Extraction of Anthocyanin Pigments from Purple Sunflower Hulls

The anthocyanin pigments in hulls of purple sunflower seeds were extracted using three solvent systems, 50:1:49 ethanol-acetic acid-water (EAW), 0.01M acetic acid (AAc), or water containing SO₂. Solvent, extraction time, size of ground hulls, pH of extracting solvent, hulls/solvent ratio, and concentration of SO₂ in water, were investigated. All were significant factors affecting yield of extracted anthocyanins. EAW and SO₂ were more effective extractants than AAc. Optimum conditions from response surface optimization for the extraction with sulphurous water were: SO₂ at 200 mg/L, hull size 20 mesh, extraction time 5 min at 22°C, and solvent/hulls ratio = 20.     

Strawberry juice colour: The effect of some processing variables on the stability of anthocyanins

The colour stability of juice and purées made from a mixture of two strawberry varieties, stored at + 20°C or at –20°C under aerobic and anaerobic conditions, was studied. High-performance liquid chromatography and spectrophotometric analysis were used to monitor the changes in colour during storage. Pelargonidin 3-glucoside comprised 80% of the total anthocyanin content. Four other pelargonidin-based peaks were found, being 10.4%, 3.5%, 0.7% and 0.3% of the total and two cyanidin peaks were present, being 3.3% and 0.4% of the total. Clarification before storage caused considerable losses in the initial anthocyanin concentrations. Storage conditions (air versus nitrogen) did not influence the rate of loss of anthocyanins during storage or the formation of polymeric pigments. There were no losses in anthocyanins and no increase in the amount of colour measured at 510 nm due to polymers in samples stored at–20°C. Polymerisation occurred in the samples stored at + 20°C, especially in the clarified samples.     

Effects of Berry Anthocyanins on Cognitive Performance,Vascular Function and Cardiometabolic Risk Markers: A Systematic Review of Randomized Placebo-Controlled Intervention Studies in Humans

Supplementation with anthocyanins, which are a type of flavonoids mainly found in various berries, is hypothesized to be a promising approach to lower the risk of developing cognitive decline. The aim of this systematic review was to provide a comprehensive overview of dietary intervention trials describing effects of berry anthocyanins on cognitive performance in humans, while also addressing potential underlying mechanisms. A total of 1197 articles were identified through a systematic search, and 49 studies reporting effects on cognitive performance (n = 18), vascular function (n = 22), or cardiometabolic risk markers (n = 32) were included. Significant improvements were observed on memory, while some of the studies also reported effects on attention and psychomotor speed or executive function. Vascular function markers such as brachial artery flow-mediated vasodilation were also affected and consistent evidence was provided for the beneficial effects of berry anthocyanins on endothelial function. Finally, studies reported improvements in blood pressure, but effects on metabolic risk markers (e.g. carbohydrate and lipid metabolism) were less consistent. In conclusion, this review provides evidence for the beneficial effects of berry anthocyanins on cognitive performance as memory improved. Whether observed anthocyanin-induced improvements in vascular function and blood pressure underlie beneficial effects on cognitive performance warrants further study.     

Rice β-Glucosidase 4 (Os1βGlu4) Regulates the Hull Pigmentation via Accumulation of Salicylic Acid

Salicylic acid (SA) is a stress hormone synthesized in phenylalanine ammonia-lyase (PAL) and the branching acid pathway. SA has two interconvertible forms in plants: SAG (SA O-β-glucoside) and SA (free form). The molecular mechanism of conversion of SA to SAG had been reported previously. However, which genes regulate SAG to SA remained unknown. Here, we report a cytoplasmic β-glucosidase (β-Glu) which participates in the SA pathway and is involved in the brown hull pigmentation in rice grain. In the current study, an EMS-generated mutant brown hull 1 (bh1) displayed decreased contents of SA in hulls, a lower photosynthesis rate, and high-temperature sensitivity compared to the wild type (WT). A plaque-like phenotype (brown pigmentation) was present on the hulls of bh1, which causes a significant decrease in the seed setting rate. Genetic analysis revealed a mutation in LOC_Os01g67220, which encodes a cytoplasmic Os1βGlu4. The knock-out lines displayed the phenotype of brown pigmentation on hulls and decreased seed setting rate comparable with bh1. Overexpression and complementation lines of Os1βGlu4 restored the phenotype of hulls and normal seed setting rate comparable with WT. Subcellular localization revealed that the protein of Os1βGlu4 was localized in the cytoplasm. In contrast to WT, bh1 could not hydrolyze SAG into SA in vivo. Together, our results revealed the novel role of Os1βGlu4 in the accumulation of flavonoids in hulls by regulating the level of free SA in the cellular pool.     

超滤、纳滤膜技术分离浓缩玫瑰茄花青素研究

对超滤膜、纳滤膜技术在玫瑰茄花青素的纯化、浓缩过程中的影响进行研究。在单因素实验的基础上,再对微滤膜、超滤膜、纳滤膜和反渗透膜进行膜组件的整合,确定了玫瑰茄色素制备的最佳膜组件,即UH100超滤膜和NS027纳滤膜的组合,并明确了各自的操作条件,即操作压力分别为0.4 MPa和1.5 MPa、操作温度分别为30~35℃和40℃。通过优化的膜组件处理的实验组与对照组的对比研究表明:实验组产品得率高,并且纯化物中花青素含量也高,可达32.7 mg/g干粉重。      

复合花青素饮料的制备及提高其稳定性的方法

本实验将以葡萄皮、黑米、紫甘薯提取物为原料的复合花青素应用于果味饮料中,通过选择最适辅色剂种类并确定添加量,提高了花青素在酸性饮料体系中的保存率。通过正交实验确定饮料的最佳配方为:柠檬酸0.16%,果葡糖浆10%,蓝莓香精0.06%,复合花青素0.1%;结合杀菌条件选择茶多酚作为最适辅色剂,添加量为500 mg/kg时效果最佳,饮料颜色在杀菌条件下的保存率可达90.9%。实验中的饮料产品在低温下贮存时间更长,其中在4℃时饮料中花色苷的贮存期为230 d左右。      

黑豆皮花色苷抗禽白血病病毒A亚群活性的研究

为探寻黑豆皮花色苷（anthocyanins from black soybean seed coat,ABSC）抗禽白血病病毒A亚群（subgroup A avian leukosis virus,ALV-A）的活性效果。本文以ABSC粉为原料,采用高效液相色谱仪与质谱仪联机（HPLC-MS）的方法鉴定了其花色苷主要活性成分,随后采用体外实验,应用MTT法和观察细胞形态法检测了ABSC对鸡成纤维细胞系（DF-1）的细胞毒性,建立细胞模型,研究加入ABSC后对ALV-A的预防和治疗作用。结果表明:黑豆皮花色苷粉中含四种花色苷成分,其中主要为矢车菊色素-3-葡萄糖苷;ABSC对DF-1无细胞毒性的最大相对安全质量浓度为20μg/mL;ABSC在安全浓度范围内能抑制ALV-A的增殖,且抑制程度成剂量关系。结论,ABSC质量浓度为12μg/mL能够显著抑制ALV-A诱导的DF-1细胞形态变化,降低凋亡。      

山桃稠李果实花色苷对HepG2细胞抗氧化系统的影响

目的:研究山桃稠李果实花色苷对人肝癌细胞（HepG2）抗氧化系统的影响。方法:质量浓度0.1～1.2mg/mL的花色苷作用于HepG2细胞,MTT法检测HepG2细胞生长抑制率;检测各组细胞内抗氧化酶活性和谷胱甘肽、丙二醛的含量变化;采用DCFH-DA探针检测细胞内活性氧（ROS）含量的变化。结果:随着花色苷质量浓度的增加,HepG2细胞的抗氧化酶（T-SOD、GSH-PX）活性显著降低;谷胱甘肽（GSH）含量下降,丙二醛（MDA）及活性氧的含量上升。结论:山桃稠李果实花色苷能够明显的降低HepG2细胞的抗氧化能力。      

红提葡萄采后贮藏过程中花色苷的动力学研究

通过研究红提葡萄花色苷在不同贮藏温度和热处理时间下的稳定性,建立了花色苷降解动力学模型,研究结果表明,红提葡萄花色苷对热处理不稳定,其降解符合一级动力学反应,活化能(Ea)为21.29kJ/mol,指前因子(k0)为145.24,降解速率随温度的增高逐渐增大,而半衰期随着温度的增高逐渐降低。经验证,该降解动力学模型准确有效,可用于红提葡萄贮藏温度的选择和预测不同温度下的贮藏期。      

超声波辅助提取蓝莓果渣中花色苷的条件研究

以蓝莓果渣为原料,研究超声波辅助提取花色苷的工艺条件。结果表明最佳提取工艺条件为:超声波功率350W,提取温度45℃,提取时间50min,料液比1∶55g/mL,乙醇(pH=1.5)体积分数60%,提取2次。在此条件下进行提取,每克蓝莓果渣可提取花色苷(9.91±0.05)mg。与酸性乙醇浸提法比较,超声波辅助提取法提取时间短,提取量大。