Dorota Konopacka, Krzysztof P. Rutkowski, Dorota E. Kruczyńska, Anna Skorupińska and Witold Płocharski
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.
Dorota Konopacka, Krzysztof Rutkowski and Witold Płocharski
Changes of Acceptability of ‘Jonagold’ and ‘Gala’ Apples During Storage in Normal Atmosphere
Proper development of storage marketing strategy for apples for fresh fruit market requires not only detailed information on dynamics of changes of objective quality indices during storage but also on their impact on consumer acceptability. The experiment was aimed at determination of ‘Jonagold’ and ‘Gala’ apple quality in relation to length of cold storage.
Apples were harvested at optimal stage of ripeness and their quality was estimated monthly starting from the day when fruit were picked up to 6 months of storage. Tests were made after cold storage at 0°C and after 7 days shelf-life at 18°C. Beside measurement of the most important parameters such as firmness, soluble solids, and acidity the studies covered measurements of changes of weight of single fruit, instrumental measurement of juiciness and sensory acceptability of texture and flavour made concurrently on laboratory scale and in semi-consumer tests (in a group of 40 respondents).
The largest decreases of firmness and juiciness were observed in the first and second month of storage. Changes of acidity and weight losses were proportional to storage period, while soluble solids changes were rather small and the direction depended on storage length. It was proved that the highest score for sensory acceptability received apples stored in cold room for one month. Slightly lower score obtained fruits tested directly after picking and after 2 months of storage. With extension of storage of fruit in the cold room sensory acceptability of both cultivars decreased when judged either by expert panel or by consumers.
According to the present fruit growers custom fruits of both cultivars after storage in normal atmosphere would be directed to retailers not earlier that at the end of December or beginning of January (i.e. after at least 3 months of storage), when their quality evidently decreases, and average consumer purchasing fruits in a store or at local market has no chance to esteem potential values of such popular cultivars as ‘Gala’ and ‘Jonagold’.
Dorota Konopacka, Urszula Kaczmarek, Aneta Matulska, Anna Wawrzyńczak, Dorota Kruczyńska and Krzysztof P. Rutkowski
The aim of the study was to compare the sensory quality of scab resistant ‘Topaz’ apples grown in certified organic orchards (ECO) with those grown in orchards managed within integrated method (IP), and to determine their potential processing suitability. Fruits were harvested in five certificated IP and ECO orchards at the optimum ripeness stage and stored for two months in normal atmosphere at 1 ºC. Apple quality was assessed one day after cold storage and after 7 days of storage at the temperature 18 ºC to simulate shelf life. The results of taste and flavour sensory assessment did not explicitly demonstrate the effect of the orchard management system on the overall eating quality. Although the fruits from the organic orchards were perceived as less sweet and sourer, the management system did not influence the overall eating quality. There was no effect of the growing technology on quality traits connected with aroma and overall texture assessment. Regarding appearance evaluation, fruits from organic orchards were characterized by a higher variation in shape and size, and more frequently than in the case of IP apples had blemishes, scars and rust, which negatively affected their attractiveness. Analysis of the chemical composition of fruits indicates that apples from organic orchards are characterized on average by higher titratable acidity and higher soluble solids content than apples from IP orchards, which could favour their potential application as the additive regulating acidity and shaping the desirable sensory traits of processed organic products.
Augustyn Mika, Zbigniew Buler, Jacek Rabcewicz, Paweł Białkowski and Dorota Konopacka
The relation of hand-harvesting cost in plum and prune production to the total costs amounts to 25-40%. Mechanical harvesting makes it possible to cut drastically both the harvesting and total costs. To test the suitability of plum and prune species to be mechanically harvested, an experimental grove (area 0.8 ha) was established in 2008. Three plum cultivars and one prune cultivar grafted on semi-dwarf and vigorous rootstocks were planted at high density (1250; 1666; 2500 trees·ha−1). During the span of full yielding (2012-2014), fruits were harvested mechanically with a canopy contact, straddle harvester in continuous motion, designed at the Institute of Horticulture in Skierniewice, to harvest tart cherry, and later adapted to harvesting plums and prunes. Trees grafted on semi-dwarf rootstock (‘Wangenheim Prune’) appeared to be more suitable for mechanical harvesting than strong-growing trees grafted on Prunus cerasifera clone ‘Myrobalan’. Cumulative yield per ha (years 2012-2014) was the highest at the highest planting density. Trees grafted on the semi-dwarf rootstock had a higher productivity index than trees grafted on the vigorous rootstock. There was no significant difference in fruit quality related to planting distance. Mechanical harvesting was nearly 40 times more efficient than hand picking. The efficiency of mechanical harvest was from 85% to 90%. Over 5% of fruits were lost on the ground and from 1 to 5% of fruits were left on the tree. Up to 18% of the plums and no more than 10% of the prunes harvested mechanically showed some damage. They can be fully acceptable for processing, for up to 10 days, providing the potential deterioration processes are inhibited by cold storage. The large-fruited cultivars seem to be more susceptible to bruising than the small-fruited ones. For the latter, the share of marketable quality fruits within the mechanically harvested crop amounted to about 80%, which could be a good prognostic justifying further trials on the prune harvester.
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.
Karolina Celejewska, Monika Mieszczakowska-Frąc and Dorota Konopacka
The aim of the study was to assess the usefulness of hybrid drying methods (convective-microwave and convective-microwave-ultrasound) for sour cherry fruit preservation compared to convective drying. As the raw material, three sour cherry cultivars varying in quality characteristics (‘Łutówka’, ‘Debreceni Bötermo’, ‘Nefris’) were used. Before drying, fruits were subjected to osmotic treatment. Three different drying methods were examined: 1) convective (C), 2) hybrid with microwaves (C-MV) and 3) hybrid with microwaves and ultrasound (C-MV-US). As the quality indicators of the investigated processes, the changes in chemical composition, including alterations in the main groups of bioactive components, as well as in the antioxidant potential were monitored at each production stage. It was found that, when compared to convective drying, the use of the hybrid techniques allowed the drying time to be reduced from 9 to just 3 hours. Furthermore, employing hybrid drying eliminated the problems associated with the dehydration barrier observed during convective drying of the cultivar ‘Debreceni Bötermo’. Regrettably, although the ultrasound used as the additional source of energy in the hybrid method slightly improved water evaporation, in general no significant effect on the retention of phenolic compounds was found. Irrespectively of the drying method, the effect of the cultivar proved to be crucial to the quality of the final product. Under the same processing conditions, ‘Nefris’ turned out to be the most promising cultivar for producing ready-to-eat fruit snacks of high nutritional value.
Augustyn Mika, Zbigniew Buler, Jacek Rabcewicz, Paweł Białkowski and Dorota Konopacka
Two plum cultivars ‘Record’ and ‘Empress’ and one prune cultivar ‘Common Prune’ were planted in spring 2014, spaced at 4.5 × 1.5 × 2.0 m, to be trained to the “Y”- and “V”-trellising systems for mechanical harvesting of dessert fruits with a canopy-contact harvester. The applied trellising systems were compared with the standard central leader system at the same spacing. Trellised trees showed a tendency to grow less well than leader-trained trees, but during the four years of training, they created a higher canopy volume than the control trees because of their spreading form. Trellised trees were able to give yields comparable to those of standard trees. Light distribution within the tree canopy was acceptable in all the training systems. After 4 years of training, the trees were suitable for mechanical harvesting. The effectiveness of mechanical harvesting varied from 85% to 90%. The quality of the fruits harvested with a canopy-contact harvester was comparable to that of manually picked fruits. The consumption of quality of fruits after mechanical harvesting rated on a 5-grade scale was 0.5 grade lower than that of manually harvested fruits. These fruits were acceptable in the local fruit market. Mechanical harvesting was 10–30 times faster compared to manual picking. The cost of the trellising system calculated per 1 ha was 2.0 times higher than that of the standard system.
Augustyn Mika, Paweł Wawrzyńzak, Zbigniew Buler, Dorota Konopacka, Paweł Konopacki, Adam Krawiec, Paweł Białkowski, Barbara Michalska, Marian Plaskota and Bogdan Gotowicki
Eleven plum cultivars (Prunus domestica L.) for processing grafted on semidwarf rootstock ‘Wangenheim Prune’ and vigorous rootstock ‘Myrobalan’ were densely planted (1000, 1250, 1666, 2500 trees ha-1) and trained to central leader spindle tree. A new training system was applied to obtain trees suitable for mechanical harvesting. The leader was not headed after planting and summer training procedures were performed in May/June. From the third year onwards, renewal pruning was carried out after fruit harvesting. The new training and pruning systems resulted in very fast tree growth, abundant branching, fruit bud formation on young wood and early bearing. The plum trees appeared to be suitable for hand and mechanical harvesting within 3 years from planting. The self propelled straddle combine harvester was able to harvest 2-3 tons of plums per hour compared to 30 kg with hand picking. Harvesting effectiveness was 90-95%. The quality of mechanically harvested plums was a little worse than of those hand picked, but fruits were suitable for processing. The ‘Common Prune’ and the prune type small plums were the most suitable fruit for mechanical harvesting.