Hong Yun-Jeong, Barrett Diane M, Mitchell Alyson E
Department of Food Science and Technology, University of California-Davis, Davis, California 95616, USA.
J Agric Food Chem. 2004 Apr 21;52(8):2366-71. doi: 10.1021/jf0306082.
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.
采用正相液相色谱/质谱联用（LC/MS）技术，测定了冷冻和罐装罗斯粘核桃以及罐装过程中使用的糖浆在3个月内原花青素的含量和变化情况。在罗斯粘核桃中鉴定出了原花青素低聚物，包括从单体到十一聚体。优化后的方法能够对八聚体以下的低聚物进行定量分析。桃子中原花青素的分布情况与葡萄、巧克力以及与健康益处相关的饮料（如茶和葡萄酒）中的分布情况相似。冷冻去皮桃子中的单体含量为19.59毫克/千克。二聚体（39.59毫克/千克）和三聚体（38.81毫克/千克）在桃子低聚物中所占比例最大。四聚体到八聚体的含量分别为17.81、12.43、10.62、3.94和1.75毫克/千克。热处理导致单体含量降低11%，二聚体降低9%，三聚体降低12%，四聚体降低6%，五聚体降低5%。六聚体和七聚体损失约30%，八聚体未再检测到。热处理后对糖浆的分析表明，原花青素单体到六聚体向糖浆中迁移，这可以解释罐装过程中观察到的损失。罐装桃子储存3个月显示，较高的低聚物随时间减少，到3个月时未观察到大于四聚体的低聚物。罐装3个月后，单体含量降低了10%，二聚体降低了16%，三聚体降低了45%，四聚体降低了80%。罐装糖浆中也观察到了类似的趋势。
