摘要：为评价超微粉碎对莲子心粒径、微观结构、总黄酮和总酚提取率及抗氧化能力的影响，分别采用亚硝酸钠-硝酸铝法和福林法测定莲子心中总黄酮和总酚的含量，采用还原能力、DPPH 自由基清除、ABTS 自由基清除能力、总氧自由基吸收能力以及细胞内抗氧化活性系统评价其抗氧化能力。结果表明：莲子心超微粉的中位粒径减小，细胞破壁率增加，总黄酮提取率提高了21。82%，总酚提取率提高了24。09%。抗氧化能力评价中，超微粉碎能明显提高莲子心的还原能力、DPPH 和ABTS 自由基清除能力、总氧自由基吸收能力以及细胞内抗氧化活性。超微粉碎技术可以改善莲子心粉体的理化性质，提高莲子心抗氧化活性物质（总酚和总黄酮）的溶出率，同时超微粉碎处理后能显著提高莲子心的抗氧化能力，可作为以莲子心为原料开发功能性食品的一种前处理手段。93511

毕业论文关键词：超微粉碎，莲子心，自由基，抗氧化

Abstract: To evaluate the effect of ultrafine grinding on the particle size, microstructure, extraction rates of total phenolics and flavonoids, and antioxidant capacity of lotus plumule, the total phenolic and flavonoid contents were measured using NaNO2-Al (NO3)3 and Folin-phenol reagent methods, respectively。 Antioxidant activity was evaluated by 2,2′-diphenyl-1-picrylhydrazyl (DPPH) free radical-scavenging activity,reducing power assay, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) scavenging activity, oxygen radical absorbance capacity(ORAC), and cellular antioxidant activity (CAA) assay。 The results showed that for the samples treated by ultrafine grinding, the median particle size reduced, the cell wall-breaking rate increased, and the extraction rates of total flavonoids and phenolics increased by 21。82% and 24。09%, respectively。 In terms of antioxidant capacity, ultrafine grinding treatment significantly enhanced DPPH free radical-scavenging activity,reducing power, ABTS scavenging activity, ORAC, and CAA。 In conclusion, ultrafine grinding could improve the physicochemical properties of lotus plumule powder and increase the dissolution rates of the active ingredients (total phenolics and total flavonoids) in lotus plumule。 Meanwhile, ultrafine grinding significantly increased antioxidant capacity and could serve as a pretreatment method in the development of functional food products with lotus plumule as the raw material。

Key words: ultrafine grinding technique，lotus plumule，free radicals，antioxidant capacity

目录

1 前言 7

1。1 莲子心 7

1。1。1 莲子心的化学成分及生物活性 7

1。1。2 莲子心的开发利用现状 7

1。2 超微粉碎技术 7

1。2。1 超微粉碎技术简介 7

1。2。2 超微粉碎技术的应用现状 8

1。3 自由基与天然抗氧化剂 8

1。3。1 自由基概述 8

1。3。2 天然抗氧化剂 8

1。4 本实验的研究目的和意义 9

2 材料与方法 9

2。1 材料与试剂 9

2。2 仪器与设备 9

2。3 试验方法 10

2。3。1 样品制备 10

2。3。2 莲子心粉粒度测定 10