Elma suyunda fenolik madde dağılımı ve konsantreye işleme sırasında değişimi

Abstract

Ö2ET Doktora Tezi ELMA SUYUNDA FENOLİK MADDE DA?ILIMI VB KONSANTREÎfE İŞLEME SIRASINDA DE?İŞİMİ Feryal KARADENİZ Ankara Üniversitesi Fen Bilimleri Enstitüsü Gıda Bilimi ve Teknolojisi Anabilim Dalı Danışman: Prof. Dr. Aziz EKŞİ 1993, Sayfa:79 Jüri: Prof. Dr. Aziz EKŞİ Prof. Dr. Bekir CEMERO?LU Prof. Dr. Aydın URAL Elma suyunda fenolik madde dağılımını belirlemek için 45 farklı elma suyu analiz edilmiştir. Elma suyu örneklerinin elde edildiği meyve materyali, üç farklı elma çeşidini (AMASYA, GOLDEN, STARKİNG), üç farklı yetişme yılını (1990, 1991, 1992) ve beş farklı yetişme yöresini kapsamaktadır. Uygulanan HPLC yöntemi ile kantitatif olarak belirlenen başlıca fenolik bileşikler; klorogenik asit, (-)-epikateşin, floretin-glikozit, floridzin ve p-kumarik asittir. Yöntemin duyarlılığı, fenolik maddeye göre % ± 4.2-9.1 arasındadır. Bulgulara göre elma suyunda klorogenik asit 62.3-342.6 mg/L, (-)-epikateşin 5.3-240.1 mg/L, floretin-glikozit 5.5-60.0 mg/L, floridzin 6.9-29.7 mg/L, p-kumarik asit 1.1-16.0 mg/L arasında değişmektedir. Fenolik madde dağılımı özellikle elma çeşidinden etkilenmektedir yetişme yılı ve yetişme yöresinden kaynaklanan farklar önemli bulunmamaktadır. Elma suyundaki esmerleşme derecesi ile klorogenik asit, (-)-epikateşin, floretin-glikozit arasındaki korelasyonlar, istatistik açıdan önemlidir (P£ 0.01). Bir önceki prosese göre ortaya çıkan fenolik madde kaybı preslemede % 7.7-34.3, durultmada % 0-26.7, filtrasyonda % 0- 10.1, konsantrasyonda % 10.1-32.1 arasındadır. Konsantrenin 10 ay depolanmasında ortaya çıkan fenolik madde kaybı ise % 5.9- 61.0 arasında değişmektedir. ANAHTAR KELİMELER: Elma suyu, elma suyu konsantresi, fenolik maddeler, enzimatik esmerleşme, klorogenik asit, (-)-epikateşin, floretin-glikozit, floridzin

11 ABSTRACT « Ph.D. Thesis PHENOLIC COMPOSITION OF AP9LE JUICE AND THEIR CHANGES DURING »ROCESSINO Of THE CONCENTRATE Feryal KARADENİZ Ankara University Graduate School of Natural and Applied Sciences Department of Food Science and Technology Supervisor: Prof. Dr. Aziz EKŞİ 1993, Page:79 Jury: Prof. Dr. Aziz EKŞÎ Prof. Dr. Bekir CEMERO?LU Prof. Dr. Aydın URAL Apple juice from 45 different cultivars was analyzed for the amount of phenolic substances present. Those apple fruit varieties used in juice processing were the Amasya, Golden and S tar king cultivars. Three consecutive production years were studied : 1990, 1991 and 1992. The apple fruit were obtained from five different production areas. The principal phenolic substances were assayed by a method employing HPLC and the substances determined were : chlorogenic acid, (-)-epicatechin, phloretin glycoside, phloridzin and p-coumaric acid. According to the particular phenolic substance analyzed, the error of assay in the method used is ± 4.2 % to ± 9.1 %. According to the results, phenolic compounds of apple juice changes for chlorogenic acid between 62.3 and 342.6 mg/L, (-)- epicatechin between 5.3 and 240.1 mg/L, phloretin glycoside between 5.5 and 60.0 mg/L, phloridzin between 6.9 and 29.7 mg/L and p-coumaric acid between 1.1 and 16.0 mg/L. The distribution of phenolic substances present was especially different according to the varieties used in processing. Differences between growing years and the growing areas from which the fruit was obtained were not significant. A correlation between the browning level of apple juice and the changes in contents of chlorogenic acid, (-) -epicatechin and phloretin glycoside was found to be statistically significant (P i 0.01). The compositions of phenolic substance content declined during the processing of the fruit, with the percent loss shown in the following values and reflecting total phenolic substance contents after the step compared to total phenolic substance contents before the step : during pressing from 7.7 to 34.3 %, during clarifying from 0 to 26.7 %, during filtration from 0 to 10.1 %, during concentration from 10.1 to 32.1 %. Ten months after storage of the concentrate, loss of total phenolic substance content was between 5.9 and 61.0 %. KEY WORDS : Apple juice, apple juice concentrate, phenolic substances, enzymatic browning, chlorogenic acid, (-) -epicatechin, phloretin glycoside, phloridzin.