In vitro availability of minerals from oat products

The content of macroelements P, Mg and Ca and microelements Mn, Fe, Zn and Cu was determined in 10 commercially sold oat products made by different technological processes (dehulling, instantinising, extrusion, flaking). Phosphorus was the most prevalent of the macroelements (from 240.8 ± 2.2 to 845.5 ± 8.1 mg per 100 g), followed by magnesium (from 73.2 ± 0.7 to 271.9 ± 2.7 mg per 100 g) and calcium (from 30.69 ± 0.01 to 112.7 ± 0.3 mg per 100 g). The Ca/P ratio ranged from 1:5.3 in crushed oat to 1:8.2 in oat flakes. Regarding the microelements, manganese was present at the highest concentrations (from 2.62 ± 0.02 to 8.69 ± 0.01 mg per 100 g). The content of iron was similar and that of zinc not much lower, whereas the amount of copper was considerably smaller (from 0.23 ± 0.002 to 0.59 ± 0.002 mg per 100 g). The highest concentrations of mineral elements were found in instant oat bran flakes and the lowest in extruded oat and corn crisps containing 50% corn grouts. Samples of the products analysed were subjected to in vitro enzymatic digestion, simulating the digestive process occurring in the human alimentary tract. The supernatants thus obtained were analysed for their content of the previously determined mineral components; the percentage of minerals released from the products was calculated. The following sequence of mineral components released was observed: Cu (57.2–95.6%) > P (39.7–60.9%) > Ca (18.2–39.5%) > Mg (16.4–39.8%) > Mn (6.4–24.7%) > Fe (6.5–29%) > Zn (11–17.2%). The Ca/P ratio in the supernatant worsened from 1:8.2 in crushed oat to 1:23.3 in extruded oat and corn crisps. Crushed oat released the highest amounts of mineral elements during enzymatic hydrolysis, with oat grouts coming second. As regards the other products, it is difficult to establish their relative sequence in the release of minerals. © 2002 Society of Chemical Industry     

In vitro availability of calcium from sources of cellulose,methylcellulose, and psyllium

Certain types of dietary fibres may decrease the amount of dietary calcium available for absorption. The objective of this study was to determine the in vitro calcium availability from sources of cellulose, methylcellulose, and psyllium, such as cereals, fibre supplements, and purified fibres. Total dietary fibre, soluble and insoluble dietary fibre, acid detergent fibre, neutral detergent fibre, cellulose, hemicellulose, lignin, protein, uronic acid, phytate, water holding capacity, and total endogenous calcium content were determined. Results from the chemical analyses of the fibre sources varied significantly. Free endogenous calcium, at pH 3–8, was determined via gel filtration. Calcium was added to each fibre source and free exogenous calcium was determined via gel filtration at pH 1 and pH 8. The analysis of variance procedure was used to determine differences in binding capacities of the fibres. There was virtually no binding of exogenous calcium by sources of cellulose, methylcellulose, or psyllium.     

In vitro attenuation of acrolein-induced toxicity by phloretin, a phenolic compound from apple

In the current study, the protective effects of phloretin were investigated in acrolein-challenged amino acid, protein, and cell models. It was found that the formation of FDP-lysine (a typical acrolein-lysine adduct) was strongly inhibited in the presence of phloretin and the remaining electrophilic site in FDP-lysine was also blocked by phloretin. Moreover, direct trapping of acrolein by phloretin was found to be responsible for inhibiting the incorporation of carbonyl groups into BSA and oligomerisation in RNase A. Subsequently, the reduction of LDH release in human neuroblastoma SH-SY5Y cells under acrolein challenge suggested the cytoprotective effects of phloretin. Such protection might be mediated through inhibiting the increased cellular protein carbonyl level as revealed by Western blotting analysis. The present study highlighted an apple phenolic compound, phloretin as a promising candidate in prevention or treatment of acrolein-associated human diseases.     

真菌毒素DON和ZEN的体外联合毒性评价

选取BEL7402细胞对脱氧雪腐镰刀菌烯醇（Deoxynivalenol,DON）和玉米赤霉烯酮（Zearalenone,ZEN）的联合毒性进行评价。首先将不同浓度的DON、ZEN以及其混合物染毒对数期的BEL7402细胞,刺激24 h后,对细胞增殖率、ROS活性氧水平、钙离子水平、细胞凋亡率以及凋亡相关靶点基因的表达等指标进行监测分析,并对两种毒素的联合毒性作用进行评价。结果表明,真菌毒素DON、ZEN均可抑制细胞活性,IC₅₀分别为9.3、27.2μg/m L,可导致细胞氧化应激损伤,提高细胞内活性氧水平以及钙离子浓度,显著上调凋亡关键基因p53、Bax,下调Bal-2基因,诱导细胞产生早期凋亡甚至坏死,多种毒性指标验证了这两种毒素对细胞的联合毒性作用表现为加和作用。      

花生胚小叶的离体再生及筛选压力选择

以花生胚小叶为外植体优化离体再生条件,通过对再生苗进行筛选,为外源基因的遗传转化提供实验依据。研究表明,不同基因型胚小叶的再生能力差异显著,在供试基因型中以中花8号不定芽诱导率和成苗率最高,且外植体状态最好。中花8号胚小叶再生的最佳诱导培养基为MSB（MS无机盐＋B5有机成分）＋6-BA（4.5mg/L）＋NAA（1mg/L）＋AgNO3（2mg/L）,最佳诱导培养时间为21d。对中花8号再生苗进行筛选浓度实验,草丁膦（PPT）为20mg/L时,可筛选出抗性苗;300mg/L的卡那霉素（Km）可用于较小幼苗筛选,而对较大幼苗则需将Km的浓度提高至400mg/L以上。     

In vitro approach (solubility and Caco-2 uptake) to compare Cu availability from model cookies

Six model cookies were prepared in order to investigate the possibility of using whole grain raw materials other than wheat (inulin in combination with soy, amaranth, carob, apple dietary fibre or oat dietary fibre) for creating novel cookies with improved copper content and bioavailability. For assessment of copper solubility and intestinal uptake, in vitro enzymolysis approach was combined with Caco-2 cell culture technique and copper concentrations were determined using ICP-AES technique. Results indicate significant increase of the content of total and soluble Cu fractions in all modified cookies (with exception of cookies enriched with oat fibre). Average Cu solubility from investigated samples ranged from 51.6 to 68.9%. The highest Caco-2 cell uptake was determined in soy- and amaranth-enriched cookies. Total Cu content and proteins were determined as promoters of Cu absorption and transport, while addition of pure dietary fibre negatively influenced Cu uptake on the Caco-2 cell monolayer.     

回用糖蜜酒精废液中砷、铅对酒精发酵的影响

采用双浓度流程利用酵母菌发酵酒精 ,以甘蔗亚硫酸法、碳酸法的糖蜜为原料 ,对其酒精废液中主要的两种有毒元素 Pb、As在发酵过程中的影响进行单因素试验。采用原子吸收分光法测定了糖蜜的 Pb、As含量 ,在此基础上对发酵原料添加不同量的 Pb、As元素 ,考察各元素对发酵产酒的抑制点 ,初步得出各元素对发酵的抑制点为 As3+3mg/L、Pb2 +2 1m g/L。     

In vitro calcium availability from brassica vegetables (Brassica oleracea L.) and as consumed in composite dishes

In vitro calcium availability from four varieties of Brassica oleracea L. (broccoli, cauliflower, green cabbage and kale) was evaluated. The effect of including some brassica vegetables in composite dishes (macaroni and broccoli, macaroni and cauliflower) was also studied. Brassica vegetables were rich in calcium (20.6–35.3 mg/100 g) and in organic acids. Dietary fibre content in brassica vegetables (2.4 g/100 g) was lower than in composite dishes, the latter having a higher content of the soluble fraction. Uronic acids represented 50% of the soluble fibre fraction of brassica vegetables and only 24% of that of composite dishes. Approximately 25% of the total calcium of brassica vegetables was dialysable; ionic dialysable calcium was about 7% of the total calcium. The addition of macaroni to vegetables significantly lowered only calcium dialysability (p<0.001). Unlike vegetables, composite dishes had a percentage of soluble calcium higher (p<0.001) than that of dialysable calcium. The presence in dialysates of higher amounts of bound calcium compared to free ionic calcium implies that most of the absorbable calcium was bound to low molecular weight compounds. Organic acids might constitute the main association of calcium in brassica vegetables. Brassicaceae can be regarded as a good source of available calcium; their consumption in the diet may contribute to an adequate calcium nutriture.     

In vitro model for the evaluation of toxicity and antinutritional effects of sulphites.

The food preservatives, sulphur dioxide and its salts, are known to present some toxic, mutagenic and antinutritional effects; in fact they interact with a number of nutrients, e.g. some vitamins, notably thiamine (Th) and folic acid (FA). The effect of different concentrations of sodium bisulphite in cell culture media has been studied in vitro on a human cell line, HEp-2, deriving from a carcinoma of the larynx. Moreover, the sulphites have been tested with different levels of Th and FA with the aim of elucidating how much the cellular response depended on either the anti-nutritional effect or the toxicity of sulphites. Cell growth has been taken as an index of cytotoxicity and measured both as total protein content and as colony-forming ability. With no Th and FA in the culture medium, a clear decrease of cell growth was observed either with or without addition of sodium bisulphite. A dose-dependent reduction of protein content was detected in cells treated with 10, 50, 100, 200, 250 or 500 microM sodium bisulphite. Moreover, when the cells were treated with 10 or 100 microM of this compound, the colony-forming ability was reduced both in number and colony size. As far as the interaction of the two vitamins with sodium bisulphite is concerned, when these nutrients were present in the medium at 0.5, 1.0, 1.5, 2.0 or 2.5 mg/l, a similar growth profile, determined from their concentration, was observed in treated and control cells, the growth levels being affected by the sodium bisulphite contents. At higher levels of Th and FA, the growth index was still increasing only in treated cells, this phenomenon being particularly evident in cultures treated with 200 microM sodium bisulphite. The colony-forming ability was reduced in controls but still increased in treated cells at the highest concentration of vitamins.     

In vitro assessment of grapevine resistance to two populations of phylloxera from Australian vineyards

A perlite-based medium is described for in vitro cocultivation of phylloxera with micropropagated vines. Using this system, as well as cocultivations on excised primary roots, six vine types were screened for resistance to one or two populations of phylloxera (SRU-1 or VWL-1) sourced from different Australian vineyards. When inoculated with VWL-1 phylloxera, V. vinifera cv. Shiraz was rated as susceptible, Ramsey as resistant, Schwarzmann, V. riparia and Börner as highly resistant and V. rotundifolia as immune. When inoculated with SRU-1 phylloxera, both V. vinifera and Schwarzmann were rated as susceptible. The potential use of these in vitro methods for rootstock resistance screening and determination of phylloxera biotypes is discussed. Phylloxera behaviour and root responses observed in vitro are also described.     

In vitro assessment of water resistance of sun care products: a reproducible and optimized in vitro test method

The aim of the study was to develop a simple reproducible and reliable in vitro water resistance (WR) method to assess the sun care products. This paper is the result of a scientific collaboration between seven different international industrial laboratories and testing institutes. The same group has already achieved an in vitro protocol for the sun protection factor (SPF) determination [1]. The in vitro WR of sunscreens was tested by applying the same principle as in vivo, which determines the percentage of retention of sunscreen products by assessing the SPF before and after water immersion. Special care was taken to study the parameters influencing the WR and the possibility to follow the kinetics of sunscreen retention during water immersion. The influence of different water qualities has been tested, and osmosed water (1-3 microS cm(-1)) was chosen for the main ring study. Measurement was carried out after 5, 20 and 40 min of immersion. Histograms of selected products demonstrate the percentage of WR at all measuring times and centres, and the regression coefficient to the in vivo determination was shown and statistical calculations clearly demonstrate the reproducibility of the results between the different evaluation centres. The presented method is a practical, convenient and relevant tool for WR screening of sun care and skin care products. It even has the potential to be the starting point for the replacement of the in vivo method in future.     

In vitro availability of minerals of some tropical and citrus fruits as influenced by antinutritional factors

Four tropical fruits and three citrus fruits were analyzed for moisture, ash, antinutritional factors (phytate, oxalate, and polyphenols) contents, and total and available minerals. Moisture contents ranged from 6.0 to 83.17% for tropical fruits while that of citrus fruits ranged from 88.20 to 89.50%. Ash contents ranged from 2.56 to 4.50% and from 3.83 to 4.83%, for tropical and citrus fruits, respectively. All fruits contained no oxalate while phytate and polyphenols ranged from 48.1 to 134.1 mg/ 100 g and from 0.115 to 0.34%, respectively. For all fruits major minerals contents ranged from 7.7 to 433.3 while trace ones ranged from 0.116 to 1.91 mg/100 g. In vitro availabilities of major minerals (% of total) varied from 11.1 to 86.2% while for minor ones it ranged from 13 to 72.5%.     

In vivo-in vitro and XANES spectroscopy assessments of lead bioavailability in contaminated periurban soils

Lead (Pb) bioaccessibility was assessed using 2 in vitro methods in 12 Pb-contaminated soils and compared to relative Pb bioavailability using an in vivo mouse model. In vitro Pb bioaccessibility, determined using the intestinal phase of the Solubility Bioaccessibility Research Consortium (SBRC) assay, strongly correlated with in vivo relative Pb bioavailability (R(2) = 0.88) following adjustment of Pb dissolution in the intestinal phase with the solubility of Pb acetate at pH 6.5 (i.e., relative Pb bioaccessibility). A strong correlation (R(2) = 0.78) was also observed for the relative bioaccessibility leaching procedure (RBALP), although the method overpredicted in vivo relative Pb bioavailability for soils where values were <40%. Statistical analysis of fit results from X-ray absorption near-edge structure (XANES) data for selected soils (n = 3) showed that Pb was strongly associated with Fe oxyhydroxide minerals or the soil organic fraction prior to in vitro analysis. XANES analysis of Pb speciation during the in vitro procedure demonstrated that Pb associated with Fe minerals and the organic fraction was predominantly solubilized in the gastric phase. However, during the intestinal phase of the in vitro procedure, Pb was strongly associated with formation of ferrihydrite which precipitated due to the pH (6.5) of the SBRC intestinal phase. Soils where Fe dissolution was limited had markedly higher concentrations of Pb in solution and hence exhibited greater relative bioavailability in the mouse model. This data suggests that coexistence of Fe in the intestinal phase plays an important role in reducing Pb bioaccessibility and relative bioavailability.     

In vitro assessment of the upper gastrointestinal tolerance of potential probiotic dairy propionibacteria

This study aimed to assess the transit tolerance of potential probiotic dairy propionibacteria strains in human upper gastrointestinal tract in vitro, and to evaluate the effect of food addition on viability of these strains in simulated pH 2.0 gastric juices. The transit tolerance of 13 dairy propionibacteria strains was determined at 37 degrees C by exposing washed cell suspensions to simulated gastric juices at pH values at 2.0, 3.0, and 4.0, and simulated small intestinal juices (pH 8.0) with or without 0.3% bile salts. The viability of dairy propionibacteria in pH 2.0 simulated gastric juice with So-Good original soymilk or Up & Go liquid breakfast was also determined. The simulated gastric transit tolerance of dairy propionibacteria was strain-dependent and pH-dependent. All tested strains were tolerant to simulated small intestinal transit. The addition of So-Good original soymilk or Up & Go liquid breakfast greatly enhanced the survival of dairy propionibacteria strains in pH 2.0 simulated gastric juices. Dairy propionibacteria strains demonstrate high tolerance to simulated human upper gastrointestinal tract conditions and offer a relatively overlooked, yet alternative source for novel probiotics besides Lactobacillus and Bifidobacterium.     

In vitro digestion of bovine and caprine milk by human gastric and duodenal enzymes

In vitro digestion was performed by human proteolytic enzymes on bovine and caprine individual milks. Two types of caprine milk were investigated: with high and low contents of α_S1-casein (CN). In addition the influence of heating of the milk on digestion was examined. The digestion was performed in two steps using human gastric and duodenal juice. Protein and peptide profiles were studied by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and isoelectric focusing (IEF). Caprine milk proteins were digested faster than bovine milk proteins. This was confirmed by the degradation profile obtained for both cows’ and goats’ milk, and was most evident for β-lactoglobulin. Comparing the digestion of milk protein from two groups of goats, high and low in α_S1-CN content, respectively, did not show significant differences. Heat treatment of milk had a strong and significant effect on the level of digestion. Raw milk was degraded faster than the heat-treated milk, and the effect of heating was different for bovine and caprine milk.     

In vitro assessment of properties associated with the survival through the gastro-intestinal tract of staphylococci isolated from traditional sausage fermentation

Thirteen Staphylococcus sp. strains, previously isolated from spontaneous sausage fermentation, were in vitro examined for properties associated with their ability to survive through the gastro-intestinal tract. None of the strains were able to survive exposure to pH 1 or pH 2, while for most of them, a population reduction, ranging from 77.3% to 99.0% and a surviving population from 1.7 x 10(8) to 9.0 x 10(6) was observed after exposure to pH 3. None of the strains exhibited bile salt hydrolase activity or production of antimicrobial compounds, while all of them were resistant to pancreatin. Only S. cohnii cohnii LQC 5112 was found to be alpha-haemolytic, seven other strains were beta-haemolytic and the rest gamma-haemolytic. All strains were sensitive to erythromycin, ampicillin (but S. intermedius LQC 5023) and chloramphenicol while most of them were sensitive to tetracycline. On the other hand, most of the strains were resistant to novobiocin. Furthermore, their aptitude, not only to withstand, but to proliferate in the presence of bile salts, as well, even at an acidic environment and their ability to adhere to stainless-steel plates, indicate the need for an in vivo study.     

In vitro assessment of the gastrointestinal transit tolerance of taxonomic reference strains from human origin and probiotic product isolates of Bifidobacterium

Next to health promoting effects, the functional aspect of probiotic strains also involves their capacity to reach the colon as viable metabolically active cells. The present study aimed to assess the potential of 24 probiotic product isolates and 42 human reference strains of Bifidobacterium to survive gastrointestinal transit under in vitro conditions. The survival capacity of exponential and stationary phase cultures upon exposure to gastric and small intestinal juices was determined using a recently developed microplate-based assay in combination with the LIVE/DEAD BacLight Bacterial Viability kit. All 66 strains tested displayed a considerable loss in viability during exposure to an acidic pepsin containing solution (pH 2.0). Among the 10 taxa tested, cultures of B. animalis ssp. lactis appeared to be most capable to survive gastric transit. Although to a lesser extent, the presence of bile salts also affected the viability of most of the strains tested. Except for 3 strains, all 66 strains showed bile salt hydrolase activity using an agar-based assay. In contrast, the bifidobacterial strains used in this study appeared to possess a natural ability to survive the presence of pancreatin (pH 8.0). Although the effect was not significant, a slightly enhanced tolerance to gastrointestinal transit was observed when cells were in the stationary phase, especially when exposed to acid, compared with cells being in the exponential phase. Survival in the gastrointestinal tract appeared to be largely strain-dependent and hence implies that different strains will likely display a different behavior in functionality. The assay used in this study allows an initial assessment of strains for use as probiotic cultures prior to selecting potential candidate strains for further investigation in vivo.