Dorota Konopacka - Academia.edu (original) (raw)

Papers by Dorota Konopacka

Przemysł Fermentacyjny i Owocowo-Warzywny, 2006

Food and Bioprocess Technology, Nov 19, 2015

The effect of sonication time and kind of liquid medium on polyphenol retention and microstructur... more The effect of sonication time and kind of liquid medium on polyphenol retention and microstructure changes during predrying treatment of apple tissue was investigated. The apple cubes from 'Idared' cultivar were submerged in water or sucrose solution and sonicated indirectly in beakers placed in a water bath fitted with ultrasound transducers (25 kHz, 0.1 W/cm 3) at 40°C. The treatment was conducted with and without ultrasound applied for 45 and 90 min. The content of individual polyphenols was monitored by a reversephase high-performance liquid chromatography (RP-HPLC) method. The dominant phenolic compounds in apple were procyanidins, accounting for 56 % of total polyphenols. While a significant effect of sonication on mass transfer intensification was observed when the samples were dehydrated in sucrose solution, almost no negative effects of ultrasound application were perceived on polyphenols concentration, except for dimers of catechin. When using ultrasound in water solution, an increase in polyphenol compound losses was noted. Furthermore, the ultrasound energy caused an apple tissue structure modification which additionally affected polyphenol retention during predrying treatment.

Journal of Texture Studies, Feb 1, 2010

Contact acoustic emission (AE) measurement, together with a puncture test, were used to evaluate ... more Contact acoustic emission (AE) measurement, together with a puncture test, were used to evaluate the crispness and crunchiness of three apple cultivars. A storage program was used to induce changes in apple crispness and crunchiness. The instrumental measurements were compared with the results of sensory evaluation. It was found that crispness and crunchiness could be evaluated instrumentally by measuring firmness, AE events, mean AE amplitude or the product of AE events and mean AE amplitude. For one cultivar, however, firmness was not correlated with any sensory attribute. Generally, the best correlation with sensory attributes was found for the exponential value of AE events. Contact AE allows the measurement of sensory crispness or crunchiness for a given apple cultivar or independently for any apple cultivar. Contact AE can be considered as a useful method for the evaluation of sound properties of wet-crisp foods. PRACTICAL APPLICATIONS Contact acoustic emission method can be used for instrumental evaluation of crispness and crunchiness of apples. The method allows more accurate evaluation of these attributes than firmness measurement. There is a chance to extend the application to other wet-crisp foods and to use the method together with other destructive tests, like texture profile analysis or single edge notched bend.

Acta horticulturae, Mar 1, 2012

In our study within the European ISAFRUIT project, we examined in Poland and Switzerland the acce... more In our study within the European ISAFRUIT project, we examined in Poland and Switzerland the acceptance of representative organic and conventional food buyers for new disease resistant apple cultivars in comparison to similar-type common cultivars (6 cultivars per country). In total 120 testers were involved. The panel tests were carried out with blinded samples in a first run, and in a second run as branded samples where information on production system (organic or integrated) and price (+26% for organic fruit) was given. With additional questionnaires we assessed the importance of the testers' general knowledge and perception on organic (fruit) production on their preference behavior. With blinded samples, in both countries both consumer groups rated the appearance and eating quality of resistant and susceptible apple cultivars relatively equal with minor advantages for the standard cultivars. However, when the samples were branded, organic buyers of both countries significantly increased their preference in appearance and on taste for the organic samples. In Poland, even the conventional buyers increased their rating for branded 'bio' samples; meanwhile the Swiss conventional buyers decreased it clearly. The analysis of the questionnaires revealed that: (i) in both countries and with both buyer groups, the awareness for the high importance of resistant cultivars for organic production is only mediocre; (ii) to increase their buying of organic apple they mainly require more basic and apple-specific information on organic production; (iii) the consumers expect from organic apples an outstanding inner quality but also a good price; (iv) the consumer's trust in the control and certification of organic production is only mediocre.

Journal of Horticultural Research, Dec 1, 2019

To study possibility of protection of sweet cherry fruit against cracking several rows of 'Lapins... more To study possibility of protection of sweet cherry fruit against cracking several rows of 'Lapins' sweet cherry (Prunus avium L.) trees grafted on 'Colt' rootstock, spaced 5 × 2.5 m and trained to a central leader were covered with a plastic foil to a height of 5 m. Several rows were left uncovered as a control. In the years 2016 and 2018, sun irradiation, air temperature and fruit quality were evaluated. The plastic cover reduced solar irradiation under the tunnel roof by around 40%. Light distribution within tree canopies was depleted by roughly 50%, but in the lower parts of the tree canopies, it was reduced to 6%, which is below the critical level (20%) estimated for apple trees. These results indicate the necessity to remove the covers as soon as possible after harvesting. Mean daily temperature near the ground was lower under the covers than outside, but at the height of 4.0 m, daily mean temperature was 0.4 °C higher and mean temperature during midday hours was 1.5 °C higher. The plastic covering reduced the fruit cracking from about 20% to 2% in both seasons but did not affect the fruit yield. The plastic covering did not affect the firmness and antioxidant activity and total anthocyanin content, but in the year 2018, it reduced the mean fruit weight, soluble solid, titratable acidity, dry matter and total polyphenols content.

Journal of Horticultural Science & Biotechnology, 2009

The aim of our work was to measure sorption isotherms on freeze-dried and convectively-dried frui... more The aim of our work was to measure sorption isotherms on freeze-dried and convectively-dried fruits (apple cv. Idared; sour cherry cv. English Morello; blackcurrant cv. Tiben), previously osmotically dehydrated in fructooligosaccharide solution, or concentrated apple juice. Isotherms were fitted using the Guggenheim-Anderson-de Boer Model. In none of the cases studied was isotherm non-continuity in the vicinity of the initial value of a w observed. All isotherms, classified as type III, demonstrated an increase in the equilibrium water content, along with an increase in water activity. A higher water content was observed in lyophilised material compared to material dried by convection. The water content in the monolayer (100 g-1 dry matter) ranged from 12.0 g for dried apple, to 17.0 g for dried sour cherry. These values can be considered as optimal in order to ensure safe storage conditions. The dried fruits should therefore be kept in a water activity range of 0.45-0.54 for lyophilised, and 0.46-0.63 for convectively-dried material.

Lebensmittel-Wissenschaft & Technologie, May 1, 2016

The aim of this study was to investigate whether ultrasound (US) assistance during the osmotic pr... more The aim of this study was to investigate whether ultrasound (US) assistance during the osmotic pretreatment of sour cherries has any influence on quality and changes in the levels of bioactive compounds present in dried product during storage using an accelerated shelf-life test. Sour cherries of 'Nefris' variety were pitted in a frozen state and subjected to osmotic dehydration in a water bath fitted with ultrasound transducers (25 kHz, 0.4 W/cm 2) and a shaking plate (30 rpm) in sucrose solution (60 Bx, fruit to syrup ratio 1:4, 40 C) and then convectively dried (60 C, 9 h, 2.5 m/s). The osmotic dehydration lasted 120 min with (60US) and without US (0US) treatment. The application of US resulted in the enhancement of mass transfer after osmotic dehydration (higher dry matter content and lower water activity in dried 60US sample in comparison to 0US). Storage caused the deterioration of anthocyanin content and after 8 weeks of storage significant differences between samples became visible. Samples treated with US application had a lower antiradical capacity than those untreated. It can be anticipated that ultrasound application had a negative influence on anthocyanin content and may speed up the loss of antioxidant potential.

Acta horticulturae, Mar 1, 1998

International Journal of Food Engineering, Mar 8, 2017

In Poland, Amelanchier berries are of considerable interest to both consumers and potential produ... more In Poland, Amelanchier berries are of considerable interest to both consumers and potential producers, which presents marketing challenges and opportunities. An attempt was made to preserve Amelanchier berries using a vacuum-microwave method of drying in order to determine its usefulness for producing microbiologically stable dried fruit with a high nutritional values. The berry variety "Prince William" (Amelanchier canadensis) was chosen as the experimental material. Vacuum-microwave drying was performed in two variants: (convective drying [CD] + vacuum microwave method [VMW]) after convective pre-drying of fruit and (VMW) without pre-drying. Unassisted CD was used as the reference method. Application of a vacuum-microwave drying method to Amelanchier berries makes it possible to obtain a stable preserved product of high-quality, yielding moderate shrinkage and good retention of bioactive compounds. An optimized method of vacuum-microwave drying, applied directly to frozen fruit, allows the retention of 70 % of cyanidin glycosides present in the raw material.

Acta horticulturae, Jul 1, 2003

Journal of Food Processing and Preservation, Feb 21, 2012

The objective of the study was to investigate the stability of polyphenols and ascorbic acid in o... more The objective of the study was to investigate the stability of polyphenols and ascorbic acid in osmo-dried fruits: apples, sour cherries and blackcurrants, stored for 12 months. After 1 year of storage, the content of total polyphenols and anthocyanins in convectively dried blackcurrants was decreased by 45% and 90%, respectively. Flavonols remained highly stable. Convectively dried sour cherries contained particularly labile substances, including cyanidin derivatives, which content decreased by 98% after 6 months. Polyphenols in freeze-dried materials were more stable. After 1 year of storage, their content remained at 60-80% of the initial level. A high stability was in particular observed for delphinidin-3-rutinoside in blackcurrants, and cyanidin derivatives, chlorogenic acid, neochlorogenic acid and quercetin glucoside in sour cherries. The stability of ascorbic acid was also much higher in freeze-dried blackcurrants than in convectively dried fruit. After 1 year of storage, almost 70% of ascorbic acid was preserved in freeze-dried material. PRACTICAL APPLICATIONS Analyzed material was obtained in industrial conditions. Final products were used to produce bars; it can also be used in manufacturing of muesli and similar products. The results of performed analyses show a change in the content of polyphenols and ascorbic acid during product storage and could be useful to define the time in which a product is characterized by the highest content of health-promoting substances.

Journal of Horticultural Research, Jun 1, 2019

Two plum cultivars 'Record' and 'Empress' and one prune cultivar 'Common Prune' were planted in s... more 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.

The firmness and sensory texture of apples from two laboratories are analyzed. The goal of this e... more The firmness and sensory texture of apples from two laboratories are analyzed. The goal of this experiment was checking consistency of results between laboratories and finding important differences affecting texture evaluation of apples. Also, various postharvest treatments on firmness and sensory texture are discussed. Six apple cultivars, stored at different atmospheres and followed by shelf life, were selected for this study. The experiment simultaneously was performed in two laboratories where firstly firmness and secondly sensory texture were analyzed on each individual apple. The results of the experiment showed that even small differences, such as speed of puncturing and method of determination of the penetration limits significantly influence the results of firmness measurements. Comparison of sensory attributes between two expert panels confirmed that a longer experience in apples testing results in lower standard deviations of assessments; however, in terms of mean values, this factor can be neglected. The experiment showed that treatment with 1-methylcyclopropene and then storage in CA had the most positive influence on apple texture. CA storage gives also profit of better texture. However, for unknown reasons, CA storage gave the same results as the simple NA storage for 'Szampion' and 'Gloster' apples.

International Agrophysics, 2003

A method was developed based on the measurement of the apparent modulus of the elasticity of plum... more A method was developed based on the measurement of the apparent modulus of the elasticity of plums, using a cylindrical probe and a force of 1 N. This method is extremely sensitive and is fully non-destructive. The measurements are taken using an Instron Universal Testing Machine. The results obtained correlate very well with other objective quality indices and sensory tests. The method was verified on several plum cultivars. This method is suitable in estimating the different grades at which any particular fruit has ripened by the day of picking and during storage and may be used to establish the firmness of the plums from the point of view of the consumer. It was found that fruit of the D¹browicka, Amerf and Valjevka varieties should have-at the consumption stage of maturity-an apparent modulus of elasticity ranging from 0.100 to 0.250 MPa (optimum at 0.150 MPa), when measured using a 6 mm probe and when recalculated using a 4 mm probe, respectively 0.071-0.217 MPa (optimum at 0.120 MPa). K e y w o r d s: modulus of elasticity, ripeness, sensory assessment, quality

Journal of Horticultural Research, Dec 1, 2015

The relation of hand-harvesting cost in plum and prune production to the total costs amounts to 2... more 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.

Postharvest Biology and Technology, May 1, 2004

Experiments were carried out to determine whether storage of apples under different atmospheres m... more Experiments were carried out to determine whether storage of apples under different atmospheres may influence the relationship between fruit firmness and sensory texture acceptability. Apples ('Elstar', 'Jonagold' and 'Gloster' cultivars) were stored at 3 • C in either normal atmosphere, standard controlled atmosphere (CA) (5% CO 2 :3% O 2) or low oxygen CA (1.5% CO 2 :1.5% O 2). After storage, firmness of the apples was varied by further storage at 0 • C and/or 18 • C for various periods. Fruit were then subjected to the Magness-Taylor test and sensory analyses. There was a distinct effect of storage conditions on the relationship between firmness and acceptability of fruit texture. The effect depended on apple cultivar. For 'Jonagold' and 'Gloster' fruit stored in CA conditions, higher values of optimum firmness and wider ranges of highly acceptable firmness were found than for normal atmosphere-stored apples. For 'Elstar' fruit such differences were not observed.

Przemysł Fermentacyjny i Owocowo-Warzywny, Sep 5, 2015

Przemysł Fermentacyjny i Owocowo-Warzywny, Dec 5, 2017

janów może wzrosnąć kilkukrotnie [3, 12]. Owoce świdośliwy zawierają też więcej białka, tłuszczów... more janów może wzrosnąć kilkukrotnie [3, 12]. Owoce świdośliwy zawierają też więcej białka, tłuszczów i błonnika pokarmowego niż inne owoce, a także są źródłem potasu, magnezu, żelaza i fosforu oraz witamin z grupy B [5].