Browsing by Author "Guterres, Umbelina"
Now showing 1 - 2 of 2
Results Per Page
Sort Options
- Biochemical markers to predict internal browning disorders in ‘Rocha’ pear during storage under high CO2Publication . Deuchande, Teresa; Larrigaudière, Christian; Guterres, Umbelina; Carvalho, Susana M. P.; Vasconcelos, Marta W.BACKGROUND: The aim of this studywas to identify biochemical markers to predict internal browning disorders (IBD) in 'Rocha' pear. Fruits from five orchards were stored for 45 days under cold air followed by 100 days in browning-inducing controlled atmosphere (CA) conditions (1 kPaO(2) + 10 kPaCO(2)). RESULTS: Relationships between concentrations of ethanol (EtOH), acetaldehyde (AcDH) and ascorbic acid (AA), activities of peroxidase (POX) and polyphenoloxidase (PPO) and IBD incidence were established. The partial least square (PLS) model using the most promising markers, EtOH and AcDH, explained 89% of the variance in IBD incidence, whereas the univariate models based on the same markers explained between 89 and 94%. In contrast, the models based on AA levels and AA depletion rate only explained 57 and 82% of the variance in IBD incidence respectively. Model validation confirmed the robustness of EtOH for the prediction (R-2 = 0.91, RMSE= 11.1) and allowed proposing a threshold level of 30 mu L EtOH L-1 above which IBD may occur. Using this threshold value, the storage time limit associated with the occurrence of the first IBD symptoms was predicted with an acceptable RMSE of 9 days. CONCLUSION: Thiswork clearly identifies biochemical IBDmarkers for ` Rocha' pear and shows that dynamic changes in ethanol concentration during the beginning of storagemay be used to predict IBD development. Therefore the results presented herein represent a major step forward in the prediction of IBD in 'Rocha' pear.
- Dynamic controlled atmosphere for prevention of internal browning disorders in ‘Rocha’ pearPublication . Deuchande, Teresa; Carvalho, Susana; Guterres, Umbelina; Fidalgo, Fernanda; Isidoro, Nelson; Larrigaudière, Christian; Vasconcelos, Marta W.This study aimed to evaluate the potential of two dynamic controlled atmospheres, DCA-CF (chlorophyll fluorescence sensor) and DCA-EtOH (ethanol sensor) when compared to controlled atmosphere (CA), in the prevention of internal browning disorders (IBD) in ‘Rocha’ pear stored under commercial conditions. Pears harvested at optimal maturity were stored for 145 days at 0.5 C and 95% relative humidity, under three atmospheres: (1) CA (3 kPa O2 þ 0.5 kPa CO2), (2) DCA-CF and (3) DCA-EtOH. At the end of storage, fruits in DCA-CF did not develop IBD while fruits in DCA-EtOH had an IBD incidence of 15 and 20% after 125 and 145 days of storage, respectively. The higher incidence of IBD under DCA-EtOH may be related to the higher levels of fermentative metabolites and to the lower ascorbate content. In contrast, the higher levels of ascorbate in DCA-CF showed that this technology contributes to maintaining the fruit's antioxidant potential. Collectively our results suggest that DCA-CF is an effective strategy to prevent IBD in ‘Rocha’ pear. On the contrary, the DCA-EtOH is not suitable to prevent the induction of fermentation and IBD development. The results also suggest that the IBD development in ‘Rocha’ pear is related to fermentative metabolism.