Farklı hasat döneminde toplanmış taze çay yaprağının biyoaktif bileşiklerinin optimize edilerek belirlenmesi ve invitro biyoerişilebilirliğinin araştırılması
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Date
2022-06-27
Authors
Chebbi, Hind
Journal Title
Journal ISSN
Volume Title
Publisher
Bursa Uludağ Üniversitesi
Abstract
Bu çalışmada, farklı hasat yılı ve döneminin taze çay yaprağının toplam polifenol (TP), radikal tutma aktivitesi (RTA), toplam flavonoid (TF) ve askorbik asit (AA) içeriğine etkisi incelenmiştir. Taze çay yaprağından polifenollerin ekstraksiyonu yanıt yüzey yöntemi (RSM) kullanılarak optimize edilmiştir. Optimizasyon sonucunda en yüksek TP değeri elde edilebilmesi için optimum koşullar olarak, ürün/solvent (Ü/S) oranının 1/60,86, etanol konsantrasyonunun %84,65 ve ekstraksiyon süresinin 50 dak olması gerektiği belirlenmiştir. Çay yapraklarından polifenollerin optimum koşullarda yapılan ekstraksiyonu sonucunda, 2020 yılının Eylül ayında toplanmış yaprakların TP, RTA ve TF içeriği daha yüksek bulunmuştur. Ayrıca, 2020 yılının Eylül ayında toplanmış yaprakların bireysel fenolik bileşikleri yüksek performanslı sıvı kromatografisi (HPLC) ile analiz edilmiş olup, en fazla epigallokateşin gallat (EGCG) (57,52 mg/g kuru madde (KM)) tespit edilmiştir. Aynı örneklerin in-vitro sindirim sonrasında, TP ve RTA değerleri, en fazla intestinal aşamada olmak üzere önemli oranda azalmıştır (p<0,05). Bununla birlikte, polifenollerin biyoerişilebilirliği %48,98 olarak belirlenmiştir. İki yıl farklı dönemlerde toplanmış yaprakların HPLC ile AA analizi sonucunda, en yüksek AA içeriği, 2019 yılı için Mayıs dönemi yaprağında (41,92 mg/100 g KM), 2020 yılı için de Temmuz dönemi yaprağında (38,55 mg/100 g KM) gözlenmiştir. Bu çalışmada ayrıca, örneklerin TP içeriği ve RTA için kullanılan spektrofotometrik yöntemler, bu yöntemlerin literatürde en çok kullanılan modifikasyonları ile karşılaştırılmıştır. TP ve RTA açısından, yöntemler arasında önemli farklılıklar saptanmıştır. Spektrofotometrik olarak elde edilen TP sonuçları, HPLC ile elde edilen sonuçlarla karşılaştırılmış ve uygulanan beş farklı yöntemden sadece birinin (FCR yöntemi 1) en iyi uyumu sağladığı ve bu nedenle en fazla güvenilirliğe sahip olduğu sonucuna varılmıştır.
In this study, the effect of different plucking years and periods on total polyphenol (TP), radical scavenging activity (RSA), total flavonoid (TF) and ascorbic acid (AA) of fresh tea leaves extracts were evaluated. The extraction of polyphenols from fresh tea leaves was optimized by using the response surface methodology (RSM). The results showed that in order to obtain the highest TP, the optimal extraction conditions were found to be material-to-solvent (M/S) ratio of 1/60,86, ethanol concentration of 84,65% and extraction time of 50 min. As a result of the extraction of polyphenols from tea leaves under the optimal conditions, the leaves plucked in September 2020 had the highest TP, RSA and AA. In addition, the analysis of individual phenolic compounds of tea leaves was performed by high performance liquid chromatography (HPLC) and the result indicated that the leaves plucked in September 2020 contained the highest amount of EGCG content (57,52 mg/g dry weight (DW)). After the in-vitro digestion of the same samples, TP and RSA values showed a significant decrease, mostly at the intestinal phase (p<0,05). However, the bioaccessibility of polyphenols was determined as 48,98%. The AA identification and quantification of tea leaves from different periods of two years were performed by HPLC. The obtained results revealed that leaves plucked in May for 2019 (38,55 mg/100 g DW) and those in September for 2020 (41,92 mg/100 g DW) had the highest AA contents. Additionally, in this study, the spectrophotometric methods used for TP content and RSA of the samples were compared to the modifications of these methods which are most widely used in the literature and significant differences were found between the methods regarding TP and RSA. The TP results obtained spectrophotometrically were compared with the results obtained by HPLC and it was concluded that only one of the five different methods applied (FCR method 1) provided the best fit and therefore had the most reliability.
In this study, the effect of different plucking years and periods on total polyphenol (TP), radical scavenging activity (RSA), total flavonoid (TF) and ascorbic acid (AA) of fresh tea leaves extracts were evaluated. The extraction of polyphenols from fresh tea leaves was optimized by using the response surface methodology (RSM). The results showed that in order to obtain the highest TP, the optimal extraction conditions were found to be material-to-solvent (M/S) ratio of 1/60,86, ethanol concentration of 84,65% and extraction time of 50 min. As a result of the extraction of polyphenols from tea leaves under the optimal conditions, the leaves plucked in September 2020 had the highest TP, RSA and AA. In addition, the analysis of individual phenolic compounds of tea leaves was performed by high performance liquid chromatography (HPLC) and the result indicated that the leaves plucked in September 2020 contained the highest amount of EGCG content (57,52 mg/g dry weight (DW)). After the in-vitro digestion of the same samples, TP and RSA values showed a significant decrease, mostly at the intestinal phase (p<0,05). However, the bioaccessibility of polyphenols was determined as 48,98%. The AA identification and quantification of tea leaves from different periods of two years were performed by HPLC. The obtained results revealed that leaves plucked in May for 2019 (38,55 mg/100 g DW) and those in September for 2020 (41,92 mg/100 g DW) had the highest AA contents. Additionally, in this study, the spectrophotometric methods used for TP content and RSA of the samples were compared to the modifications of these methods which are most widely used in the literature and significant differences were found between the methods regarding TP and RSA. The TP results obtained spectrophotometrically were compared with the results obtained by HPLC and it was concluded that only one of the five different methods applied (FCR method 1) provided the best fit and therefore had the most reliability.
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Keywords
Biyoaktif bileşik, Biyoerişilebilirlik, Hasat dönemi, HPLC, Taze çay yaprağı, RSM, Bioaccessibility, Bioactive compound, Fresh tea leaf, Plucking period
Citation
Chebbi, H. (2022). Farklı hasat döneminde toplanmış taze çay yaprağının biyoaktif bileşiklerinin optimize edilerek belirlenmesi ve invitro biyoerişilebilirliğinin araştırılması. Yayınlanmamış yüksek lisans tezi. Bursa Uludağ Üniversitesi Fen Bilimleri Enstitüsü.