In vitro binding of bile acids by lupin protein isolates and their hydrolysates

This study investigates the in vitro binding of bile acids by lupin, lupin protein isolates, and their hydrolysates compared to soybean products and cholestyramine. Sodium cholate, sodium deoxycholate, sodium chenodeoxycholate, sodium glycocholate and sodium taurocholate were individually tested and analyzed spectrophotometrically by enzymatic reaction. A degree of hydrolysis of up to 20% did not affect the bile-acid binding capacity. De-oiled lupin and its hydrolysate bound all the bile acids to a significantly greater extent than de-oiled soy and its hydrolysate. Acid-soluble protein isolate from lupin showed a greater bile-acid binding capacity than acid-insoluble protein isolate. The amount of bile acid bound by acid-soluble lupin protein isolate was sometimes greater than the amount of bile acid bound by cholestyramine, which is well known as a cholesterol-reducing agent. There was no selective binding of particular types of bile acids. It can be concluded from these results that acid-soluble protein isolate from lupin may have potential application as a cholesterol-reducing agent for hypercholesterolemic patients.     

Preparation of succinylated derivatives of psyllium and their physicochemical and bile acid-binding properties

The succinyl psyllium derivatives were successfully prepared by reacting psyllium with succinic anhydride, 4-dimethylaminopyridine and tributylamine in N,N-dimethylformamide. Three succinyl psyllium derivatives with different degrees of substitution were prepared and denoted as S-Psy-L, S-Psy-M and S-Psy-H. FT-IR spectrum and ¹H NMR of the succinylated psyllium showed that its monoester derivative, with succinyl groups, was formed successfully. The succinyl derivatives were also evaluated for their surface structure, gelling properties, water uptake capacities, swelling volumes, and bile acid-binding abilities in vitro. The results showed that succinylation significantly reduced the gelling properties and swelling ability of psyllium, as well as increased water uptake abilities and bile-acid binding capacities. The results of this study suggested that succinylation could be a potential approach for obtaining novel derivatives of psyllium with improved physicochemical and biological properties for application in functional foods or other consumer products.     

Effect of the presence of glycerol and Tween 20 on the chemical and physical properties of films based on chitosan with different degree of deacetylation

Chitosans with two different deacetylation degree (DD) (60.9% and 96%) were used to elaborate edible films. The influence of the degree of deacetylation and the presence of glycerol and Tween 20 in the formulation on the surface tension of the film forming solutions as well as on the chemical structure, optical and mechanical properties and water vapor permeability (WVP) of the resulting films were studied.IR spectra showed no significant differences on the chemical structures of chitosan of the different films. However, X-ray diffraction analysis indicated that the use of chitosan with higher DD and the use of glycerol as additive resulted in higher crystallinity. Films made of chitosan with the lower DD (60.9%) were found to have higher tensile strength (TS) and elongation (E) in a tensile test. Degree of deacetylation did not have any effect on WVP. The presence of glycerol resulted in less resistant, more elastic and more permeable films.The presence of Tween 20 improved the wettability of film solutions and affected significatively mechanical, optical and barrier properties of the films. A positive interaction between glycerol and Tween 20 was observed for WVP.     

In vitro binding of bile acids by bananas,peaches, pineapple,grapes, pears,apricots and nectarines

The in vitro binding of bile acids by bananas (Musa × paradisiaca), peaches (Prunus persica), pineapple (Ananus comosus), grapes (Vitis spp.), pears (Pyrus communis), apricots (Prunus armeniaca) and nectarines (Prunus persica, nectarina) was determined using a mixture of bile acids secreted in human bile at a duodenal physiological pH of 6.3. Six treatments and two blank incubations were conducted, testing various fresh fruits on an equal dry matter basis. Considering cholestyramine (bile acid binding, cholesterol lowering drug) as 100% bound, the relative in vitro bile acid binding percentages on dry matter (DM), total dietary fibre and total polysaccharides basis were 2–9%, 15–101% and 10–101%, respectively. Bile acid binding, on a DM basis, for bananas was significantly (P ? 0.05) higher and that for nectarines significantly lower than those for peaches, pineapple, grapes, pears and apricots. The bile acid bindings for peaches and pineapple were similar and significantly higher than those for grapes, pears and apricots. Binding values for grapes and pears were significantly higher than apricots. These results point to the relative health promoting potential of bananas > peaches = pineapple > grapes = pears > apricots > nectarines, as indicated by their bile acid binding on a DM basis. The variability in bile acid binding between the fruits tested maybe related to their phytonutrients, antioxidants, polyphenols, flavonoids (anthocyanins, flavonols, and proanthocyanidins), structure, hydrophobicity of undigested fractions, anionic or cationic nature of the metabolites produced during digestion or their interaction with active binding sites. Animal studies are planned to validate in vitro bile acid binding of fruits, observed herein, to their healthful potential, atherosclerosis amelioration and cancer prevention.     

水溶性黑木耳多糖体外结合胆酸盐能力的分析

本文通过水提醇沉提取黑木耳多糖,同时用除蛋白和不除蛋白两种方法处理,得到12种不同浓度醇沉水溶性混合多糖;并对12种多糖的体外结合胆酸盐能力进行分析。结果显示:70%乙醇醇沉得到的水溶性黑木耳多糖体外结合胆酸作用较强,并且除蛋白多糖比不除蛋白多糖体外结合甘氨酸胆酸钠的能力强。同时,多糖浓度0.8 mg/m L时,结合达到稳定,为最适宜加入量。实验结果为AAP在降血脂机制方面的进一步研究提供理论依据。      

In vitro binding of bile acids by spinach, kale, brussels sprouts, broccoli, mustard greens, green bell pepper, cabbage and collards

The in vitro binding of bile acids by spinach (Spinacia oleracea), kale (Brassica oleracea acephala), Brussels sprouts (Brassica oleracea gemmifera), broccoli (Brassica oleracea italica), mustard greens (Brassica juncea), green bell peppers (Capsicum annuum), cabbage (Brassica oleracea capitala) and collards (Brassica oleracea acephala) was determined using a mixture of bile acids secreted in human bile at a duodenal physiological pH of 6.3. Six treatments and two blank incubations were conducted testing various fresh raw green vegetables on an equal dry matter basis. Considering cholestyramine (bile acid binding, cholesterol lowering drug) as 100% bound, the relative in vitro bile acid binding of various vegetables tested on equal dry matter and total dietary fibre basis was 2–9% and 6–32%, respectively. Bile acid binding for spinach, kale and brussels sprouts was significantly higher than for broccoli and mustard greens. For broccoli and mustard greens binding values were significantly higher those for cabbage, bell pepper and collards. These results point to the health promoting potential of spinach = kale = brussels sprouts > broccoli = mustard greens > cabbage =  green bell peppers =  collards, as indicated by their bile acid binding on dry matter basis.     

Selective in vivo effect of chitosan on fatty acid,neutral sterol and bile acid excretion: A longitudinal study

Chitosan, a deacetylated form of chitin, is a dietary fibre known for its hypolipidemic properties, which are mainly attributed to its unique cationic characteristics. We studied the selective in vivo effect of chitosan on fat excretion in order to elucidate its hypolipidemic mechanism. A 4-week longitudinal study was conducted in guinea pigs and the effect of chitosan on fat-absorption was compared to that of a soluble fibre: digestion-resistant maltodextrin. Animals were fed with high-fat isocaloric diets containing 12/100 g of cellulose, digestion-resistant maltodextrin or chitosan. Subsequently, the excretion of fatty acids, neutral sterols and bile acids was determined. Chitosan selectively reduced fat absorption in comparison to digestion-resistant maltodextrin. The excretion of lauric, myristic and palmitic fatty acids of animals fed with chitosan was more than 10-, 5- and 2-fold higher, respectively, than in the cellulose group, whereas stearic acid excretion was not significantly altered. Oleic, linoleic and α-linolenic acid excretion were also significantly higher (P < 0.001). The n−6/n−3 ratio in faeces of the chitosan group was 23.68, compared to 13.95 in the cellulose group. Total neutral sterol excretion was increased by both dietary fibres, whereas bile acid excretion was only increased by chitosan. Nevertheless, chitosan inhibited the intestinal bioconversion of cholesterol and primary bile acids to secondary metabolites. Hence, these results reveal that chitosan and digestion resistant maltodextrin exert their hypolipidemic activity by different mechanisms.     

Effect of pH on the in vitro interactions between bile acids and pectin

 The interactions between pectin and bile acids (BA) were investigated after in vitro incubation at 37°C in the pH range of 5.0 – 8.0, separation of the non-absorbed BA using membrane filtration and their estimation by HPLC and HPTLC. In general, the interactions increased with the degree of esterification and the molecular weight (viscosity) of the pectin. They were reduced if the carboxyl groups in the polysaccharide molecules are arranged in a blockwise manner and in the presence of Ca²⁺. The highest interactions were found for unconjugated BA, followed by the corresponding glycine-conjugates. Taurine-conjugates showed the lowest interaction with pectin. Chenodeoxycholic acid and deoxycholic acid reacted more effectively than the trihydroxy bile acid cholic acid in the in vitro experiments. The results show that structural parameters of both BA and pectin play an important role in the extent of their interaction. Received: 28 November 1996 / Revised version: 20 January 1997     

Effect of pH on the in vitro interactions between bile acids and pectin

 The interactions between pectin and bile acids (BA) were investigated after in vitro incubation at 37°C in the pH range of 5.0 – 8.0, separation of the non-absorbed BA using membrane filtration and their estimation by HPLC and HPTLC. In general, the interactions increased with the degree of esterification and the molecular weight (viscosity) of the pectin. They were reduced if the carboxyl groups in the polysaccharide molecules are arranged in a blockwise manner and in the presence of Ca²⁺. The highest interactions were found for unconjugated BA, followed by the corresponding glycine-conjugates. Taurine-conjugates showed the lowest interaction with pectin. Chenodeoxycholic acid and deoxycholic acid reacted more effectively than the trihydroxy bile acid cholic acid in the in vitro experiments. The results show that structural parameters of both BA and pectin play an important role in the extent of their interaction. Received: 28 November 1996 / Revised version: 20 January 1997     

In vitro binding of bile acids by okra,beets, asparagus,eggplant, turnips,green beans,carrots, and cauliflower

The in vitro binding of bile acids by okra (Abelmoschus esculentus), beets (Beta vulgaris), asparagus (Asparagus officinalis), eggplant (Solanum malongena), turnips (Brassica rapa rapifera), green beans (Phaseolus vulgaris), carrots (Daucus carota), and cauliflower (Brassica oleracea botrytis) was determined using a mixture of bile acids secreted in human bile at a duodenal physiological pH of 6.3. Six treatments and two blank incubations were conducted, testing various fresh raw vegetables on an equal dry matter basis. Considering cholestyramine (bile acid-binding, cholesterol-lowering drug) as 100% bound, the relative in vitro bile acid binding on dry matter (DM) and total dietary fibre (TDF) basis was 1–16% and 2–54%, respectively. Bile acid binding for okra was significantly higher than for all the other vegetables tested. For beets, binding values were significantly higher than for asparagus. Binding values for asparagus were significantly higher than for eggplant, turnips, beans green, carrots and cauliflower. These results point to the health promoting potential of okra > beets > asparagus > eggplant = turnips = green beans = carrots = cauliflower, as indicated by their bile acid binding, on a dry matter basis.     

Effect of chitosan on the stability and properties of modified lecithin stabilized oil-in-water monodisperse emulsion prepared by microchannel emulsification

The effect of chitosan (CHI) on the stability of monodisperse modified lecithin (ML) stabilized soybean oil-in-water (O/W) emulsion was investigated. Monodisperse emulsion droplets with particle size of 24.4 ± 0.7 μm and coefficient of variation below 12% were prepared by microchannel (MC) emulsification using a hydrophilic asymmetric straight-through MC silicon 24 × 24 mm microchip consisting of 23,348 microchannels. The stability of the ML stabilized monodisperse emulsion droplets was investigated as a function of CHI addition at various concentration, pH, ionic strength, thermal treatment and freezing-thawing treatment by means of particle size and ζ-potential measurements as well as microscopic observation. The monodisperse O/W emulsions were diluted with CHI solution at various concentrations to a final droplet concentration of 1 wt% soybean oil, 0.25 wt% ML and 0–0.5 wt% CHI at pH 3. Pronounced droplet aggregation was observed when CHI was present at a concentration range of between 0.01 and 0.04 wt%. Above this concentration range, flocculations were less extensive, indicating some restabilization. ML stabilized emulsions were stable at a wide range of NaCl concentrations (0–1000 mM) and pH (3–8). On the contrary, in the presence of CHI, aggregation of the emulsion droplets was observed when NaCl concentration was above 200 mM and when the pH started to approach the pKa of CHI (i.e. ∼6.2–7.0). Emulsions containing CHI were found to have better stability at high temperature (>70 °C) in comparison to the emulsion stabilized only by ML. With sucrose/sorbitol as cryoprotectant aids, emulsions with the addition of CHI were found to be more resistant to droplet coalescence as compared to those without CHI after freezing at −20 °C for 22 h and thawing at 30 °C for 2 h. The use of CHI may potentially destabilize ML-stabilized O/W emulsions but its stability can be enhanced by selectively choosing the appropriate CHI concentrations and conditions of preparation.     

In vitro binding of bile acids by blueberries (Vaccinium spp.), plums (Prunus spp.), prunes (Prunus spp.), strawberries (Fragaria X ananassa), cherries (Malpighia punicifolia), cranberries (Vaccinium macrocarpon) and apples (Malus sylvestris)

The in vitro binding of bile acids by blueberries (Vaccinium spp.), plums (Prunus spp.), prunes (Prunus spp.), strawberries (Fragaria X ananassa), cherries (Malpighia punicifolia) cranberries (Vaccinium macrocarpon) and apples (Malus sylvestris) was determined using a mixture of bile acids secreted in human bile at a duodenal physiological pH of 6.3. Six treatments and two blank incubations were conducted to testing various fresh raw fruits on an equal dry matter basis. Considering cholestyramine (bile acid binding, cholesterol lowering drug) as 100% bound, the relative in vitro bile acid binding on dry matter (DM), total dietary fiber (TDF) and total polysaccharides (PCH) basis was for blueberries 7%, 47% and 25%; plums 6%, 53% and 50%; prunes 5%, 50% and 14%; strawberries 5%, 23% and 15%; cherries 5%, 37% and 5%; cranberries 4%, 12% and 7%; and apple 1%, 7% and 5%, respectively. Bile acid binding on DM basis for blueberries was significantly (P ? 0.05) higher than all the fruits tested. The bile acid binding for plums was similar to that for prunes and strawberries and significantly higher than cherries, cranberries and apples. Binding values for cherries and cranberries were significantly higher than those for apples. These results point to the relative health promoting potential of blueberries > plums = prunes = strawberries = cherries = cranberries > apples as indicated by their bile acid binding on DM basis. The variability in bile acid binding between the fruits tested maybe related to their phytonutrients (antioxidants, polyphenols, hydroxycinnamic acids, flavonoids, anthocyanins, flavonols, proanthocyanidins, catechins), structure, hydrophobicity of undigested fractions, anionic or cationic nature of the metabolites produced during digestion or their interaction with active binding sites. Inclusion of blueberries, plums, prunes, strawberries, cherries and cranberries in our daily diet as health promoting fruits should be encouraged. Animal studies are planned to validate in vitro bile acid binding of fruits observed herein to their potential of atherosclerosis amelioration (lipid and lipoprotein lowering) and cancer prevention (excretion of toxic metabolites).     

旋流与酸浆法甘薯淀粉性能及粉条品质比较

研究了旋流与酸浆法两种甘薯淀粉的性能,并对其所制粉条的色泽、老化、膨胀系数、烹饪损失率和质构性质等进行了比较。旋流法甘薯淀粉的亮度、膨胀度(55～95℃)和溶解度(55～95℃)与酸浆法淀粉的相比明显偏低(p<0.05),而4℃下放置1周的老化速率明显偏高(p<0.05)。与酸浆法淀粉粉条相比,旋流法淀粉粉条的色泽和膨胀系数显著地降低(p<0.05),而其老化速率、拉伸形变及剪切应力显著升高(p<0.05)。      

溶胶-凝胶法制备的纳米In2O3气敏性能研究

以氯化铟为前驱体 ,通过溶胶 -凝胶法制备了纳米In2 O3 颗粒 .经TG -DSC热分析表明 :In(OH) 3 在 2 72 9℃附近脱水形成In2 O3 .经XRD ,TEM等手段表征的结果显示 :所合成的纳米In2 O3属立方晶型 ,晶粒尺寸约 2 0nm .气敏性能测试结果表明 :纳米In2 O3 气敏元件对TMA及NH3 灵敏度高 .通过与某公司提供的粒度为 3.0 77μm的In2 O3 制成的气敏元件比较得知 ,纳米In2 O3 气敏元件对TMA的灵敏度提高特别明显 .     

In vitro application of selected essential oils and their major components in controlling fungal pathogens of crown rot in Embul banana (Musa acuminata– AAB)

The necessity for pesticide‐free fresh produce have prompted investigating the effect of selected essential oils and their major components on inhibition of conidial germination, appressoria formation and membrane permeability changes of the pathogens responsible for crown rot of banana. Eugenol, which is the major component of the essential oil of Ocimum basilicum, was the most effective chemical component in inhibiting conidial germination of Colletotrichum musae and Fusarium proliferatumin vitro while Cymbopogon citratus oil was the least effective. Both O. basilicum and C. citratus oils and their major components (Eugenol, citral a + b) inhibited appressoria formation by C. musae and changed the selective permeability of conidial membranes. Ocimum basilicum oil, eugenol and citral a + b could be satisfactorily used for inhibition of conidial germination and disruption of conidial activity of banana pathogens.     

In vitro caecum fermentation and in vivo (Gallus gallus) of calcium delivery systems fabricated by desalted duck egg white peptides and chitosan oligosaccharide on gut health

As calcium supplements, two novel calcium delivery systems were prepared with desalted duck egg white peptides (DPs) and chitosan oligosaccharide (COS) by Amadori-linkage and transglutaminase (TGase)-induced reaction, with high calcium-binding ability of promoting calcium absorption in vivo and in vitro. However, there are relatively few studies on the gut health of calcium delivery systems. In this experiment, in vitro caecum fermentation experiment and Gallus gallus intra amniotic feeding model were used to assess the gut health of calcium delivery systems and phytic acid. Results showed that two calcium delivery systems improved the microbial community structure by inhibiting the proliferation of Escherichia coli, and promoting the proliferation of Bifidobacterium and Lactobacillus. The addition of calcium delivery systems significantly increased short chain fatty acids (SCFAs) and improved the boundary membrane function of brush nutrients by significantly increasing villi structure, surface area, cup cell expansion and production of associated genes (P < 0.05). Moreover, calcium delivery systems present significant reverse of the inhibitory effect of phytic acid on gut health through in vitro and in vivo experiments. This study suggested that DPs-COS-Ca systems were superior to the commercially available calcium supplement CaCO₃ and had excellent calcium absorption and gut health regulating effects.