Quantitative studies on the enzymatic hydrolysis of milk proteins brought about by cardosins precipitated by ammonium sulfate

Hydrolysis of whey proteins may produce peptide mixtures with better functional properties than the original protein mixture, viz. higher solubilites and lower allergenic effects. Cynara cardunculus is a wild plant that possesses (aspartic) proteases in its flower cells; those enzymes exhibit general proteolytic and specific milk clotting activities, which are rather useful in traditional cheesemaking. This study was thus aimed at characterizing the enzymatic action of crude extracts of said plant after preliminary purification by salting out with ammonium sulfate at two different concentration levels, viz. 30% and 70% saturation. The coagulant activity on milk, and the proteolytic activity using casein and azocasein as substrates, of the crude extract and of each precipitated fraction were measured at 37°C and pH 5.2. The profile of hydrolysis of the major whey proteins, i.e. α-lactalbumin (α-La), β-lactoglobulin (β-Lg) and bovine serum albumin (BSA) was characterized by gel permeation chromatography and polyacrylamide gel electrophoresis (PAGE) in the presence of sodium dodecyl sulfate. The 30% and 70% saturation fractions exhibited lower coagulant and proteolytic specific activities than the crude extract. However, the relative ratio of coagulant to proteolytic activity, which is a useful indicator of appropriateness for cheesemaking, was higher for the partially purified fractions. The extents of hydrolysis of whey proteins brought about by the partially purified extracts were above those by their crude counterpart, but qualitative hydrolysis patterns were essentially identical to each other; by 24 h, α-La was substantially depleted, whereas β-Lg was very poorly hydrolyzed and BSA was only slightly hydrolyzed. The native proteins were converted to lower and lower molecular weight peptides

Obtaining triplet-triplet absorption spectra and triplet lifetimes of long-lived molecules with a UV-Visible spectrophotometer

A simple method for obtaining triplet-triplet absorption (TTA) spectra and triplet state (T1) lifetimes of long-lived triplets is presented and demonstrated with the polycyclic aromatic hydrocarbon coronene (both normal and perdeuterated forms) in a polymer matrix at room temperature. The TTA spectra obtained with a camera flash and a spectrophotometer are noisier but otherwise identical to those obtained with a state-of-the-art flash photolysis apparatus. The triplet lifetimes obtained from transient absorption are identical to the phosphorescence lifetimes of the same samples.This article is based upon work from COST Action CA21126 - Carbon molecular nanostructures in space (NanoSpace), supported by COST (European Cooperation in Science and Technology), and by projects iBB (UIDB/04565/2020 and UIDP/04565/2020) and i4HB (LA/P/0140/2020), Fundação para a Ciência e a Tecnologia (FCT), Portugal

Evolutionary patterns and development prospects for e-government: a Delphi-based approach to perceptions of the administrative agent

Information technology is an open door for governments to service citizens in a more timely, cost-efficient and effective manner. Even considering citizen resistance, cultural adversity or changes in the economic agents’ relationship, few would contest that concern over the state of electronic government (e-government) has increased over the years. This concern has been responsible for the emergence of a wide range of new initiatives devoted to development of the information and knowledge society, which occupies a central place in government policies and planning strategies worldwide. In this paper, we aim to analyze the evolutionary patterns of e-government in Portugal and, based on an application of the Delphi technique, provide development prospects considering the perceptions of a panel of administrative agents. Despite the low use of e-government services, our study demonstrates that the administrative agent expresses overall satisfaction with its use. Additionally, the high level of modernization allows us to forecast the increased use of information and communication technologies in terms of e-government services

Energy requirements for the continuous biohydrogen production from Spirogyra biomass in a sequential batch reactor

The current energy market requires urgent revision for the introduction of renewable, less-polluting and inexpensive energy sources. Biohydrogen (bioH2) is considered to be one of the most appropriate options for this model shift, being easily produced through the anaerobic fermentation of carbohydrate-containing biomass. Ideally, the feedstock should be low-cost, widely available and convertible into a product of interest. Microalgae are considered to possess the referred properties, being also highly valued for their capability to assimilate CO2 [1]. The microalga Spirogyra sp. is able to accumulate high concentrations of intracellular starch, a preferential carbon source for some bioH2 producing bacteria such as Clostridium butyricum [2]. In the present work, Spirogyra biomass was submitted to acid hydrolysis to degrade polymeric components and increase the biomass fermentability. Initial tests of bioH2 production in 120 mL reactors with C. butyricum yielded a maximum volumetric productivity of 141 mL H2/L.h and a H2 production yield of 3.78 mol H2/mol consumed sugars. Subsequently, a sequential batch reactor (SBR) was used for the continuous H2 production from Spirogyra hydrolysate. After 3 consecutive batches, the fermentation achieved a maximum volumetric productivity of 324 mL H2/L.h, higher than most results obtained in similar production systems [3] and a potential H2 production yield of 10.4 L H2/L hydrolysate per day. The H2 yield achieved in the SBR was 2.59 mol H2/mol, a value that is comparable to those attained with several thermophilic microorganisms [3], [4]. In the present work, a detailed energy consumption of the microalgae value-chain is presented and compared with previous results from the literature. The specific energy requirements were determined and the functional unit considered was gH2 and MJH2. It was possible to identify the process stages responsible for the highest energy consumption during bioH2 production from Spirogyra biomass for further optimisation

Energetic and environmental evaluation of microalgae biomass fermentation for biohydrogen production

This paper presents an energetic and environmental evaluation of the fermentative hydrogen production from the sugars of Scenedesmus obliquus biomass hydrolysate by Clostridium butyricum. The main purpose of this work was to evaluate the potential of H2 production and respective energy consumptions and CO2 emissions in the global fermentation process: hydrolysis of S. obliquus biomass, preparation of the fermentation medium, degasification and incubation. The scale-up to industrial production was not envisaged. Energy consumption and CO2 emissions estimations were based on SimaPro 7.1 software for the preparation of the fermentation medium and the use of degasification gas, nitrogen. The functional unit of energy consumption and CO2 emissions was defined as MJ and grams per 1 MJ of H2 produced, respectively. The electricity consumed in all hydrogen processes was assumed to be generated from the Portuguese electricity production mix. The hydrogen yield obtained in this work was 2.9 ± 0.3 mol H2/mol sugars in S. obliquus hydrolysate. Results show that this process of biological production of hydrogen consumed 281-405 MJ/MJH2 of energy and emitted 24-29 kgCO2/ MJH2. The fermentation stages with the highest values of energy consumption and CO2 emissions were identified for future energetic and environmental process optimisation

Effect of polymer type on the properties of polypropylene composites with high loads of spent coffee grounds

The main focus of this work is to study the processability and characteristics of highly loaded spent coffee grounds (SCG) thermoplastic polymer composites, for sustainable applications. SCG powder was characterized in terms of size distribution, moisture, morphology and thermal stability. Polymer/SCG composites were prepared by extrusion compounding. Polypropylene (PP) homopolymer and copolymer were used as the polymeric matrix. Upon compounding by extrusion composites were injection moulded and characterized for its physical, morphological and mechanical properties in order to determine the effect of polymer type and filler content. Morphological characteristics of the composites were investigated using optical microscopy and SEM analysis. The results for PP homopolymer showed little deterioration of the mechanical properties when using the highest SCG load. In the case of PP homopolymer, the greatest variations occurred when increasing from 0 to 20 %. With higher SCG loads, the measured properties changed little. PP copolymer showed a more continuous pattern of properties decay with increasing SCG load, especially for tensile strength, elongation at break and impact strength. Regarding PP copolymer, with maximum SCG load, the tensile strength decreased from 26.8 GPa (neat PP) to 10.8 GPa, the elongation at break showed a drop of more than 95 %, while the Young's modulus increased from 800 MPa to 1160 MPa. This research work has shown that SCG can be used as fillers in the preparation of environmentally friendly composites with SCG load up to 60 wt% thus contributing to the reuse of waste generated by the coffee industry.This research was supported by FEDER funds through the COMPETE 2020 Programme and National Funds through FCT (Portuguese Foundation for Science and Technology) under the projects UID-B/05256/ 2020, UID-P/05256/2020

Comparison of vaginal microbiota fingerprints from healthy and bacterial vaginosis-positive portuguese women

Bacterial Vaginosis (BV) is a common disease in women of reproductive age and is characterized by the substitution of Lactobacillus species,which are predominant in the normal vaginal microbiota,by rapidly proliferating anaerobic bacteria, particularly Gardnerellavaginalis. The aim of this study was to study microbial communities’ structure in the vaginal microbiota of healthy and BV-positive Portuguese women. To this end, DNA obtained from vaginal samples of 22 BV-negative and 19 BV-positive women was analyzed using a PCR-DGGE approach.Total bacterial communities were amplified using general 16S rRNA gene primers. Group-specific primers were also used targeting Lactobacillus and Bifidobacterium genera and G.vaginalis. DGGE profiles were compared using the BioNumericsTM software package (Applied Maths, Belgium). Similarity between DGGE profiles was determined by calculating similarity indices of the densitometric curves of the compared profiles, using the Dice product-moment correlation. Different DGGE profiles could be obtained for BV-positive and BV-negative samples and this was verified for all primers sets utilized, suggesting that alteration of microbial community structure of BV-positive and -negative samples could be detected by PCR-DGGE. DGGE profiles obtained from samples of BV-positive women were more diverse that the ones from healthy women (as determined by a higher number of DGGE bands). The analysis of the standard electrophoretic bands for bacteria reveals an intrinsic diversity even within the two groups studied: similarities in bacterial DGGE profiles vary between 14- 78% and 47-100% in BV-positive and BV-negative samples, respectively. Among the 19 BV-positive women studied 18 were colonized with G. vaginalis. G.vaginalis was not detected in any of the healthy women samples. The analysis of Lactobacillus communities revealed a higher diversity in BV-negative women than in BV-positive ones, which confirms the association of Lactobacillus in healthy vaginal microbial communities. A more thoroughly comparison between BV-negative and BV-positive, including the retrieval of sequencing data from these samples, is necessary for getting more insight on BV influence on vaginal microbiota

Synergisms in antioxidant and anti-hepatocellular carcinoma activities of artichoke, milk thistle and borututu syrups

Artichoke, borututu and milk thistle are three medicinal plants well-known for their capacity to prevent oxidative stress and many liver diseases. In a previous work, we reported the bioactivity of infusions and pills based on these plants; herein, the aim was to provide scientific information about the antioxidant and anti-hepatocellular carcinoma activities of syrups based on these medicinal plants and evaluate the synergism among the combined plants by using syrups based on the mixed plants or prepared form the combinations of individual species. The antioxidant activity was measured by radical scavenging activity, reducing power and lipid peroxidation inhibition, while the anti-hepatocellular carcinoma activity and the hepatotoxicity were evaluated using HepG2 human cell line and a primary culture of porcine liver cells, respectively. Milk thistle syrup proved to have the highest antioxidant activity in all the assayed methods, providing the best results either in single syrup or included in mixed syrups. Synergistic effects were the main interactions observed in the mixture of artichoke, borututu and milk thistle; mixing the syrups based on each single plant proved to be more efficient regarding antioxidant proposals than mixing plants in the same syrup. The latter was advantageous for anti-hepatocellular carcinoma activity.The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) for financial support to the research center CIMO (PEst-OE/AGR/UI0690/2011) and L. Barros researcher contract under "Programa Compromisso com Ciencia-2008

Maize (Zea mays L) cultivars nutrients concentration in leaves and stalks

There is pressure for crop residue removal for use as biofuel, animal feed, animal bedding and many other func¬tions which may increase nutrient export. However, there is little information about nutritional composition of maize stover considering the wide variability of cultivars used. The aim of this study was to evaluate the influence of maize cultivar on macronutrient (P, K, Ca, and Mg), micronutrient (Fe, Mn, Zn, and Cu) and Na concentration in leaves and stalks. We selected five pairs of cultivars, ranging from creole to high potential hybrid (creole, commer¬cial variety, single, double and triple cross hybrid). The cultivars were cropped under field conditions in high fertile Rhodic Ferralsol Eutric during two growing seasons. The first was characterized by severe drought (2005/2006) while the second with an abundant water supply (2006/2007). The leaf and stalk concentrations of P, K, Ca, Mg, Fe, Mn, Na, Zn, Cu, and C/P ratio were quantified at maturation stage. The results indicated that the P concen¬tration in leaves and stalks was inversely related to the technological level when simple hybrid was compared to creole cultivars. Similar behavior was observed for K in the leaf and stalk tissues. For Ca, Mg, Fe, Mn, Zn, Cu, and Na, it was not possible to establish the influence of maize selection. The C/P ratio of leaves and stalks underwent influence of the technological level with high values for simple hybrids. Maize selection seems to decrease P and K concentration for two major residue fractions, leaves and stalks