Abstract The aim of this study was to evaluate the physiological response and quality of the ‘Tahiti’ acid lime coated with carboxymethylcellulose (N-CMC), pectin (N-PEC) and starch (N-ST) nanocomposites based on cellulose nanocrystals (NC). Respiratory rate, ethylene production, loss of fresh weight, total chlorophyll and fruit firmness were evaluated during 9 days of storage. At the end of storage, only fruits coated with N-CMC and N-PEC exhibited significantly lower ethylene yield (0.92 and 0.98 μg C2H4 kg-1 h-1, respectively) than fruits coated with CMC and PEC (1.6 and 2.02 μg C2H4 kg-1 h-1, respectively). On the 3rd day of storage, fruits coated with N-PEC showed a respiratory rate (12.01 mg CO2 kg-1 h-1) similar to the fruits of the control (13.52 mg CO2 kg-1 h-1), but it was significantly lower than the fruits coated with PEC (14.93 mg CO2 kg-1 h-1). Only fruits coated with N-PEC showed significantly lower fresh weight losses than the control fruits. Fruits coated with N-PEC had chlorophyll retention levels (18.95 mg g-1) higher than fruits with PEC (13.25 mg g-1). This work showed that the N-PEC nanocomposite, based on NC, was the coating that showed greater potential for preserving quality of the ‘Tahiti’ acid lime.

RESUMO. Objetivou-se com o presente trabalho avaliar os compostos bioativos, atividade antioxidante e características físico-químicas de frutos de doviális, a fim de obter conhecimentos tecnológicos a respeito desta frutífera nas condições de Marechal Candido Rondon, PR. Foram colhidos em março de 2016 frutos de doviális provenientes de pomar experimental da Unioeste, instalado em 2012. Os frutos utilizados de doviális foram coletados de diversas plantas, maduros e divididos em três lotes. Após a colheita, os frutos foram imediatamente levados ao Laboratório de Pós-colheita para a avaliação da atividade antioxidante, através dos métodos DPPH, ABTS e FRAP. Também foram avaliadas as características físico-químicas dos frutos de doviális e compostos fenólicos totais, flavonoides, ácido ascórbico, antocianinas, respiração e coloração dos frutos. O delineamento experimental utilizado foi inteiramente casualizados, contendo três grupos e três repetições por grupo. Frutos de doviális apresentam elevada capacidade antioxidante, sendo caracterizados como frutos ácidos, devido ao aumento da atividade de FRAP. Frutos de doviális possuem coloração muito atrativa e alta acidez, destinando-se ao processamento. Para a atividade antioxidante presente no fruto, os mais bioativos são flavonoides e antocianinas. Elevado teor de ácido ascórbico foi observado nos frutos maduros de doviális. Os frutos de doviális podem ser considerados climatéricos.

ABSTRACT. The objective of this work was to evaluate the bioactive compounds, antioxidant activity, and physicochemical characteristics of dovyalis fruit to obtain technological knowledge about this fruit when grown under the conditions found in the municipality of Marechal Cândido Rondon, Paraná State, Brazil. Dovyalis fruits from the State University of Western Parana, which was established in 2012, were harvested in March 2016. Dovyalis fruits were collected from several plants and were divided among three lots. After the harvest, were immediately taken to the Post-Harvest Laboratory for evaluation of the antioxidant activity by the DPPH, ABTS and FRAP methods. The physicochemical characteristics of the fruits and the total phenolic compounds, flavonoids, ascorbic acid, anthocyanins, respiration, and fruit color were evaluated. The experimental design was completely randomized, with the study containing three groups and three replicates per group. Dovyalis fruits present high antioxidant capacity and are characterized as acidic fruits, due to the high FRAP activity. Dovyalis fruits have a very attractive color and high acidity, which makes them appropriate for processing. Regarding the antioxidant activity present in the fruit, the most bioactive components are flavonoids and anthocyanins. High ascorbic acid content was observed in mature dovyalis fruits. Dovyalis fruits are considered climacteric.

RESUMO O déficit hídrico leva à formação de espécies reativas de oxigênio, que resultam em degradação de pigmentos foliares e morte celular. Objetivou-se avaliar a atividade de enzimas oxidativas e o teor de pigmentos fotossintéticos em sementes e/ou folhas de Urochloa ruziziensis (syn. Brachiaria) inoculada com Azospirillum brasilense, sob déficit hídrico. As avaliações do teor de proteínas solúveis, clorofilas a e b e carotenoides e da atividade das enzimas superóxido dismutase (SOD), peroxidase (POD) e catalase (CAT) foram realizadas no início do déficit hídrico, no estágio de déficit hídrico severo e na reidratação das plantas. A inoculação das sementes demonstrou redução na ação da SOD sob déficit hídrico, sendo incrementada após a reidratação. A POD apresentou maior atividade que a CAT em todas as avaliações, contudo, não se diferenciou estatisticamente sob déficit severo. A CAT teve atividade aumentada sob déficit severo em todos os tratamentos, com destaque para a inoculação foliar. A clorofila a foi pouco degradada, mantendo os níveis do controle irrigado, enquanto os conteúdos de clorofila b e carotenoides nas plantas inoculadas com A. brasilense via foliar foram superiores, sob déficit hídrico. Conclui-se que a inoculação foliar de U. ruziziensis com A. brasilense torna a planta mais eficiente na remoção de espécies reativas de oxigênio e na proteção da clorofila a.

ABSTRACT Water stress leads to the formation of reactive oxygen species, resulting in degradation of leaf pigments and cell death. This study aimed at assessing the oxidative enzyme activity and photosynthetic pigment content in seeds and/or leaves of Urochloa ruziziensis (syn. Brachiaria) inoculated with Azospirillum brasilense under water stress. Assessments of soluble proteins, chlorophylls a and b and carotenoid contents, as well as the activity of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) enzymes, were conducted at the beginning of the water stress process and also under severe water stress and during plant rehydration. Seed inoculation showed a reduction in the action of SOD, under water stress, with an increase after rehydration. POD exhibited an activity greater than CAT in all the assessments, but it did not differ statistically under severe water stress. CAT activity increased under severe stress in all treatments, particularly for leaf inoculation. Chlorophyll a was slightly degraded, maintaining the levels of the irrigated control, while the chlorophyll b and carotenoid contents, in plants subjected to leaf inoculation with A. brasilense, were higher under water stress. It was concluded that the leaf inoculation of U. ruziziensis with A. brasilense makes the plant more efficient at removing reactive oxygen species and protecting chlorophyll a.