Physiological bases for texture and color changes in fresh-cut ‘rocha’ pear: im...

• Author(s): Gomes, Maria Helena ; Almeida, Domingos P. F.
• Date: 2010
• Persistent ID: http://hdl.handle.net/10400.1/2905
• Origin: Sapientia - Universidade do Algarve
• Subject(s): Minimally processed; Modified atmosphere packaging; PH; Pyrus communis; Respiration
• Document Type: Part of book or chapter of book
• Language: English
• Editor(s): Nunes, Carla

Description

Proceedings of the International Conference “Environmentally friendly and safe technologies for quality of fruit and vegetables”, held in Universidade do Algarve, Faro, Portugal, on January 14-16, 2009. This Conference was a join activity with COST Action 924. The physiological bases for the effectiveness of technologies used in fresh-cut fruit were examined in an attempt to foster the shift from a market-pull to a science-push innovation model. Respiration rate of fresh-cut ‘Rocha’ pear were measured at various oxygen concentrations. Apparent Km values for oxygen uptake were very close to the fermentation thresholds, indicating that it is physiologically impossible to reduce the respiration rate of fresh-cut pear by more than 50% without inducing fermentation. Based on this information, we hypothesize that optimizing oxygen concentration inside packages is of little or no value in fresh-cut pears. Additionally, additives used to reduce enzymic browning and softening may have pleiotropic effects on quality. It was found that pH significantly affected the rate and intensity of browning of fresh-cut pears. Browning was more intense in pears treated at pH 3.0 and less pronounced at pH 7.0, but the softening rate was lower at the latter pH value. Calcium salts also affected texture and color in a salt-specific manner. Larger color changes were observed with propionate and lactate. Although calcium ascorbate reduced color changes, fruit slices treated with this salt were softer than those treated with calcium propionate, lactate or chloride. Based on the physiological information gathered, we will develop and evaluate an integrated process to maximize the quality of fresh-cut ‘Rocha’ pear throughout the distribution chain.