黑米中黄酮类化合物的稳定性分析

以黑龙江五常黑米为原料,研究利用超声波辅助水浴浸提黑米中黄酮类化合物的稳定性。对黑米黄酮浸提液在不同温度、pH值、光照、氧化剂、还原剂、金属离子等条件下的稳定性进行测定。结果表明:温度在20℃~60℃时黄酮类化合物含量基本不变;长时间的光照对黄酮的稳定性影响较大;在弱酸性条件下比较稳定;对氧化剂H_2O_2具有较好的抗氧化性,但对还原剂Na_2SO_3显示出很大的不稳定性;K~+和Na~+两种金属离子对黑米黄酮稳定性无明显影响,Al~(3+)、Ca~(2+)、Mg~(2+)、Fe~(3+)对其影响较大。     

黑米色素稳定性研究

通过对可能影响黑米色素稳定性的因素进行研究,结果表明,在酸性环境,温度40℃以下,Na+、Mg2+、Ca2+、Zn2+环境,还原剂,低浓度防腐剂,室内自然光或避光环境下,黑米色素表现良好的稳定性;而碱性环境,相对长时间高温,Fe3+环境,氧化剂,高浓度防腐剂,阳光或紫外线直射等均不利于黑米色素的稳定。     

黑米色素的稳定性及其对羊毛织物的染色

从黑米中提取天然色素并对其进行紫外-可见光谱分析,探讨该色素对酸碱、金属离子及温度变化的稳定性;以该色素上染羊毛织物,研究染色pH值、温度、时间、媒染剂对染色织物K/S值的影响,并优化了染色工艺。结果表明,黑米色素对pH值变化及金属离子较敏感,对温度变化(≤90℃)相对稳定。不同媒染剂可染得不同色泽的羊毛织物,且染色样品的摩擦牢度及皂洗沾色牢度均较好,但褪色牢度除Cu2+和Fe2+媒染样品较好外,其余较差。     

黑米色素提取工艺优化及其稳定性

以黑米为材料,采用醇提法提取黑米色素,从而达到多元化利用黑米资源的目的。考察了料液比、乙醇体积分数、浸提温度、浸提时间对黑米色素提取液吸光值的影响,在此基础上,利用响应面法对黑米色素提取工艺参数进行了优化,并探讨了温度、pH、光照、氧化剂对黑米色素稳定性的影响。结果表明:提取黑米色素的最佳提取工艺参数为:料液比1:30.5 g/mL、乙醇体积分数44%、浸提温度90 ℃、浸提时间104 min。黑米色素在低于90 ℃、光照、pH为2~6的酸性环境条件下稳定,但氧化剂过氧化氢的存在会影响黑米色素的稳定性。因此黑色色素在具体应用中应在低温、酸性条件下进行,可以不避光保存,但在储运过程中要避免其与氧化剂接触。该工艺合理可靠,为工业大量提取黑米色素提供了一定的理论依据。     

诃子色素溶液的稳定性研究

诃子色素用于染色能够满足人们对颜色的需求,还能赋予被染物一定的药物保健功能,但目前对于诃子色素稳定性的研究较少。文中研究了温度、酸碱度、光照、金属离子、氧化剂和还原剂条件下诃子色素溶液的稳定性。结果表明:pH值对诃子色素溶液稳定性影响较大,诃子色素溶液在酸性或中性条件下具有较好的稳定性;诃子色素溶液的光稳定性较好,80℃以上高温会显著降低色素溶液的稳定性;Na~+、K~+、Mg~(2+)、Zn~(2+)、Co~(2+)对诃子色素溶液稳定性影响较小;Fe~(2+)、Fe~(3+)、Ag~+、Cu~(2+)易导致色素变色;还原剂NaHSO_3对色素溶液的稳定性没显著影响,氧化剂H_2O_2对色素溶液的稳定性影响较大。     

密蒙花黄色素稳定性研究

对密蒙花黄色素分别在pH值、温度、光照、蔗糖、葡萄糖、D-果糖、可溶性淀粉、山梨酸钾、Na_2SO_3、H_2O_2、金属离子等存在条件下进行稳定性研究。结果表明:弱酸和中性条件下密蒙花黄色素稳定性较好,随着温度升高和光照时间延长,色素降解越严重;蔗糖、葡萄糖、D-果糖、Ca~(2+)、Cu~(2+)对密蒙花黄色素均具有保护作用;可溶性淀粉、H_2O_2、K~+、Na~+、Sn~(2+)、Zn~(2+)、Al~(3+)、Mg~(2+)对密蒙黄色素的影响不明显;山梨酸钾、Na_2SO_3、Fe~(3+)、Pb~(2+)对密蒙花黄色素具有破坏作用。     

籽瓜色素的稳定性及其清除自由基能力的研究

目的:研究籽瓜瓤中色素的稳定性及其清除自由基能力。方法:将籽瓜色素添加在氧化性、还原性、食品添加剂、金属离子中,对其稳定性及清除羟自由基、抗超氧阴离子自由基及总抗氧化能力(T-AOC)进行试验。结果:籽瓜色素在一定范围内,耐氧化性较好,在还原剂及葡萄糖中稳定性好,在柠檬酸中稳定性较差,Fe~(3+),Fe~(2+)对该色素均有增色作用,Fe~(3+)的影响最大,Zn~(2+),Cu~(2+),Al ~(3+),Na~+均有降色作用,Zn~(2+)降色影响较大,Cu~(2+),Al ~(3+),Na~+影响较小。抑制羟自由基1.268U/mg prot,抗超氧自由基能力18U/g prot,每分钟每毫克色素粗提物的总抗氧化活性0.238单位。结论:籽瓜色素具有良好的清除自由基活性,稳定性较好,可作为一种天然抗氧化活性色素来源。     

媒染剂对柞蚕丝黑米色素冷堆染色的影响

为解决天然染料染色缺少蓝、紫色调的问题,提取天然黑米色素用于柞蚕丝绸的冷轧堆染色工艺。试验研究Cu2+、Fe2+、Sn2+等单一媒染离子以及不同浓度配比的Sn2+/Fe2+及Sn2+/Cu2+复合媒染离子对染色织物色光、色深值及染色牢度的影响,结果表明:黑米色素冷轧堆染色柞蚕丝绸可获得较好的染色效果,采用不同媒染剂媒染,可得到不同色泽的柞蚕丝绸,Sn2+/Fe2+及Sn2+/Cu2+拼混媒染,可分别得到一系列蓝、紫色调的柞蚕丝绸,复合媒染剂较单一媒染剂表现出更优异的色深值及染色牢度,拼混媒染样品的皂洗和摩擦牢度可达到3~4级。     

Cu~(2+)、Fe~(2+)和Fe~(3+)对红曲霉液态发酵产色素影响

采用液体发酵研究了三种金属离子Cu~(2+)、Fe~(2+)和Fe~(3+)对红曲霉发酵代谢产色素的影响。添加不同浓度的CuSO_4溶液、FeSO_4·7H_2O溶液和FeCl_3溶液到培养基中发酵培养,测量发酵液中的红曲色素色价,进行对比分析,发现当CuSO_4溶液浓度逐渐增大时,红曲色素的色价逐渐降低;当Fe~(2+)逐渐增加时,色素含量上升;当添加Fe~(3+)后,色素含量不稳定。因此,Cu~(2+)和Fe~(3+)不适合作为优化培养基的金属离子,Fe~(2+)利于色素生成,合适的FeSO_4添加浓度为0.05 mmol/L。     

火龙果色素的提取工艺优化及色素稳定性研究

以不同品种火龙果果皮为材料,在单因素试验的基础上,采用L_9(3~4)正交试验法优化火龙果果皮色素的提取工艺,并对色素稳定性进行研究。结果表明,两种火龙果色素的提取条件及含量都有所差异,白肉品种火龙果果皮的最优提取条件为:浸取液40%乙醇、料液比1∶40(g/mL)、浸取时间25min、浸取温度40℃;红肉红皮品种则为:浸取液40%乙醇、料液比1∶30(g/mL)、浸取时间15min、浸取温度30℃。稳定性分析结果:高温不利于色素的稳定,Mg~(2+)、Fe~(2+)、蔗糖、VC和苯甲酸钠对色素稳定性影响不大,而Zn~(2+)、Cu~(2+)和H_2O_2对色素有强烈褪色作用,两种火龙果的色素稳定性差异不大。     

黑米、薏米、荞麦混合挤压膨化工艺及机理的研究

以优质的黑米、薏米、荞麦粉为原料,采用先进的现代挤压膨化技术,研制集营养、保健、食用为一体的五谷杂粮膨化粉及主食品。通过双螺杆挤压机、单螺杆挤压机对物料进行对比膨化实验,确定相应的混合物料挤压膨化工艺流程及参数。结果表明,双螺杆挤压比单螺杆挤压膨化效果理想,3种物料混合后膨化效果好,各原料比例为:m(黑米)∶m(薏米)∶m(荞麦粉)=45∶15∶40。对混合物料膨化的操作参数为:物料水分15%～20%,挤压温度171～184℃,螺杆转速90～114r/min,膨化物的糊化度可达83.3%～86.4%。本文还讨论了混合物挤压膨化的物理化学变化和机理。     

Effects of temperature,solid content and pH on the stability of black carrot anthocyanins

Anthocyanin stability of black carrots was studied at various solid contents (11, 30, 45 and 64° Brix) and pHs (4.3 and 6.0) during both heating, at 70–90 °C, and storage at 4–37 °C. Monomeric anthocyanin degradation fitted a first-order reaction model. Degradation of monomeric anthocyanins increased with increasing solid content during heating, while it decreased during storage. For example, at pH 4.3, half-life periods for anthocyanins at 30, 45 and 64° Brix were, respectively, 8.4, 6.9 and 5.2 h during heating at 80 °C and 18.7, 30.8 and 35.9 weeks during storage at 20 °C. At 30–64° Brix, increasing pH from 4.3 to 6.0 enhanced the degradation of anthocyanins during heating. The effect of pH on thermal stability of anthocyanins was also studied at six different pHs (2.5–7.0) in citrate-phosphate buffer solutions and significant decrease in anthocyanin stability was observed at pHs above 5.0. Higher activation energies (E_a) were obtained during heating than during storage with increasing solid contents. At 30–64° Brix, E_a values ranged from 68.8 to 95.1 kJ mol⁻¹ during heating and from 62.1 to 86.2 kJ mol⁻¹ during storage. Q₁₀ values at 20–37 °C were as high as 3.1 at 45° Brix and 3.6 at 64° Brix.     

Comparisons of flavonoids and anti-oxidative activities in seed coat,embryonic axis and cotyledon of black soybeans

Flavonoids contents, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activities and the ferric-reducing antioxidant power (FRAP) were compared in three black soybean varieties CRWD, Tainan 3 and Tainan 5. Varietal differences in antioxidant contents existed among the tested varieties. Variety CRWD accumulated more total phenolics (7.49 mg g⁻¹) and isoflavones (1.77 mg g⁻¹) than varieties Tainan 3 (7.05 mg g⁻¹ total phenolics and 1.58 mg g⁻¹ isoflavones) and Tainan 5 (4.38 mg g⁻¹ total phenolics and 0.63 mg g⁻¹ isoflavones). CRWD also accumulated more proanthocyanidins in seed coat than Tainan 3 and Tainan 5. CRWD also demonstrated greater DPPH and FRAP activities than the other two cultivars. Stepwise regressions indicated that both DPPH and FRAP activities were correlated well with the total contents of phenolics and flavonoids, with total phenolics being the most important anti-oxidative factor. The present results indicate that CRWD has greater anti-oxidative responses than Tainan 3 or Tainan 5, and is useful in functional food and other applications.     

发酵型海带、黑芝麻酸奶冻的研究

利用海带、脱脂乳粉为主要原料,选择海带与水的料液比、蔗糖和脱脂乳粉的添加量3个因素,采用 L9(34)正交设计,对发酵型海带、黑芝麻酸奶冻的工艺条件进行了研究.结果表明,选择1:20海带与水的料液比,加入质量分数6%的蔗糖,质量分数13%的脱脂乳粉,接种5%的乳酸菌发酵剂,42℃发酵24 h,发酵后加入琼脂、蔗糖、黑芝麻.由此制得的发酵型海带、黑芝麻酸奶冻具有牛奶特有的乳白色,凝块软硬适度,入口即化,营养丰富.     

热敏黑TF-BL可逆热致变色复配物的制备和微胶囊化研究

通过实验确定了热敏黑TF-BL可逆热致变色复配物中热敏黑TF-BL、双酚A、十六醇的最佳质量比.探讨了以明胶-阿拉伯胶为囊壁时将热敏黑TF-BL可逆热致变色复配物微胶囊化的适宜反应条件,并测试分析了该微胶囊的结构、变色性能、耐溶剂、耐酸碱以及热稳定性能.     

Composition of industrial seedless black currant pomace

The aim of the work was to characterize the basic chemical composition including polyphenols of seedless industrial dried black currant pomace from two subsequent harvest seasons, 2006 and 2007. Pomace after removing seeds was separated into three fractions: with particles smaller than 0.8 mm, 2–5 mm and greater than 5 mm. The pomace was analyzed for dry substance, protein, fat, ash, total dietary fiber (TDF), soluble solids content, acidity, organic acids, saccharides and polyphenols. In addition, the antioxidant activity of the pomace was assayed by the DPPH method. All the fractions were characterized by a high content of total dietary fiber above 63% and a low content of saccharides below 3.15% and acidity below 3.2%. The composition of polyphenol compounds of all the fractions was qualitatively determined, yet it was shown that the fraction of the pomace of 2–5 mm is characterized by the greatest content of phytocompounds, of which anthocyanins constitute about 90% of the polyphenols determined. Moreover, the presence of myricetin and quercetin glycosides as well as considerable quantities of myricetin and quercetin aglycones was found in the pomace. The pomace had a high antioxidant activity ranging from 93.3 to 126.5 μM TEAC/g. It was also found that the content of most polyphenol compounds investigated, as well as protein, ash, TDF, acidity and saccharides, was statistically dependent on the type of fraction. Disclaimer: The views and opinions expressed in this publication are purely those of the writers and may not in any circumstances be regarded as stating an official of European Commission.     

Fatty acid profile, thymoquinone content, oxidative stability, and antioxidant properties of cold-pressed black cumin seed oils

Six different batches of cold-pressed black cumin seed oils (BCSO) were evaluated for their fatty acid profiles, thymoquinone contents, oxidative stability, and antioxidant properties. Linoleic, oleic, and palmitic acids were the major fatty acids in the tested oils. The cold-pressed BCSO samples differed in their oxidative stability measured as the oxidative stability index (OSI). The greatest OSI was about 155 h, and the lowest OSI was proximately 76 h, reflecting a 2-fold difference in their oxidative stability. These BCSO contained significant level of phenolic components with a concentration ranging from 1.02 to 1.40 mg gallic acid equivalents/g oil. In addition, BCSO contained about 3.48-8.73 mg/g thymoquinone and trace amount of dithymoquinone. Electron spin resonance (ESR) analysis showed that cold-pressed BCSO contained natural antioxidants and was able to suppress radical mediated lipid peroxidation in fish oil. The methanol extracts of BCSO could directly react with and quench DPPH radicals, which further confirmed the antioxidant property of these BCSO. The results from the present study suggest that cold-pressed black cumin seed oil may serve as an excellent dietary source of thymoquinone and natural antioxidants.     

Ochratoxigenic Black Aspergilli Isolated from Dried Agricultural Products in Yogyakarta, Indonesia

Black aspergilli, the potential ochratoxin A （OTA） producers, were predominant fungi in fermented cocoa bean, coffee bean and dried cassava in Yogyakarta. Identification of black aspergilli at species level will be useful to make clear link between OTA contamination on food product and the toxin producer. The objective of this study was to identify the species of the black aspergilli producing OTA which contaminated dried agriculture products. In this study, 16 isolates were obtained, and four isolates among of them （YAC-9, YAK-6, YAK-12 and YAG-2） were found as OTA producing-strains, with the highest OTA found on Yeast Extract Sucrose （YES） solid medium of 57.68 ppb. Based on morphological characters, 16 isolates can be grouped into four species, after confirmation by molecular data based on PCR method, the groups were identified as A. carbonarius, A. niger, A. tubingensis and A. aculeatus. OTA producing-strains were identified as A. carbonarius and A. niger, meanwhile, A. tubingensis and A. aculeatus were found as non-OTA producing-strains.