Influence of different drying techniques on drying parameters of mango

Abstract This research inspected the effects of freeze, microwave (120 and 350 W) and hot air (60, 70 and 80 °C) drying techniques on the color, drying characteristics, antioxidant capacity and total phenolic content of mango slices. Midilli et al., Two-term and Page models which exemplify drying characteristics are superior than alternative models. All of the color values (a, b, L, C, α and ΔE) were altered notably based on the used drying technique and colors nearest to the fresh sample were attained with freeze drying. In comparison to the fresh sample, the dried samples showed a decrease of 18.4-54.6% in antioxidant capacity. The total phenolic content value was notably highest one for the microwave dried sample at 350 W and the lowest one for a hot air dried sample at 80 °C (P<0.05). This research showed that microwave drying at 350 W is able to yield high-quality mango slices with the extra advantage of shortened drying time in relation to hot air and freeze drying

Total phenolics, antioxidant capacity, colour and drying characteristics of date fruit dried with different methods

Abstract Date slices were dried with the three drying methods convective (60, 70 and 80 °C), microwave (120 W) and freeze drying to determine drying characteristics and to compare the dried fruit quality. All colour parameters changed depending on the drying method and colours closest to the fresh sample were obtained with freeze drying. It is interesting to note that the total phenolic content and antioxidant capacity in each sample rose when looked at in relation to the fresh sample. In particular, microwave-dried samples were recorded as having the highest total phenolic content and the highest antioxidant capacity. To explain the drying kinetics of the date slices, nine thin-layer drying models were also attempted. Based on statistical tests, the model developed by Midilli et al. model was found to be the best model for convective and microwave drying, but the Two Term model was the best for freeze drying. This study shows that microwave drying can produce high quality date slices with the additional advantage of reduced drying times compared to convective and freeze drying

Drying kinetics, colour, total phenolic content and antioxidant capacity properties of kiwi dried by different methods

This study analysed the convective (60, 70 and 80 degrees C), microwave (120 and 350 W) and freeze drying methods in terms of their effects on the drying characteristics, colour, total phenolic content (TPC) and antioxidant capacity of kiwi slices. Nine different mathematical models were applied to experimental data to achieve the most accurate calculation for drying curves. The Midilli et al. and Wang and Singh models proved to be the most suitable at explaining the drying kinetics of kiwi samples as compared to other models according to the statistical tests. Each drying method was significantly affected by colour parameters (L*, a*, b*, C, alpha and Delta E). The dried samples exhibited respectively 5-49 % and 10-47 % less TPC and antioxidant capacity compared to the fresh sample. According to the correlation analysis conducted between TPC and antioxidant capacity for kiwi slices, there is a positive correlation (R (2) = 0.7796). Microwave dried samples at 120 W particularly had the lowest TPC and antioxidant capacity. Freeze drying method yielded the closest values with respect to colour values, total phenol content and antioxidant capacity to those of fresh samples when compared to the other methods

Total phenolics, antioxidant capacity, colour and drying characteristics of date fruit dried with different methods

Abstract Date slices were dried with the three drying methods convective (60, 70 and 80 °C), microwave (120 W) and freeze drying to determine drying characteristics and to compare the dried fruit quality. All colour parameters changed depending on the drying method and colours closest to the fresh sample were obtained with freeze drying. It is interesting to note that the total phenolic content and antioxidant capacity in each sample rose when looked at in relation to the fresh sample. In particular, microwave-dried samples were recorded as having the highest total phenolic content and the highest antioxidant capacity. To explain the drying kinetics of the date slices, nine thin-layer drying models were also attempted. Based on statistical tests, the model developed by Midilli et al. model was found to be the best model for convective and microwave drying, but the Two Term model was the best for freeze drying. This study shows that microwave drying can produce high quality date slices with the additional advantage of reduced drying times compared to convective and freeze drying

Farklı Kurutma Uygulamalarının Armut Meyvesinin Bazı Kalite Özellikleri Üzerine Etkileri

Bu çalışmada; mikrodalga-sıcak hava kombinasyonu kurutma yönteminin küp ve halka şeklinde hazırlanan armut meyvelerinin renk parametreleri, toplam fenolik madde miktarı ve antioksidan kapasitesi değerleri üzerine etkileri tespit edilmiştir. Laboratuvar tipi mikrodalga-sıcak hava fırını kullanılarak gerçekleştirilen denemelerde iki farklı mikrodalga gücü (90W ve 160W) ve üç farklı kurutma sıcaklığı (55, 65 ve 75C) uygulanmıştır. Tüm kurutma koşullarından elde edilen örneklerin renk değerleri istatistiksel açıdan önemli ölçüde farklı bulunmuştur. Uygulanan mikrodalga gücü ve kurutma sıcaklığının artması ile armut örneklerinin L* (parlaklık) değerlerinde azalma, a* (yeşillik(-)/kırmızılık(+)) değerinde ise artış meydana gelmiştir. Taze armut örneklerinin renk parametrelerine en yakın değerler halka şeklinde hazırlanıp 160W-55C uygulaması ile kurutulan örneklerden (∆e=9,90) elde edilmiştir. En yüksek toplam fenolik madde miktarı (164,75 mg GA/100g K.M.) halka kesim şekli ve 160W-65C uygulamasında belirlenirken, en yüksek antioksidan kapasite değeri taze örnekte (5,13 µmol trolox/g K.M.) saptanmıştır. Bu çalışmada, uygulanan kurutma parametreleri ve kesim şeklinin ürün kalitesini doğrudan etkilediği belirlenmiştir. Özellikle halka şeklinde kesilerek kurutulan armut örneklerinden hem renk değerleri hem de toplam fenolik madde miktarı açısından daha başarılı sonuçlar elde edilmiştir