Kinetics of Polyphenol Losses During Soaking and Drying of Cider Apples

Abstract

A regular consumption of fresh or processed fruits can contribute to preventing cardiovascular diseases and cancer. Polyphenols, which are naturally present in fresh apples (Malus x domestica), are widely acknowledged as antioxidants. Cider apples contain high concentrations of polyphenols, but their composition differs markedly as a function of cultivar. Two of which were studied in this respect. The first cultivar was Marie Menard, which is highly concentrated in polyphenols and has a standard profile showing high levels of hydroxycinnamic acids and monomeric catechins, widely involved in oxidation reactions catalyzed by the polyphenol oxidase; the second one was Guillevic, which has an atypical phenolic profile for a cider apple, with highly polymerized procyanidins and no monomeric catechins, which thus induces a low sensitivity to enzymatic browning. Both cultivars were subjected to osmotic dehydration at two temperatures (45 and 60°C) or to convective air-drying, and a combination of the two processes was also tested. Phenolic compounds were quantified by high performance liquid chromatography for various processing times and regardless of the quantity of impregnated sugar. The results revealed different behaviors depending on the polyphenolic groups of compounds. Procyanidins were better preserved by the processes than hydroxycinnamic acids or monomeric catechins. Indeed, these latter groups of polyphenols were first of all involved in enzymatic browning but could also diffuse more easily as their molecular weight was lower. Polyphenol retention was also dependent on the process applied. Polyphenols were better retained by convective drying than by osmotic dehydration, and when soaking was applied as a pretreatment, polyphenol losses were limited during subsequent drying. Moreover, the level of sucrose impregnation could mask the astringency of procyanidins.

Effects of Ultrasound on Polyphenol Retention in Apples After the Application of Predrying Treatments in Liquid Medium

“…It is therefore advisable to use less detrimental processing methods, thus allowing the maximum possible level of polyphenols to be retained in the processed product. In the case of dried apple products, the main reason of polyphenol deterioration is related to prolonged material exposure to air flow and elevated temperature which substantially speed up oxidation as well as further condensation processes (Krokida et al 1998;Devic et al 2010b). These undesirable polyphenol alterations, visible as browning reactions, diminish external product quality and are also considered an indicator of bioactive components losses (Akyıldız and Öcal 2006).…”

Unveiling of Brazilian cider composition by stable isotopes and physicochemical analysis

“…Estes valores baixos podem ser um indício de diluição do produto. Na década de 70 a sidra foi estilizada para ficar semelhante ao champanha, desta maneira a cor natural não era interessante e foi eliminada do produto (CARVALHO et al, 2011) através da adição de dióxido de enxofre que inibe a reação de escurecimento enzimático, bloqueando a formação de cor, além de agir como um bacteriostático (RIBEREAU-GAYON et al, 1998, DEVIC et al, 2010. A concentração de anidrido sulfuroso em sidras comerciais variou de 44,8 a 138,0mg/L (Tabela 1), porém os valores estavam abaixo do máximo (350 mg/L) estabelecido pela legislação brasileira (BRASIL, 1988).…”

ANALISIS PROKSIMAT, SENYAWA FENOLIK, SIFAT ANTIOKSIDAN DAN ANTIBAKTERI KULIT BUAH Lepisanthes alata

“…Polifenol oksidase (PPO) memiliki peran terbatas dalam menurunkan kadar antosianin oleh sebab gugus glikosida yang dimilikinya (Madrau et al, 2009). Degradasi komponen prosianidin dan antosianin dapat terjadi dikarenakan proses asidolisis (Devic et al, 2010). Selain antosianin, flavonoid yang umum ditemukan pada buah-buahan kaya polifenol adalah kuersetin dan kaemferol dari kelompok flavonol, serta katekin dari kelompok flavanol.…”

“…Dibanding dengan faktor waktu, suhu pengeringan merupakan faktor utama yang mempengaruhi degradasi polifenol kulit buah bengalun. Hasil ini serupa dengan pengeringan apel (Devic et al, 2010).…”