Polyphenol profiles of apple juices

Abstract

Focusing on 17 constituents, the polyphenol profiles of juices freshly made from various dessert (n = 4) and cider apple cultivars (n = 7) as well as commercially available apple juices (n = 24) were investigated using high-performance liquid chromatography-photodiode array detection (HPLC-DAD) and (HPLC)-electrospray ionization-tandem mass spectrometry (ESI(neg)-MS/MS) analyses. Significant differences in the total polyphenol content as well as the profiles of the apple cultivars under study were observed. For dessert apples the total polyphenol content ranged from 154 to 178 mg/L, whereas for 'old' German cider apple cultivars 261-970 mg/L were determined. Boskoop showed the highest (970 mg/L) and Granny Smith the lowest (154 mg/L) polyphenol content of the freshly prepared samples under study. Hydroxycinnamic acids, with chlorogenic acid as dominating constituent, ranged from 57 to 68 mg/L as well as from 134-593 mg/L in juices made from dessert apples and that from cider apples, respectively. Dessert apple juices showed lower contents of dihydrochalcones (10-35 mg/L) and flavan-3-ols (50-95 mg/L) compared to that of cider apples (34-171 mg/L and 70-393 mg/L, respectively). Quercetin and its derivatives were found from 0.4-4 mg/L and 0.4-27 mg/L in juices made from dessert apples and that of cider apples, respectively. Compared with freshly made juices, lower contents of polyphenols were determined in the commercial samples under study. Amounts ranging from 110-459 mg/L, dominated by chlorogenic acid with concentrations from 53-217 mg/L, were determined. Information about cultivar-typical apple polyphenol content and profile is important for bioactivity studies and, consequently, essential for the development of consumer-relevant products with particular nutritional functionalities.

Influence of postharvest processing and storage on the content of phenolic acids and flavonoids in foods

“…However, higher concentrations were found in cider apples [112,115] than in dessert apples. Due to the fact that some compounds are sometimes fixed to flesh components, cloudy juice contains more dihydrochalcon glycosides than clear apple juice [112]. Freshly home pressed juice showed a higher content than commercial varieties [112].…”

“…Very low concentrations (0.4 -4 mg/L) of quercetin derivatives in dessert apple juice have been found, while in cider apple juice quercetin glycosides reached concentrations of up to 27 mg/L. No free quercetin was found in the apple juice [112]. In blueberry juice produced by three different types of treatment (initial heat treatment, SO 2 and no treatment), polyphenolic levels remain similar [58].…”

“…[39,112], freezing [47,110], enzymatic treatment and maceration [39,111], and effects of high temperature and oxygen [113].…”

“…Due to the fact that some compounds are sometimes fixed to flesh components, cloudy juice contains more dihydrochalcon glycosides than clear apple juice [112]. Freshly home pressed juice showed a higher content than commercial varieties [112]. Storage of up to 4 months at 4 or 208C led to no considerable changes in the content of glycosides while in other phenolic compounds drastic changes were observable.…”

“…The following list gives an enumeration of all the measures or procedures investigated: Maturity, ripening and time of harvest [63,74,82,99,115,116,176,178,179,188,189,194] 58,112,142,162,181,191,196], differentiation in fractions [114,167,174], peeling [109,142,153,180], special pressing or extraction [2, 64,72,165], enzymatic treatment and maceration [51], irradiation [53,158,175,183], drying [8,102,132,152,159], sensory effects [51], germination [88], browning-blanching and polyphenoloxidase (PPO) activity [124], proveniences [8,12,63,107,110,112,…”