Impact of Innovative Technologies on the Content of Vitamin C and Its Bioavailability from Processed Fruit and Vegetable Products

Nowadays, thermal treatments are used for extending the shelf-life of vegetable and fruit products by inactivating microorganisms and enzymes. On the other hand, heat treatments often induce undesirable changes in the quality of the final product, e.g., losses of nutrients, color alterations, changes in flavor, and smell. Therefore, the food industry is opening up to new technologies that are less aggressive than thermal treatment to avoid the negative effects of thermal pasteurization. Non-thermal processing technologies have been developed during the last decades as an alternative to thermal food preservation. Processing changes the structure of fruit and vegetables, and hence the bioavailability of the nutrients contained in them. In this review, special attention has been devoted to the effects of modern technologies of fruit and vegetable processing, such as minimal processing (MPFV), high-pressure processing (HPP), high-pressure homogenization (HPH), ultrasounds (US), pulsed electric fields (PEF), on the stability and bioavailability of vitamin C

Quality Of Cloudy Plum Juice Produced From Fresh Fruit Of Prunus Domestica L. – The Effect Of Cultivar And Enzyme Treatment

The quality of cloudy juices produced from two plum cultivars varied in chemical characteristics and native polyphenol oxidase (PPO) activity, and was studied in relation to specific pectinolytic activity of enzyme preparations used for fresh fruit maceration before pressing. Process effectiveness expressed as juice yield, turbidity and the rate of transfer of anthocyanins and polyphenols were determined for five different enzyme preparations, whose activity was also analysed. Juice yields obtained after 1 hour mash maceration (50 ºC, 100 g·t−1) were between 86.6 and 95.4%. The anthocyanins content of the obtained juices strongly depended on the cultivar and ranged from 26 to 50 mg·L−1 for ‘Promis’, and from 269 to 289 mg·L−1 for ‘Čačanska Najbolja’, which could be related to the differences in the measured PPO activity (175.4 and 79.8 nkat·g−1, respectively). The type of enzyme preparation strongly affected the degradation rate of anthocyanins during juice processing. Peonidin-3-rutinoside proved to be the most stable during plum juice production in contrast to cyanidin-3-glucoside. Irrespectively of the cultivar, the juice prepared with the mixture of Rohapect PTE + Rohament PL (2 : 1) showed the highest turbidity among the investigated combinations. The results suggest that for the production of cloudy plum juice use of a preparation with low pectin methyl esterase and polygalacturonase activities and high pectin lyase activity could be recommended

Quality Of Cloudy Plum Juice Produced From Fresh Fruit Of Prunus Domestica L. – The Effect Of Cultivar And Enzyme Treatment

The quality of cloudy juices produced from two plum cultivars varied in chemical characteristics and native polyphenol oxidase (PPO) activity, and was studied in relation to specific pectinolytic activity of enzyme preparations used for fresh fruit maceration before pressing. Process effectiveness expressed as juice yield, turbidity and the rate of transfer of anthocyanins and polyphenols were determined for five different enzyme preparations, whose activity was also analysed. Juice yields obtained after 1 hour mash maceration (50 ºC, 100 g·t−1) were between 86.6 and 95.4%. The anthocyanins content of the obtained juices strongly depended on the cultivar and ranged from 26 to 50 mg·L−1 for ‘Promis’, and from 269 to 289 mg·L−1 for ‘Čačanska Najbolja’, which could be related to the differences in the measured PPO activity (175.4 and 79.8 nkat·g−1, respectively). The type of enzyme preparation strongly affected the degradation rate of anthocyanins during juice processing. Peonidin-3-rutinoside proved to be the most stable during plum juice production in contrast to cyanidin-3-glucoside. Irrespectively of the cultivar, the juice prepared with the mixture of Rohapect PTE + Rohament PL (2 : 1) showed the highest turbidity among the investigated combinations. The results suggest that for the production of cloudy plum juice use of a preparation with low pectin methyl esterase and polygalacturonase activities and high pectin lyase activity could be recommended

Quality Potential Of Some New Pear Cultivars – How To Obtain Fruit Of The Best Sensory Characteristics?

The eating quality of nine new pear cultivars grown in Poland was investigated in 2008-2011. Fruits of two summer cultivars: ‘Alfa’ and ‘Radana’, as well as late season varieties: ‘Hortensia’, ‘Dicolor’, ‘Concorde’, ‘Uta’, ‘Xenia’, ‘Erika’ and ‘Verdi’ were compared to fruits of ‘Clapp’s Favorite’ and ‘Conference’, which were taken as cultivars of reference. Fruits of all cultivars were harvested from the Experimental Orchard of the Research Institute of Horticulture at the commercial maturity stage and stored at +2.5 °C or -0.5 °C in a normal atmosphere (NA) or at -0.5 °C in a controlled atmosphere (CA) (0.7% CO2 : 2% O2) for 6 to 16 weeks. At the end of storage, the fruits of each cultivar were subjected to an individual ripening schedule at 18 °C (up to 14 days), which generated samples of diversified quality attributes. Based on instrumental analyses and descriptive sensory assessment the quality attributes of each cultivar were examined. The gathered data on the dynamics of quality attribute changes during the ripening stage confirm that each new cultivar needs an individual strategy during storage and ripening in order to maximise their specific sensory attributes to increase potential market value. The obtained data leads to the conclusion that ‘Xenia’ and ‘Concorde’ fruits have the biggest chance to fulfil consumer expectations, as they were appreciated more than the reference ‘Conference’ cultivar. Among the others also ‘Hortensia’, ‘Verdi’ and ‘Dicolor’ were scored higher than ‘Conference’, but their advantages were not so evident