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The effects of green pretreatment processes, such as ultrasonic process (US) and deep eutectic solvent (DES), applied to the biomass on kinetic parameters are as important as their effects on characteristic properties. Process conditions and course of reaction progression depend on the knowledge about kinetic parameters, activation energy and reaction model of thermal degradation in scale-up studies. Therefore, in this study, the change in the kinetic parameters with US applied with both distilled water and DES (glycerol:sodium acetate) at 100 W power and 20 kHz frequency for 10 minutes to sunflower seed husk (SSH) was revelaed. Isoconversional methods Kissinger-Akahira-Sunose (KAS) and Flynn-WallOzawa (FWO) were preferred for the evaluation of activation energy of SSH and pretreated SSH at 15°C/min, 20°C/min and 25°C/min heating rates. US pretreatment with DES instead of water resulted in increment of average activation energy values (Ea) from 113.13 to 143.65 kJ/mol in the KAS method. Ea values for all SSH samples changed in the range of 87.72-143.65 kJ/mol and higher Ea values was obtained with KAS method for pretreated SSH samples. Consequently, the use of DES in US pretreatment was more effective to change kinetic parameters of SSH compared to water. [ABSTRACT FROM AUTHOR]

In this study, the drying performance of lemon peel samples was investigated by drying processes with microwave, hot air and their combinations. Three different temperatures (40, 50 and 60°C) and three different microwave powers (90, 180 and 360 W) were used. Effects of drying conditions on drying rate and drying time were determined. Page and Modified Page models were found to be the best expressing models of the drying kinetics of lemon peels. With the increase in temperature and microwave power, the drying rate increased, while the drying time decreased. It was observed that the drying process performed with the combination of 60°C hot air and 360 W microwave had the highest drying rate with the shortest drying time of 24 minutes. The effect of drying processes on the color of lemon peels was determined by determining the L*, a*, b*, Hue angle, Chroma and AE* values and the color differences between fresh and dry samples. Due to the darkening of the samples under high microwave power, it was concluded that the use of 90 and 180 W is more suitable than 360 W. Total amount of phenolic substances increased in the dried samples compared to the fresh samples, while the antioxidant activity decreased. At 40°C, which has the longest drying time, the decrease in antioxidant activity was the highest with 85.54%. The drying process performed with the combination of 60°C and 360 W was the drying condition in which the total phenolic content increased the most with 186.11%. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Agriculture & Nature / Kahramanmaraş Sütçü İmam Üniversitesi Tarım & Doğa Dergisi is the property of Kahramanmaras Sutcu Imam Universitesi and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The changes in ascorbic acid-(AA) content, hydroxymethylfurfural-(HMF) content, total color difference-(ΔE*) and browning index-(BI) of optimally thermosonicated (59°C-455 J/g) cloudy strawberry nectar during storage (3 months at 4°C) were evaluated. Also, the data obtained were modelled. The initial AA content (104.86 mg/L) decreased ~99% after storage, while HMF level increased from 20.46 to 494.44 μg/L. The significant increases in BI-(0.45-0.56) and ΔE*-(5.21-11.23) were consistent with each other and over storage time. The changes in HMF content-(R2=0.849), BI-(R2=0.942) and ΔE* were best fitted to zero-order kinetic model, while decrease in AA content-(R2=0.9755) was described with the first-order kinetic model. The reaction rate constants of AA, HMF, ΔE* and BI were determined as 5.58x10-2 1/day, 4.34 mg/L.day, 6.40x10-2 mg/L.day and 14x10-2 mg/L.day, respectively. The highest correlation with the change in ΔE* was observed in AA-(R2=0.955) followed by BI-(R2=0.859). Therefore, the greatest effect on color might be caused by AA degradation. [ABSTRACT FROM AUTHOR]

Bu çalışmanın amacı, zeytin çekirdeği antioksidan bileşiklerinden elde edilen mikroenkapsüllerin su aktivitesi, renk, partikül özellikleri, yığın özellikleri ve rekonstitüsyon özelliklerinin belirlenmesi ve mikrokapsüllerin -20°C, 4°C ve 25°C olmak üzere üç farklı sıcaklıkta 6 ay süre ile depolanmasıyla polifenol ve antioksidan içeriğindeki değişimin kinetik modellemeyle incelenmesidir. Mikrokapsüllerin 0,43 su aktivitesi değerine, az kırmızılık içeren parlak açık sarı renge ve homojen olmayan oyuklu partiküllere sahip olduğu gözlenmiştir. Higroskobik (%32,47) ve yüksek kekleşme özelliğine (%61,32) sahip olduğu, ıslanabilirlik (52 dk) ve dağılabilirliğinin (%34,44) düşük olduğu ve uygun yığın yoğunluğu (0,26 g/cm3) ve sıkıştırılmış yoğunluk (%0,33 g/cm3) değerlerini sergilediği belirlenmiştir. Mikrokapsüllerin akabilirlik (CI:22,65) ve yapışkanlık (HR:1,29) davranışları kabul edilebilir düzeydedir. Ayrıca depolama sonucunda polifenol ve antioksidan içeriğindeki değişimin (yüzey polifenol miktarı ve mikroenkapsülasyon etkinliği hariç) birinci dereceden kinetik modelle en iyi açıklanabildiği bulunmuştur. Her depolama sıcaklığında incelen tüm bileşiklere ait kinetik katsayılar (reaksiyon hız sabiti (k), yarılanma süresi (t1/2) ve Q10 değeri) hesaplanmıştır. Depolama boyunca mikrokapsüllerin polifenol ve antioksidan içeriğindeki korunumun en iyi olduğu sıcaklığın 4°C, en kötü olduğu sıcaklığın ise -20°C olduğu belirlenmiştir. Zeytin çekirdeği antioksidan bileşiklerinden elde edilen mikroenkapsüllerin özellikle 4°C’de depolanan gıdaların hem fonksiyonelliğinin artırılması hem de raf ömrünün uzatılması amacıyla kullanıma uygun olduğu düşünülmektedir.

This study examined kinetic modeling of the detoxification induced by dechlorination of laccase enzyme obtained from Trametes versicolor which is a white rot fungi strain and 2,4,6-trichlorophenol which is a toxic chlorinated phenolic compound. In the evaluation of the kinetics of detoxification induced by dechlorination of 2,4,6-trichlorophenol used as substrate, the Systat 10 software package which is a statistics program was used while two-substrate solution environment was used to explain the kinetic behavior of the dechlorination. It was observed as a result of experiments and statistical analysis that Moser equation is the optimal kinetic model. Given the statistical data obtained and the graph, the dual-substrate model was found to be compatible with the experimental data. The bio-kinetic parameter values obtained for the model that identifies enzymatic dechlorination kinetics were calculated as Vmax =9.341 ppmO2/min, Ks =38.254 g/L, Ko =20.747 ppm, R = 1.895 and N = 1.233. In the literature, no studies were found on kinetic modeling for the degradation of 2,4,6-trichlorophenol, and through this study, we have been first to conduct a study on kinetic modeling of the degradation induced by enzymatic dechlorination of 2,4,6-trichlorophenol. The GC/MS analysis results showed that the chlorophenolic compound used throughout the enzymatic dechlorination performed with laccase enzyme was degraded 80% to 100%. Based on the GC/MS analysis results, the conclusion that the enzyme responsible for the dechlorination was laccase was also found to support the findings available in literature.

Copyright of Yuzuncu Yil Universitesi Journal of Agricultural Sciences (YYU J Agr Sci) is the property of Yuzuncu Yil University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)