Liquid Chromatography/Mass Spectrometry Investigation of the Impact of Thermal Processing and Storage on Peach Procyanidins

Abstract

Normal-phase liquid chromatography/mass spectrometry (LC/MS) was used to determine the levels and fate of procyanidins in frozen and canned Ross clingstone peaches as well as in the syrup used in the canning over a 3 month period. Procyanidin oligomers, monomers through undecamers, were identified in Ross clingstone peaches. Optimized methods allowed for the quantitation of oligomers through octamers. The profile of procyanidins in peaches is similar to profiles found in grapes, chocolate, and beverages linked to health benefits such as tea and wine. The monomer content in frozen peeled peaches was found to be 19.59 mg/kg. Dimers (39.59 mg/kg) and trimers (38.81 mg/kg) constituted the largest percent composition of oligomers in the peaches. Tetramers through octamers were present in levels of 17.81, 12.43, 10.62, 3.94 and 1.75 mg/kg, respectively. Thermal processing resulted in an 11% reduction in monomers, a 9% reduction in dimers, a 12% reduction in trimers, a 6% reduction in tetramers, and a 5% reduction in pentamers. Hexamers and heptamers demonstrated an approximate 30% loss, and octamers were no longer detected. Analysis of the syrup after thermal processing indicates that there is a migration of procyanidin monomers through hexamers into the syrup that can account for the losses observed during the canning process. Storage of canned peaches for 3 months demonstrated a time-related loss in higher oligomers and that by 3 months oligomers larger than tetramers are not observed. At 3 months postcanning, levels of monomers had decreased by 10%, dimers by 16%, trimers by 45%, and tetramers by 80%. A similar trend was observed in the canning syrup.

Tannins: Current knowledge of food sources, intake, bioavailability and biological effects

“…Analysis of the syrup after processing revealed a migration of procyanidins into the syrup, which could account for the losses observed during the canning process. In canned peaches stored for 3 months, there was a timerelated loss of higher oligomers, and compounds larger than tetramers were no longer observed [108].…”

Secondary Metabolites in Fruits, Vegetables, Beverages and Other Plant‐based Dietary Components

“…3-O-Caffeoylquinic acid also occurs in stone fruits and in larger amounts than 5-O-caffeoylquinic acid (Clifford 2003). They also contain (+)-catechin, (−)-epicatechin and proanthocyanidins including procyanidin B 1 (Figure 7.25), the levels of which decline with thermal processing and storage in cans (Hong et al 2004). Apricots and peaches both contain carotenoids principally in the form of β-carotene.…”

Changes of antioxidant activity in honey after heat treatment

“…Preservation methods are generally believed to be responsible for depletion of naturally occurring antioxidants in food. However, some reports have shown that processing can cause some or no loss of the content and activity of naturally occurring antioxidants (Hong et al 2004;Amin & Lee 2005;Oszmianski et al 2007). On the other hand, some reports say that antioxidant activity increases after processing (Dewanto et al 2002;Turkmen et al 2005;Durmaz & Alpaslan 2007).…”