Digestion and bioavailability of bioactive phytochemicals

There are many scientific reports on determination of the content and biological activity of compounds found in food. However, these analyses are not sufficient to determine their effect on the human body. During digestion of food ingredients, many changes can modify their structure and this may affect their absorption and bioactivity. Many phenolic aglycones are hydrophilic and can be absorbed through biological membranes by diffusion. However, most polyphenols occur in the glycosidic form, which undoubtedly affects their absorption in the intestine. Oligopeptides are also absorbable via secondary active transport but based on the hydrogen ion gradient or with transporter PepT1. The bioavailability of phytochemicals is determined by their molecular weight or chemical structure and the food matrix. Accordingly, the aim of this work was to present the novel scientific reports related to the influence the many factors on digestibility, bioaccessibility and activity of selected bioactive compounds of plant origin.     

不同烹调方式对蔬菜植物化学物及V_C的影响

目的:研究不同家庭烹调方法对紫薯、西兰花和青辣椒中的花色苷、硫苷、辣椒素和V C的影响。方法:三种蔬菜经过微波、蒸制、焯制和油炒等烹调后,以pH示差法测定花色苷,以高效液相色谱法测定硫苷和辣椒素,以2,6-二氯靛酚滴定法测定V C。结果:保存V C效果:蒸制>微波蒸制,焯制>油炒>微波煮制;保存花色苷效果:蒸制>微波蒸制,且蒸制使花色苷增加;保存总硫苷效果:油炒>焯制>微波煮制;保存辣椒素效果:微波煮制>焯制>油炒。结论:若控制烹调时间不过长,蒸制是最适宜保存蔬菜植物化学物及维生素的烹调方法。      

Anti-inflammatory effects of phytochemicals from fruits,vegetables, and food legumes: A review

Inflammation is the first biological response of the immune system to infection, injury or irritation. Evidence suggests that the anti-inflammatory effect is mediated through the regulation of various inflammatory cytokines, such as nitric oxide, interleukins, tumor necrosis factor alpha-α, interferon gamma-γ as well as noncytokine mediator, prostaglandin E₂. Fruits, vegetables, and food legumes contain high levels of phytochemicals that show anti-inflammatory effect, but their mechanisms of actions have not been completely identified. The aim of this paper was to summarize the recent investigations and findings regarding in vitro and animal model studies on the anti-inflammatory effects of fruits, vegetables, and food legumes. Specific cytokines released for specific type of physiological event might shed some light on the specific use of each source of phytochemicals that can benefit to counter the inflammatory response. As natural modulators of proinflammatory gene expressions, phytochemical from fruits, vegetables, and food legumes could be incorporated into novel bioactive anti-inflammatory formulations of various nutraceuticals and pharmaceuticals. Finally, these phytochemicals are discussed as the natural promotion strategy for the improvement of human health status. The phenolics and triterpenoids in fruits and vegetables showed higher anti-inflammatory activity than other compounds. In food legumes, lectins and peptides had anti-inflammatory activity in most cases. However, there are lack of human study data on the anti-inflammatory activity of phytochemicals from fruits, vegetables, and food legumes.     

Total antioxidant activity in 35 Ugandan fruits and vegetables

The objective of this study was to analyse antioxidant activity (AA) in fruits and vegetables from Uganda and to investigate whether AA in traditional food is sufficiently high to prevent oxidative stress and thus combat disease. We used the FRAP (ferric reducing ability of plasma) procedure. The results showed great variation in AA, ranging from 72.3 ± 13.5 (Syzygium cuminii seed) to 0.09 ± 0.05 (Cucurbita maxima fruit) mmol/100 g fresh weight (FW). We estimated serving sizes and determined the total antioxidant capacity (TDAC) per day of three traditional Ugandan diets. The dietary plants with highest AA per serving size were pomegranate (Punica granatum), Canarium schweinfurthii, guava (Psidium guajava), mango (Mangifera indica) and tree tomato (Cyphomandra betacea) with values ranging from 8.91 to 3.00 mmol/serving. Of the traditional diets, the central/eastern (C/E) and the western (W) diets had almost the same AA (9.31–9.78 and 9.75 mmol/day), while the northern (N) diet had an AA of 7.50–8.02 mmol/day.     

Antioxidant and micronutrient quality of fruit and root vegetables from the Indian subcontinent and their comparative performance with green leafy vegetables and fruits

Commonly consumed, fruit vegetables (12) and root vegetables (15) in the Indian subcontinent in cooked and uncooked states assessed for inhibition of thiobarbituric acid reactive substances (TBARS), superoxide radical scavenging activity (SOSA), ferrous iron chelating ability (FICA) and nine micronutrients, exhibited large variability in these parameters. SOSA and FICA were significantly associated (r = 0.803, p < 0.001) with each other. Inhibition of TBARS showed marginal correlation with both FICA (0.38, p < 0.05) and SOSA (0.29, p > 0.05). There were significant cooking losses for each of the assessed antioxidant capacity parameters (p < 0.05). Contents of ascorbic acid, per 100 g of cooked fruit and root vegetables were high (61.9 and 31.3% of recommended daily allowance (RDA)). However, both the food classes were not good sources of beta‐carotene, riboflavin and thiamine (1.66–5.26% RDA). When compared with our data on 30 cooked green leafy vegetables (GLV) and 30 fresh fruits, root vegetables showed significantly (p < 0.05) higher levels of zinc and selenium. Cooked root vegetables were comparable with cooked GLVs but uncooked GLVs gave the highest values for inhibition of TBARS (0.73 ± 0.21 mM vitamin E/100g). SOSA (40.7 ± 15.6 mM tannic acid/100g) and FICA (41.6 ± 14.9 mM EDTA/100g) were highest for uncooked fruit vegetables. Root vegetables had the highest levels of polyphenols (251.4 ± 107.3 mg/100g). For the present study, popular fruits and vegetables such as guava, spinach, bitter gourd (Momordica charantia), yam, ginger and beetroot, and also less common ones like bael (Aegle marmelos), kokum (Garcinia indica) and mango‐ginger (Curcuma ameda), showed potential in vitro to combat oxidative stress. Copyright © 2005 Society of Chemical Industry     

Strawberry-tree,blackthorn and rose fruits: Detailed characterisation in nutrients and phytochemicals with antioxidant properties

The chemical composition and biological properties of three wild fruits (strawberry-tree berries, sloes and dog rose hips) were evaluated, in order to valorise these products as sources of nutrients and nutraceuticals. The analysed fruits contain very useful bioactive phytochemicals such as phenolics, vitamins (ascorbic acid and tocopherols) and carotenoids. All the samples proved to have antioxidant activity (measured by four different in vitro assays) being more significant for rose fruits (EC₅₀ values lower than 90 μg/ml). The combination of bioactive compounds and rich nutritional composition (high contents in carbohydrates, low contents in fat with the precious contribution of polyunsaturated fatty acids, precursors of omega-3 and omega-6 fatty acids) of the studied wild fruits make them a very special food. .     

The cellular antioxidant activity in red blood cells (CAA-RBC): A new approach to bioavailability and synergy of phytochemicals and botanical extracts

In the present work, human red blood cells (RBC) were used to determine cellular antioxidant activity (CAA-RBC) of pure phytochemicals and botanical extracts, with the aim to predict their bioavailability.     

Dried fruits: phytochemicals and their fate during in vitro digestion

Mediterranean dried fruits that are cultivated and produced in Greece; that is, Corinthian currants, figs, prunes, cherries, apricots and peaches were evaluated in terms of total polar phenols, individual simple phenolics, anthocyanins and antioxidant capacity in vitro. The potential release of dried fruit polar phenols among the different fractions of an in vitro digestion model was also determined. Total polar phenol, flavanol, flavone/flavonol content and antioxidant capacity was in the range 86–551 mg GAE/100g, 0.2–57 mg CE/100g, 9–71 mg RE/100g and 6–47 mg AAE/100g, respectively. A 12–82% release of total phenolics was observed post-mastication, which further increased post-gastric digestion. The same trend was also followed in the case of total flavanols and flavones/flavonols. Total polar phenols and flavones/flavonols were found to enter the simulated epithelial cell wall. Simple polar phenolics and anthocyanins were identified and quantified in all dried fruit extracts and in some of the digestion fractions.     

Nanoemulsions: formation,stability and an account of dietary polyphenol encapsulation

To enhance nutraceutical performance, vehicle systems are required to promote the usage of food supplements, which have shown an increasingly growing demand. These food supplements such as dietary polyphenols are nutritious constituents but with varying solubility, sensitivity to oxygen, light, temperature, or adverse effects encountered during processing, making their incorporation difficult in foods. Additionally, these are bound to the food matrix so tightly, that they are not available to be taken up in the digestive system causing less absorption in the gastrointestinal tract. To counter these challenges, polyphenols are encapsulated in nanoemulsion-based delivery systems which forms an effective approach to enhance and improve their bioavailability. Because of their small droplet size, these exhibit various benefits over conventional emulsions making them suitable for usage in the food industry. This review summarises the basic characteristics of nanoemulsions and their application to enhance the stability of polyphenols.     

In vitro bioavailability of calcium and iron from selected green leafy vegetables

The objective of the present investigation was to analyze the relative influence of oxalic acid, phytic acid, tannin and dietary fiber on in vitro availability of iron and calcium from green leafy vegetables (GLV). Thirteen GLV were selected and analyzed for iron, calcium, oxalic acid, phytic acid, tannin and dietary fiber contents using standard methods. The bioavailability of calcium and iron in the GLV was estimated by equilibrium dialysis. Oxalic acid content was less than 1 g kg^?1 in four greens and ranged between 1.22 to 11.98 g kg^?1 in the remaining. Dietary fiber ranged from 19.5 to 113.7 g kg^?1. Tannin content ranged between 0.6138 and 2.1159 g kg^?1 with the exception of two GLV that had 0.1332 and 14.8619 g kg^?1. Four GLV were found to have approximately 40% bioavailable iron, while the others were in the range of 6–30%. In vitro available calcium was less than or equal to 25% in eight GLV and between 34% and 52% in five GLV. Multiple regression analysis revealed that these factors together accounted for 53% (r² = 0.53) and 45% (r² = 0.45) inhibition of iron and calcium absorption, respectively. These findings infer that calcium and iron availability is influenced by the constituents present in the GLV. Copyright © 2006 Society of Chemical Industry     

Effects of light quality on the accumulation of phytochemicals in vegetables produced in controlled environments: a review

Phytochemicals in vegetables are important for human health, and their biosynthesis, metabolism and accumulation are affected by environmental factors. Light condition (light quality, light intensity and photoperiod) is one of the most important environmental variables in regulating vegetable growth, development and phytochemical accumulation, particularly for vegetables produced in controlled environments. With the development of light‐emitting diode (LED) technology, the regulation of light environments has become increasingly feasible for the provision of ideal light quality, intensity and photoperiod for protected facilities. In this review, the effects of light quality regulation on phytochemical accumulation in vegetables produced in controlled environments are identified, highlighting the research progress and advantages of LED technology as a light environment regulation tool for modifying phytochemical accumulation in vegetables. © 2014 Society of Chemical Industry     

短波紫外线法处理对鲜切果蔬抗氧化系统影响的研究进展

短波紫外线（ultraviolet-C,UV-C）作为一种绿色无污染的非热处理技术,近年来在鲜切果蔬保鲜中的研究越来越多,主要研究热点在UV-C对鲜切果蔬抗氧化系统的影响。鲜切加工、贮藏、运输、销售等过程会引发一系列的不利于果蔬贮藏的生理生化和品质特性改变,导致其食用品质和商用价值下降,带来重大的经济损失。鲜切果蔬抗氧化系统主要由酚类物质、黄酮类物质、维生素类等物质组成非酶抗氧化系统,超氧化物歧化酶、过氧化氢酶、过氧化物酶、抗坏血酸氧化酶等组成酶促抗氧化系统,共同发挥对鲜切果蔬贮藏品质的调节作用。本文介绍了UV-C和鲜切果蔬的特点,综述了UV-C对不同鲜切果蔬中非酶抗氧化系统和酶促抗氧化系统的影响,并对未来研究前景进行了展望,旨在为探究果蔬鲜切伤害条件下,UV-C处理对果蔬抗氧化系统响应机制的影响和鲜切果蔬贮藏品质特性影响的机理,并为UV-C在鲜切果蔬上的进一步推广、应用提供参考。     

Effect of two cooking procedures on phytochemical compounds,total antioxidant capacity and colour of selected frozen vegetables

The effect of boiling and steaming on content of phytochemicals (carotenoids, chlorophylls, polyphenols and ascorbic acid) all evaluated by HPLC, total antioxidant capacity (TAC) measured by means of TEAC and FRAP assays and colour (L^∗, a^∗, b^∗, C, H°) of three frozen vegetables (carrot, cauliflower and spinach) was evaluated. Steaming increased the content of polyphenols in all vegetables and limited the depletion of carotenoids in spinach. Accordingly, TAC remained unvaried or increased both for steamed carrot and spinach. Boiling had a more marked effect on nutritional pattern of frozen vegetables in comparison with steaming, leading to a general loss of phytochemical compounds and TAC for all vegetables. Ascorbic acid was detected only in cauliflower and decreased after both treatments. Colour of frozen vegetables was only slightly influenced by cooking, probably due to blanching pre-treatment. Slight decrements of redness (a^∗) for carrot in relation with loss of carotenoids and greenness (−a^∗) for steamed spinach, due to a significant loss of total chlorophylls, were observed.     

The multiple nutrition properties of some exotic fruits: Biological activity and active metabolites

The main objective of this review was to describe the physicochemical and nutritional characteristics of twenty selected exotic fruits and the influence of their physiologically active compounds on human health, through scientifically proven information. The review presents the biologically active metabolites derived from exotic fruits (polyphenols, flavonoids, flavanols, tannins, ascorbic acid, anthocyanins, volatile compounds, minerals, and organic acids) and various analytical methods for their detection (elemental analysis, electrophoretic separation by SDS-polyacrylamide gel electrophoresis, and fast protein liquid and ion-exchange chromatography; GC-MS, HPLC/diode array detection (DAD), circular dichroism (CD), differential scanning calorimetry (DSC), Fourier transform infrared (FT-IR), ultraviolet spectroscopy, two- and three-dimensional fluorimetry (2D-FL) and (3D-FL), and antioxidant radical scavenging assays (DPPH, FRAP, CUPRAC, ABTS, and ORAC). The correlation between the polyphenols and other bioactive compounds, and their antioxidant activities was reported for different fruit extracts. During the last two decades our international scientific group investigated in vitro the physicochemical and nutritional characteristics of avocado, dragon fruit, durian, kiwifruit, mango, mangosteen, persimmon and snake fruit, and in vivo their influence on laboratory animals and humans. Supplementation of diets with exotic fruits positively affects plasma lipid profile, antioxidant activity and histological examination of aorta in rats fed cholesterol-containing diets.The interaction between drugs and serum albumin plays an important role in the distribution and metabolism of drugs. The properties of polyphenol methanol extracts of exotic fruits showed the ability to quench serum albumin by forming the complexes similar with the ones between proteins and pure flavonoids. Our experimental data and a wide range of other investigations are included in this review. In conclusion, it is nessasary to promote a consumption of exotic fruits (a rich source of natural antioxidants) as a supplement to everyday human diet.     

原花青素与果胶相互作用对果蔬加工特性的影响

原花青素、果胶作为果蔬中常见的功能成分,因具有良好的功能特性被广泛应用于食品工业。该文综述了原花青素与果胶之间共价、非共价相互作用机制,分析了原花青素和果胶结构、环境因素(温度、pH等)对相互作用的影响,以及相互作用对果蔬感官特性、功能特性、生物利用度的影响,并对二者相互作用未来研究方向进行展望。研究结果表明,二者相互作用对食品涩味,果汁果酒体系稳定性,复合物抗氧化活性,原花青素生物利用度等方面均存在一定的正向影响,这为果汁果酒澄清、稳定和食品营养添加剂开发等方面提供一定的参考。     

果蔬中酚类成分及其与蛋白质相互作用的研究进展

水果和蔬菜富含多酚和蛋白质等功能活性成分,是膳食的重要组成部分。多酚具有多种功效,在食品中的应用是现在研究的热点。蛋白质是食品体系中重要的营养素,其功能特性直接影响食品品质。本文主要综述了果蔬中的酚类成分及其与蛋白质的相互作用,包括多酚蛋白质相互作用的机制、相互作用对蛋白质功能特性和对多酚功能活性的影响、研究多酚蛋白质相互作用的方法等,以期为果蔬多酚在食品中的应用以及蛋白质改善功能特性提供参考和思路。      

Phytonutrients affecting hydrophilic and lipophilic antioxidant activities in fruits,vegetables and legumes

The antioxidant activities of fruits (n = 21), vegetables (n = 67) and legumes (n = 7) commonly consumed in Korea were determined by both the lipophilic antioxidant performance assay (LAP) and the hydrophilic oxygen radical absorbance capacity assay (ORAC). The LAP assay used the lipophilic radical initiator MeO‐AMVN [2,2′‐azobis(4‐methoxy‐2,4‐dimethylvaleronitrile)] and the lipophilic probe BODIPY 581/591 [4,4‐difluoro‐5‐(4‐phenyl‐1,3‐butadienyl)‐4‐bora‐3a, 4a‐diaza‐s‐indacene‐3‐undecanoic acid]. The ORAC assay used the hydrophilic radical initiator AAPH [2,2′‐azobis(2‐amidinopropane) dihydrochloride] and the hydrophilic probe fluorescein. In addition, the lipid‐soluble phytonutrients, carotenoids and tocopherols were determined by a reverse‐phase HPLC system using a C30 column with a UV detector. The water‐soluble phytonutrient, ascorbic acid, was analyzed using an HPLC system with an electrochemical detector. Total phenols were determined by UV spectrophotometry. Tocopherols (r = 0.774, p < 0.0001) and carotenoids (r = 0.569, p < 0.0001) were significantly correlated with LAP in total samples (n = 95). ORAC was significantly correlated with total phenols (r = 0.893, p < 0.0001), but not with ascorbic acid (r = 0.009, p = 0.929) in total samples (n = 95). These data indicate that carotenoids and tocopherols and total phenols are the major contributors to the lipophilic and hydrophilic antioxidant capacities, respectively. Therefore, the contribution of both the hydrophilic and lipophilic components of fruits and vegetables should be considered when determining the actual ‘total’ antioxidant activity of fruits and vegetables. Copyright © 2007 Society of Chemical Industry     

采前和采后贮藏对果蔬中抗氧化物质影响的研究进展

自由基是人体正常代谢的产物, 但自由基过量会引发一系列的疾病。越来越多的研究表明, 食用果蔬有助于预防由过量自由基引起的多种疾病, 这主要源于果蔬中富含的各种抗氧化物质。本文主要从采前和采后贮藏保鲜两个阶段对果蔬组织中的抗氧化物质(重点包括总酚、总黄酮、抗坏血酸、花青素)以及抗氧化能力的影响因素及其影响效果进行了较为全面的综述。