天然棕色棉色素的液相色谱分离

采用聚酰胺柱层析、高效液相色谱（HPLC）、制备液相色谱对天然棕色棉色素进行了分离。结果表明聚酰胺柱可以有效将棕棉色素分段富集,依据分段后色素的颜色、HPLC图可知棕棉色素由两部分组成,利用反相C18制备柱反复分离得到了其中一部分色素混合物中的两种有色成分和一种无色成分。但是反相制备柱不能将另一部分色素有效分离,依据该部分色素的各种色谱保留行为,其可能由一系结构十分相似的多酚类化合物组成。     

碱溶液对天然棕色棉色素提取效果及成分的影响

不同学者采用的提取方法不同,对棕色棉色素定性结果产生较大差异。根据多酚类化合物易溶于碱这一特点,结合超声波辅助萃取技术,采用不同pH值碱溶液对天然棕色棉纤维色素进行提取。结果表明碱溶液提取能力较好,pH值为14.1的氢氧化钠溶液能比较彻底的对色素进行提取。去离子水提取产物经过碱性条件处理后调回中性,UV吸收光谱发生变化,采用不同pH值溶液提取的产物HPLC分离结果也表明碱性环境下会使得部分物质发生不可回复性改变,说明色素物质具有多组分性质和复杂性。碱溶液不能用于以结构鉴定为目的的色素物质提取。     

天然棕色棉的抗菌性能

为探究天然棕色棉的抗菌特性,以金黄色葡萄球菌和大肠杆菌分别作为革兰氏阳性菌和革兰氏阴性菌的代表,通过平板菌落计数法和比浊法测试了棕色棉纤维的抗菌性能,并用晕圈法、荧光显微镜以及扫描电子显微镜分析了棕色棉色素提取物的抗菌活性及抗菌机制。结果表明:棕色棉纤维对2种细菌的生长繁殖都有良好的抑制作用,抗菌率分别为87.9%和79.5%;常规的碱精练和酶精练可在一定程度上提高棕色棉纤维的抗菌性能;棕色棉纤维的抗菌性能来源于其色素,色素可通过与细菌的细胞膜结构的结合来破坏细胞膜的转运能力,进而破坏细菌正常的生长和繁殖过程,达到杀死细菌的效果。     

荧光增白剂对天然棕色棉色泽的影响及作用机制

为了探究荧光增白剂(FWA)对天然棕色棉(NBC)色泽的影响,采用具有不同带电基团的双三嗪氨基二苯乙烯型荧光增白剂对天然棕色棉进行处理,通过对样品的相关颜色性能进行测试分析,并进一步研究荧光增白剂对棕色棉色素的作用机制。结果表明：末端带正电基团的双三嗪氨基二苯乙烯型荧光增白剂对NBC具有较好增深作用;FWA与NBC色素的作用反应并不是生成新物质的化学反应,而是在NBC上形成了物理吸附;静电作用力,范德华力和氢键等可以影响FWA对棕棉色素的物理作用。经过FWA处理过后的NBC颜色明显增深,色泽有明显改进,对天然棕色棉产品开发具有实用价值。     

基于紫外-可见漫反射光谱的天然棕色棉/染色棕棉混纺比定量分析

为了建立一种便捷测定天然彩色棉和染色彩棉混纺比的方法,以天然棕色棉与染色棕棉为例,通过对不同比例混合的天然棕色棉及染色棕棉进行紫外-可见漫反射光谱测定,用导数法进行数据分析。结果表明:天然棕色棉与染色棕棉的紫外-可见漫反射光谱曲线有明显不同,不同混合比例的天然棕色棉与染色棕棉的光谱曲线根据混合比例呈规律性变化,对它们的紫外-可见漫反射光谱进行导数法处理并与色差法对比发现,661nm波长处混纺比与一阶导数值的拟合曲线相关性最好。同时,该拟合方程可用于快速定量测定天然棕色棉和染色棕棉的混纺比。     

超声波辅助萃取天然绿色棉色素

本文利用紫外分光光度法研究了天然绿色棉色素乙醇溶液的紫外光谱性质,分析得出360nm处的吸收值与色素浓度呈线性关系,R2达到了0.9992。文中研究了温度、时间等条件对萃取效果的影响,并与普通浸提进行了对比,结果发现超声波辅助萃取效率明显高于普通浸提,超声波辅助萃取天然绿色棉色素20min达到普通浸提5小时的萃取效果,两种萃取方法得到的色素成分相同。     

处理条件对天然绿色棉色素抗氧化活性的影响

基于天然绿色棉色素含有多酚类物质以及其结构的不稳定性,采用清除1,1?二苯基?2?苦基肼（ DPPH）自由基法,探讨温度、光辐射、酸碱条件对绿色棉色素的抗氧化活性的影响。结果表明,高碱条件对绿色棉色素的抗氧化影响较大。经pH值为13的碱溶液处理后,色素的DPPH自由基清除率下降至2?97％,调回中性后,自由基清除能力恢复至原先的81?38％,说明碱性条件导致抗氧化性的消失大部分可以恢复。结合紫外光谱可以看出,碱性条件下色素主体结构不变,但部分组分结构发生了不可逆的破坏。光辐照对天然绿色棉色素的抗氧化活性有明显的影响,日晒5 d后,绿色棉色素自由基清除能力下降57?10％。高温150℃处理1 h对绿色棉色素的自由基清除能力影响不大。     

葡萄酒中外源性天然色素掺伪检测

研究确定了葡萄酒中可能添加的天然色素种类是花青素类物质,并建立了葡萄酒中花色苷的检测方法,样品经SPE提取后高效液相色谱荧光法进行定性、定量分析。确定了葡萄酒中6种主要呈色物质:锦葵素-3-葡萄糖苷;锦葵素-3-乙酰葡萄糖苷;锦葵素-3-p-香豆酰葡萄糖苷;芍药素-3-葡萄糖苷;飞燕草素-3-葡萄糖苷;矮牵牛色素-3-葡萄糖苷,比例分别为5∶1.5∶1∶0.5∶0.4∶0.4,当酒中原有花色苷种类和比例出现剧烈变化时,即可判定添加了外源花色苷,方法可以有效判定酒中是否添加外源花色苷。     

葡萄酒中外源性天然色素掺伪检测

研究确定了葡萄酒中可能添加的天然色素种类是花青素类物质,并建立了葡萄酒中花色苷的检测方法,样品经SPE提取后高效液相色谱荧光法进行定性、定量分析。确定了葡萄酒中6种主要呈色物质:锦葵素-3-葡萄糖苷;锦葵素-3-乙酰葡萄糖苷;锦葵素-3-p-香豆酰葡萄糖苷;芍药素-3-葡萄糖苷;飞燕草素-3-葡萄糖苷;矮牵牛色素-3-葡萄糖苷,比例分别为5∶1.5∶1∶0.5∶0.4∶0.4,当酒中原有花色苷种类和比例出现剧烈变化时,即可判定添加了外源花色苷,方法可以有效判定酒中是否添加外源花色苷。      

天然色素对棉针织物染色探讨

介绍了提高天然色素对棉针织物染色性能的传统方法和新技术,传统方法包括媒染法染色和加盐促染,新技术包括阳离子改性剂改性和超声波法。分析了天然色素对棉针织物染色存在的问题,包括染深性差、色牢度低、稳定性差、色相单调,并阐述了解决方法。     

Effect of condensed tannin in cottonseed hulls on endogenous ileal amino acid loss in the growing rat

The effect of condensed tannin (CT) in cottonseed hulls (CSH) on endogenous ileal amino acid flow in the growing rat was evaluated. CSH contain around 900 g kg^?1 fibre and 52 g kg^?1 total CT. Twenty-four rats were allocated to four semi-synthetic diets, which contained enzymically hydrolysed casein (EHC) as the sole source of dietary nitrogen and chromic oxide as an indigestible marker. Two of the diets contained no CSH while the remaining two contained 50 g kg^?1 CSH. At each level of hull inclusion (0 and 50 g kg^?1), polyethylene glycol (PEG: MW 3500) was added (6 g kg^?1) to one of the diets. The effect of CT was assessed by determining endogenous ileal amino acid loss in the presence or absence of PEG, which binds and inactivates CT. The rats were given their respective experimental diets ad libitum for 14 days. Samples of digesta were collected at slaughter from the terminal 15 cm of ileum. The digesta samples were centrifuged and the supernate ultrafiltered. The precipitate plus retentate (MW > 10000) fraction affords an estimate of endogenous loss. Inclusion of CSH in the EHC based diet increased ileal flow of total nitrogen (1387 versus 1623 μgg^?1 dry matter intake; P ≤ 0.05), increased ileal flow of total amino acids (23%; P ≤ 0.01), and significantly increased ileal flow of several individual amino acids. There was no significant effect of PEG and no PEG × diet interaction; showing that the CSH effects could not be explained by action of CT. The presence of hulls in commercial cottonseed meal would appear to contribute to the reported low apparent ileal amino acid digestibility coefficients for cottonseed meal by increasing endogenous ileal amino acid flow, but this effect is not due to the CT component of the hulls.     

加工魔芋粉褐色素控制研究进展及问题

色素对食品加工品质具有重要影响,如何对其进行控制以保证产品色泽、性能等品质是研究重点。针对魔芋粉加工中产生褐色素问题,该文综述对褐色素控制研究进展及存在问题,并对其研究方向提出展望和建议,以期为食品色素研究、提高产品品质提供参考。     

The addition of cottonseed hulls to the starter and supplementation of live yeast or mannanoligosaccharide in the milk for young calves

The objectives of this study were to investigate the effects of the addition of cottonseed hulls (CSH) to the starter and the supplementation of live yeast product (YST) or mannanoligosaccharide product (MOS) to milk, on growth, intake, rumen development, and health parameters in young calves. Holstein (n = 116) and Jersey (n = 46) bull (n = 74) and heifer (n = 88) calves were assigned randomly within sex at birth to treatments. All calves were fed 3.8 L of colostrum daily for the first 2 d. Holstein calves were fed 3.8 L of whole milk, and Jersey calves were fed 2.8 L of whole milk through weaning at 42 d. Calves continued on trial through 63 d. Six treatments were arranged as a 2 × 3 factorial. Calves received either a corn-soybean meal-based starter (21% crude protein and 6% acid detergent fiber; −CSH) or a blend of 85% corn-soybean meal-based starter and 15% CSH (18% crude protein and 14% acid detergent fiber; +CSH) ad libitum. In addition, calves received whole milk with either no supplement (NONE) or supplemented with 3 g/d of mannanoligosaccharide product (MOS) or 4 g/d of live yeast product (YST) through weaning at 42 d. Twelve Holstein steers [n = 6 (per starter type); n = 4 (per supplement type)] were euthanized for collection and examination of rumen tissue samples. Dry matter intake (DMI) was greater for Holstein calves fed +CSH (0.90 kg/d) than −CSH (0.76 kg/d). Final body weight at 63 d of Holstein calves fed +CSH (75.8 kg) was greater than that of those fed −CSH (71.0 kg). Average daily gain (ADG) was greater for Holstein calves fed +CSH (0.58 kg/d) than −CSH (0.52 kg/d). However, Holstein calves fed −CSH had a greater feed efficiency (FE; 0.71 kg of ADG/kg of DMI) than those fed +CSH (0.65 kg of ADG/kg of DMI). Also, Holstein calves fed +CSH had narrower rumen papillae (0.32 mm) compared with those fed −CSH (0.41 mm). There were no significant effects of CSH on DMI, ADG, or FE in Jersey calves. There were no significant effects of YST or MOS on DMI, ADG, FE, or rumen papillae measures in Holstein calves. Jersey calves fed YST or MOS had greater final body weight at 63 d (51.2 kg and 51.0 kg, respectively) than calves fed NONE (47.5 kg). However, there were no significant effects of YST or MOS on DMI, ADG, or FE in Jersey calves.     

板栗壳棕色素的提取工艺研究及性能初探

以板栗壳棕色素的提取条件,工艺以及该色素的抗氧化、抑菌性进行了研究。实验结果表明,板栗壳棕色素的抗氧化性能优于同浓度的BHT,并对大肠杆菌,枯草杆菌、青霉有一定的抑制作用。     

板栗壳棕色素的提取及理化性质研究

研究了板栗壳棕色素的提取及其理化性质。实验结果表明，该色素对光、热稳定性很好，具有一定应用开发价值。