Electrocoagulation as a key technique in the integrated urban water cycle – A case study in the centre of Spain

Electrocoagulation (EC) presents operational advantages over chemical coagulation, including no requirement for the addition of chemicals. This work compares the performance of electrocoagulation in two stages of the urban water cycle: drinking water production and wastewater regeneration. A case study focussed on the treatment of actual effluents from different locations in the centre of Spain is performed. It was observed that electrocoagulation with aluminium anodes is an efficient technique to remove turbidity and total organic carbon (TOC) from surface water and to deplete turbidity and Escherichia coli (E. coli) from urban treated wastewater (taken from the outlet of an urban wastewater treatment facility, WWTF). Although electrocoagulation can be applied to the treatment of both effluents, the technique is more efficient in the case of the production of drinking water from surface sources. This behaviour is related to the nature of the natural organic matters (NOM) present in both effluents.     

On the improvement of chemical conversion in a surface-wave microwave plasma reactor for CO2 reduction with hydrogen (The Reverse Water-Gas Shift reaction)

A novel surface-wave microwave discharge reactor configuration to generate syngas via gaseous CO₂ reduction with H₂ (non-catalytic Reverse Water-Gas Shift reaction) is studied in the context of power-to-chemicals concept. Improvement of CO₂ conversion to maximize CO production is explored by adding an external cylindrical waveguide downstream of the plasma generation system. A 2D self-consistent argon model shows that power absorption and plasma uniformity are improved in the presence of the waveguide. We show experimentally that CO₂ conversion is increased by 50% (from 40% to 60%) at the stoichiometric feed ratio H₂:CO₂ equal to 1 when using the waveguide. At higher H₂:CO₂ ratios, the effect of the waveguide on the reactor performance is nearly negligible. Optical emission spectroscopy reveals that the waveguide causes significant increase in the concentration of O atoms at a ratio H₂:CO₂ = 1. The effects of the operating pressure and cooling rate are also investigated. A minimum CO₂ conversion is found at 75 mbar and ratio H₂:CO₂ = 1, which is in the transition zone where plasma evolves from diffusive to combined operation regime. The cooling rates have significant impact on CO₂ conversion, which points out the importance of carefully designing the cooling system, among other components of the process, to optimize the plasma effectiveness.     

Nutritional and functional properties of Vicia faba protein isolates and related fractions

The goal of this research was the characterisation of Vicia faba (broadbean) protein isolates and related fractions in order to determine whether this grain legume could be used for production of high quality protein products and other fractions rich in functional components. Alkaline extraction of the defatted seed flour, followed by precipitation at the isoelectric pH, yielded a 92% protein isolate with a high oil absorption capacity. The contents of the favism-inducing glycosides, vicine and convicine, in the isolate were reduced by more than 99% as compared to the original flour, although the amino acid composition was similar to that of the flour. Some of the by-products of protein isolate production may also be of interest from a nutritional and functional point of view. Thus, the oil resulting from hexane extraction of the flour is rich in unsaturated fatty acids, and polyphenols (resulting from extraction of the defatted flour with acetone) showed a high ABTS radical-scavenging activity. In addition, the solid residue (resulting from protein solubilisation) was high in fibre and showed good water absorption. These results show good nutritional and functional properties in V. faba protein isolates and related fractions, which may favour the revalorisation of this traditional bean crop.     

Effect of lactoferrin and its derivatives against gram-positive bacteria in vitro and, combined with high pressure, in chicken breast fillets

The bactericidal activity of lactoferrin (LF), amidated lactoferrin (AMILF), pepsin digested lactoferrin (PDLF), and its activated (ALF) commercial form, against six strains of three gram-positive bacterial species was investigated. Listeria monocytogenes was most sensitive in vitro, Staphylococcus aureus showed a moderate resistance, and Enterococus faecalis was highly resistant to antimicrobials. When chicken breast fillets were inoculated with L. monocytogenes CECT5725 and treated with antimicrobials, reductions were below 0.5 log CFU/ml in all cases. In combination with high pressure (HHP) treatment at 400 MPa for 10 min, antimicrobials showed a slight additional bactericidal effect, always below 1 log CFU/g. Incorporation of antimicrobials 18 h before or 1 h after HHP treatment generally yielded better results than incorporation 1 h before HHP treatment, although reductions remained below 1.5 log CFU/g in all cases. LF and its derivatives showed a limited potential for pathogen control in meat.     

Antioxidant and chelating activity of Jatropha curcas L. protein hydrolysates

BACKGROUND: Antioxidant and chelating activities were determined in protein hydrolysates that were produced by treating a protein isolate of a non‐toxic genotype of Jatropha curcas with the protease preparation alcalase. RESULTS: 50 min protein hydrolysate with a degree of hydrolysis of 31.7% showed highest antioxidant and chelating activity. These activities were also determined in six peptidic fractions that were separated by gel filtration chromatography of the 50 min hydrolysate. The lower‐molecular‐weight peptidic fractions had the highest antioxidant and chelating activities, which correlated with a higher content in antioxidant and chelating amino acids such as tyrosine and histidine. CONCLUSION: Results show that J. curcas represents a good source of bioactive peptides. This may be important for the revalorization of defatted J. curcas flour, a by‐product resulting form oil extraction for biodiesel production. This is especially important in Third World and developing countries such as Mexico. Copyright © 2011 Society of Chemical Industry     

Fatty acid composition of the triglyceride and free fatty acid fractions in different cows-, ewes- and goats-milk cheeses

Summary The fatty acid composition of the triglyceride fraction and the individual and total free fatty acids in different cows-, ewes- and goats-milk cheeses were analysed. The highest total free fatty acid levels were recorded in blue cheeses (Roquefort: 26.0 g/kg; Cabrales: 57.3 g/kg) and in the aged Manchego cheese (32.4 g/kg), followed by those in hard cheeses manufactured using unpurified rennet pastes containing pregastric esterases (Parmesan: 13.7 g/kg; Majorero: 20.8 g/kg). These samples had sharp flavours. The soft cheeses with surface flora presented moderate levels of free fatty acids (Camembert: 5.1 g/kg; de la Vera: 9.9 g/kg). The remaining cheeses considered (Mahôn: 8.7 g/kg; Roncal: 8.2 g/kg; Tetilla: 5.8 g/kg; Idiazabal: 5.6 g/kg) also exhibited moderate levels of lipolysis. A comparison of the fattyacid profiles for the two fractions studied yielded higher contents for the short-chain fatty acids in the free fatty acid fraction, except in the blue and goats-milk cheeses.

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Fettsäurenzusammensetzung der Triglyceridfraktionen und der freien Fettsäuren in verschiedenen Käsesorten aus Kuh-, Schaf- und Ziegenmilch

Zusammenfassung Es wurde die Fettsäurezusammensetzung der Triglyceridfraktionen und der freien Fettsäuren in verschiedenen Käsesorten aus Kuh-, Schaf- und Ziegenmilch untersucht. Die Blauschimmelkäsesorten Cabrales, Roquefort und der Manchegokäse zeigten die höchsten freien Fettsäurewerte: 57.3; 26.0 und 32,4 g/kg, gefolgt von denen, die mit Hilfe von unreinem Lab hergestellt wurden (Majorero: 20.8 g/kg; Parmesan: 13.7 g/kg). Diese Proben zeigten ein pikantes Aroma. Die Schimmelkäsesorten wie Camembert und de la Vera hatten einen mittleren freien Fettsäuregehalt von 5.1 und 9.9 g/kg. Die anderen untersuchten Proben wiesen ebenfalls niedrige Lipolysewerte auf (Mahón: 8.7 g/kg; Roncal: 8.2 g/kg; Tetilla: 5.8 g/kg; Idiazabal: 5.6 g/kg. Im Vergleich der Fettsäureprofile der untersuchten Fraktionen wurde bei den freien Fettsäurefraktionen ein höherer Gehalt an kurzen Fettsäuren beobachtet, mit Ausnahme der Blauschimmelkäse und der Ziegenmilchkäsesorten.

     

Effects of technological settings on yield,curd, whey,and cheese composition during the cheese-making process from raw sheep milk in small rural dairies: Emphasis on cutting and cooking conditions

The technological conditions of cheese-making affect cheese yield and compound losses in the whey, especially the processes of cutting and cooking. Although significant compositional and functional differences have been reported among animal species, there is a lack of studies on the effects of cheese-making technology on cheese yield and losses for sheep milk. Thus, we examined the cheese-making settings in 8 small rural dairies working with raw sheep milk and their effects on cheese yield and compound losses in whey during the cheese-production season. Actual cheese yield varied in 2 to 3 kg of cheese/100 kg of milk among dairies due to the cheese-making conditions, particularly the duration of cutting and cooking and the final cooking temperature. The combination of the conditions used during cutting and cooking, especially, determined fat losses in the whey. Fat losses were increased with high-speed and short cutting time settings together with high stirring speed and long duration of cooking. Additionally, cheese-makers should adapt the cutting and cooking conditions to the seasonal variations of milk composition, especially during early summer, when fat losses in the whey are higher. Our results suggest that it could be useful to use approximately 10 to 15 min of cutting time and moderate cooking speed and duration. The data reported in this study may assist the improvement of the cheese-making process in small rural dairies using sheep milk, where facilities are limited and the role of the cheese-maker is crucial.     

Fatty acid profile and CLA isomers content of cow,ewe and goat milks processed by high pressure homogenization

High pressure homogenization (HPH) is a novel technology that promotes fat globule size reduction and microbial inactivation, but little research exists on the fate of milk fat lipids. This work studied the effect of HPH (0–350 MPa) of raw cow, goat and ewe milks on the fatty acid total content and profile to elucidate whether this technology has a major impact on the lipid fraction of milk and especially on CLA isomers. Fatty acids in processed milks were determined by GC-FID and CLA isomers by Ag+-HPLC.Our results indicate that the total amount of fat extracted from the milk samples decreased as the homogenization pressure increased, whereas no significant differences were found in the fatty acid composition, especially in the PUFA and CLA isomers profile of raw milk treated by HPH process up to 350 MPa.Industrial relevanceThe absent of significant modifications of the fatty acids content and CLA isomers profile in milk by using high-pressure homogenization is relevant in the development of nonthermal technologies able to pasteurize/sterilize foods, without the organoleptic, functional, and chemical alterations associated to thermal processing.     

Effect of partial exchange of lactose with fat in milk replacer on ad libitum feed intake and performance in dairy calves

Compared with Holstein whole milk, commercial milk replacers (MR) for calves deliver relatively high levels of lactose and low levels of fat, and protein levels are rather comparable, resulting in a lower energy density and energy-to-protein ratio of the diet. Thus, the objective of this study was to determine the effects of partially exchanging lactose with fat in MR on voluntary feed intake, growth performance, and feeding behavior. Thirty-two male Holstein calves (2.1 ± 0.16 d of age, 46.4 ± 0.77 kg of body weight; BW) were assigned to 16 blocks of 2 calves per block based on arrival date and serum IgG. Within each block, calves were randomly assigned to 2 treatments: a high-lactose MR (HL; 17% fat; 44% lactose), or a high-fat MR (HF; 23% fat; 37% lactose). Lactose was exchanged by fat on a weight per weight basis, resulting in a 6% difference in metabolizable energy density per kilogram of MR. The experiment was divided into 3 phases: preweaning (P1; 0–35 d), weaning (P2; 36–56 d), and postweaning (P3; 57–84 d). For the first 2 wk of P1, calves were individually housed, fed their respective MR ad libitum through teat buckets, and provided access to water. At 14.2 ± 0.5 d of age, calves were group-housed (4 blocks/pen, 8 calves) and housed in group pens for the remainder of the study. In the group pens, calves were fed ad libitum MR, starter feed, chopped wheat straw, and water via automated feeders. During P2, calves were gradually weaned until complete milk withdrawal by 57 d and then monitored until 84 d (P3). Measurements included daily intakes and feeding behavior (rewarded and unrewarded visits), weekly BW and body measurements, and biweekly blood samples. Increasing fat content at the expense of lactose decreased MR intake during P1 by 15% (HL = 1.32 ± 0.04; HF = 1.17 ± 0.04 kg of dry matter per day), whereas total starter intake was not affected by MR composition. Once MR was restricted during P2, HL calves were reported to have more unrewarded visits to the automatic milk feeder than HF calves (11.9 ± 0.95 vs. 8.4 ± 1.03 visits/d, respectively). Crude protein intake was higher for HL calves during P1 (352.1 ± 11.2 vs. 319.6 ± 11.6 g/d), which was attributed to the higher intake of MR during that period, and metabolizable energy intake and protein-to-energy ratio remained comparable between treatments. Plasma cholesterol and nonesterified fatty acids levels were higher in HF calves as a consequence of the diet. Nevertheless, final BW (84 d) did not differ between treatments. Overall, calves fed ad libitum seemed to regulate their intake of MR based on its energy density, without significant effects on solid feed intake and overall growth.     

Ripening changes in Ras cheese prepared from ultrafiltered milk

Summary The changes in the proteins and fats of Ras cheese prepared from ultrafiltered milk (UF) were followed during ripening. The soluble protein fraction was made up of whey protein which resisted hydrolysis during ripening. The insoluble protein fraction of fresh cheese was made up mainly of-casein,-casein ands₁-I, indicating pronounced proteolysis during the salting step. Further ripening was accompanied with decrease ins₁-I and increase in-casein. The free fatty acids (FFA) of UF Ras cheese increased with advanced ripening. The pattern of FFA in Ras cheese was similar to that of bovine milk triacylglycerols.

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Veränderungen in der Zusammensetzung von Ras-Käse aus ultrafiltrierter Milch während der Reifung

Zusammenfassung Es wurden die Veränderungen der Proteine und der Fettfraktionen von Ras-Käse aus ultrafiltrierter Milch während der Reifung studiert. Die lösliche Proteinfraktion bestand aus Molkeproteinen, die der Hydrolyse während der Reifung widerstand. Die unlösliche Proteinfraktion des frischen Käses bestand aus-Casein,-Casein unds₁-I, was auf starke Proteolyse während des Einsalzens hinweist. In der nachfolgenden Reifung wurde eine Abnahme dess₁-Caseins und eine Zunahme der-Caseine beobachtet. Die freien Fettsäuren des Ras-Käses nahmen während der Reifung zu. Das Muster der freien Fettsäuren des Ras-Käses und das der Milchtriglyceride sind ähnlich.