffeinated coffee. After six months, the closed packs of both the grades kept under vacuum at 20°C did not show significant changes from the initial results; the open packs stored at 4°C showed small but statistically significant reductions and the open packs stored at 20°C showed higher and statistically significant losses (p < 0.05). Oxygen was the most important factor for these losses but temperature also played an important role. Tests showed that the storage conditions were very important to preserve the quality of coffees regarding the analyzed parameters.Item Production of herbicide-resistant coffee plants (Coffea canephora P.) via Agrobacterium tumefaciens-mediated transformation(Instituto de Tecnologia do Paraná - Tecpar, 2006-01) Ribas, Alessandra Ferreira; Kobayashi, Adilson Kenji; Pereira, Luiz Filipe Protasio; Vieira, Luiz Gonzaga EstevesTransgenic plants of Coffea canephora P. resistant to the herbicide ammonium glufosinate were regenerated from leaf explants after co-culture with Agrobacterium tumefaciens strain EHA105 harboring pCambia3301, a plasmid that contains the bar and the uidA genes both under control of 35S promoter. Direct somatic embryogenesis was induced on basal medium contained 1⁄4 strength macro salts and half strength micro salts of MS medium, organic constituents of B 5 medium and 30 g.L -1 sucrose supplemented with 5 μ M N 6 – (2-isopentenyl)-adenine (2-iP). Ten μ M ammonium glufosinate was used for putative transgenic somatic embryos selection. Presence and integration of the bar gene were confirmed by PCR and Southern blot analysis. Selected transgenic coffee plants sprayed with up to 1600 mg.L -1 of Finale , a herbicide containing glufosinate as the active ingredient, retained their pigmentation and continued to grow normally during ex vitro acclimation.Item Modifications on leaf anatomy of Coffea arabica caused by shade of pigeonpea (Cajanus cajan)(Instituto de Tecnologia do Paraná - Tecpar, 2004-11) Morais, Heverly; Medri, Moacyr Eurípedes; Marur, Celso Jamil; Caramori, Paulo Henrique; Ribeiro, Ana Maria de Arruda; Gomes, José CarlosModifications on leaf anatomy in Coffea arabica shaded with pigeonpea (Cajanus cajan), compared to cultivation under full sun, were assessed. The leaves fully exposed to sunlight presented thicker cuticles and cellular walls, narrower epidermis cells, palisade parenchyma with longer cells, thicker lacunar parenchyma, fewer intercellular spaces and a larger stomata number. Leaves under dense shade presented a narrower cuticle and cellular wall; a mesophyll with smaller volume, but with larger intercellular spaces; and epidermis with thicker cells and a smaller stomata amount, surrounded by subsidiary cells of smaller dimensions. Plants grown under full sunlight presented higher values of net photosynthesis. The results evidenced that the species C. arabica has a wide range of phenotypic adaptation to changes in the radiation intensity.Item Effect of leaf water potential on cold tolerance of Coffea arabica L.(Instituto de Tecnologia do Paraná - Tecpar, 2002-12) Caramori, Lázara Pereira Campos; Caramori, Paulo Henrique; Manetti Filho, JoãoYoung coffee plants from cultivar Mundo Novo of Coffea arabica were grown without irrigation for 32 consecutive days, to evaluate the effect of leaf water potential on damage caused by low temperatures, under controlled conditions. À wide range of leaf water potentials were evaluated, from — 0.45MPa (wet soil) at the beginning of the experimental period, to — 4.8MPa (severe leaf wilting) at the end. Results showed that under moderate water stress, there was a higher frequency of undamaged plants and lower frequency of severely damaged plants. These results help explain part of the regional variability observed after a frost and stress the importance of new studies associating cold and drought tolerance in coffee.Item Caffeine Formation by Suspension Cultures of Coffea dewevrei(Instituto de Tecnologia do Paraná - Tecpar, 2000-01) Sartor, Rosana Mary; Mazzafera, PauloThe low caffeine content in leaves of C. dewevrei (~ 0.5 mg/g) is due to a low biosynthesis associated with a fast degradation. On the other hand, high biosynthesis and low degradation confer a higher content (~ 8 mg/g) in leaves of C. arabica. In this work it was observed that cell cultures of C. dewevrei recovered the ability to synthesize caffeine almost in similar levels of C. arabica cultures. Tracer experiments with labelled carbon dioxide showed a significant accumulation of radioactivity in caffeine and metabolites, indicating an active biosynthesis. When the cultures were fed with labelled caffeine most of the radioactivity was recovered in caffeine, indicating that although active, degradation was not so efficient as in leaves, and therefore, contributing for the alkaloid accumulation in the cell cultures.