Tonyali Bade, Sensoy Ilkay, Karakaya Sibel
Department of Food Engineering, Middle East Technical University, 06800 Ankara, Turkey.
Present Address: Department of Animal Science and Industry, Food Science Institute, Kansas State University, Manhattan, KS USA.
J Food Sci Technol. 2020 Sep;57(9):3426-3435. doi: 10.1007/s13197-020-04376-8. Epub 2020 Apr 9.
It is possible to enhance the functional properties of extruded products with the inclusion of fruit and vegetable by-products. Onion skin, a rich source of quercetin and fiber, is considered as waste in the industry and can be used as an alternative ingredient to improve the nutritional value of the extruded products. Three levels (3, 6, and 9%) of onion skin powder (OSP) were added to wheat flour and compared with control (0% OSP). The effect of the extrusion process on accessible quercetin, total phenolic content, and antioxidant activity of the samples were investigated. In addition, carbohydrate digestibility analyses were conducted for the products. Mass spectrometry (LC-MS/MS) results indicated that increasing the OSP level increased the quercetin content. The process caused the release of the entrapped quercetin from OSP, which was revealed by significantly higher quercetin levels for the extrudates. Some of the quercetin was lost during in vitro digestion process. Increasing the OSP level increased antioxidant activity and total phenolic contents of the samples. Total phenolic contents decreased significantly after the processing, yet antioxidant activities were not affected. The extruded products showed high amounts of rapidly available glucose (69.5 g/100 g). The OSP enhancement did not change the carbohydrate digestibility of products. The results indicated that the extrusion process could increase the level of accessible bioactive ingredients, and the level of functional compound addition can be optimized further.
通过添加水果和蔬菜副产品可以增强挤压产品的功能特性。洋葱皮富含槲皮素和纤维，在食品工业中被视为废弃物，可作为一种替代成分来提高挤压产品的营养价值。将三个水平（3%、6%和9%）的洋葱皮粉（OSP）添加到小麦粉中，并与对照组（0% OSP）进行比较。研究了挤压过程对样品中可利用槲皮素、总酚含量和抗氧化活性的影响。此外，还对产品进行了碳水化合物消化率分析。质谱（LC-MS/MS）结果表明，增加OSP水平会提高槲皮素含量。该过程导致了OSP中包裹的槲皮素的释放，挤压物中槲皮素水平显著升高就表明了这一点。在体外消化过程中，部分槲皮素有所损失。增加OSP水平会提高样品的抗氧化活性和总酚含量。加工后总酚含量显著降低，但抗氧化活性未受影响。挤压产品显示出大量快速可用葡萄糖（69.5克/100克）。添加OSP并未改变产品的碳水化合物消化率。结果表明，挤压过程可以提高可利用生物活性成分的水平，并且功能化合物的添加水平可以进一步优化。
