Effects of drying methods on physicochemical properties and bioactive compounds of wild fruits native to the Gümüşhane flora of NE Türkiye

Öz

Wild fruits are valuable natural sources of bioactive compounds with significant nutritional and functional properties. This study comparatively evaluated the effects of freeze-drying (FD), oven drying (OD), and open-air drying (AD) on the physicochemical properties, total phenolic content (TPC), vitamin C content, and antioxidant properties of five wild fruit species naturally growing in the Gümüşhane region of Türkiye: wild pear (Pyrus elaegrifolia Pall.), hawthorn (Crataegus orientalis), rosehip (Rosa canina L.), cornelian cherry (Cornus mas L.), and barberry (Berberis vulgaris). Drying method markedly affected both physicochemical characteristics and bioactive compounds. Oven drying produced the lowest water activity values (0.10–0.34), indicating enhanced microbiological stability, whereas freeze-dried samples generally showed superior preservation of phenolic compounds and antioxidant activity. The highest TPC was observed in air-dried cornelian cherry (935.59 mg GAE/kg), while freeze-dried rosehip exhibited the highest TPC among freeze-dried samples (907.63 mg GAE/kg). Vitamin C was highly sensitive to thermal processing, and most oven-dried samples showed values below the detection limit (<0.30 mg/kg). In contrast, air-dried rosehip retained the highest vitamin C content (1594 mg/kg). Freeze-dried cornelian cherry exhibited the highest DPPH radical scavenging activity (93.45%), whereas oven-dried rosehip showed the highest total antioxidant content (33.38 mg/g). Correlation and hierarchical cluster analyses revealed that antioxidant behavior and clustering patterns were strongly dependent on fruit matrix composition rather than drying method alone. The findings demonstrate that the effects of drying treatments are strongly fruit matrix-dependent and that no single drying method is universally optimal for preserving all quality attributes of wild fruits.

Anahtar Kelimeler

• Antioxidant activity
• Drying methods
• Freeze-drying
• Total phenolic content
• Vitamin C
• Wild fruits

Dondurularak kurutma, fırında kurutma ve havada kurutmanın beş yabani meyve türünün fizikokimyasal özellikleri ve biyoaktif bileşikleri üzerindeki karşılaştırmalı etkileri

Öz

Rosehip, Cornelian cherry, Barberry gibi yabani meyveler, önemli besinsel ve fonksiyonel özelliklere sahip biyoaktif bileşiklerin değerli doğal kaynaklarıdır. Bu çalışmada, Türkiye’nin Gümüşhane bölgesinde doğal olarak yetişen beş yabani meyve türünün; yabani armut (Pyrus elaegrifolia Pall.), alıç (Crataegus orientalis), kuşburnu (Rosa canina L.), kızılcık (Cornus mas L.) ve karamuk (Berberis vulgaris) örneklerinde dondurarak kurutma (FD), etüvde kurutma (OD) ve açık havada kurutma (AD) yöntemlerinin fizikokimyasal özellikler, toplam fenolik madde miktarı (TPC), C vitamini içeriği ve antioksidan özellikler üzerindeki etkileri karşılaştırmalı olarak değerlendirilmiştir. Kurutma yöntemi hem fizikokimyasal özellikleri hem de biyoaktif bileşenleri belirgin şekilde etkilemiştir. Etüvde kurutma, en düşük su aktivitesi değerlerini (0.10–0.34) sağlayarak daha yüksek mikrobiyolojik stabilite göstermiştir. Buna karşılık, dondurarak kurutulan örnekler genellikle fenolik bileşiklerin ve antioksidan aktivitenin korunmasında daha üstün sonuçlar vermiştir. En yüksek toplam fenolik madde miktarı hava ile kurutulmuş kızılcık örneğinde (935.59 mg GAE/kg) belirlenirken, dondurarak kurutulmuş örnekler arasında en yüksek TPC değeri kuşburnunda (907.63 mg GAE/kg) gözlenmiştir. C vitamini ısıl işlemlere karşı oldukça hassas bulunmuş ve etüvde kurutulan örneklerin çoğunda değerler tayin limitinin altında (<0.30 mg/kg) kalmıştır. Buna karşılık, açık havada kurutulan kuşburnu en yüksek C vitamini içeriğini (1594 mg/kg) korumuştur. Dondurarak kurutulmuş kızılcık en yüksek DPPH radikal giderme aktivitesini (%93.45) gösterirken, etüvde kurutulmuş kuşburnu en yüksek toplam antioksidan kapasite değerine (33.38 mg/g) sahip olmuştur. Korelasyon ve hiyerarşik kümeleme analizleri, antioksidan davranışının ve kümelenme örüntülerinin yalnızca kurutma yöntemine değil, büyük ölçüde meyve matriksinin bileşimine bağlı olduğunu ortaya koymuştur. Bulgular, kurutma işlemlerinin etkilerinin meyve matriksine güçlü biçimde bağlı olduğunu ve yabani meyvelerde tüm kalite özelliklerini korumak açısından evrensel olarak en uygun tek bir kurutma yönteminin bulunmadığını göstermektedir.

Anahtar Kelimeler

• Antioksidan aktivite
• Kurutma yöntemleri
• Dondurularak kurutma
• Toplam fenolik içeriği
• C vitamini
• Yabani meyveler

Kaynakça

1. WHO, Healthy diet, World Health Organization, 2018.
2. J.L. Slavin, B. Lloyd, Health benefits of fruits and vegetables, Adv Nutr, 3, 2012, 506-516.
3. A.K. Yadav, D. Yadav, K. Shanker, R.V. Verma, A.K. Saksena, M.M. Gupta, Flavone glycoside based validated RP-LC method for quality evaluation of Prishniparni (Uraria picta), Chromatographia, 69, 2009, 653-658.
4. R. Aslantas, L. Pirlak, M. Güleryüz, The nutritional value of wild fruits from the North Eastern Anatolia region of Turkey, Asian J Chem, 19, 2007, 3072-3078.
5. S. Ercisli, Chemical composition of fruits in some rose (Rosa spp.) species, Food Chem, 104, 2007, 1379-1384.
6. M. Özgen, S. Serçe, C. Kaya, Phytochemical and antioxidant properties of anthocyanin-rich Morus nigra and Morus rubra fruits, Sci Hortic, 119, 2009, 275-279.
7. P.J. Fellows, Food Processing Technology: Principles and Practice (3rd edition), 2009, Cambridge, Woodhead Publishing.
8. D. Arslan, M. Özcan, Dehydration of red bell-pepper (Capsicum annuum L.): Change in drying behavior, colour and antioxidant content, Food Bioprod Process, 89, 2011, 504-513.

9. D.I. Onwude, N. Hashim, R.B. Janius, M.M. Nawi, K. Abdan, Modeling the thin-layer drying of fruits and vegetables: A review, Compr Rev Food Sci Food Saf, 15, 2016, 599-618.
10. V.R. Sagar, P.S. Kumar, Recent advances in drying and dehydration of fruits and vegetables: A review, J Food Sci Technol, 47, 2010, 15-26.
11. C. Ratti, Hot air and freeze-drying of high-value foods: A review, J Food Eng, 49, 2001, 311-319.
12. M. Radojčin, I. Pavkov, D.B. Kovačević, P. Putnik, A. Wiktor, Z. Stamenković, K. Kešelj, A. Gere, Effect of selected drying methods and emerging drying intensification technologies on the quality of dried fruit: A review, Processes, 9, 2021, 132.
13. C.S. Nwankwo, E.O. Okpomor, N. Dibagar, M. Wodecki, W. Zwierz, A. Figiel, Recent developments in the hybridization of the freeze-drying technique in food dehydration: A review on chemical and sensory qualities, Foods, 12, 2023, 3437.
14. T. Vashisth, R.K. Singh, R.B. Pegg, Effects of drying on the phenolics content and antioxidant activity of muscadine pomace, LWT Food Sci Technol, 44, 2011, 1649-1657.
15. AOAC, Official Methods of Analysis of AOAC International, Method 934.06: Moisture in Dried Fruits (18th edition), 2006, Gaithersburg, AOAC International.
16. AOAC, Official Methods of Analysis of AOAC International, Method 942.05: Ash of Fruits and Fruit Products (18th edition), 2006, Gaithersburg, AOAC International.
17. V.L. Singleton, J.A. Rossi, Colorimetry of total phenolics with phosphomolybdic-phosphotungstic acid reagents, Am J Enol Viticult, 16, 1965, 144-158.
18. D. Ahmed, M.M. Khan, R. Saeed, Comparative analysis of phenolics, flavonoids, and antioxidant and antibacterial potential of methanolic, hexanic and aqueous extracts from Adiantum caudatum leaves, Antioxidants, 4, 2015, 394-409.
19. W. Brand-Williams, M.E. Cuvelier, C. Berset, Use of a free radical method to evaluate antioxidant activity, LWT Food Sci Technol, 28, 1995, 25-30.
20. P. Prieto, M. Pineda, M. Aguilar, Spectrophotometric quantitation of antioxidant capacity through the formation of a phosphomolybdenum complex: Specific application to the determination of vitamin E, Anal Biochem, 269, 1999, 337-341.
21. AOAC, Official Methods of Analysis of AOAC International, Method 967.21: Ascorbic Acid in Vitamin Preparations and Juices—2,6-Dichloroindophenol Method (18th edition), 2006, Gaithersburg, AOAC International.
22. P.P. Lewicki, Water as the determinant of food engineering properties: A review, J Food Eng, 61, 2004, 483-495.
23. J.G. Brennan, Food Processing Handbook, 2006, Weinheim, Wiley-VCH.
24. M.A. Silva-Espinoza, M.D.M. Camacho, N. Martínez-Navarrete, Effect of storage temperature on the crispness, colour and bioactive compounds of an orange snack obtained by freeze-drying, Br Food J, 123, 2021, 2095-2106.
25. A. Mediani, H.S. Hamezah, F.A. Jam, N.F. Mahadi, S.X.Y. Chan, E.R. Rohani, N.H. Che Lah, U.K. Azlan, N.A. Khairul Annuar, N.A.F. Azman, H. Bunawan, M.N. Sarian, N. Kamal, F. Abas, A comprehensive review of drying meat products and the associated effects and changes, Front Nutr, 9, 2022, 1057366.
26. T. Belwal, C. Cravotto, M.A. Prieto, P.R. Venskutonis, M.D. Daglia, H.P. Devkota, G. Cravotto, Effects of different drying techniques on the quality and bioactive compounds of plant-based products: a critical review on current trends, Dry Technol, 40, 2022, 1539-1561.
27. P.H. Santos, M.A. Silva, Retention of Vitamin C in Drying Processes of Fruits and Vegetables—A Review, Dry Technol, 26, 2008, 1421-1437.
28. A. Wojdyło, K. Lech, P. Nowicka, F. Hernandez, A. Figiel, A.A. Carbonell-Barrachina, Influence of different drying techniques on phenolic compounds, antioxidant capacity and colour of Ziziphus jujube Mill. fruits, Molecules, 24, 2019, 2361.
29. B. Halliwell, J.M.C. Gutteridge, Free Radicals in Biology and Medicine (3rd edition), 1999, Oxford, Oxford University Press.
30. B. Medveckienė, J. Kulaitienė, E. Jarienė, N. Vaitkevičienė, E. Hallman, Carotenoids, Polyphenols, and Ascorbic Acid in Organic Rosehips (Rosa spp.) Cultivated in Lithuania, Appl Sci, 10, 2020, 5337.
31. A. Vega-Gálvez, K. Di Scala, K. Rodríguez, R. Lemus-Mondaca, M. Miranda, J. López, M. Perez-Won, Effect of air-drying temperature on physico-chemical properties, antioxidant capacity, colour and total phenolic content of red pepper (Capsicum annuum L. var. Hungarian), Food Chem, 117, 2009, 647-653.
32. C. López-Alarcón, A. Denicola, Evaluating the antioxidant capacity of natural products: A review on chemical and cellular-based assays, Anal Chim Acta, 763, 2013, 1-10.
33. R. Apak, M. Özyürek, K. Güçlü, E. Çapanoğlu, Antioxidant activity/capacity measurement. 1. Classification, physicochemical principles, mechanisms, and electron transfer (ET)-based assays, J Agric Food Chem, 64, 2016, 997-1027.
34. M.C. Giannakourou, P.S. Taoukis, Effect of alternative preservation steps and storage on vitamin C stability in fruit and vegetable products: Critical review and kinetic modelling approaches, Foods, 10, 2021, 2630.
35. H.M. Bayram, K. Ozkan, A. Ozturkcan, O. Sagdic, E. Gunes, A. Karadag, Effect of drying methods on free and bound phenolic compounds, antioxidant capacities, and bioaccessibility of Cornelian cherry, Eur Food Res Technol, 250, 2024, 2461-2478.
36. A. Ciurzyńska, A. Lenart, Freeze-drying – Application in food processing and biotechnology: A review, Pol J Food Nutr Sci, 61, 2011, 165-171.