M.M. Muñío

Water quality characterization in real biofilm wastewater treatment systems by particle size distribution.

This article analyses the relation between wastewater quality parameters and particle size distribution (PSD) in three real wastewater treatment plants with different biofilm technologies: submerged biofilter system, trickling filter system, and rotating biological contactor system. The main quality parameters, (suspended solids, turbidity and COD), and PSD in the influent and effluent water of each different biofilm treatment were analyzed during 1year. The PSD was fitted using the power law (n(d(p))= partial differentialN(d(p))/ partial differentiald(p)=A x d(p)(-)(b)(Log(d)(p)())) obtaining the coefficients A and b to define the particle distribution. Mathematical correlations between this coefficients and the rest of parameters studied were found (SS=0.0713 x A(0.585), turbidity=4.549 x 10(-4) x A(1.096), COD=0.0201 x A(0.774)). The relation with the average particle size by mass was also found, (d(pma)=60.3137 x b(-2.242)). Moreover a relation between PSD and the particle elimination efficiency of the secondary treatment was study, (eta=2.844-2.498 x b(relative)+0.0863 x A(relative)). These expressions are very useful to understand the behavior of the biofilm treatment system using PSD analyses.

Production of resistant starch by enzymatic debranching in legume flours.

Resistant starch (RS) was produced by enzymatic hydrolysis of flours from five different legumes: lentil, chickpea, faba bean, kidney bean and red kidney bean. Each legume was firstly treated thermally, then hydrolyzed with pullulanase for 24h at 50°C and pH 5 and lyophilized. At the end of each hydrolysis reaction, the RS amount ranged from 4.7% for red kidney beans to 7.5% for chickpeas. With respect to the curves of RS against hydrolysis time, a linear increase was observed initially and a plateau was generally achieved by the end of reaction. These curves were successfully modeled by a kinetic equation including three parameters: initial RS, RS at long operation time and a kinetic constant (k). Furthermore, the relative increase in hydrolysis, calculated using the kinetic parameters, was successfully correlated to the percentage of amylose.

Lipid characterization and properties of protein hydrolysates obtained from discarded Mediterranean fish species

BACKGROUND Discards are an important fraction of the by-products produced by the fishing industry. As a consequence of their low commercial acceptance, it is necessary to provide added value to these underutilized materials. In this study the lipid fraction of three discarded fish species in the western Mediterranean Sea, namely sardine (Sardina pilchardus), mackerel (Scomber colias) and horse mackerel (Trachurus trachurus), was characterized and the angiotensin I-converting enzyme (ACE)-inhibitory and antioxidative activities of their protein hydrolysates were evaluated. RESULTS Processing of these biomaterials led to oils with a high content of omega-3 polyunsaturated fatty acids (PUFAs), ranging from 220.5 g kg(-1) for horse mackerel to 306.0 g kg(-1) for sardine. Regarding the protein fraction, most of the hydrolysates presented ACE inhibition values higher than 60%, corresponding to IC50 values varying from 345 µg protein mL(-1) for mackerel to 400 µg protein mL(-1) for sardine. Moreover, most of the hydrolysates exhibited acceptable antioxidative activity, namely 35-45% inhibition of 1,1-diphenyl-2-picrylhydrazyl (DPPH). CONCLUSION This study suggests that the three discarded species evaluated are valuable raw materials for the production of bioactive ingredients such as omega-3 PUFAs and protein hydrolysates exhibiting antihypertensive and antioxidative activities.

Combined treatment of textile wastewater by coagulation–flocculation and advanced oxidation processes

AbstractTextile wastewater is one of the main environmental pollutants which exist in our society. Textile effluents cause great concern due to the alteration of properties of water bodies such as differences in temperature, organic load, pH, colour and turbidity. Turbidity is one of the most important parameters that should be removed from industrial wastewater because the penetration of ultraviolet (UV) light into the water body can be affected. As a consequence, the main aim of this research was to study the improvements of the efficiency of advanced oxidation processes (AOPs) with the introduction of a coagulation–flocculation (CF) as a pre-treatment to remove the turbidity of textile wastewater. The experiments were carried out with five industrial coagulants under different concentrations. The turbidity was removed to a level of almost 99% with one of the coagulants (FLOCUSOL-PA/18). The total organic carbon (TOC) and colour removals were studied for each AOP after the CF process in this research. T...

Development of an up-grading process to produce MLM structured lipids from sardine discards

The aim of the work was to produce MLM structured lipids with caprylic acid (M) as medium chain fatty acid located at the external bonds of the glycerol backbone and concentrated polyunsaturated fatty acids (L) from sardine discards (Sardine pilchardus) in the central bond of the glycerol. To that end, the following steps were conducted: (i) fish oil extraction, (ii) Omega-3 free fatty acids (FFA) concentration (low temperature winterization), (iii) two-steps enzymatic esterification and (iv) triacylglycerols (TAG) purification (liquid column chromatography). The resultant purified triacylglycerols accomplished with the oxidative state (peroxide and anisidine value, PV and AV) required for refined oils. As enzymatic treatment, Omega-3 concentrate FFA (Omega-3>600mg Omega-3 per g oil) were esterified with dicaprylic glycerol employing Novozyme 435. This process presented high regioselectivity, with ∼80mol% of concentrated fatty acids esterified at the sn-2 position.

A lumped model of the lipase catalyzed hydrolysis of sardine oil to maximize polyunsaturated fatty acids content in acylglycerols

The aim of this work was to produce diacylglycerols (DAG) and monoacylglycerols (MAG) with a high content of polyunsaturated fatty acids (PUFA). Rhizomucor miehei lipase mediated-hydrolysis of sardine oil was conducted at several water activities. The system was mechanistically modeled to predict the time evolution of the concentration of triacylglycerols, DAG, MAG and free fatty acids (FFA) and the concentration of saturated, mono- and polyunsaturated fatty acids. The release of the first fatty acid from the triacylglycerol was independent on the unsaturation degree. Contrary, the hydrolysis of the second one was highly affected by the degree of unsaturation, PUFA being the fatty acids that showed the highest resistance to hydrolysis. MAG percentage was maximum (7mol%) at lower water activities, while DAG content was favored at higher water activities (35mol%), achieving a 2-fold concentration of DHA.

Effects of temperature on the permeability and critical flux of the membrane in a moving bed membrane bioreactor

AbstractEffects of temperature on the permeate flux and the permeability of the membrane have been studied in a membrane bioreactor system with a moving bed pilot plant to treat real urban wastewater. In the present study, the permeability of the membrane has been determined under four different suspended solids concentrations and three different degrees of fouling in order to compare the effects of the temperature in different operational conditions. The permeate flux, critical flux and permeability of the membrane at seven different temperatures between 10 and 35°C have been checked. The study showed that the permeate flux increased to 19.2 and 21.2% between 10 and 15°C and between 15 and 20°C respectively, which was higher than the 8.70% obtained between 20 and 25°C, and similarly it increased to 15.6 and 15.6% obtained between 25 and 30°C and between 30 and 35°C, respectively. This trend has been also observed in critical flux values, under the different conditions of suspended solids and fouling degr...

Modeling of Water Sorption Isotherms Characteristics of Spray-Dried Cherimoya (Annona cherimola) Purée

Spray drying is a solution to preserve food products from spoiling and moisture adsorption isotherms of dry products can be used to predict their shelf life during storage and distribution. Sorption isotherms of spray-dried cherimoya purée were determined using a gravimetric method between 10°C and 50°C and water activities from 0.05 to 0.96. The data obtained were fitted to Guggenheim, Anderson, and De Boer (GAB), GAB modified, Henderson modified, Oswin modified, Chung–Pfost modified, and Hasley isotherms and the Henderson model best fitted experimental data. The net isosteric heat of sorption values determined using Clausius–Clapeyron ranged from 3.04 and 0.92 kJ/mol between 5% and 30% moisture content in dry basis, respectively. Differential entropy also decreased with moisture content. The compensation theory was applied to sorption isotherms and higher value of isokinetic temperature than harmonic mean temperature denotes that adsorption process was enthalpy controlled and a negative value of Gibbs free energy reflected a spontaneous process.