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This study aimed to determine the effects of osmotic dehydration on the kinetics of hot air drying of apricot halves under conditions that were similar to the industrial ones. The osmotic process was performed in a sucrose solution at 40 and 60 °C and concentrations of 50% and 65%. As expected increased temperatures and concentrations of the solution resulted in increased water loss, solid gain and shrinkage. The kinetics of osmotic dehydration were well described by the Peleg model. The effective diffusivity of water 5.50–7.387 × 10−9 m2/s and solute 8.315 × 10−10–1.113 × 10−9 m2/s was calculated for osmotic dehydration. Hot air drying was carried out at 40, 50, and 60 °C with air flow velocities of 1.0 m/s and 1.5 m/s. The drying time shortened with higher temperature and air velocity. The calculated effective diffusion of water was from 3.002 × 10−10 m2/s to 1.970 × 10−9 m2/s. The activation energy was sensitive to selected air temperatures, so greater air velocity resulted in greater activation energy: 46.379–51.514 kJ/mol, and with the osmotic pretreatment, it decreased to 35.216–46.469 kJ/mol. Osmotic dehydration reduced the effective diffusivity of water during the hot air drying process. It also resulted in smaller shrinkage of apricot halves in the hot air drying process.
Ivan Pavkov; Milivoj Radojčin; Zoran Stamenković; Krstan Kešelj; Urszula Tylewicz; Péter Sipos; Ondrej Ponjičan; Aleksandar Sedlar. Effects of Osmotic Dehydration on the Hot Air Drying of Apricot Halves: Drying Kinetics, Mass Transfer, and Shrinkage. Processes 2021, 9, 202 .
AMA StyleIvan Pavkov, Milivoj Radojčin, Zoran Stamenković, Krstan Kešelj, Urszula Tylewicz, Péter Sipos, Ondrej Ponjičan, Aleksandar Sedlar. Effects of Osmotic Dehydration on the Hot Air Drying of Apricot Halves: Drying Kinetics, Mass Transfer, and Shrinkage. Processes. 2021; 9 (2):202.
Chicago/Turabian StyleIvan Pavkov; Milivoj Radojčin; Zoran Stamenković; Krstan Kešelj; Urszula Tylewicz; Péter Sipos; Ondrej Ponjičan; Aleksandar Sedlar. 2021. "Effects of Osmotic Dehydration on the Hot Air Drying of Apricot Halves: Drying Kinetics, Mass Transfer, and Shrinkage." Processes 9, no. 2: 202.
Drying is one of the oldest methods for food preservation that removes the water from fruit and makes it available for consumption throughout the year. Dried fruits can be produced by small- and large-scale processors, which makes them a very popular food among consumers and food manufacturers. The most frequent uses of drying technology include osmotic dehydration, vacuum drying, freeze-drying and different combinations of other drying technologies. However, drying may provoke undesirable changes with respect to physiochemical, sensory, nutritional and microbiological quality. Drying process energy efficiency and the quality of dried fruits are crucial factors in fruit drying. Recently, innovative technologies such as ultrasound, pulsed electric field and high pressure may be used as a pretreatment or in combination with traditional drying technologies for process intensification. This could result in quality improvements of dried fruits and enhanced efficiency and capacity of the production process, with a positive impact on environmental and economic benefits.
Milivoj Radojčin; Ivan Pavkov; Danijela Bursać Kovačević; Predrag Putnik; Artur Wiktor; Zoran Stamenković; Krstan Kešelj; Attila Gere. Effect of Selected Drying Methods and Emerging Drying Intensification Technologies on the Quality of Dried Fruit: A Review. Processes 2021, 9, 132 .
AMA StyleMilivoj Radojčin, Ivan Pavkov, Danijela Bursać Kovačević, Predrag Putnik, Artur Wiktor, Zoran Stamenković, Krstan Kešelj, Attila Gere. Effect of Selected Drying Methods and Emerging Drying Intensification Technologies on the Quality of Dried Fruit: A Review. Processes. 2021; 9 (1):132.
Chicago/Turabian StyleMilivoj Radojčin; Ivan Pavkov; Danijela Bursać Kovačević; Predrag Putnik; Artur Wiktor; Zoran Stamenković; Krstan Kešelj; Attila Gere. 2021. "Effect of Selected Drying Methods and Emerging Drying Intensification Technologies on the Quality of Dried Fruit: A Review." Processes 9, no. 1: 132.
Raspberries are one of Serbia’s best-known and most widely exported fruits. Due to market fluctuation, producers are looking for ways to preserve this fresh product. Drying is a widely accepted method for preserving berries, as is the case with freeze-drying. Hence, the aim was to evaluate convective drying as an alternative to freeze-drying due to better accessibility, simplicity, and cost-effectiveness of Polana raspberries and compare it to a freeze-drying. Three factors were in experimental design: air temperature (60, 70, and 80 °C), air velocity (0,5 and 1,5 m · s−1), and state of a product (fresh and frozen). Success of drying was evaluated with several quality criteria: shrinkage (change of volume), color change, shape, content of L-ascorbic acid, total phenolic content, flavonoid content, anthocyanin content, and antioxidant activity. A considerable influence of convective drying on color changes was not observed, as ΔE was low for all samples. It was obvious that fresh raspberries had less physical changes than frozen ones. On average, convective drying reduced L–ascorbic acid content by 80.00–99.99%, but less than 60% for other biologically active compounds as compared to fresh raspberries. Convective dried Polana raspberry may be considered as a viable replacement for freeze-dried raspberries.
Zoran Stamenković; Ivan Pavkov; Milivoj Radojčin; Aleksandra Tepić Horecki; Krstan Kešelj; Danijela Bursać Kovačević; Predrag Putnik. Convective Drying of Fresh and Frozen Raspberries and Change of Their Physical and Nutritive Properties. Foods 2019, 8, 251 .
AMA StyleZoran Stamenković, Ivan Pavkov, Milivoj Radojčin, Aleksandra Tepić Horecki, Krstan Kešelj, Danijela Bursać Kovačević, Predrag Putnik. Convective Drying of Fresh and Frozen Raspberries and Change of Their Physical and Nutritive Properties. Foods. 2019; 8 (7):251.
Chicago/Turabian StyleZoran Stamenković; Ivan Pavkov; Milivoj Radojčin; Aleksandra Tepić Horecki; Krstan Kešelj; Danijela Bursać Kovačević; Predrag Putnik. 2019. "Convective Drying of Fresh and Frozen Raspberries and Change of Their Physical and Nutritive Properties." Foods 8, no. 7: 251.
Rolnice od sušene voćne kaše su proizvod koji se sve više može naći na tržištu. Sirovina za njihovu proizvodnju je voće koje ne odgovora tehnološkim procesima proizvodnje sušenog voća (zrelije voće). Postupak proizvodnje predstavlja konvektivno sušenje kaše od jagode nanesene na lesu sušare u sloju debljine do 5 mm. Prilikom pripreme voćne kaše i tokom konvektivnog sušenja dolazi do oksidacije voćnog tkiva. Kako bi se smanjio uticaj oksidacije u kašu se dodaju antioksidansi, poput L-askorbinske kiseline. Ispitan je uticaj temperature vazduha za sušenje (45°C i 65°C) i dodatak L - askorbinske kiseline (0,5% i 1,5%, od mase pripremljene kaše) na promenu boje krajnjeg poizvoda. Boja kaše od jagode merena je odmah nakon pripreme i nakon konvektivnog sušenja kaše, kolorimetrom Konika Minolta CR400. Najniža promena boje ΔE= 12,57, ostvarena je pri temperaturi vazduha za sušenje od 65°C i 1% dodatku L - askorbinske kiseline. Najviša promena boje ΔE = 14,66, ostvarena je pri temperaturi vazduha za sušenje od 45°C i dodatku askorbinske kiseline u vrednosti od 0,5%. Kontrolni uzorak konvektivno je osušen bez dodatka askorbinske kiseline. Ukupna promena boje kontrolnog uzorka osušenog vazduhom temperature 45°C je ΔE=22,95, odnosno ΔE=25,71 pri temperaturi vazduha od 65°C. Za aproksimaciju eksperimentalnih rezultata kinetkie konvektivnog susenja korišćeni su pet matematickih modela koji se mogu naci u referentnoj literaturi iz ove oblasti (Newton, Page, Modified Page, Henderson and Pabis and Logarithmic), proširenih bezdimenzionalnim koeficijentom koji predstavlja temperaturu vazduha za sušenje. Na osnovu vrednosti statističkih pokazatelja R, X2 i RMSE može se zaključiti da Prošireni Modifikovani Page model najbolje aproksimuje kinetiku konvektivnog sušenja kaše od kruške. jagoda; kinetika konvektivnog sušenja; matematičko modelovanje; promena boje; voćne rolnice
Zoran Stamenković; Ivan Pavkov; Milivoj Radojčin; Krstan Kešelj; Anita Vakula; Tihomir Novaković. Mathematical modeling of the kinetics of strawberry pulp convective drying and the effect of ascorbic acid on strawberry pulp color preservation. Journal on Processing and Energy in Agriculture 2019, 23, 170 -175.
AMA StyleZoran Stamenković, Ivan Pavkov, Milivoj Radojčin, Krstan Kešelj, Anita Vakula, Tihomir Novaković. Mathematical modeling of the kinetics of strawberry pulp convective drying and the effect of ascorbic acid on strawberry pulp color preservation. Journal on Processing and Energy in Agriculture. 2019; 23 (4):170-175.
Chicago/Turabian StyleZoran Stamenković; Ivan Pavkov; Milivoj Radojčin; Krstan Kešelj; Anita Vakula; Tihomir Novaković. 2019. "Mathematical modeling of the kinetics of strawberry pulp convective drying and the effect of ascorbic acid on strawberry pulp color preservation." Journal on Processing and Energy in Agriculture 23, no. 4: 170-175.
U centrima za sušenje često se prebiranjem javlja određeni udeo voća koje je 'prezrelo' za ovakav vid prerade. Jedan od novijih metoda prerade prezrelih voćnih plodova jeste proizvodnja rolnica od sušene voćne kaše. U radu je predstavljen uticaj konvektivnog sušenja kaše od kruške proizvedene po organskim principima sorte 'Kiferov sejanac'. Ekperiment je izveden kao dvofaktorski sa dva nivoa faktora. Prvi faktor je temperatura vazduha za sušenje od 45°C i 65°C, pri brzini vazduha za sušenje od 1,5 m/s, a drugi faktor ekperimenta je dodatak askorbinske kiseline u kaši od kruške u količini od 1% i 2%, od mase pripremljene kaše. Cilj rada je da se ispita uticaj konvektivnog sušenja, na promenu boje, sadržaj vitamina C i da se definišu matematički modeli kinetike konvektivnog sušenja kaše od kruške. Najniža promena boje ostvarena je kod kaše sa dodatkom askorbinske kiseline u vrednosti 2% od mase kaše i temperaturi vazduha za sušenje od 45°C (ΔE= 23,981). Najviša promena boje ostvarena je pri temperaturi vazduha za sušenje od 65°C i dodatkom askorbinske kiseline u vrednosti od 1% (ΔE= 30,039). Zabeležena je razgradnja vitamina C u svim uzorcima. Kod kontrolnih uzoraka razgradnja vitamina C je ≈ 77-80%. Kod uzoraka sa dodatkom askorbinske kiseline razgradnja vitamina C prelazi preko 99%, kod svih uzoraka. Page model najbolje prikazuje konvektivno sušenje kaše od kruške pri temperaturi vazduha od 65°C. Koeficijent korelacije izonosi R= 0,998, vrednost of the reduced X2= 0,000262 i RMSE= 0,02. Konvektivno sušenje kaše od kruške, vazduhom temperature 45°C, najbolje prikazuje Logarithmic model. Koeficijent korelacije iznosi R= 0,999660, vrednost of the reduced is X2= 0,000066 i RMSE= 0,01. organska kruška; kinetika konvektivnog sušenja; matematički modeli; sadržaj vitamina C; promena boje; voćne rolnice
Zoran Stamenković; Ana Dolovac; Ivan Pavkov; Vojislava Bursić; Milivoj Radojčin; Mirko Babić; Krstan Kešelj. Convective drying of organic pear pulp in a thin stagnant layer. Journal on Processing and Energy in Agriculture 2018, 22, 153 -156.
AMA StyleZoran Stamenković, Ana Dolovac, Ivan Pavkov, Vojislava Bursić, Milivoj Radojčin, Mirko Babić, Krstan Kešelj. Convective drying of organic pear pulp in a thin stagnant layer. Journal on Processing and Energy in Agriculture. 2018; 22 (4):153-156.
Chicago/Turabian StyleZoran Stamenković; Ana Dolovac; Ivan Pavkov; Vojislava Bursić; Milivoj Radojčin; Mirko Babić; Krstan Kešelj. 2018. "Convective drying of organic pear pulp in a thin stagnant layer." Journal on Processing and Energy in Agriculture 22, no. 4: 153-156.