Modified Dietary Fiber from Cassava Pulp and Assessment of Mercury Bioaccessibility and Intestinal Uptake Using an In Vitro Digestion/Caco‐2 Model System

The ability of modified dietary fiber (MDF) generated from cassava pulp to modulate the bioaccessibility and intestinal absorption of heavy metals may be helpful to mitigate health risk associated with select foods including select fish high in methyl mercury. Using a coupled in vitro digestion/Caco‐2 human intestinal cell model, the reduction of fish mercury bioaccessibility and intestinal uptake by MDF was investiaged. MDF was prepared from cassava pulp, a byproduct of tapioca production. The highest yield (79.68%) of MDF was obtained by enzymatic digestion with 0.1% α‐amylase (w/v), 0.1% amyloglucosidase (v/v) and 1% neutrase (v/v). MDF and fish tissue were subjected to in vitro digestion and results suggest that MDF may reduce mercury bioaccessibility from fish to 34% to 85% compared to control in a dose‐dependent manner. Additionally, accumulation of mercury from digesta containing fish and MDF was only modestly impacted by the presence of MDF. In conclusion, MDF prepared from cassava pulp may be useful as an ingredient to reduce mercury bioavailability from food such as fish specifically by inhibiting mercury transfer to the bioaccessibile fraction during digestion.     

Oral bioaccessibility and human risk assessment of organochlorine pesticides (OCPs) via fish consumption,using an invitro gastrointestinal model

The oral bioaccessibility of dichlorodiphenyltrichloroethane (DDT) and hexachlorocyclohexanes (HCHs) in twenty fish species were evaluated using an in vitro gastrointestinal model. Relatively high concentrations of ∑HCH (0.33–9.88 ng g⁻¹, mean 1.57 ng g⁻¹) and ∑DDT (0.74–131 ng g⁻¹, mean 12.2 ng g⁻¹) were observed in all market fish. The average bioaccessibilities for ∑HCHs were 3.35% and 8.73% in gastric and intestinal conditions, respectively, and for ∑DDTs were 5.48% and 17.6%, respectively. Significant (p < 0.05) correlations were observed between OCP congener digestible concentrations in fish muscle and their corresponding concentrations in human tissues of Hong Kong residents. The health risk assessments based on solvent and digestible concentrations were found to be contradictory due to the fact that only a limited proportion of OCP was bioaccessible. It was concluded that human health risk assessment based on solvent concentrations should be modified by taking bioaccessibility of the contaminant into account.     

黑木耳中不同形态的铬在in vitro系统中生物可给性分析

利用In vitro系统模拟黑木耳在消化过程中不同形态的铬的生物可给性,采用HPLC-ICP-MS测定不同形态铬的含量。结果表明:29个样品经过In vitro系统模拟消化后,铬在胃中的生物可给性为15.10%～35.87%;在肠中的生物可给性为11.02%～20.36%,同一样品胃中的生物可给性铬大于肠中的,且检测出的铬均以三价形态存在。可以证明在In vitro系统中,黑木耳能有效吸附对人体有害的Cr(Ⅵ)。对0.5μg/L的Cr(Ⅲ)和Cr(Ⅵ)混标测定7次,RSD在2.55%～4.98%之间,方法重现性较好;对同一样品设置6平行实验,测量结果相对偏差均小于9.5%,说明该方法的精密度能够满足实验要求。可见,黑木耳的生物可给性铬是对人体有益的Cr(Ⅲ),且证明了在模拟消化过程中黑木耳能够完全吸附对人体有害的Cr(Ⅵ),为黑木耳中铬在消化过程中可能发生的形态转变及生物有效性提供了数据参考,也为研究制定菌类中铬的限量标准提供参考。     

Synthesis and bioaccessibility of Fe-pheophytin derivatives from crude spinach extract

ABSTRACT:  Heme iron is recognized as a highly bioavailable source of iron suitable for treatment of iron deficiency anemia. However, the animal origin of purified heme limits its broad applicability due to religious, personal, and food safety issues. Development of chlorophyll-derived heme mimetics offers opportunities to expand current iron fortification strategies. The objective of this study was the synthesis of Fe-pheophytin (FePhe) derivatives from natural chlorophyll and subsequent evaluation of their digestive behavior and bioaccessibility in vitro . FePhe a and a ' were synthesized from crude spinach extracts by treatment with 1.3 M iron(II)chloride and 0.25 M Na-acetate dissolved in glacial acetic acid at 80 °C for 30 min. FePhe-rich extracts (approximately 1 mM) were formulated into corn starch based test meals (7.5% lipid) and subjected to a 2-step in vitro digestion designed to simulate in vivo gastric and small intestinal conditions. Recovery of FePhe following digestion and transfer of FePhe and pheophytins (Phe) from test meal matrix to mixed micelles was assessed by RP C18-HPLC to determine the digestive stability and micellarization efficiency (bioaccessibility). FePhe a and a ' derivatives were moderately stable to digestive conditions with recoveries of 52.3% and 58.7%, respectively. Residual Phe a was stable to digestion. Micellarization efficiency of FePhe a (4%) and a ' (3.4%) was significantly ( P < 0.05) lower than Phe a (25.8%) from test meals. While digestive stability and micellarization efficiency are limiting, the presence of lipophilic FePhe derivatives in mixed micelles suggests that these compounds would be available for subsequent absorption in the intestinal tract.     

利用超微粉碎提高花色苷生物可接受率

探讨超微粉碎对不同食物来源花色苷体外模拟消化生物可接受率的影响。选择蓝莓、紫甘蓝、紫番薯和黑米分别作为浆果、蔬菜、薯类和谷物的代表性食物,充分干燥后进行分级粉碎,得到粗粉和超微粉,测定粉体粒径分布和营养成分;经过模拟胃肠消化后利用高相液相色谱法检测消化液花色苷峰面积,计算得到花色苷生物可接受率。与粗粉相比,超微粉粒径分布更加均匀,平均粒径<25μm,主要营养成分含量没有明显差异,而花色苷含量检测值显著升高;超微粉碎能够将花色苷生物可接受率提高23.78%~87.72%,差异均具有统计学意义(p<0.05)。超微粉碎可以解除细胞壁和纤维素等食物基质对花色苷释放的阻碍作用,提高不同食物来源的花色苷生物可接受率。     

Evidence on the Bioaccessibility of Glucosinolates and Breakdown Products of Cruciferous Sprouts by Simulated In Vitro Gastrointestinal Digestion

Cruciferous vegetables are gaining importance as nutritious and sustainable foods, rich in phytochemical compounds such as glucosinolates (GSLs). However, the breakdown products of these sulfur-based compounds, mainly represented by isothiocyanates (ITC) and indoles, can contribute to human health. In the human digestive system, the formation of these compounds continues to varying extents in the different stages of digestion, due to the contact of GSLs with different gastric fluids and enzymes under the physicochemical conditions of the gastrointestinal tract. Therefore, the aim of the present work was to uncover the effect of gastrointestinal digestion on the release of glucosinolates and their transformation into their bioactive counterparts by applying a simulated in vitro static model on a range of brassica (red radish, red cabbage, broccoli, and mustard) sprouts. In this sense, significantly higher bioaccessibility of ITC and indoles from GSLs of red cabbage sprouts was observed in comparison with broccoli, red radish, and mustard sprouts, due to the aliphatic GSLs proportion present in the different sprouts. This indicates that the bioaccessibility of GSLs from Brasicaceae sprouts is not exclusively associated with the initial content of these compounds in the plant material (almost negligible), but also with the release of GSLs and the ongoing breakdown reactions during the gastric and intestinal phases of digestion, respectively. Additionally, aliphatic GSLs provided higher bioaccessibility of their corresponding ITC in comparison to indolic and aromatic GSLs.     

体外模拟消化过程中胡萝卜中新烟碱类杀虫剂的生物可及性研究

目的 基于体外胃肠道模型研究胡萝卜中啶虫脒、噻虫胺、吡虫啉、噻虫嗪4种新烟碱类杀虫剂(neonicotinoid insecticides,NNIs)的生物可及性,为其风险评估提供依据。方法 基于3种体外模型和胡萝卜在消化液中对NNIs的吸附过程,采用液相色谱-质谱法分析4种NNIs的含量,计算胡萝卜中NNIs的生物可及性和吸附量。结果 油脂的添加会增加胡萝卜中噻虫胺、噻虫嗪、吡虫啉的生物可及性,分别从(63.3±5.9)%、(60.7±4.5)%、(81.1±9.9)%增加到(79.3±6.1)%、(79.7±7.5)%、(94.3±2.7)%;而消化液中低浓度胆盐和胰酶的存在会降低NNIs的生物可及性。当胰酶质量浓度为0.25 g/L时,降幅可达4.1%(噻虫胺)～26.7%(噻虫嗪)。吸附实验结果表明,模拟肠液中4种NNIs的吸附亲和性系数KF值高于背景溶液。这表明胡萝卜在模拟肠液中有更高的吸附量,胆盐的加入增强了胡萝卜与NNIs的相互作用,降低了其生物可及性。结论 胡萝卜在不同体外消化模型中NNIs生物可及性存在差异,胃肠道中胆盐和胰酶含量的升高在一定程度上会降低NNIs的生物...     

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。     

Effect of ultrasound treatments of tomato pulp on microstructure and lycopene in vitro bioaccessibility

The influence of ultrasound treatments of tomato pulp on microstructure and lycopene in vitro bioaccessibility was investigated. To this purpose, samples were subjected to ultrasound at a frequency and amplitude of 24 kHz and 100 μm, respectively, for increasing lengths of time. Results showed that ultrasound was responsible for loss of tomato cell integrity, as well as a decrease in the degree of pectin esterification. In contrast, rheological measurements showed that ultrasonically treated tomato pulp had greater gel-like properties than an untreated sample. It was inferred that ultrasound promoted the formation of a new network due to hydrogen bonding and hydrophobic interactions among the de-esterified pectin molecules. Such a reinforcement of the tomato pulp structure resulted in a decrease in lycopene in vitro bioaccessibility of the ultrasonically treated tomato pulp, probably due to the fact that the presence of a stronger network may make lycopene less available to the digestion process.