神秘果种子多酚大孔树脂纯化工艺研究

分别采用6种大孔树脂(AB-8、D101、HPD-500、S-8、DM130、X-5)纯化神秘果种子多酚,以吸附量、吸附率、解吸量、解吸率为评定参数,优选出X-5为最佳树脂。研究其吸附等温线,发现其与Langmuir等温线拟合良好。静态吸附与解吸结果表明:最佳pH 5.8,最佳解吸液为70%乙醇。动态吸附与解吸结果表明:最优样品液浓度为1.2mg/mL,吸附液体积为100mL,解吸液体积为50mL,吸附流速为1.0mg/mL,解吸流速为1.5mg/mL。研究结果表明:经X-5纯化后的神秘果种子多酚含量提高了2倍,T-AOC测定总抗氧化能力提高了2.5倍。说明该工艺适用于神秘果种子多酚的纯化。     

神秘果种子营养成分分析与评价

以神秘果种子为原料,依据国标及常规方法对神秘果种子的水分、灰分、粗纤维、粗脂肪、粗蛋白、还原糖、多酚、多糖、脂肪酸、18种氨基酸及12种矿物质元素等营养成分进行分析和评价。结果表明,神秘果种子中水分、灰分、粗纤维、粗脂肪、粗蛋白、还原糖、多酚、多糖含量分别为6.74 g/100 g、7.14 mg/g、4.40、15.69、26.76 g/100 g、0.59 mg/g、11.56 mg/g和12.33 mg/g;检测出20种脂肪酸,其中不饱和脂肪酸占脂肪酸总量的54.80%,主要是十八碳烯酸(29.96%);检测出18种氨基酸,富含多种药用氨基酸(63.75%),8种必需氨基酸含量占总氨基酸总量的40.69%,必需氨基酸比值系数分(SRC)达到了94.22;测定了12种矿物质元素含量,常量元素和微量元素中含量最高的分别为K和Mn,Cd、Hg、As、Pb四种重金属元素含量很低,均符合《中国药典》(2010版)标准。因此,神秘果种子是营养和保健价值较高的新资源食品,具有良好的开发前景。      

神秘果种子多糖的响应面优化提取及其抗氧化活性研究

采用响应面法优化超声波提取神秘果种子多糖最佳提取工艺,并考察其抗氧化能力。在单因素实验的基础上,以料液比、超声波时间、提取温度为自变量,以神秘果种子多糖得率为响应值,建立三因素三水平响应面回归分析。优化得到神秘果种子多糖的超声波提取最佳工艺条件为:料液比1∶43（g/m L）、提取温度50℃、超声时间40 min,实测多糖得率为12.33%,与预测得率12.36%接近,说明该模型稳定可行。并测定了神秘果种子多糖清除DPPH、ABTS+、·OH和O-2自由基的能力,半数抑制浓度IC50分别为:0.31、0.41、0.24和0.19 mg/m L,与VC相比抗氧化活性较弱。结果表明,神秘果种子多糖对四种自由基均有较强的清除能力,且呈剂量相关性。      

神秘果种子多酚超声双水相复合提取工艺及其抗氧化活性

利用超声波与双水相体系复合提取神秘果种子多酚,研究不同条件下提取的多酚的抗氧化能力。分别考察丙酮浓度、硫酸铵用量、超声波温度、超声波时间、料液比对神秘果种子多酚提取率的影响;采用单因素试验及响应面设计,优化神秘果种子多酚提取工艺。结果表明,最佳提取工艺条件为:丙酮浓度50%、硫酸铵用量0.22g、超声波温度60℃、超声波时间100min、液料比1∶20(m∶V),多酚理论提取率为11.54%。该条件下神秘果种子多酚的平均提取率为11.56%。该体系提取的多酚纯度为87.85%,优于单独采用超声波提取,可实现初步纯化。抗氧化性试验结果表明,神秘果种子多酚提取物对DPPH·的清除能力和还原能力较强,且还原力和DPPH·清除率与总多酚含量呈正比关系;其抗氧化活性强于抗坏血酸。     

神秘果中齐墩果酸和五环三萜含量的测定

微波提取神秘果中齐墩果酸和五环三萜,并用HPLC测定齐墩果酸含量,比色法测定五环三萜的含量。结果表明:齐墩果酸在0.01~0.05 mg/mL范围内线性关系良好,回归方程为:Y=5.8672E-8X-2.908 07E-4,RSD=1.33%,相关系数r=0.995 72,含量为0.03 mg/g。五环三萜在0.1~0.6 mg/mL范围内线性关系良好,A=2.92C+1.272,相关系数r=0.990 04,含量为0.9 mg/g。试验建立的两种方法操作简便、准确、快速,适合神秘果中齐墩果酸及五环三萜含量的测定。     

桑椹果醋体外抗肿瘤活性的研究

采用3-（4,5-二甲基噻唑-2）-2,5-二苯基四氮唑溴盐（MTT）比色法来测定桑椹果醋的体外抗肿瘤效果,并进行细胞形态学观察。结果显示,桑椹果醋具有较强的抗肿瘤活性,并且随着桑椹果醋含量的增加,其抑制活性增大。细胞形态学观察结果表明,在桑椹果醋作用下,人肝癌细胞系SMMC-7721和宫颈癌细胞Hela两种肿瘤细胞均呈现数量减少、细胞膜加深变暗、成群聚在一起等不规则的生长趋势,表明桑椹果醋对两肿瘤细胞有较强的抑制作用。结果表明,桑椹果醋对Hela细胞的抑制效果强于SMMC-7721细胞。     

果梅果实浸提液抑菌活性的研究

比较"小叶猪肝"和"软条红梅"两个梅品种果实不同浸提液的抑菌活性,结果表明:梅果实浸提液对大肠杆菌、枯草芽孢杆菌和猪链球菌三种待测细菌均有抑制作用,其中对大肠杆菌和枯草芽孢杆菌的抑制作用强于猪链球菌;以不同的浸提剂浸提,采用正己烷作浸提剂时的浸提成分抑菌活性最强,丙酮次之;采用不同的浸提方法浸提抑菌活性差异不显著;两个品种的梅果实抑菌活性差异不显著。     

桑椹的功能成分及药理作用

桑椹中含有多种功能性成分，如白黎芦醇、芦丁、原花色素等，具有预防心血管疾病，防癌、抗衰老、抗溃疡、抗病毒等药理作用。已有以桑椹作原料，研制成桑椹酒、桑椹汁、桑椹冰淇淋、桑椹酸奶等营养保健食品的试验报道。     

百香果全果酒发酵工艺优化及体外抗氧化性比较分析

以紫皮百香果（Passiflora edulis）为原料发酵百香果全果酒,通过单因素试验结合响应面法,确定百香果全果酒的最适发酵工艺,并通过四个抗氧化体系（DPPH·、ABTS+·、·OH、还原能力）来评价其与百香果果汁酒和原汁的抗氧化活性。结果表明,百香果全果酒最适发酵工艺条件为初始糖度21%、酵母接种量0.04%、发酵温度29 ℃、发酵时间5 d。在此优化工艺条件下,百香果全果酒酒精度为11.9%vol;在四种抗氧化体系中,自由基清除率和还原能力均随样品体积的增加而增大,抗氧化活性的大小顺序为全果酒＞果汁酒＞原汁。     

桑椹花色苷生理活性及加工稳定性研究进展

花色苷是桑椹所含的重要生理活性物质之一,具有抗氧化、抗癌、神经保护、心脑血管保护和抑制体重增加等功效,但在桑椹加工与贮藏过程中,花色苷对热和光等因素较敏感,易发生不利降解,从而降低其生物活性。本文综述了近年来国内外桑椹花色苷的研究进展,主要涉及桑椹花色苷的生理活性和加工及贮藏过程中的稳定性,旨在为桑椹花色苷资源的高效利用提供理论支撑。      

油茶蒲中总三萜提取工艺研究

以油茶蒲为原料,利用甲醇作为浸提剂,研究了总三萜的提取工艺。采用单因素试验考察了甲醇体积分数、料液比、浸提温度和浸提时间对总三萜提取效果的影响,并通过正交试验分析确定了总三萜的最佳提取工艺条件。结果表明:影响总三萜提取的因素主次顺序为浸提时间料液比甲醇体积分数浸提温度;最佳提取工艺条件为甲醇体积分数80%、料液比1∶25、浸提温度80℃、浸提时间2.0 h,在此条件下,总三萜产率为0.115%。     

Antifungal activity of chitosan and its application to control post‐harvest quality and fungal rotting of Tankan citrus fruit (Citrus tankan Hayata)

In this study, the antifungal activity of chitosan A (MW = 92.1 kDa) and B (MW = 357.3 kDa), with 94.2% N‐deacetylation were examined at various concentrations against fungi including Penicillium digitatum, Penicillium italicum, Botrydiplodia lecanidion and Botrytis cinerea. The effectiveness of these chitosans to control the post‐harvest quality of Tankan fruit, a popular sub‐tropical citrus fruit, was investigated. It was found that chitosan, depending on type and concentration, caused 25.0–90.5% growth inhibition on test organisms after 5 days of cultivation at 24 °C. Chitosan treatment significantly reduced (P < 0.05) the percentage decay of Tankan fruit during storage at 24 °C. After 42 days of storage at 13 °C, chitosan‐coated Tankan fruits were firmer, exhibited less decay and weight loss, and showed higher titratable acidity, ascorbic acid, and total soluble solids than the control fruit. Weight loss of Tankan fruits decreased as the concentration of chitosan was increased. On the other hand, chitosan A, regardless of concentration tested, was found to be more effective in retaining the firmness, titratable acidity and water content, total solid content and ascorbic acid content of Tankan fruits than chitosan B. Copyright © 2006 Society of Chemical Industry     

In vitro study of antioxidant activity of Syzygium cumini fruit

Food rich in antioxidants plays an essential role in the prevention of diseases. The fruits of wild Indian Syzygium cumini (L.) Skeels (Myrtaceae), also known as black plum, are edible. Traditionally they are also used to cure a number of ailments. In this paper, the antioxidant activity of the fruit skin has been analysed using different assays, such as hydroxyl radical-scavenging assay, based on the benzoic acid hydroxylation method, superoxide radical-scavenging assay, based on photochemical reduction of nitroblue tetrazolium (NBT) in the presence of a riboflavin-light-NBT system, DPPH radical-scavenging assay, and lipid peroxidation assay, using egg yolk as the lipid-rich source. Total antioxidant capacity was determined by the assay based on the reduction of Mo(VI)–Mo(V) by the extract and subsequent formation of a green phosphate/Mo(V) complex. In all the systems, a significant correlation existed between concentration of the extract and percentage inhibition of free radicals or percentage inhibition of lipid peroxidation. The antioxidant property of the fruit skin may come in part from the antioxidant vitamins, phenolics or tannins and anthocyanins present in the fruit.     

Lipoxygenase activity associated to fruit ripening and senescence in chayote (Sechium edule Jacq. Sw. cv. “virens levis”)

Lipoxygenase (LOX) enzyme activity and their putative isoforms were investigated during postharvest life in chayote fruit (Sechium edule Jacq. Sw. cv. “virens levis”). Possible associations of LOX with fruit quality parameters are discussed. Five LOX isoforms were identified (SeLOX‐1 to ?5) displaying different activity patterns during ripening and senescence as well as in roots, stems, and leaves. The probable role of SeLOX‐5 as a specific isoform linked to senescence was examined. The highest relative activity of LOX was registered in fruit tissue, followed by leaves, stem, and roots. Correlations were found between LOX and fruit composition variables such as the contents of linoleic (LA) and linolenic (LNA) acids, weight loss, CO₂ and ethylene production rates. LOX activity, and LA and LNA concentration decreased from Day 1 to Days 13–17, when early seed germination events became visible, indicating a transition stage between late fruit ripening and early senescence characterized by a deteriorative process.

Practical applications

Detrimental effects on fruit composition variables such as dehydration, weight loss, wilting, and sprouting symptoms, have been reported as the main causes that reduce the commercial quality and shelf life in chayote fruit and prevent their export to distant markets. To the best of our knowledge, the association of lipoxygenase (LOX) enzymes to non‐climacteric fruit ripening—like chayote—or their loss of commercial quality during prolonged shelf life has not yet been described. This is the first study that explores the role of chayote LOX activity in fruit, identifies various specific LOX isoforms associated to ripening or to the senescence process and provides new evidence that supports the hypothesis that putative LOX isoforms might be related to several postharvest detrimental effects on chayote fruit. This information could be useful to food processors or packers to pursue better profitability and consumer satisfaction.     

Bioactive properties of Snake fruit (Salacca edulis Reinw) and Mangosteen (Garcinia mangostana) and their influence on plasma lipid profile and antioxidant activity in rats fed cholesterol

Two exotic fruits (Snake fruit and Mangosteen) were characterized by polyphenols, proteins and antioxidant potentials and by their influence on plasma lipids and antioxidant activity in rats fed cholesterol. The content of polyphenols (14.9±1.5 and 9.2±0.8 mg GAE g⁻¹) and antioxidant potential (46.7±4.7 and 72.9±7.4 μmol TE g⁻¹) in Snake fruit was significantly higher than in Mangosteen (P<0.05). Twenty male Wistar rats were divided into four dietary groups: Control, Chol, Chol/Snake and Chol/Mangosteen. After 4 weeks of the experiment diets supplemented with Snake fruit and to a lesser degree with Mangosteen significantly hindered the rise in plasma lipids and hindered a decrease of antioxidant activity. Changes were found in fibrinogen fraction, such as solubility and mobility by the number of protein bands detected in SDS-electrophoresis: Chol/Snake differed from Chol/Mangosteen. In conclusion, Snake fruit and Mangosteen contain high quantity of bioactive compounds, therefore positively affect plasma lipid profile and antioxidant activity in rats fed cholesterol-containing diets. Such positive influence is higher in rats fed diet with added Snake fruit.     

沙棘鲜果抗氧化成分提取参数优化及抗氧化性能分析

以沙棘鲜果为原料,总抗氧化能力（FRAP）值为评价指标优化其抗氧化成分的提取参数。在单因素实验的基础上,选择乙醇浓度、料液比、提取时间、提取温度为自变量,FRAP值为响应值,利用Box-Behnken中心组合设计原理和响应面分析法,研究各自变量及其交互作用对FRAP值的影响。根据预测模型得到最佳的提取工艺条件为:乙醇浓度51%,料液比1∶22（g/m L）,提取时间1h,提取温度86℃,在此条件下得到的提取液的FRAP值为8.784mmol/L。抗氧化性能分析表明沙棘果抗氧化成分具有很好的清除自由基能力,作用于DPPH自由基EC50值为93.79μg/m L,羟自由基为4.14mg/m L,超氧阴离子为0.856mg/m L。