基于响应曲面法优化文冠果种仁油的提取工艺研究

以文冠果种仁为原料,利用响应曲面法优化文冠果种仁油的提取工艺。在单因素实验的基础上,应用Box-Behnken设计方法建立数学模型,选择提取温度、提取时间和液料比为影响因子,以文冠果种仁油提取率为响应值,进行响应曲面分析。确定文冠果种仁油的最佳提取工艺条件为：提取温度58℃、提取时间31 min、液料比6∶1（mL∶g）,在此条件下文冠果种仁油的平均提取率为59.58%,与模型高度拟合。     

Flavonoids in Onion Cultivars (Allium cepa L.)

ABSTRACT: Total phenol and flavonoid contents were analyzed by HPLC coupled with a diode array detector in 5 traditional onion cultivars from Tenerife (Guayonje, San Juan de la Rambla, Carrizal Alto, Carrizal Bajo, and Masca) and a commercial cultivar (Texas Early Grano 502). Five quercetin chemical species (isoquercetin, quercetin diglucoside, quercetin monoglucoside 1, quercetin monoglucoside 2, and free quercetin) and kaempferol were identified and quantified in the onion samples. Quercetin monoglucoside 1 and quercetin diglucoside were the major flavonoids accounting for 80% of the total quercetin content. The mean quercetin monoglucoside 1: quercetin diglucoside ratio (QMG/QDG) was 1: 2.2. There were differences between the onion cultivars in the cases of total phenol, quercetin diglucoside, isoquercetin, QMG/QDG ratio, and kaempferol. The Texas cultivar had a higher QMG/QDG ratio and a higher kaempferol content than the traditional cultivars. The correlation study showed significant correlations between the analyzed phenolic components.     

Antioxidant and free radical scavenging activities of phenols from onion (Allium cepa)

Four (red, violet, white and green) varieties of Allium cepa were studied for their total phenolic contents (TPC), antioxidant (AOA) and free radical scavenging activities (FRSA). The TPC varied from 4.6 to 74.1 mg/g GAE, AOA varied from 13.6% to 84.1% and FRSA showed wide range in terms of IC₅₀ (inhibitory concentration) from 0.1 to 15.2 mg/ml, EC₅₀ (efficient concentration) from 4.3 to 660.8 mg/mg and ARP (antiradical power) from 0.15 to 23.2. The outer dry layers of red and violet varieties showed better inhibition of lipid peroxidation assayed by ammonium thiocyanate than α-tocopherol. The non-site-specific inhibition of hydroxyl radical induced deoxyribose degradation was also higher in the outer dry layers of red and violet varieties than in their middle and inner layers. The outer layers were also potential inhibitors of nitroblue tetrazolium chloride (NBT) reduction caused by superoxide anions. On the other hand the ferrous ion chelating capacity of the red and violet varieties was highest in the inner layers. Specific phenolic composition performed through HPLC and LC–MS/MS showed the presence of gallic acid, ferulic acid, protocatechuic acid, quercetin, and kaempferol. The unutilised outer layers of the red variety were a rich source of quercetin (5110 μg/g) with high AOA, FRSA and also showed significant protection of DNA damage caused by free radicals.     

葱属植物生物活性物质的研究进展

葱属植物含有含硫化合物、甾体皂苷、黄酮类化合物和多糖等活性物质,具有多种生理功能,如抑菌消炎、抗血小板聚集、抗氧化、降低胆固醇、抗肿瘤和缓解糖尿病等作用。本文综述了葱属植物中的生物活性物质及其生理功能的研究进展。     

利用4-MP测定大蒜中的蒜氨酸

为快速、方便地测定大蒜中的蒜氨酸,以鲜蒜为原料,经去皮、加热、制汁、与4-巯基吡啶(4-MP)反应、324纳米测定其吸光度等处理,测知鲜蒜中蒜氨酸的含量为0.74%～0.92%,变异系数2.4%～8.8%,结果表明,4-MP比色法测定大蒜中的蒜氨酸,简单、快速、方便,可用于鲜蒜与保藏大蒜中蒜氨酸含量的测定。     

不同方法提取的文冠果籽油的GC-MS分析

本研究分别采用冷榨、微波萃取、索氏提取、超声波萃取等方法提取文冠果籽油,利用气相色谱-质谱(GC-MS)分析了四种方法提取的文冠果籽油化学成分。结果是四种方法提取的文冠果籽油的化学成分有差异,通过比较确定超声波萃取提取率高,文冠果籽油的品质较好,质量稳定,无需脱色,工艺简单,所以超声波萃取法为提取文冠果籽油的较理想方法。     

藠头醋的研制

利用盐渍藠头生产中的下脚料-藠头皮，经过脱盐、压榨、补糖、酒精发酵和醋酸发酵制得藠头醋，其不挥发酸含量高，酸味柔和。藠头中盐分含量高，还含有某些抑菌成分，大多数醋酸菌无法正常发酵，因此从醋胚中筛选到1株适合酿造藠头醋的醋酸菌，能正常发酵蓖头酒液，发酵周期48h。     

文冠果落果黄酮成分分析及抑菌性评价

目的：提取并纯化文冠果落果黄酮,测定黄酮含量,确定单体种类,评价抑菌活性。方法：采用紫外分光光度法测定黄酮含量,采用显色反应、傅里叶红外光谱和高效液相色谱三者相结合的方法分析黄酮单体种类,同时评价文冠果落果黄酮对枯草芽孢杆菌、大肠杆菌、金黄色葡萄球菌生长的影响。结果：文冠果落果中黄酮含量为18.4?mg/g;落果黄酮纯化物中含有芦丁单体及其他14?种未知的黄酮类单体物质,其中芦丁的含量为27?mg/g,占文冠果落果总黄酮的6%左右;文冠果落果黄酮对枯草芽孢杆菌、大肠杆菌、金黄色葡萄球菌均有一定的抑制作用,其中对大肠杆菌抑制效果最佳。结论：文冠果落果中黄酮含量丰富,芦丁是其重要的单体成分,具有良好的抑菌活性。     

Effect of heat treatment on internal atmosphere and leaf extension of minimally processed leek stalks

Leeks trimmed at 20 cm from their base were immersed in a 55 °C hot water bath. During the heat treatment (HT), the internal gases released from each stalk were collected, and their volume as well as CO₂ and O₂ concentrations were determined. After HT, cooling and storage at 10 °C for 8 days, the weight, maximum leaf extension and internal atmosphere (volume and gas composition) were measured. It was found that HT inhibited leaf extension during storage at 10 °C for 8 days and induced significant modification of the stalk internal atmosphere, both immediately after HT and after storage. Therefore, in heat‐treated leek stalks, the growth zone of the innermost leaves was subjected to an environment of elevated CO₂ concentration, which was accompanied by the inhibition of leaf extension growth.