Maria Raquel Alcântara de Miranda

The Impact of Organic Farming on Quality of Tomatoes Is Associated to Increased Oxidative Stress during Fruit Development

This study was conducted with the objective of testing the hypothesis that tomato fruits from organic farming accumulate more nutritional compounds, such as phenolics and vitamin C as a consequence of the stressing conditions associated with farming system. Growth was reduced in fruits from organic farming while titratable acidity, the soluble solids content and the concentrations in vitamin C were respectively +29%, +57% and +55% higher at the stage of commercial maturity. At that time, the total phenolic content was +139% higher than in the fruits from conventional farming which seems consistent with the more than two times higher activity of phenylalanine ammonia lyase (PAL) we observed throughout fruit development in fruits from organic farming. Cell membrane lipid peroxidation (LPO) degree was 60% higher in organic tomatoes. SOD activity was also dramatically higher in the fruits from organic farming. Taken together, our observations suggest that tomato fruits from organic farming experienced stressing conditions that resulted in oxidative stress and the accumulation of higher concentrations of soluble solids as sugars and other compounds contributing to fruit nutritional quality such as vitamin C and phenolic compounds.

Compostos bioativos e atividade antioxidante total de pedúnculos de caju (Anacardium occidentale L.) durante o amadurecimento de clones de cajueiro anão-precoce

Lately, tropical fruit consumption has increased due to a higher knowledge of its nutritional and therapeutic value. The aim of this work was to evaluate the antioxidant potential of cashew apples from different early dwarf clones during their ripening. The clones analyzed included: CCP 76, CCP 09, BRS 189 and BRS 265 in seven ripening stages. They were analyzed for vitamin C, total carotenoid, total anthocyanin, yellow flavonoids and polyphenol content and total antioxidant capacity. Clone BRS 265 ripe cashew apple presented the highest vitamin C content (279.37 mg x 100 g-1). The ripe BRS 189 cashew apple is colored bright red, and its total anthocyanin content was the highest (21.16 mg x 100 g-1). The yellow flavonoids content was higher for ripe CCP 76 and BRS 189 cashew apples with 56.32 and 50.75 mg x 100 g-1, respectively. The highest levels of extrable polyphenols and antioxidant capacity were observed in CCP 09 in the first five ripening stages. The antioxidant activity of cashew apples (Anacardium occidentale L.) is mainly attributed to polyphenol content (r = 0.90; p < 0.01), and, therefore, they may be considered relevant sources of antioxidant compounds, which are necessary for human health. Cashew apples are consumed fresh which confers direct benefits for human health and present high potential for the development of new products with functional properties.

Understanding the physiological effects of UV-C light and exploiting its agronomic potential before and after harvest

There is an abundant literature about the biological and physiological effects of UV-B light and the signaling and metabolic pathways it triggers and influences. Much less is known about UV-C light even though it seems to have a lot of potential for being effective in less time than UV-B light. UV-C light is known since long to exert direct and indirect inhibitory and damaging effects on living cells and is therefore commonly used for disinfection purposes. More recent observations suggest that UV-C light can also be exploited to stimulate the production of health-promoting phytochemicals, to extent shelf life of fruits and vegetables and to stimulate mechanisms of adaptation to biotic and abiotic stresses. Clearly some of these effects may be related to the stimulating effect of UV-C light on the production of reactive oxygen species (ROS) and to the stimulation of antioxidant molecules and mechanisms, although UV-C light could also trigger and regulate signaling pathways independently from its effect on the production of ROS. Our review clearly underlines the high potential of UV-C light in agriculture and therefore advocates for more work to be done to improve its efficiency and also to increase our understanding of the way UV-C light is perceived and influences the physiology of plants.

Antioxidant metabolism during fruit development of different acerola (Malpighia emarginata D.C) clones.

The present research work describes the major changes in the antioxidant properties during development of acerola from five different clones. Ripening improved fruit physicochemical quality parameters; however, total vitamin C and total soluble phenols (TSP) contents declined during development, which resulted in a lower total antioxidant activity (TAA). Despite the decline in TSP, at ripening, the anthocyanin and yellow flavonoid content increased and was mainly constituted of cyanidin 3-rhamnoside and quercetin 3-rhamnoside, respectively. The activities of oxygen-scavenging enzymes also decreased with ripening; furthermore, the reduction in vitamin C was inversely correlated to membrane lipid peroxidation, indicating that acerola ripening is characterized by a progressive oxidative stress. Among the studied clones, II47/1, BRS 237, and BRS 236 presented outstanding results for vitamin C, phenols, and antioxidant enzyme activity. If antioxidants were to be used in the food supplement industry, immature green would be the most suitable harvest stage; for the consumers market, fruit should be eaten ripe.

In vitro digestibility of globulins from cowpea (Vigna unguiculata) and xerophitic algaroba (Prosopis juliflora) seeds by mammalian digestive proteinases: a comparative study

Globulins were purified from mature and immature cowpea and algaroba seeds by gel filtration (S-200), anion exchange (DEAE-Sepharose) and other chromatographic methods. These globulins (native and heated) were submitted to hydrolysis by pepsin, chymotrypsin and trypsin and their digestion products were analysed by SDS-PAGE. Results showed that native globulins of both legumes were weakly digested by pepsin and were not digested by serine proteases. Heated proteins from cowpea were digested more rapidly by pepsin and chymotrypsin than was algaroba globulin. Trypsin rapidly digested proteins from both cowpea and algaroba. Comparing the hydrolysis of bean globulins to the algaroba globulins by mammalian enzymes, the globulins from immature cowpea showed better digestibility than mature cowpea; globulins from algaroba pod, which is used as an alternative food, were difficult to digest.

Armazenamento de dois tipos de sapoti sob condição de ambiente

This work aims to evaluate the postharvest life of two types of sapodilla at ambient temperature and with or without modified atmosphere (PVC film packing). The experiment consisted in storing fruits, harvested at Embrapa´s (Agroindustria Tropical) Experimental Station located in Paraipaba, Ceara, Brazil, under ambient condition (24 ± 2oC and 90 ± 5% U.R), on retail trays where half of these trays was wrapped in PVC and the other half, was not wrapped. Fruits of two types were evaluated for weight loss; pulp firmness; total soluble solids; titrable acidity; pH; total soluble sugars, reducing sugars and starch contents. Fruits stored under MA had less weight loss and greater reduction in pulp firmness when compared to those under AA. Decreases in acidity, soluble solids and total sugar contents and pH were found in both types of fruit during storage under both atmosphere conditions, as well as an increase in reduced sugars content. The type II fruits, had the longest post-harvest shelf-life.

Cell wall biochemistry of sapodilla (Manilkara zapota) submitted to 1-methylcyclopropene

Sapoti (Manilkara zapota) e um fruto climaterico que amadurece rapidamente apos a colheita e os estudos acerca da extensao de sua vida util pos-colheita sao principalmente restritos ao uso de baixa temperatura e atmosfera modificada. Este trabalho avaliou a influencia do 1-metilciclopropeno (1-MCP) sobre o amolecimento e bioquimica da parede celular durante o amadurecimento de sapoti, assim como o seu potencial de conservacao pos-colheita. Sapotis foram tratados com 1-MCP, um antagonista do etileno, a 300 nL L-1 por 12 h e, em seguida, armazenados sob atmosfera modificada a 25oC por 23 d. O 1-MCP retardou significativamente o amadurecimento de sapoti por 11 d, via diminuicao da atividade das enzimas hidroliticas da parede celular e, portanto, os frutos tratados com 1-MCP exibiram menor solubilizacao dos poliuronideos, hemicelulose e acucares neutros livres quando comparados com os frutos-controle. O 1-MCP retardou o amaciamento do sapoti, indicando que esse processo e dependente da producao e percepcao de etileno.

Anti-inflammatory and wound healing potential of cashew apple juice (Anacardium occidentale L.) in mice

Cashew apple is a tropical pseudofruit consumed as juice due to its excellent nutritional and sensory properties. In spite of being well known for its important antioxidant properties, the cashew apple has not been thoroughly investigated for its therapeutic potential. Thereby, this study evaluated the antioxidant capacity, anti-inflammatory, and wound-healing activities of cashew apple juice. Juices from ripe and immature cashew apples were analyzed for antioxidant, anti-inflammatory, and wound-healing properties. Those were evaluated in murine models of xylene-induced ear edema and wound excision. Swiss mice were treated with cashew juice by gavage. Edema thickness was measured and skin lesions were analyzed by planimetry and histology. Both antioxidant content and total antioxidant activity were higher in ripe cashew apple juice (RCAJ) than in unripe cashew apple juice (UNCAJ). The UNCAJ presented the main anti-inflammatory activity by a significant inhibition of ear edema (66.5%) when compared to RCAJ (10%). Moreover, UNCAJ also showed the best result for wound contraction (86.31%) compared to RCAJ (67.54%). Despite of higher antioxidant capacity, RCAJ did not promote better anti-inflammatory, and healing responses, which may be explained by the fact that treatment increased antioxidants level leading to a redox “imbalance” turning down the inflammatory response modulation exerted by reactive oxygen species (ROS). The results suggest that UNCAJ presents a greater therapeutic activity due to a synergistic effect of its phytochemical components, which improve the immunological mechanisms as well as an optimal balance between ROS and antioxidants leading to a better wound healing process.

Atividade de enzimas e degradação de pectinas de sapoti submetido ao 1-metilciclopropeno

The objective of this work was to investigate the influence of 1-methylcyclopropene (1-MCP) at 300 nL L-1 on activities of cell wall hidrolytic enzymes and pectin breakdown changes which Sapodilla (Manilkara zapota cv. Itapirema 31) cell wall undergoes during ripening. Sapodilla were treated with ethylene antagonist 1-MCP at 300 nL L-1 for 12 hours and then, stored under a modified atmosphere at 25o C for 23 days. Firmness, total and soluble pectin and cell wall enzymes were monitored during storage. 1-MCP at 300 nL L-1 for 12 hours delayed significantly softening of sapodilla for 11 days at 25o C. 1-MCP postharvest treatment affected the activities of cell wall degrading enzymes pectinmethylesterase and polygalacturonase and completely suppressed increases in beta-galactosidase for 8 days, resulting in less pectin solubilization. Beta-galactosidase seems relevant to softening of sapodilla and is probably responsible for modification of both pectin and xyloglucan-cellulose microfibril network.

Comparative digestibility and the inhibition of mammalian digestive enzymes from mature and immature cowpea (Vigna unguiculata (L.) Walp.) seeds

Globulins and albumins from mature cowpea seeds had inhibitory activity levels of 9.5 and 67.1 units trypsin inhibited per mg protein and globulins and albumins from immature seeds had trypsin inhibitory activity levels of 6.3 and 26.6 units trypsin inhibited per mg protein, respectively. Albumins from immature seeds had inhibitory activity level of 4 units salivary amylase inhibited per mg albumin. The globulins (native and heated) from both seeds were submitted to hydrolysis by trypsin and analyzed by SDS-PAGE. Native globulins from mature and immature seeds showed digestion products of ∼30 and ∼20 kDa, respectively. Trypsin strongly digested heated globulins from both kinds cowpeas.