Search results for " Digestion"
showing 10 items of 239 documents
Thermophilic anaerobic conversion of raw microalgae: Microbial community diversity in high solids retention systems
2019
[EN] The potential of microbial communities for efficient anaerobic conversion of raw microalgae was evaluated in this work. A long-term operated thermophilic digester was fed with three different Organic Loading Rates (OLR) (0.2, 0.3 and 0.4¿g·L¿1·d¿1) reaching 32¿41% biodegradability values. The microbial community analysis revealed a remarkable presence of microorganisms that exhibit high hydrolytic capabilities such as Thermotogae (~44.5%), Firmicutes (~17.6%) and Dictyoglomi, Aminicenantes, Atribacteria and Planctomycetes (below ~5.5%) phyla. The suggested metabolic role of these phyla highlights the importance of protein hydrolysis and fermentation when only degrading microalgae. The …
Potential risk analysis of human anisakiasis through the consumption of mackerel, Scomber scombrus, sold at Spanish supermarkets
2016
Abstract Herein, the potential risk of human anisakiasis through the consumption of mackerel, Scomber scombrus , sold at nationwide Spanish supermarket chains is assessed, by means of the identification of anisakid and other nematode species found, and the analysis of intrinsic and extrinsic factors that may influence the prevalence and abundance of nematode worms, as well as their presence in the viscera or in the flesh. 231 fresh mackerel specimens caught between 2008 and 2014 (140 from the Atlantic and 91 from the Mediterranean), captured in autumn and spring and acquired at nationwide Spanish supermarket chains, were examined dissecting their viscera and submitting their flesh to artifi…
Quality characteristics and in vitro digestibility study of barley flour enriched ditalini pasta
2016
A ditalini pasta with a mixture of durum wheat and beta-glucan enriched barley flour (BF) (60/40%, w/w) was found to have a final content of 5% beta-glucan (BF-ditalini). Main quality parameters of BF-ditalini, water uptake and starch-protein texture, were comparable with those of 100% durum wheat ditalini (control). After in vitro simulated intestinal digestion, the content of beta-glucan in the post intestinal (PI) supernatant of BF-ditalini processed with its cooking water (soup) was six fold higher than that of pasta asciutta. BF-ditalini soup, but not pasta asciutta, strongly delayed the hydrolysis of the starch, without difference of viscosity between PI supernatant and control. PI su…
Optimization of electrospraying conditions for the microencapsulation of probiotics and evaluation of their resistance during storage and in-vitro di…
2016
Electrospraying has recently emerged as a novel microencapsulation technique with potential for the protection of probiotics. However, research efforts are still needed to minimize the viability loss observed during the processing of sensitive strains, and to maximize productivity. The aim of the present work was the optimization of the electrospraying conditions for the microencapsulation of a model probiotic microorganism, Lactobacillus plantarum, within a whey protein concentrate matrix. In a pre-optimization step, the convenience of encapsulating fresh culture instead of freeze-dried bacteria was established. Additionally, a surface response methodology was used to study the effect of t…
Microbial community characterization during anaerobic digestion of Scenedesmus spp. under mesophilic and thermophilic conditions
2017
[EN] Microbial communities were thoroughly characterized in a mesophilic anaerobic membrane bioreactor (AnMBR) and a thermophilic continuous stirred tank reactor (CSTR), which were both treating recalcitrant microalgal biomass dominated by Scenedesmus. 16S rRNA amplicon sequencing analysis was performed when the AnMBR achieved 70% algal biodegradation and revealed high microbial diversity, probably due to the high solid retention time (SRT) of the AnMBR configuration. The bacterial community consisted of Chloroflexi (27.9%), WWE1 (19.0%) and Proteobacteria (15.4%) as the major phyla, followed by Spirochaetes (7.7%), Bacteroidetes (5.9%) and Firmicutes (3.6%). These phyla are known to exhibi…
Considering syntrophic acetate oxidation and ionic strength improves the performance of models for food waste anaerobic digestion.
2021
Current mechanistic anaerobic digestion (AD) models cannot accurately represent the underlying processes occurring during food waste (FW) AD. This work presents an update of the Anaerobic Digestion Model no. 1 (ADM1) to provide accurate estimations of free ammonia concentrations and related inhibition thresholds, and model syntrophic acetate oxidation as acetate-consuming pathway. A modified Davies equation predicted NH3 concentrations and pH more accurately, and better estimated associated inhibitory limits. Sensitivity analysis results showed the importance of accurate disintegration kinetics and volumetric mass transfer coefficients, as well as volatile fatty acids (VFAs) and hydrogen up…
Digestion and absorption rates of [3H]-oleic acid and [14C]-triolein do not differ in rats fed heated (-) and (+) gossypol cottonseed and soybean flo…
1998
This study was conducted to compare in vivo the acute effects of heated (+) and (-) gossypol cottonseed flours with those of soybean flour on lipid digestion and absorption in growing rats. Rats were fed by gastric intubation mixed [ 3 H]-oleic acid and [ 14 C]-triolein with heated flours or without flour (control). Lipid digestion and absorption were determined for 6 h after meal intubation. Both radioactivities recovered in gastrointestinal tract were significantly higher in rats fed (+) gossypol cottonseed flour than in all other groups. The majority of both recovered radioactivities was found in stomach contents, then in stomach wall and finally in intestinal wall. The distribution of b…
Effect of simulated gastrointestinal digestion on plant sterols and their oxides in enriched beverages
2013
Abstract This study evaluates the bioaccessibility (percentage of soluble compound available for absorption) of plant sterols (PS) and their oxides (phytosterol oxidation products, POPs) after simulated gastrointestinal digestion in fruit (Fb), milk (M) and fruit-based milk beverages with (FbM a ) or without (FbM b ) tangerine juice. In beverages and their bioaccessible fraction (BF), campesterol, campestanol, stigmasterol, β-sitosterol and sitostanol were detected. Bioaccessibility of total PS ranged between 2.62 and 6.48%, FbM b yielding the highest value, followed by FbM a > Fb > M. Campesterol/campestanol were the most bioaccessible PS. Only oxides of β-sitosterol were detected in beve…
Some observations on the determination of total heavy metals in sewage sludge by atomic absorption spectrophotometry after a pressurized acid digesti…
1990
Abstract An economical and simple method for the flame atomic absorption spectrometric determination of Cd, Pb, Ni, Cu, Fe, and Zn in sewage sludges is described. Samples are treated with concentrated HNO 3 in a thermal oven using Pyrex glass tubes hermetically sealed with Bakelite screw caps. The effect of the digestion parameters, such as digestion time, acid volume, sample mass, and temperature, were studied. The precision and accuracy of this procedure were evaluated by the analysis of two BCR (Community Bureau of Reference, European Communities) certified sewage sludge samples (CRM 146 and 144).
Flame atomic absorption analysis of gold in jewelry samples
1990
A new procedure is proposed for the determination of gold by flame atomic absorption in jewelry samples. The method is based on the acid digestion of 10 mg of sample in a microwave oven and on the on-line dilution, using a three-way valve. The dynamic range of the technique is extended to 100 mg/l gold solutions and using a weighted bracketing method for the treatment of the results, accuracy errors lower than 2% can be found in the analysis of real samples as compared with those obtained by fire assay. The method is very fast and implies only little damage to the jewelry samples.