College of Food Science, South China Agricultural University, 483 Wushan Road, Guangzhou, Guangdong 510642, China.
Food Funct. 2019 Feb 20;10(2):951-963. doi: 10.1039/c8fo01083h.
Apple pomace, a by-product of juice production, is a high-fibre, high-polyphenol functional food ingredient. Extrusion (barrel moisture 15%, 20% or 30%) of apple pomace, followed by drying, allows it to be supplied in a convenient form. Extrusion caused degradation of the apple pomace cell wall structure. Water solubility was significantly increased by extrusion but oil holding capacity was reduced. Total extractable polyphenols, measured as gallic acid equivalents, were reduced by extrusion (barrel moisture 30%) but were not affected by extrusion at lower barrel moisture contents (15% or 20%). However, individual sub-groups of extractable flavanols, flavonols, phenolic acids and dihydrochalcones were increased by extrusion. There was little effect of extrusion on the release of total polyphenols from the matrix into the supernatant, as measured by total extractable polyphenols (measured as gallic acid equivalents) released during in vitro digestion. There was a marked increase in total flavanols, phenolic acids and dihydrochalones released into the supernatant during the gastric phase but changes in flavonoids were less obvious. The changes in the bioaccessibility of individual polyphenols released during intestinal digestion were dependent on the type of polyphenol and extrusion conditions. The antioxidant activity, as measured using oxygen radical absorbance capacity (ORAC) of the bioaccessible nutrients released upon in vitro intestinal digestion, was significantly enhanced by extrusion (from 78.2 to 400-500 μmol Trolox equivalents per mL at the ileal phase). The increased ORAC may be attributed in part to the increased release of individual polyphenols.
苹果渣是果汁生产的副产品，是一种富含膳食纤维和多酚的功能性食品原料。挤压（机筒水分 15%、20%或 30%）苹果渣，然后干燥，可将其以方便的形式供应。挤压会导致苹果渣细胞壁结构降解。水溶性通过挤压显著增加，但持油能力降低。以没食子酸当量计，总可提取多酚通过挤压（机筒水分 30%）减少，但在较低的机筒水分含量（15%或 20%）下不受挤压影响。然而，可提取黄烷醇、黄酮醇、酚酸和二氢查耳酮的各个亚组通过挤压增加。通过体外消化释放的总可提取多酚（以没食子酸当量计）测量，挤压对从基质中释放到上清液中的总多酚的释放影响不大。在胃阶段，总黄烷醇、酚酸和二氢查耳酮大量释放到上清液中，但黄酮类化合物的变化不太明显。在肠道消化过程中释放的个别多酚的生物利用度的变化取决于多酚的类型和挤压条件。使用体外肠道消化释放的可生物利用营养素的氧自由基吸收能力（ORAC）测量的抗氧化活性，通过挤压显著增强（从 78.2 到 400-500 μmol Trolox 当量/ mL 在回肠阶段）。增加的 ORAC 可能部分归因于个别多酚释放的增加。
