石榴副产物提取物在体外消化过程中总酚浓度和抗氧化能力的稳定性
Stability of total phenolic concentration and antioxidant capacity of extracts from pomegranate co-products subjected to in vitro digestion.
作者信息
Fawole Olaniyi Amos, Opara Umezuruike Linus
机构信息
South African Research Chair in Postharvest Technology, Department of Horticultural Science, Stellenbosch University, Private Bag X1, Stellenbosch, 7602, South Africa.
South African Research Chair in Postharvest Technology, Department of Food Science, Stellenbosch University, Private Bag X1, Stellenbosch, 7602, South Africa.
出版信息
BMC Complement Altern Med. 2016 Sep 13;16(1):358. doi: 10.1186/s12906-016-1343-2.
BACKGROUND
Co-products obtained from pomegranate juice processing contain high levels of polyphenols with potential high added values. From value-addition viewpoint, the aim of this study was to evaluate the stability of polyphenolic concentrations in pomegranate fruit co-products in different solvent extracts and assess the effect on the total antioxidant capacity using the FRAP, DPPH˙ and ABTS(+) assays during simulated in vitro digestion.
METHODS
Pomegranate juice, marc and peel were extracted in water, 50 % ethanol (50%EtOH) and absolute ethanol (100%EtOH) and analysed for total phenolic concentration (TPC), total flavonoids concentration (TFC) and total antioxidant capacity in DPPH˙, ABTS(+) and FRAP assays before and after in vitro digestion.
RESULTS
Total phenolic concentration (TPC) and total flavonoid concentration (TFC) were in the order of peel > marc > juice throughout the in vitro digestion irrespective of the extraction solvents used. However, 50 % ethanol extracted 1.1 to 12-fold more polyphenols than water and ethanol solvents depending on co-products. TPC and TFC increased significantly in gastric digests. In contrast, after the duodenal phase of in vitro digestion, polyphenolic concentrations decreased significantly (p < 0.05) compared to those obtained in gastric digests. Undigested samples and gastric digests showed strong and positive relationships between polyphenols and the antioxidant activities measured in DPPH, ABTS(+) and FRAP assays, with correlation coefficients (r (2)) ranging between 0.930-0.990. In addition, the relationships between polyphenols (TPC and TFC) and radical cation scavenging activity in ABTS(+) were moderately positive in duodenal digests.
CONCLUSION
Findings from this study showed that concentration of pomegranate polyphenols and the antioxidant capacity during in vitro gastro-intestinal digestion may not reflect the pre-digested phenolic concentration. Thus, this study highlights the need to provide biologically relevant information on antioxidants by providing data reflecting their stability and activity after in vitro digestion.
背景
石榴汁加工过程中获得的副产物含有高水平的多酚，具有潜在的高附加值。从增值的角度来看，本研究的目的是评估不同溶剂提取物中石榴果实副产物中多酚浓度的稳定性，并在模拟体外消化过程中使用FRAP、DPPH˙和ABTS(+) 测定法评估其对总抗氧化能力的影响。
方法
将石榴汁、果渣和果皮分别用水、50%乙醇（50%EtOH）和无水乙醇（100%EtOH）提取，并在体外消化前后通过DPPH˙、ABTS(+) 和FRAP测定法分析总酚浓度（TPC）、总黄酮浓度（TFC）和总抗氧化能力。
结果
无论使用何种提取溶剂，在整个体外消化过程中，总酚浓度（TPC）和总黄酮浓度（TFC）的顺序均为果皮＞果渣＞果汁。然而，50%乙醇提取的多酚比水和乙醇溶剂多1.1至12倍，具体取决于副产物。TPC和TFC在胃消化液中显著增加。相比之下，在体外消化的十二指肠阶段后，与胃消化液相比，多酚浓度显著降低（p＜0.05）。未消化样品和胃消化液在DPPH、ABTS(+) 和FRAP测定中测得的多酚与抗氧化活性之间呈现强正相关，相关系数（r(2)）在0.930 - 0.990之间。此外，在十二指肠消化液中，多酚（TPC和TFC）与ABTS(+) 中的自由基阳离子清除活性之间的关系呈中度正相关。
结论
本研究结果表明，石榴多酚的浓度和体外胃肠消化过程中的抗氧化能力可能无法反映消化前的酚类浓度。因此，本研究强调需要通过提供反映其体外消化后稳定性和活性的数据，来提供有关抗氧化剂的生物学相关信息。
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