羧甲基化南瓜多糖的制备及抗氧化、降血糖活性研究

目的：提高南瓜多糖体外抗氧化活性和降血糖活性。方法：以南瓜为研究对象,考察一氯乙酸浓度、反应温度和反应时间对羧甲基化南瓜多糖取代度的影响,并进行抗氧化活性和降血糖试验。结果：羧甲基化南瓜多糖的最佳制备条件为一氯乙酸浓度1.9 mol/L、反应温度73 ℃、反应时间3 h,该条件下的羧甲基化多糖取代度为1.247。在一定质量浓度范围内,南瓜多糖(PP)、羧甲基化南瓜多糖(CM-PP)的抗氧化能力与质量浓度呈剂量依赖性,与修饰前南瓜多糖相比,多糖的羧甲基化修饰可以提高其对 α-葡萄糖苷酶的抑制活性。结论：羧甲基化南瓜多糖的优化工艺合理可行,且具有较强的抗氧化活性和降血糖活性。     

Phytochemical,antioxidant, and antibacterial activities of fermented Citrus unshiu byproduct

Food Science and Biotechnology - Citrus unshiu is an economically important fruit on Jeju Island, Korea, but byproducts are a major source of agricultural waste. The aim of this study is to examine...     

Chemical composition and antibacterial activities of lupin seeds extracts

Determination of influence of lupin natural phenolic compounds on antibacterial properties of its seeds was carried out. Raw material were seeds of Lupinus albus, L. luteus, and L. angustifolius. The methods included the determination of the content of proteins, total phenolic compounds, free phenolic acids, and tannins as well as antibacterial properties with ethanol extracts. The content of total phenolic compounds was smaller in testas than in cotyledons and the highest levels are observed in bitter cultivars of Lupinus albus cv. Bac and L. angustifolius cv. Mirela. Lupin tannins mainly occurred in cotyledons of the white lupin, predominantly in the bitter cultivar Bac. Free phenolic acids were mainly found in testas. Only extracts from the testas displayed antibacterial properties, which excludes the possibility of alkaloid influence on the results. The results suggest that inhibition of test bacteria growth depended mainly upon the content of the total phenolic compounds.     

荔枝核水提物抗氧化和抑菌作用的研究

以荔枝核为原料,经过粉碎,采用传统中药水煎法制备得到荔枝核水提物。通过测定还原能力、总抗氧化能力以及水提物对1,1-二苯基-2-三硝基苦肼自由基(DPPH.)、羟自由基(.OH)、超养阴离子自由基(O2-.)的清除能力来评价水提物的抗氧化活性。同时,通过侧定抑菌圈直径大小和最小抑菌浓度研究的荔枝核水提物对金黄色葡萄球菌的抑菌效果。实验结果表明:荔枝核水提物有较好的抗氧化性,对DPPH.、.OH、O2-.的IC50分别是0.1819mg/mL、16.3652mg/mL、31.6767mg/mL。同时荔枝核水提物表现出一定的还原能力和抗氧化能力。通过抑菌实验,得出荔枝核水提物对金黄色葡萄球菌有抑制效果。当水提物的浓度为3.125%,抑菌圈直径为8.8±0.58mm。荔枝核水提物对金黄色葡萄球菌的最小抑菌浓度为6.25%。     

In-vitro antioxidant activities of an ethanolic extract of the oyster mushroom,Pleurotus ostreatus

The antioxidant potential of an ethanolic extract of the oyster mushroom, Pleurotus ostreatus, was investigated. The extract exhibited the most potent radical-scavenging activity at a maximum concentration of 10 mg/ml, and the scavenging effects were 56.20% and 60.02% on hydroxyl and superoxide radicals, respectively. The IC₅₀ values of the extract were found to be 8 mg/ml for hydroxyl and superoxide radicals. Ascorbic acid used as a standard was highly effective in inhibiting hydroxyl and superoxide radicals, showing IC₅₀ values of 6 mg/ml and 4 mg/ml respectively. At a maximum concentration of 10 mg/ml, the extract effected 56.12% inhibition of lipid peroxidation and 60.68% chelation of ferrous ions; also, at a maximum concentration 10 mg/ml, the extract manifested significant (p < 0.05) reducing power (1.367) which exceeded even that of butylated hydroxyl toluene (1.192). Increasing concentrations of the extract were found to cause progressively decreasing intensity of fluorescence 2, 3-diazabicyclo [2, 2, 2] oct-2-ene (DBO). In addition, the known antioxidants were identified as components of the extract. The data generated by this study strongly suggest that an ethanolic extract of the oyster mushroom, P. ostreatus, has potent antioxidant activity.Industrial relevanceThe present study suggests that an ethanolic extract of the mushroom, Pleurotus ostreatus, could serve as an easily accessible item of food rich in natural antioxidants, as a possible food supplement or even as a pharmaceutical agent. Hence this study is considerable relevant to the food and pharmaceutical industries.     

Egyptian chia seeds (Salvia hispanica L.) during germination: Upgrading of phenolic profile,antioxidant, antibacterial properties and relevant enzymes activities

Food Science and Biotechnology - Little studies on chia sprouts were not deeply address the polyphenols profiles and their functional properties during long period of germination. This study aims...     

Influence of roasting on chemical profile,antioxidant and antibacterial activities of dried chili

Food Science and Biotechnology - Roasted dried chili, used to improve texture and taste, is important for various cuisines. The effect of roasting at 90&nbsp;°C for 25&nbsp;min on the...     

柠檬果皮精油的化学组成、抗氧化及抑菌活性研究

采用GC-MS法分析经水蒸气蒸馏法所提柠檬果皮精油的化学组分,并对其抗氧化与抑菌活性进行了研究。实验结果表明:鉴定出23种挥发性成分,占精油总量的94.57%,主要为dl-柠檬烯(42.93%)、γ-萜品烯(8.41%)、α-松油醇(6.39%)和E-柠檬醛(6.09%)等;柠檬精油对OH自由基有较好的清除效果,清除率可达95.14%;而对DPPH自由基的清除率在实验条件下最高为34.81%,远低于同浓度的PG和TBHQ。200mg/kg添加量的柠檬精油可延缓猪油和花生油的贮藏期,但略差于同浓度TBHQ和VE的抗氧化效果。抑菌活性实验结果表明柠檬精油对6种供试菌都有一定的抑菌作用,其中对大肠杆菌的抑菌效果最好,其最低抑菌浓度(MIC)为0.1μL/m L。     

Evaluation of antioxidant,antibacterial and anti-tyrosinase activities of four Macaranga species

The methanolic fresh leaf extracts of Macaranga gigantea, Macaranga pruinosa, Macaranga tanarius and Macaranga triloba were screened for their antioxidant properties (AOP), tyrosinase inhibition and antibacterial activities. Total phenolic content (TPC), 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging, ferric-ion reducing power (FRAP), ferrous-ion chelating (FIC) and lipid peroxidation inhibition (LPI) activities were used to evaluate the AOP. Modified 3,4-dihydroxy-L-phenylalanine (L-DOPA) method was used to determine tyrosinase inhibition activity, whereas antibacterial activity was determined using the disc-diffusion technique. TPC screening of the same species from different collection sites showed no significant difference between sites. M.triloba showed the highest ascorbic acid equivalent antioxidant activity (AEAC), FRAP and LPI values. M. tanarius, which showed the lowest TPC, AEAC, FRAP and LPI activities, exhibited the best FIC activity. M. pruinosa showed the best tyrosinase inhibition activity, whereas M. triloba showed the best antibacterial activity against Gram-positive bacteria species, with minimal inhibition dosage (MID) values as low as 10 μg/disc.     

草果精油的化学组成、抗氧化及抑菌活性研究

以正己烷为溶剂提取草果精油,利用气相-质谱联用技术（GC-MS）分析其化学成分,同时研究了草果精油的抗氧化和抑菌活性。结果表明,草果精油成分比较复杂,其中有23种化合物被鉴定,主要成分为香叶醇（29.42%）、橙花叔醇（9.87%）、十八碳烯酸（8.62%）等。草果精油对DPPH和ABTS自由基均显示出了较好的清除效果,EC50值分别为3.84、3.20mg/mL;不同浓度的草果精油对5种测试菌都有一定的抑菌作用,其中对大肠杆菌的抑菌效果最好,其最低抑菌浓度（MIC）为2.0mg/mL。      

新疆凤仙花色素抑菌及抗氧化活性研究

以凤仙花为植物材料,采用滤纸片法以四种常见致病菌(金黄色葡萄球菌、大肠杆菌、枯草芽孢杆菌和变形杆菌)为供试菌,测定凤仙花色素的体外抑菌作用;以还原力、清除DPPH自由基、羟基自由基的能力测定色素的抗氧化性能。结果表明凤仙花色素对金黄色葡萄球菌、大肠杆菌、枯草芽孢杆菌和变形杆菌的最低抑菌浓度(MIC)分别为1.563%、3.125%、3.125%、1.563%,其抑菌活性随着浓度的增大而逐渐增强;凤仙花色素具有较好的还原力、清除DPPH自由基和羟基自由基能力。     

迷迭香叶对葵花籽抗氧化性的影响研究

通过在煮制葵花籽过程中加入迷迭香叶,采用Schaal烘箱法研究迷迭香叶添加量、煮制时间、烘烤时间对葵花籽酸价、过氧化值和感官评分的影响。并根据单因素试验结果,以过氧化值为指标进行正交试验得出在添加25%迷迭香叶、煮制120 min、烘烤100 min的工艺条件下,葵花籽产品抗氧化效果和感官品质最好。     

蒌叶挥发油的提取及抗氧化和抑菌活性研究

采用水蒸气提取法对蒌叶挥发油进行提取,在单因素实验的基础上,以正交实验筛选最佳的提取工艺条件;同时考察蒌叶挥发油抗氧化和抑菌活性。结果表明,蒌叶挥发油提取的最佳工艺条件为:料液比m_干蒌叶粉∶V_水=50∶1000（g/m L）,超声时间为30 min,超声温度70℃,超声功率192 W,加热回流提取4 h,蒌叶挥发油的得率为2.96%。蒌叶挥发油清除DPPH·和·OH的IC₅₀分别为33.19、71.11μg/m L;挥发油对金黄色葡萄球菌、枯草杆菌、大肠杆菌、蜡状芽孢杆菌、四联球菌、藤黄八叠球菌、白色葡萄球菌、黑曲霉、毛霉、青霉均有明显的抗菌活性,其MIC分别为0.625、1.25、0.625、0.625、0.625、2.50、1.25、0.313、0.625、0.313 mg/m L,故蒌叶挥发油具有较强的抗氧化和抑菌活性。      

Comparisons of physicochemical properties and antioxidant activities among pumpkin (Cucurbita moschata L.) flour and isolated starches from fresh pumpkin or flour

Physicochemical properties (pasting and thermal properties, swelling power, water solubility and antioxidant activities) and chemical composition of pumpkin flour (PF) and starches, isolated from fresh pumpkin (SFF) or flour (SFP) were compared. SFP and SFF had similar proximate composition and amylose content. Drying process during PF preparation modified starch properties. PF exhibited greater antioxidant activities (DPPH, ABTS and FRAP), but had lower β‐carotene than fresh pumpkin. SFF and SFP had higher amylose content than PF, and exhibited a B‐type X‐ray diffraction pattern with spherical and dome‐like starch granules. Peak viscosity of SFP was relatively higher than that of SFF, probably due to lower swelling power and water solubility, which indicated increased granular rigidity in the SFP starch structure. Compared with SFF and SFP, PF had significantly higher onset (T_o), peak (T_p) and conclusion (T_c) temperatures due to a lower starch content and relatively higher fibre content, which resulted in lower gelatinisation enthalpy (ΔH).     

香橼精油体外抗氧化及其抑菌活性研究

为了研究香橼精油的抗氧化性及对细菌、酵母和霉菌的抑菌活性,本文采用体外抗氧化法和琼脂平板扩散法,研究香橼精油总还原力,清除DPPH自由基、·OH自由基和H2O2能力,以及对大肠杆菌、金黄色葡萄球菌、枯草芽孢杆菌、酿酒酵母、黑曲霉的抑制作用。结果表明:香橼精油的抗氧化能力与质量浓度呈正相关,对DPPH自由基、·OH自由基(IC50值为0.32 mg/m L)和H2O2(IC50值为148μg/m L)均有一定的清除能力。香橼精油对霉菌的抑制作用明显强于酵母与细菌,其中对黑曲霉的抑制效果最显著(25.39±1.12)mm,对金黄色葡萄球菌抑制最弱(14.04±1.35)mm。最小抑菌浓度在0.31~1.25 mg/m L,且在p H5~7范围内、温度80、115、121℃及一定时间紫外线照射(20、40 min)影响下,对大肠杆菌和酿酒酵母仍保持较强的抑制作用。      

Contents of phenolics and flavonoids and antioxidant activities in skin, pulp, and seeds of miracle fruit

Miracle Fruit (Synsepalum dulificum) has been studied because of its unique taste modifying properties. This study investigated contents of phenolics, flavonoids, and antioxidant activities in skin, pulp, and seeds of Miracle Fruit. The free phenolic content in skin was almost 3 times of that in pulp and 4 times of that in seeds. Skin contributed 43.96% of free phenolic compounds with 15.91% of freeze-dried solids due to its high phenolic content. As the trend observed for phenolic content, the free flavonoid content in the skin was tremendously higher than that in the seed and pulp. The skin contributed about 52% of total flavonoid with 15.91% of dried solids. On other hand, the differences in the bound phenolic contents were not so distinct among the 3 components. The free antioxidant activities in skin and pulp were comparable, and were significantly higher than that in seeds. Although the antioxidant activities in seeds was considerably lower than that in skin, 49.45% free antioxidant activity, 76.41% bound antioxidant activity, and 58.56% of total antioxidant activity were contributed by seeds due to about 66% of solid of total solids. In general, the results of antioxidant activities using sequential methods were higher than that using direct method. This study suggests that Miracle Fruit is a good source not only for flavor and color, and also antioxidant activity for functional food applications.     

桦菌芝多糖抗氧化性及抑菌活性研究

以桦菌芝为原料,采用水提取乙醇沉淀法提取桦菌芝多糖,分析其清除DPPH自由基和ABTS自由基能力,并用滤纸片法测定不同浓度桦菌芝多糖对大肠杆菌、金黄色葡萄球菌、枯草杆菌和四联球菌的抑菌活性及最低抑菌浓度(MIC)。结果表明,桦菌芝多糖对DPPH自由基和ABTS自由基均具有消除作用,当浓度为1.0mg/mL时,桦菌芝多糖对DPPH自由基和ABTS自由基的清除能力均超过BHT对照品,但较弱于VC对照品;不同浓度桦菌芝多糖的抗氧化活性具有显著性差异。桦菌芝多糖对4种受试菌均具有抑制作用且存在显著性差异,其中对大肠杆菌的抑制活性最强。大肠杆菌、金黄葡萄球菌、枯草杆菌和四联球菌的最小抑菌浓度分别为1.25,1.25,2.50,5.00mg/mL。综上,桦菌芝多糖具有较好的抗氧化及抑菌活性,且抗氧化及抑菌活性随多糖浓度的增大而逐渐加强。     

沙枣黄酮提取工艺、抗氧化及抑菌活性研究

利用单因素和正交实验研究了沙枣黄酮的提取工艺,采用DPPH自由基清除法、Rancimat实验研究沙枣黄酮的抗氧化性能,用滤纸片法检测其抑菌活性。结果显示,沙枣黄酮最佳提取工艺为:料液比1∶18、超声时间10min,乙醇浓度60%,超声功率320W,在此条件下沙枣黄酮得率达5.28%;抗氧化实验表明,沙枣黄酮有较好的抗氧化活性,且在同浓度下,其抗氧化活性强于VC;抑菌实验结果显示,沙枣黄酮对六种供试菌种均有抑制效果。对大肠杆菌、金黄色葡萄球菌的最小抑菌浓度为1.0g/L;对枯草芽孢杆菌、青霉、毛霉、黑曲霉的最小抑菌浓度为1.5g/L。      

香蕉皮单宁的提取及其提取物的抑菌抗氧化活性

以香蕉皮为原料,采用微波提取法,以单宁提取率为评价指标,在单因素试验基础上,通过响应面法优化了香蕉皮单宁提取工艺;滤纸片法测定了单宁对细菌、霉菌和酵母菌的抑菌性能;通过对O-2·和·OH的清除能力,确定了香蕉皮单宁的抗氧化能力。结果表明:香蕉皮单宁微波提取的最优工艺条件为,乙醇体积分数75%、提取时间为80 s、微波功率375 W、料液比1∶30(g∶m L),在此条件下单宁的提取率为87.04%;抑菌试验结果显示,香蕉皮单宁对大肠杆菌、金黄色葡萄球菌、根霉、青霉及酵母菌都有一定的抑菌效果,对大肠杆菌的最低抑菌浓度为0.78 mg/m L,金黄色葡萄球菌和酵母菌为6.25 mg/m L,霉菌为1.56 mg/m L;香蕉皮单宁对超氧阴离子自由基和羟自由基具有较好的清除能力,并在低浓度时(<1.0 mg/m L)抗氧化性要高于Vc,在浓度为1.8mg/m L时,香蕉皮单宁对超氧阴离子和羟自由基的清除率可达(66.04±3.926)%和(73.14±4.128)%。