Yazar "Sahin, F. Hasturk" seçeneğine göre listele

Listeleniyor 1 - 2 / 2
  • [ X ]
    Öğe
    Effects of Different Drying Methods on Drying Kinetics and Color Parameters of Strawberry Tree (Arbutus unedo L.) Fruit
    (Univ Namik Kemal, 2013) Aktas, T.; Orak, H. H.; Sahin, F. Hasturk; Ekinci, N.
    Changing of drying kinetics and color parameters of strawberry tree fruits that were notreated (NPT), ethyl oleate pretreated (EO) and water blanched at 80 degrees C (WB) for one minute were evaluated during hot air drying at 50 degrees C, 60 degrees C and 70 degrees C and vacuum drying at 60 degrees C, 70 degrees C and 80 degrees C for halved and whole fruits. In addition to drying behaviors of strawberry tree fruits at different drying methods, tri-stimulus color parameters such as Hunter L*, a* and b* values were measured. HMF (formation of 5-hydroxymethylfurfural) occurring was also determined due to drying process. EO pretreatment was found highly effective on decreasing of drying time both for hot air drying and vacuum drying processes while WB pretreatment found to be more effective to keep color properties of strawberry tree fruits. Color properties were found to be better in half samples compared to whole dried fruits. HMF values verified this result. Hot air drying process caused to shorter drying time. High drying air temperatures (70 degrees C for hot air drying and 80 degrees C for vacuum drying) for all samples caused to occur HMF while HMF occurred in only whole dried NPT and WB treated fruits for hot air drying process at 60 degrees C. All these data show that hot air drying method at 60 degrees C drying temperature and, halving of fruits before drying can be proposed for drying of strawberry tree fruits in respect of drying kinetics, color and HMF values.
  • [ X ]
    Öğe
    Effects of hot air and freeze drying methods on antioxidant activity, colour and some nutritional characteristics of strawberry tree (Arbutus unedo L) fruit
    (Sage Publications Ltd, 2012) Orak, H. H.; Aktas, T.; Yagar, H.; Isbilir, S. Selen; Ekinci, N.; Sahin, F. Hasturk
    Antioxidant activity, colour and some nutritional properties of hot air and freeze-dried strawberry tree (Arbutus unedo L.) fruits were investigated. Additionally, the effects of two pre-treatments, namely ethyl oleate and water blanching, were compared in terms of drying characteristics. For determination of antioxidant activities in ethanol extracts, two different analytical methods were used: 1,1-diphenyl-2-picrylhydrazyl scavenging activity and beta-carotene bleaching activity. As a result, the ethyl oleate pre-treatment shortened the drying time by hot air method and gave a higher 1,1-diphenyl-2-picrylhydrazyl scavenging activity (82.16 +/- 0.34%), total phenolic content (7.62 +/- 1.09 mu g GAE/g extract), ascorbic acid content (236.93 +/- 20.14 mg/100 g), besides hydromethylfurfural was not observed. Freeze- dried fruits exhibited higher ascorbic acid content (368.63 +/- 17.16 mg/100 g) than those fresh fruits (231.33 +/- 19.51 mg/100 g) and nearly 1,1-diphenyl-2- picrylhydrazyl activity (93.52 +/- 0.41 %) to fresh fruits (94.03 +/- 1.18%). Colour characteristics, sugar content and mineral contents of fruits were significantly affected by pre-treatments and drying methods (p < 0.05). It is concluded that the drying of strawberry tree fruits should bring a valuable and attractive foodstuff to food industry due to the rich nutritional components, antioxidant activity and colour. Another conclusion from this study is that the freeze-drying is the best drying method to keep the nutritional value, antioxidant activity and sensory properties of fruits.