米糠贮藏时间对米糠可溶性膳食纤维抗氧化性质的影响

以新鲜米糠为原料贮藏0、1、3、5、10 d得到不同酸败程度的米糠,稳定化和脱脂后制备米糠可溶性膳食纤维,研究米糠贮藏时间对米糠可溶性膳食纤维抗氧化性质的影响。结果表明:随着新鲜米糠贮藏时间的延长,米糠可溶性膳食纤维的还原能力、金属离子螯合能力和清除ABTS~+·、DPPH·、·OH、O_2~-·能力均先上升后下降;米糠可溶性膳食纤维还原能力、金属离子螯合能力和清除ABTS~+·、DPPH·、·OH在新鲜米糠贮藏5 d时达到最大值,分别为0.943(OD_(700))、35.16%、32.28%、73.51%和13.83%,米糠可溶性膳食纤维清除O_2~-·能力在新鲜米糠贮藏1 d达到最大值,为60.58%。     

藜麦可溶性膳食纤维提取工艺优化及其抗氧化活性研究

为推广藜麦的食用和加大藜麦深加工食品的开发,采用超声波辅助酶法提取藜麦可溶性膳食纤维,在单因素试验基础上结合响应面法,优化提取工艺并对提取的藜麦可溶性膳食纤维进行抗氧化活性研究.结果显示,藜麦可溶性膳食纤维的最佳提取工艺为:料液比1∶10,酶添加量0.70％,酶解pH为5.10,酶解温度51℃,酶解时间60min,超声...     

Effects of drying on the phenolics content and antioxidant activity of muscadine pomace

Three drying technologies [i.e., vacuum belt drying (VBD), hot air drying (HAD), and freeze drying (FD)] were evaluated for the processing of muscadine pomace in terms of their impact on drying time requirement, moisture content (MC), water activity (a_w), total phenolics content (TPC), and antioxidant activity (AA). Muscadine pomace discs of two thicknesses (2 and 4 mm) were dried using 16 different time-temperature combinations for VBD, 12 different time-temperature and air velocity combinations for HAD, and one treatment for FD. The TPC and AA in lyophilised samples were 583 ± 8 and 608 ± 16 μmol GAE/g d.w. and 2.21 ± 0.15 and 2.30 ± 0.17 mmol Fe²⁺ E/g d.w. for the 2 and 4 mm thick discs, respectively. The VBD treatment of 60-80-100-100 °C for 60 min (i.e., TV2) for 2 mm thick discs showed the highest TPC value, and no significant (P > 0.05) differences were observed in AA of 2 mm thick discs dried by VDB and FD. The TPC and AA for the VBD treatment of 60-80-100-100 °C for 90 min and HAD treatment of 70 °C at 0.6 m/s for 3 h for the 2 mm thick discs were not significantly (P > 0.05) different compared to freeze dried samples. For 4 mm thick samples, the TPC and AA for the VBD treatments of 60-80-100-100 °C, 60-90-120-120 °C, 70-90-110-110 °C, 80-90-100-100 °C, and 90-105-120-120 °C for 90 min as well as 70-90-110-110 °C for 60 min were not significantly (P > 0.05) different compared to those for freeze dried discs. VBD is a promising drying technology, as the resultant products possessed high TPCs and were dried in less than ¼ of the time compared with that of FD.     

豆渣膳食纤维的结构表征及其抗氧化性研究

采用扫描电镜、红外光谱、热重及化学分析等方法对豆渣膳食纤维(soybean dregs dietary fiber,SDF)的结构进行表征,对其抗氧化性及其对维生素C(VC)抗氧化活性的影响进行了探讨。研究发现,SDF中不溶性膳食纤维含量占总膳食纤维含量的92%左右。SDF颗粒形貌各异,结构紧密,内部由纤维素类物质形成支撑主体,热力学稳定。SDF具有良好的羟自由基(·OH)清除能力,且呈量-效关系,但DPPH·清除能力很弱。SDF-VC复合物清除·OH的能力表现为简单的加和作用,但其在DPPH·体系中则表现出良好的协同增效作用,能有效抑制VC的降解。     

红枣可溶性膳食纤维的抗氧化活性研究

为研究红枣可溶性膳食纤维（Soluble Dietary Fiber,SDF）的体外抗氧化活性,采用Na NO₂-Al（NO₃）₃-Na OH法和Folin-Ciocalteu法分别测定红枣SDF中总黄酮和总多酚含量,并通过DPPH·、ABTS⁺·、·OH、O₂^-·和H₂O₂自由基清除体系和还原能力评价红枣SDF的抗氧化活性。结果表明:红枣SDF中总黄酮和总多酚含量分别为（1.78±0.04）mg/g和（4.12±0.09）mg/g;红枣SDF具有较强的体外抗氧化活性,对DPPH·和H₂O₂清除能力较强,2.0 mg/m L红枣SDF的清除率分别可达到79.81%和50.07%,尤其对DPPH·的清除能力最强,其半数抑制浓度(IC₅₀)为0.725 mg/m L,对ABTS⁺·、·OH、O₂^-·的清除能力较弱,并具有一定还原能力。红枣SDF具有一定的体外抗氧化活性,可作为一种有效的天然食品抗氧化剂或用于开发红枣膳食纤维功能性食品。      

Gamma-oryzanol content,phenolic acid profiles and antioxidant activity of rice milling fractions

This study was aimed to determine γ-oryzanol content and total phenolics, individual phenolic acid profile and the antioxidant activity of the free and bound extracts of rice milling fractions namely, brown rice, unpolished rice, white rice, chalky rice, raw seed and rice bran. Gamma-oryzanol content of milling fractions which is designated with a simple chromatographic method was in the range of 12.19–3,296.5 mg/kg. The whitening and polishing steps reduced approximately 94% of γ-oryzanol of the brown rice when becoming the white rice. The contribution of bound phenolics to the total phenolic content was approximately 40%. Ferulic and p-coumaric acids were the most abundant phenolic acids in bound phenolic extracts and their amounts were 119.98 and 18.10 μg/g, respectively, in rice bran. The best source of γ-oryzanol, phenolics and antioxidants was clearly rice bran and followed by raw seed and brown rice.     

Effect of extrusion process on antioxidant activity, total phenolics and β-glucan content of extrudates developed from barley-fruit and vegetable by-products

The aim of this study was to determine the effects of extrusion processing variables on antioxidant activity (AA), total phenolic content (TP) and β-glucan content (BG) of extrudates. Products were prepared by extrusion cooking of barley flour, barley flour–tomato pomace and barley flour–grape pomace blends. Antioxidant activity as measured by the DPPH method was 43.17 ± 0.362, 27.57 ± 0.120 and 82.23 ± 0.785% while TPs, expressed as ferulic acid equivalents, were 5.29 ± 0.126, 4.66 ± 0.023 and 9.15 ± 0.015 mg g⁻¹ dry sample in the extracts obtained from barley flour, tomato and grape pomaces, respectively. Extrusion cooking decreased AA and TP of barley, barley–tomato pomace and barley–grape pomace extrudates. Temperature and screw speed had significant ( P  <   0.05) effect on BGs of barley flour and barley–grape pomace extrudates. However, BG of tomato pomace blend extrudates had significantly ( P  <   0.05) influenced from pomace level only. Results indicated that the content of β-glucan is higher in barley flour than in extrudates of barley flour and pomace blends.     

植物性膳食纤维抗氧化活性的研究与应用

抗氧化膳食纤维(antioxidant dietary fiber,ADF)是一类从植物中提取的、含生物抗氧化成分的膳食纤维.文章综述国内外对源自谷物类、水果类、坚果类以及蔬菜类膳食纤维抗氧化活性的研究进展及其应用现状,为进一步研究和开发抗氧化膳食纤维食品及配料提供参考.     

Total phenolics, flavonoids and antioxidant activity of tropical fruit pineapple

Pineapple has several beneficial properties including antioxidant activity. The fruit of pineapple was extracted with ethyl acetate, methanol and water. The phenolic content of the extracts was determined by Folin-Ciocalteu method and antioxidant activity was assayed through some in vitro models such as antioxidant capacity by phosphomolybdenum, ??-carotene-linoleate, and radical scavenging activity using ??,??-diphenyl-??-picrylhydrazyl (DPPH) method. The phenolic contents of the extracts as caffeic acid equivalents were found to be highest in methanol (51.1%) followed by ethyl acetate (13.8%) and water extract (2.6%). Antioxidant capacity of the extracts as equivalent to ascorbic acid (??mol/g of the extract) was in the order of methanol extract > ethyl acetate extract > water extract. In comparison with butylated hydroxyanisole (BHA), at 100 ppm of concentration, the antioxidant and free radical scavenging activities of the extracts assayed through ??-carotene-linoleate and DPPH method were also found to be highest with methanol extract followed by ethyl acetate and water extracts. The results indicated that the extent of antioxidant activity of the extract is in accordance with the amount of phenolics present in that extract and the pineapple fruit being rich in phenolics may provide a good source of antioxidant.     

Effect of ultrafine grinding on hydration and antioxidant properties of wheat bran dietary fiber

Wheat bran dietary fiber (DF) powders was prepared by ultrafine grinding, whose effects were investigated on the composition, hydration and antioxidant properties of the wheat bran DF products. The results showed that ultrafine grinding could effectively pulverize the fiber particles to submicron scale. As particle size decrease, the hydration properties (water holding capacity, water retention capacity and swelling capacity) of wheat bran DF were significantly (p < 0.05) decreased and a redistribution of fiber components from insoluble to soluble fractions was observed. The antioxidant activities of wheat bran and DF before and after grinding were in terms of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, ferrous ion-chelating activity, reducing power and total phenolic content (TPC). Compared with DF before and after grinding, micronized insoluble DF showed increased chelating activity, reducing power and TPC yet decreased DPPH˙ radical scavenging activity. Positive correlations were detected between chelating activity, reducing power and TPC.     

米糠膳食纤维口服片制备工艺及质构研究

以米糠为原料,制备米糠膳食纤维,再以米糠膳食纤维为基料,添加黏合剂、润滑剂及填充剂(麦芽糖醇:淀粉为1∶1),制备米糠膳食纤维口服片.单因素实验结果表明,米糠膳食纤维为基料、黏合剂及润滑剂的添加量对口服片的品质影响较大;正交实验结果表明,当米糠膳食纤维基料添加量为60％,黏合剂添加量为15％,润滑剂添加量为1.5％,口服片的综合评分最高,为92分.质构实验结果表明,最优条件制备的口服片与市售钙片的硬度变化趋势一致,在设定的实验条件下,口服片的硬度为12 236.0 g,低于市售钙片的硬度15 404.5 g.口服片崩解时限为21 min,符合普通片剂的要求.     

麦麸膳食纤维抗氧化和·OH自由基清除活性的研究

从麦麸中分离得到的水溶性和水不溶性膳食纤维具有抗氧化活性和·ＯＨ自由基清除能力，两者对·ＯＨ的清除率分别为８０．２％和５８．３％。     

Effect of extrusion process on the antioxidant activity and total phenolics in a nutritious snack food

The effect of screw speed (220–340 rpm), moisture content of the feed (11.0–15.0%, wet base) and feed rate (22.0–26.0 kg h^?1, wet base) on the total antioxidant capacity (TAA) and concentration of total phenolics (TP) in a nutritionally balanced extruded snack were investigated. Regression equations describing the effect of each variable on the responses were obtained. Results indicated that screw speed, moisture content of the feed and feed rate had an effect on the TAA values of the samples at 95% confidence interval (CI). The interaction between the three factors was also found to be significant at 95% CI for TAA values. Extrusion conditions applied in this study did not change the TP values in the samples. The TAA value of samples decreased with an increase in screw speed and decrease in moisture content.     

麦麸膳食纤维火腿肠的研制与营养价值评价

根据食物有机搭配可改善制品的营养、感官和质构品质的基本原理,综合肉类食品及麦麸膳食纤维原料的特点,开展麦麸膳食纤维在火腿肠中的应用研究,试制出了新型麦麸膳食纤维复合火腿肠,其主配方中猪瘦肉占62.7%,麦麸粉占7.5%,淀粉占4.4%.麦麸膳食纤维的添加改善了火腿肠的功能特性,由于同时使用了低钠食盐,与普通型火腿肠相比,麦麸膳食纤维火腿肠的脂肪含量降低了50%、热量降低了20%,氯化钠含量也有所降低,符合清淡(light)食品的第一定义.试制出的复合火腿肠在外观、组织结构、色泽和风味上均可接受,具有良好的质构.为开发利用小麦加工副产品、研制健康功能型肉制品开辟了新途径.     

马齿苋复配米工艺优化及抗氧化活性研究

目的:制备具有抗氧化特性的马齿苋复配米。方法:以碎米粉为主要原料,马齿苋为辅料。在单因素试验的基础上,以综合得分为指标,设计响应面试验,优化螺杆转速、挤压温度、马齿苋添加量和水分含量工艺参数,并通过对DPPH自由基和ABTS自由基的清除率检测复配米的抗氧化特性。结果:制备马齿苋复配米的最佳工艺参数为螺杆转速140 r/min,挤压温度120 ℃,马齿苋添加量15.5%,水分含量27%,此工艺参数下复配米综合得分为86.13。马齿苋复配米对DPPH自由基和ABTS自由基的清除率分别为92.37%,85.15%,均显著高于市售米。结论:马齿苋复配米具有良好的抗氧化特性。     

Phytochemical content and antioxidant activity of six diverse varieties of whole wheat

The phytochemical content and antioxidant activity of six diverse varieties of whole wheat are reported. The free phenolic content ranged from 255 (KanQueen) to 499 (Roane) μmol gallic acid equivalents/100 g DW. The bound phenolic content ranged from 582 (Roane) to 662 (Cham1) μmol gallic acid equivalents/100 g DW. The bound fraction contributed 53.8–69.7% of the total phenolic content of the wheat varieties analysed. Ferulic acid was the predominant phenolic acid found in whole wheat. Total ferulic acid content ranged from 310.8 (Caledonia) to 496.1 (KanQueen) μmol ferulic acid/100 g DW. The percentage of ferulic acid found in the insoluble-bound fraction ranged from 87.4% (Caledonia) to 97.2% (KanQueen). Other phenolic acids, p-coumaric acid, syringic acid, vanillic acid, and caffeic acid were also detected. Lutein was the predominant carotenoid found in the whole wheat varieties analysed. Zeaxanthin, β-carotene, and β-cryptoxanthin were also detected. Mainly α- and β-tocopherols and α- and β-tocotrienols were found in all varieties of whole wheat though γ-tocopherol was detected in all but two varieties. β-Tocotrienol was the predominant form of vitamin E found in all varieties of whole wheat. The antioxidant activity was assessed using the oxygen radical absorbance capacity (ORAC) assay. The ORAC of the free fraction ranged from 1958 to 3749 μmol Trolox equivalents/100 g DW. The ORAC of the bound fraction ranged from 3190 to 5945 μmol Trolox equivalents/100 g DW. Total phenolic content was correlated with oxygen radical absorbance capacity (R² = 0.810; p < 0.001). The phytochemicals found in whole grains may be responsible for the health benefit of whole grain consumption.     

Bioactive compound content,antioxidant activity,deoxynivalenol and heavy metal contamination of pearled wheat fractions

Wheat kernels are rich in antioxidant compounds, that are mainly present in the outer bran layers and which are removed during milling. Unfortunately, several contaminants, e.g., mycotoxins and heavy metals, are also concentrated in the external layers. Pearling of 3 wheat varieties gave five fractions (each 5% of the original grain weight), starting from the outer layer until the inner kernel, designated as 0–5%, 5–10%, 10–15%, 15–20%, 20–25%, respectively. The remaining 75% of the inner kernel was also collected. Dietary fibre, free phenolic acids and total antioxidant activity decreased progressively from the external to the internal layers. However, the 5–10% fraction was richer in β-glucan content than the external one (0–5%). Heavy metals were only found in the most external fraction. Deoxynivalenol contamination decreased from the external to the internal layers: 64% of total contamination of kernel was found in the 0–5% and 5–10% fractions. The 10–15% kernel fraction offered the best compromise between high nutritional value and low contamination risk.