Lycopene content and antioxidant activity of fresh and processed tomatoes and in vitro bioavailability of lycopene

BACKGROUND: Lycopene, a phytochemical, has attracted a great deal of interest over the past few years. This has triggered research on the biological properties of lycopene and on the numerous factors that control these properties. Therefore, the aim of the study was to investigate lycopene content and antioxidant activity of fresh, sun‐dried and canned tomatoes. In addition, in vitro bioavailability of lycopene was determined. RESULTS: Lycopene contents of fresh, sun‐dried and canned tomatoes were found to be 1.74, 5.51 and 3.55 mg 100 g^?1, respectively, on a fresh wet basis. The highest lycopene bioavailability was obtained for sun‐dried tomatoes (58.05%) and this was followed by fresh (28.67%) and canned tomatoes (21.83%). Fresh tomatoes showed the highest antioxidant activity against ABTS radical oxidation. This was followed by sun‐dried tomatoes and canned tomatoes. The inhibition effect of intestinal dialysates of the samples on ABTS radical oxidation was between 51.34% and 92.96%. CONCLUSION: Maintenance antioxidant activity and existence of lycopene following an in vitro digestion process were the main findings, which might contribute forthcoming studies in this scientific field. Copyright © 2007 Society of Chemical Industry     

Effect of increasing manganese concentration in nutrient solution on the antioxidant activity,vitamin C,lycopene and polyphenol contents of tomato fruit

ABSTRACT

This study evaluated the effect of increasing manganese (Mn) nutrition on the content of antioxidative compounds such as vitamin C, lycopene and polyphenols, and the antioxidant activity of tomato (Lycopersicon esculentum Mill., cvs ‘Alboney F1’ and ‘Emotion F₁’) fruit. Plants were grown in rockwool using a nutrient solution with the following content of Mn (mg dm^–3): 0.0, 0.3, 0.6, 1.2, 2.4, 4.8, 9.6 and 19.2. The level of vitamin C and lycopene decreased with the increasing Mn nutrition. Since the colour of fruits was correlated with the change in carotenoid content, the decrease in lycopene content promoted the reduction of redness and increase of yellowness of fruits. However, total polyphenol content and antioxidant activity significantly increased when plant were exposed to toxic levels of Mn. Observed changes could be the result of the oxidative stress induced by high concentrations of Mn. Polyphenolic compounds play a crucial role in the plant’s response to Mn stress and affect predominantly the total antioxidant properties of fruits, which could be used as a source of phenolics. Moreover, total phenolic content measurement, as an easy and inexpensive method, could be used as an indicator of Mn-induced stress in fruits of tomato.     

不同品种甘薯汁抗氧化活性的研究

研究了9个品种甘薯汁的酚类物质及其抗氧化活性,旨在为甘薯汁的开发利用提供参考依据。分别采用Folin-酚法、亚硝酸钠法、pH示差法测定了甘薯汁的总酚、总黄酮、总花色苷含量。结果表明,甘薯汁中含有丰富的酚类物质,不同品种甘薯汁的总酚、总黄酮和总花色苷含量存在差异。通过4个体外抗氧化体系（FRAP法、DPPH自由基法、ABTS+自由基法、OH自由基法）评价了甘薯汁的抗氧化能力。结果显示,不同品种甘薯汁所呈现的抗氧化能力不同,酚类物质含量较高的甘薯汁其抗氧化能力较强。从抗氧化能力方面考虑,杭引薯1号、杭引薯3号、浙紫薯1、13号这4个抗氧化能力较强的品种较适合用于果汁加工以及功能性饮品的开发。      

热水提取胡柚果皮中矿物质、酚类物质及其水提液抗氧化性研究

目的:研究热水提取胡柚果皮矿物质、酚类物质的效率及其提取液的抗氧化能力。方法:原子吸收光谱法测定七种主要矿物质;高效液相法测定胡柚皮中七种主要酚酸和六种黄酮;福林酚法、FRAP、DPPH法测定提取液的抗氧化能力。结果:热水提取可以有效提取胡柚果皮中的酚类物质与部分矿物质。抗氧化能力分析表明,热水提取液具有与甲醇提取液相近的抗氧化能力。结论:传统中药煎煮条件(100℃,30min)可以有效提取柑橘类中药的酚类物质与部分矿物质。      

不同酿酒高粱酚类物质含量测定及抗氧化活性比较

以6种酿酒高粱籽粒为研究对象,分别比较其游离态与结合态总酚、总黄酮、酚酸物质种类及含量,并对其抗氧化活性进行 分析。 结果表明,不同酿酒高粱品种游离态总酚、总黄酮;结合态总酚、总黄酮含量分别在135.47～274.38 mgGAE/100 g、94.60～ 148.31 mg/100 g;618.27～1 383.17 mgGAE/100 g、123.06～434.84 mg/100 g。 酿酒高粱籽粒中游离态酚酸以阿魏酸、丁香酸与没食 子酸为主,平均含量分别为611.19 μg/g、380.66 μg/g、359.34 μg/g;结合态酚酸以阿魏酸、丁香酸为主,平均含量为1 608.33 μg/g、 376.78 μg/g。 酿酒高粱籽粒中游离态与结合态总酚ABTS抗氧化能力值分别占总ABTS能力值14.6%与85.4%;酿酒高粱籽粒中游离 态与结合态总酚FRAP抗氧化能力值占总FRAP能力值14.3%与85.7%。 酿酒高粱籽粒具有丰富的酚类物质,良好的抗氧化活性,且品 种间有显著性的差异（P＜0.05）。     

黄参籽可溶性酯结合酚和糖苷结合酚的组成及其抗氧化活性

采用HPLC-MS对黄参籽可溶性酯结合酚和糖苷结合酚的组成进行了分析,并通过DPPH自由基清除活性、FRAP、TEAC、对羟基自由基介导的2-脱氧-D-核糖裂解的抑制作用以及对DNA氧化损伤的保护作用对黄参籽酚提取物的抗氧化能力进行了评价。结果显示,黄参籽可溶性酯结合酚中主要的酚类化合物为咖啡酸、木犀草素葡萄糖苷和儿茶酸葡萄糖苷,可溶性糖苷结合酚中主要的酚类化合物为儿茶酸葡萄糖苷;黄参籽可溶性酯结合酚的DPPH自由基清除活性、铁还原力和Trolox等量抗氧化活性均弱于可溶性糖苷结合酚;相反,对羟基自由基介导的2-脱氧-D-核糖裂解的抑制作用强于可溶性糖苷结合酚;测试浓度范围内,黄参籽酚提取物对DNA氧化损伤具有不同程度的保护作用,且可溶性酯结合酚提取物酚含量与保护作用之间存在显著（p<0.05）的正相关。      

Phenolic content and antioxidant activity of four date palm (Phoenix dactylifera L.) fruit varieties grown in Tunisia

Fruits of date palm ( Phoenix dactylifera L.) are consumed throughout the world and are a vital component of the diet in most Arabian countries. This study has been carried out to evaluate the total phenolic content and the antioxidant activity of four date palm fruit varieties grown in Tunisia. All measurements were made at the 'tamar' stage-the final stage of fruit ripeness. The date varieties were found to be rich in total phenolic ranging from 209.42 mg of equivalent gallic acid/100 g fresh weight in Kentichi to 447.73 mg equivalent gallic acid/100 g fresh weight in Allig. The date varieties studied were characterised by a high antioxidant activity ranging from 866.82 for the Deglet Nour to 1148.11 μmol Equivalent Trolox/100 g fresh weight for Khouet Kenta by the ABTS method. In fact, the DPPH method revealed that Allig having the lowest antioxidant activity (0.72) followed by Deglet Nour (1.53), Kentichi (1.68) and Khouet Kenta variety (1.96). This study suggest that Tunisian date palm fruit may serve as a good source of natural antioxidants and could potentially be considered as a functional food ingredient.     

Phenolic compounds and antioxidant activity are differentially affected by drying processes in celery,coriander and parsley leaves

Convective drying (CO) is the most common technique for drying herbs, although it may diminish phenolic compounds content. Microwave drying (MW) has been suggested as an alternative, although its effects on phenolic compounds remain to be explored. The aim of this study is to compare the effects of different convective temperatures (40, 80 and 120 °C) and microwave powers (100, 500 and 1000 W) on drying time, polyphenols classes (HPLC-DAD) and antioxidant capacity in celery, coriander and parsley leaves. Microwave procedure reduced drying time (MW: 3 h–7 min; CO: 25–1.5 h) resulting more effective than CO. Increasing temperatures led to an initial decrease in total phenolic content (TPC) and antioxidant activity followed by an increase, potentially by the release of bound phenolic acids. Regarding MW, the highest polyphenol content was generally observed at 500 W, probably due to the hydroxycinnamic acid's rise. Antioxidant capacity was similar at 500 and 1000 W. There was a good agreement between TPC and antioxidant capacity. Consequently, MW seems a good alternative to reduce drying time. However, the maintenance or improvement of phenolic activity depends on the food matrix. Indeed, the best drying system and conditions to preserve phenolic compounds were variable depending on the herb type: celery (CO at 40 °C), coriander (both CO at 40 °C and MW at 500 W) and parsley (MW at 100 W).     

压榨对酿酒葡萄皮渣酚类物质提取及抗氧化活性的影响

酿酒葡萄皮渣（皮和籽）生物活性物质含量丰富,具有很高的再加工利用价值。对鲜葡萄皮渣进行压榨处理后再干燥,研究压榨对皮渣的酚类物质提取及抗氧化活性的影响。结果表明：压榨处理可以快速降低葡萄皮渣水分含量,缩短干燥时间、提高可溶性膳食纤维提取率。压榨葡萄皮总酚、原花青素的提取量均有所增加,其含量分别为19.56 mg/g和22.64 mg/g。压榨葡萄皮的抗氧化能力高于未压榨葡萄皮,其DPPH、ABTS及羟自由基清除率分别为62.90%、70.18%和41.09%,铁氰化钾还原能力及金属离子螯合能力分别为0.23%和21.33%。压榨籽和皮籽混合物的酚类物质和抗氧化活性则明显降低。抗氧化活性与总酚、原花青素存在显著的相关关系（P＜0.01）。     

Evaluation of chemical constituents and antioxidant activity of sweet cherry (Prunus avium L.) cultivars

This research was undertaken to evaluate the sugars, organic acids, phenolic compositions and antioxidant capacities of sweet cherry cultivars (Van, Noir de Guben, Larian and 0‐900 Ziraat) grown in Turkey. High‐performance liquid chromatographic methods were used to identify and quantify four sugars (sucrose, glucose, fructose and sorbitol) and four organic acids (malic, citric, shikimic, and fumaric acid). The major organic acid was found as malic acid (8.54–10.02 g kg^?1 of FW). With regard to sugars, glucose was present in the largest amounts (44.71–48.31 g kg^?1 of FW) for sweet cherry cultivars. The sum of sugars ranged from 103.87 (Larian) to 113.13 g kg^?1 of FW (0‐900 Ziraat) and that of organic acids from 12.01 (0‐900 Ziraat) to 14.17 g kg^?1 of FW (Noir de Guben). A total of eleven phenolic compounds were identified and quantified in sweet cherry cultivars, including hydroxycinnamic acids (3), anthocyanins (5), flavan‐3‐ols (2) and flavonol (1) compounds. Total phenolic contents ranged from 88.72 (Van) to 239.54 (Noir de Guben) mg/100 g of FW, while antioxidant activities ranged from 2.02 to 7.75 μm Trolox equivalents g^?1 of FW.