类胡萝卜素的生物利用率

论述了作为VA前体的类胡萝卜素在体内的吸收代谢过程、类胡萝卜素生物利用率的定义、影响生物利用率的因素以及测定新方法。     

真空微波干燥中微波强度对胡萝卜和南瓜中类胡萝卜素生物利用率的影响

为明确真空微波干燥过程中,微波强度对胡萝卜和南瓜中类胡萝卜素生物利用率的影响,本文采用静态体外模拟消化模型评价类胡萝卜素生物利用率的变化,采用透射电镜（TEM）和光学显微镜观察细胞壁微观结构的变化。结果表明,真空微波干燥后的胡萝卜和南瓜的细胞壁断裂,有色体结构破坏严重。经体外模拟消化,胡萝卜和南瓜消化液细胞结构破坏明显,细胞壁破裂严重,类胡萝卜素从细胞内部释放到消化液中的含量明显高于鲜样,且类胡萝卜素生物利用率随微波强度的增加呈现先升高后降低的趋势。当微波强度为9 W/g时,胡萝卜和南瓜中类胡萝卜素的生物利用率较高,其β-胡萝卜素生物利用率相比于鲜样分别显著提高了12.02、24.2倍（P<0.05）。由此可知,选择合适的微波强度有助于提高蔬菜中类胡萝卜素生物利用率。     

体外消化过程中影响类胡萝卜素生物利用率的因素

类胡萝卜素是存在于很多水果蔬菜中的天然色素,具有VA原活性、抗氧化等特性,在维持人体健康方面发挥重要作用。从食物基质中释放的脂溶性类胡萝卜素包裹在脂滴中被运送到小肠,与胆盐、脂类等形成水溶性胶束,随后被小肠上皮细胞吸收并进一步代谢。在体外消化实验中,影响类胡萝卜素生物利用率的因素很多,类胡萝卜素种类及结构、食物基质、脂类、样品加工处理方法、消化模型、细胞模型、检测方法及指标等的不同都会造成最终的生物利用率评估值的不同,另外不同因素对生物利用率的影响因类胡萝卜素种类而异,且各因素间可能存在协同效应。     

高压均质对果蔬汁品质影响研究进展

高压均质是一种新型非热加工技术,在食品工业中得到广泛的应用。果蔬中含有丰富的类胡萝卜素,类胡萝卜素具有维生素A原活性、抗氧化和提高免疫力等多种生理功能。高压均质能够破坏果蔬细胞基质,影响类胡萝卜素的生物利用率。本文重点介绍了高压均质对果蔬汁稳定性、流变特性及杀菌作用影响的研究现状,并综述了高压均质对果蔬汁类胡萝卜素生物利用率的影响,分析了该领域今后的研究趋势。     

高压均质灭菌对胡萝卜橙汁理化性质及类胡萝卜素生物利用率的影响

目的 探究高压均质灭菌(high-pressure homogenization sterilization, HH)对胡萝卜橙汁理化性质和类胡萝卜素生物利用率的影响。方法 以鲜榨和巴氏杀菌胡萝卜橙汁为对照样品,对比HH过程中橄榄油和海藻酸钠的添加对胡萝卜橙汁菌落总数、粒度、浊度、色泽、活性成分含量、类胡萝卜素稳定性和生物利用率的影响。结果 巴氏杀菌(80℃, 10 min)和HH (150 MPa, 25℃)均可使菌落总数指标达到商业无菌标准。橄榄油有利于小尺寸油滴的形成(2.89μm),可提升果蔬汁的浊度与亮度;海藻酸钠可提高油滴的静电斥力,改善体系的悬浮稳定性。橄榄油可促进HH过程中类胡萝卜素的释放,显著提升其含量至626.53 mg/L。巴氏杀菌处理对类胡萝卜素稳定性和生物利用率无显著性影响,而HH时添加橄榄油和海藻酸钠可显著改善上述指标。结论 HH对胡萝卜橙汁有较好的杀菌效果,且添加橄榄油和海藻酸钠可改善胡萝卜橙汁的理化性质,提升类胡萝卜素含量、稳定性和生物利用率。     

类胡萝卜素脂质体的特性、制备与评价的研究进展

类胡萝卜素在人体的健康方面发挥着重要作用,具有抗氧化、抗衰老、增强免疫等生物活性。但类胡萝卜素在水溶液中溶解度低、稳定性差,需借助一些稳态化技术来提高其稳定性。基于脂质体的包埋技术可增加类胡萝卜素的溶解性与稳定性,并显著提高其生物利用率,拓展其应用领域,已受到人们的广泛关注。该文对类胡萝卜素脂质体的特性、制备、评价和影响因素进行了综述,以期为类胡萝卜素脂质体的深入研究提供理论参考。     

油脂添加及加工模式对果蔬中类胡萝卜素生物接近度影响

类胡萝卜素作为一种脂溶性天然色素,广泛存在于多种水果蔬菜中,具有维生素A原活性、抗氧化、提高免疫力、降低心血管疾病和癌症的发病率等多种生物学功能与药理作用,在维持人体健康方面发挥重要作用。但是,人体自身不能合成类胡萝卜素,必须从食物中摄取。未加工果蔬中的类胡萝卜素由于其在果蔬细胞基质中被包被、亲脂性、化学不稳定性及水溶性差等原因在人体中的利用率较低。因而,促使类胡萝卜素从细胞基质中释放,提高类胡萝卜素的生物接近度的方法成为近几年研究热点。文章重点综述了油脂的添加及加工模式对果蔬中类胡萝卜素生物接近度影响,并介绍了该领域今后的发展趋势。     

烹调对深色蔬菜中类胡萝卜素的影响

深绿色和橙黄色的深色蔬菜富含β-胡萝卜素、α-胡萝卜素、番茄红素和叶黄素等类胡萝卜素物质,有着重要的健康意义。漂烫和短时间煮制处理时,类胡萝卜素的保存率较高,汽蒸和微波蒸制次之;而加油炖煮和炒制、炸制烹调时,其保存率下降较为显著,同时还存在脂溶性损失。对于富含类胡萝卜素食材,蒸、煮同时保证了生物利用率,为最佳烹调选择。     

番茄红素生物利用率的研究进展

番茄红素具有很强的抗氧化活性,能有效降低癌症、心血管病的发病率,可以作为一种功能性色素广泛应用于功能食品、药品和化妆品中。与其他类胡萝卜素相比,它具有更强的抗氧化能力,但其在正常生理功能条件下营养素进入体循环,达到作用部位的比例即生物利用率较低,且易受多种因素的影响。本文简要综述了番茄红素生物利用率的研究状况及影响因素。     

果蔬食品中类胡萝卜素生物利用度研究进展

类胡萝卜素是一类重要的微量营养物质,其有益生理功效与果蔬食品中类胡萝卜素的绝对含量相关,更取决于其生物利用度。然而,由于类胡萝卜素的特殊存在形式和疏水特性,其从食物中释放并被吸收利用的比例通常非常低。本文综述了影响果蔬食品中类胡萝卜素生物利用度的关键因素,包括类胡萝卜素的种类和存在形式、食品(微观)结构和添加油脂对生物利用度的影响,展望果蔬食品中类胡萝卜素生物利用度的研究进展,可为生产具有较高类胡萝卜素生物利用度的果蔬食品及设计相应加工工艺提供理论依据。     

改善番茄红素生物利用度的研究进展

番茄红素的生物利用度是决定其营养价值的关键因素,天然存在的番茄红素生物利用度较低。番茄红素的异构化、食品分散体系以及食品组分与番茄红素之间的相互作用对番茄红素的生物利用度有着重要影响。近年来,食品加工、赋形剂乳液和构建共消化体系等方法越来越多地应用于改善番茄红素生物利用度中,相关的研究也成为热点。本文从番茄红素的吸收机制、影响番茄红素生物利用度的因素、改善番茄红素吸收的方法和番茄红素生物利用度的评价方法等方面进行综述,并对番茄红素生物利用度研究趋势和前景进行展望。     

NUTRIENT BIOAVAILABILITY IN HUMANS AND EXPERIMENTAL ANIMALS1

Nutrient bioavailability is a highly recognized concept to which great importance is attached, yet which lacks clear definition. Ambiguities in terms and methodologies used to determine bioavailability have contributed greatly to the lack of clear definition. An attempt has been made in this article to clarify some of the terminology associated with the concept of bioavailability. Factors that affect bioavailability have been discussed in terms of environmental, organic and physiological occurrences. The effect of these factors is related to nutrient metabolism. Also, the relationship of the multitude of methodologies used to study nutrient bioavailability with the hierarchy of terms used to describe it is established. Finally, the care that is needed in the interpretation of bioavailability research, which is critical to the understanding of implications derived from this concept, is emphasized through specific examples.     

Iron Bioavailability from Common Raisin-containing Foods Assessed with an In Vitro Digestion/Caco-2 Cell Culture Model: Effects of Raisins

The effects of raisins on iron bioavailability from wheat bran cereal, bread, rice pudding, and granola bars were studied. Iron bioavailability was assessed with an in vitro digestion/Caco‐2 cell culture model. Raisins reduced iron bioavailability from all foods except granola bars. Raisins also reduced iron bioavailability from samples of wheat bran cereal and bread fortified with elemental iron or ferrous sulfate, but this inhibitory effect was less pronounced in samples fortified with sodium iron ethylenediaminetetraacetate (NaFeEDTA). Iron bioavailability was markedly higher for samples fortified with NaFeEDTA, suggesting that iron in the form of NaFeEDTA is more bioavailable than elemental iron or ferrous sulfate in raisin‐containing foods.     

食品基质及加工方式对多酚生物利用度影响的研究进展

酚类化合物是植物性食品中的重要成分,具有多种功能活性,但因其生物利用度低,不能在体内完全发挥其生物活性。因此寻找到一条有效的途径来提高其生物利用率非常必要。本文综述了多糖、蛋白质、脂质三种食品基质及不同加工方式对多酚生物利用度的影响,以期为食品加工中提高多酚生物利用度提供借鉴和思考。     

In vivo and in vitro testing for selenium and selenium compounds bioavailability assessment in foodstuff

The assessment of selenium and selenium species bioavailability in foodstuff is of special concern on the context of human nutrition. In vivo (human and animal), and in vitro tests are important approaches for estimating the bioavailability of toxic and essential compounds to humans. An overview on in vivo and in vitro bioavailability assays for releasing selenium and selenium species in foodstuffs is summarized. Se and Se species content in a foodstuff critically influence Se bioavailability and bioactivity to humans and animals. Se bioavailability is affected by foodstuff-matrix major composition and minor components. Foodstuffs processing and/or treatments could enhancement or decrease Se bioavailability. Experimental conditions such as the selection of healthy status of examined people (in in vivo humans approaches), the selection of animal model (in vivo animals approaches), or the selection of GI conditions (in in vitro tests) could determines the results. Thus, international standardized protocol for in vivo and in vitro approaches assessment is mandatory.     

A Review on the Relationship Between Food Structure,Processing, and Bioavailability

This review highlights the effects of processing and food matrix on bioaccessibility and bioavailability of functional components. Human digestive system is reviewed as an element in bioavailability. Methods for bioaccessibility and bioavailability determination are described. Information about the location of functional compounds in the tissue is presented to portray the matrix information. Research data on the effects of food matrix and processing on bioaccessibility and bioavailability are summarized. Finally, trends in the development of functional component delivery systems are included.     

Evidence for bioavailable copper-dissolved organic matter complexes and transiently increased copper bioavailability in manure-amended soils as determined by bioluminescent bacterial biosensors

The short-term (3 months) dynamics of bioavailable copper (Cu) species was determined in soils amended with various amounts of manure and Cu. Bioavailable Cu species were operationally defined as those species that were able to induce gene expression in a Cu-specific Pseudomonas fluorescens biosensor. Biosensor measurements were backed by analysis of total Cu in soil and of total Cu and free Cu2+ ion activity in solution. Cu bioavailability relative to the total Cu concentration increased dramatically with increasing Cu loading of manure and with increasing manure amendment to soil. In both cases, the immediate increase in bioavailability could be explained in part by increased Cu concentration in solution and in part by an increased bioavailability of dissolved Cu species. In contrast to Cu bioavailability, Cu2+ ion activity decreased progressively with increasing manure loading. Cu bioavailability declined rapidly during the weeks after manure amendment concomitant with a marked slow-down of C mineralization indicating a shift from initially bioavailable Cu-dissolved organic matter (Cu-DOM) complexes to nonavailable Cu-DOM complexes over time. Our data do not support the conventional view of metal bioavailability being primarily related to the free metal ion activity and strongly suggest differential bioavailability of Cu-DOM complexes in manure-amended soils.     

Iron (Fe) bioavailability and the distribution of anti‐Fe nutrition biochemicals in the unpolished,polished grain and bran fraction of five rice genotypes

Iron (Fe) bioavailability in unpolished, polished grain and bran fraction of five rice genotypes with a range of Fe contents was measured by in vitro digestion and cultured Caco‐2 cells of cooked grain. There was a significant difference in Fe bioavailability among the five rice genotypes tested, in both the unpolished and polished grain. The range of Fe bioavailability variation in polished rice was much wider than that of unpolished, suggesting the importance of using Fe levels and bioavailability in polished rice grain as the basis for selecting high‐Fe rice cultivars for both agronomic and breeding purposes. Milling and polishing the grain to produce polished (or white) rice increased Fe bioavailability in all genotypes. Iron bioavailability in polished rice was high in the UBON2 and Nishiki, intermediate in both IR68144 and KDML105, and low in CMU122. All genotypes had low bioavailability of Fe in bran fraction compared to unpolished and polished grain, except in CMU122. CMU122 contained the lowest level of bioavailable Fe in unpolished and polished grain and bran, because of the dark purple pericarp colored grain and associated tannin content. The level of bioavailable Fe was not significantly correlated with grain Fe concentration or grain phytate levels among these five genotypes tested. The negative relationship between Fe bioavailability and the levels of total extractable phenol was only observed in unpolished (r = ?0.83**) and bran fraction (r = ?0.50*). The present results suggested that total extractable phenol and tannin contents could also contribute to lowering bioavailability of Fe in rice grain, in addition to phytate. Copyright © 2006 Society of Chemical Industry     

生物利用度模型在纳米载药中的研究与应用

药物的生物利用度是表示药物分子以各种途径或形式进入机体后,经口腔、胃、肠等消化吸收后进入体循环的比例参数。生物利用度是反映药物在生物体内吸收、分布、代谢和排泄情况的重要依据。在医药等领域,纳米药物递送体系是提高活性分子生物利用度非常有效的手段,药物发挥药效时需要从载体中释放才能被充分吸收。在生物活性分子的研发过程中,可通过体外模型和动物体内模型来模拟药物在机体的作用过程,以此推测药物的生物利用度。目前,广泛应用的生物利用度模型主要包括体外模拟释药模型、体外模拟消化模型、细胞模型、体内药代动力学模型等。该研究主要对常见的生物利用度研究模型构建和应用等进行总结,以期为今后纳米药物递送体系的生物利用度模型研究和拓新提供参考。