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Mineral concentrations at harvest as novel markers to predict internal browning disorders in ‘Rocha’ pear during storage under high CO 2

Publication . Deuchande, Teresa; Carvalho, Susana M. P.; Larrigaudière, Christian; Vasconcelos, Marta W.

This study aimed to identify mineral markers at harvest capable of predicting internal browning disorders (IBDs) in pear (Pyrus communis L. cv Rocha) during storage, and develop an IBD predictive model. Fruit from five orchards harvested at two different maturity stages were stored for 45 days in cold air (−0.5 °C) followed by 100 days under controlled atmosphere (CA) (1 kPa O2 + 10 kPa CO2 at −0.5 °C). Concentrations of ten minerals were measured at harvest and a multivariate predictive model using this data was developed. The model explained 78% of variance in IBD incidence during storage and after validation it showed high accuracy (R2 = 0.97; RMSEP = 7.7%). Amongst the ten analysed minerals, copper (Cu), being significantly correlated to IBD incidence during storage, was the most promising IBD marker. This type of model may be a very useful tool to predict at harvest fruit’s sensitivity to IBD during storage allowing the selection of the most adequate storage conditions for the long-term storage of a fruit batch

2017Journal article

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Transcriptional and biochemical regulation of internal browning disorder in 'Rocha' pear as affected by O-2 and CO2 concentrations

Publication . Deuchande, Teresa; Carvalho, Susana M. P.; Giné-Bordonaba, Jordi; Vasconcelos, Marta W.; Larrigaudière, Christian

The biochemical basis of internal browning disorders (IBD) in ‘Rocha’ pear has been linked to alterations in the antioxidant and fermentative metabolism. In order to further elucidate the involvement of these metabolic pathways on IBD development, we investigated their regulation at a metabolic and transcriptional level in pears that were stored under four distinct conditions: i) cold air (−0.5 °C); ii) standard controlled atmosphere (CA; 2 kPa O2 + 0.5 kPa CO2); iii) high CO2 (2 kPa O2 + 10 kPa CO2), and iv) high CO2 + low O2 (O2-switch: 60 d under high CO2 + 80 d under high CO2 and 1 kPa O2). Only the fruit stored under high CO2 were affected by IBD. The faster depletion of ascorbate in high CO2-stored fruit was associated with the down-regulation of glutathione reductase (PcGR) and ascorbate peroxidase (PcAPX) as well as a down-regulation of monodehydroascorbate reductase (PcMDHAR). The O2-switched fruit had the highest IBD incidence. Increased incidence in this sample was associated to a sharp increase in fermentation immediately after transfer to lower O2 atmosphere suggesting a synergistic effect between high CO2 and low O2 concentrations in IBD development. Overall, our results suggest that biochemical and transcriptional regulation of the antioxidant system affects IBD occurrence in ‘Rocha’ pear, and that fermentation, resulting from fruit exposure to low O2 concentrations, may further promote the browning process.

2017Journal article

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Influence of harvesting factors on sensory attributes and phenolic and aroma compounds composition of Cymbopogon citratus leaves infusions

Publication . Coelho, Marta; Rocha, C.; Cunha, L.M.; Cardoso, L.; Alves, L.; Lima, R.C.; Pereira, M. J.; Campos, Francisco M.; Pintado, M. E.

Herbal infusions are receiving increasing attention for the number of physiological benefits that can bring to human health. Cymbopogon citratus is one the most used plants in traditionalmedicine besides its characteristics and unique aroma appreciated by the consumers; however, little is known about the effects of harvesting on functional and sensory properties of this plant. The present work aimed to assess the lemongrass infusions, which were harvested following a factorial plan according to the type of cut (manual and mechanical) and part of the plant (tips and 2nd half leaves). Total phenolic content, antioxidant capacity, aroma compounds composition (terpenoids) and sensory profiles and consumer perception of different samples were assessed. The quantitative descriptive analysis (QDA) and Check-All-That-Apply (CATA) methods were used to describe the lemongrass infusion, complemented with the overall liking evaluation, using a 9-point scale. Results showed that there were significant differences between type of cut and part of the plant concerning phenolic compounds: samples obtained by mechanical cut showed in general higher content of individual phenolic compounds (in particular for chlorogenic acid) and tips showed in general the highest contents for both types of cut. Consumers panel did not found significant differences between samples. Generally, consumers indicate a bitter taste in all infusions when the content of the phenolic compounds was higher, in particular for p-coumaric acid. Concerning the aroma compounds no significant differences were observed between type of cut and part of the plant, and citral was the terpenoid present in higher quantity. Regarding the sensory profile methods, it was found that QDA and CATA were both good methods to describe this infusion. Considering the role of consumers' evaluation throughout the value chain, the infusion preparedwith plant tips of lemongrass was selected as the premium herbal tea.

2016Journal article

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Gene expression and physiological responses associated to stomatal functioning in Rosa×hybrida grown at high relative air humidity

Publication . Carvalho, Dália R.A.; Vasconcelos, Marta W.; Lee, Sangseok; Koning-Boucoiran, Carole F.S.; Vreugdenhil, Dick; Krens, Frans A.; Heuvelink, Ep; Carvalho, Susana M. P.

tHigh relative air humidity (RH ≥ 85%) during growth disturbs stomatal functioning, resulting in excessivewater loss in conditions of high evaporative demand. We investigated the expression of nine abscisic acid(ABA)-related genes (involved in ABA biosynthesis, oxidation and conjugation) and two non-ABA relatedgenes (involved in the water stress response) aiming to better understand the mechanisms underlyingcontrasting stomatal functioning in plants grown at high RH. Four rose genotypes with contrasting sen-sitivity to high RH (one sensitive, one tolerant and two intermediate) were grown at moderate (62 ± 3%)or high (89 ± 4%) RH. The sensitive genotype grown at high RH showed a significantly higher stomatalconductance (gs) and water loss in response to closing stimuli as compared to the other genotypes. More-over, high RH reduced the leaf ABA concentration and its metabolites to a greater extent in the sensitivegenotype as compared to the tolerant one. The large majority of the studied genes had a relevant role onstomatal functioning (NCED1, UGT75B2, BG2, OST1, ABF3 and Rh-APX) while two others showed a minorcontribution (CYP707A3 and BG1) and AAO3, CYP707A1 and DREB1B did not contribute to the tolerancetrait. These results show that multiple genes form a highly complex regulatory network acting togethertowards the genotypic tolerance to high RH.

2016Journal article

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