Ângelo C. Salvador

Effect of the ionic liquid [bmim]Cl and high pressure on the activity of cellulase

The effect of the ionic liquid 1-butyl-3-methylimidazolium chloride ([bmim]Cl) and of high pressure on the activity of cellulase from Aspergillus niger were studied separately and in combination. The enzyme activity decreased with increasing concentrations of [bmim]Cl, reaching 50% the value in aqueous buffer with 20% [bmim]Cl. However, when the enzyme is held in 10% [bmim]Cl and is then assayed in 1% [bmim]Cl, it showed only 8% reduction of activity. These results can be explained by the fact that the activity of the enzyme in [bmim]Cl is linearly correlated with the decrease of the thermodynamic water activity (aw). Under pressure the enzyme activity varied from less 60% (at 200MPa) to equal (at 400 MPa), compared to atmospheric pressure. In 10% [bmim]Cl under pressure, cellulase activity is improved compared to atmospheric pressure, varying from equal (at 600 MPa) to 1.7-fold higher (at 100 MPa). This opens the possibility to improve cellulase activity in ionic liquids, and possibly of other enzymes, by carrying out the reaction under pressure.

Can Volatile Organic Metabolites Be Used to Simultaneously Assess Microbial and Mite Contamination Level in Cereal Grains and Coffee Beans

A novel approach based on headspace solid-phase microextraction (HS-SPME) combined with comprehensive two-dimensional gas chromatography–time-of-flight mass spectrometry (GC×GC–ToFMS) was developed for the simultaneous screening of microbial and mite contamination level in cereals and coffee beans. The proposed approach emerges as a powerful tool for the rapid assessment of the microbial contamination level (ca. 70 min versus ca. 72 to 120 h for bacteria and fungi, respectively, using conventional plate counts), and mite contamination (ca. 70 min versus ca. 24 h). A full-factorial design was performed for optimization of the SPME experimental parameters. The methodology was applied to three types of rice (rough, brown, and white rice), oat, wheat, and green and roasted coffee beans. Simultaneously, microbiological analysis of the samples (total aerobic microorganisms, moulds, and yeasts) was performed by conventional plate counts. A set of 54 volatile markers was selected among all the compounds detected by GC×GC–ToFMS. Principal Component Analysis (PCA) was applied in order to establish a relationship between potential volatile markers and the level of microbial contamination. Methylbenzene, 3-octanone, 2-nonanone, 2-methyl-3-pentanol, 1-octen-3-ol, and 2-hexanone were associated to samples with higher microbial contamination level, especially in rough rice. Moreover, oat exhibited a high GC peak area of 2-hydroxy-6-methylbenzaldehyde, a sexual and alarm pheromone for adult mites, which in the other matrices appeared as a trace component. The number of mites detected in oat grains was correlated to the GC peak area of the pheromone. The HS-SPME/GC×GC–ToFMS methodology can be regarded as the basis for the development of a rapid and versatile method that can be applied in industry to the simultaneous assessment the level of microbiological contamination and for detection of mites in cereals grains and coffee beans.

Metabolomic-Based Strategy for Fingerprinting of Sambucus nigra L. Berry Volatile Terpenoids and Norisoprenoids: Influence of Ripening and Cultivar.

The integration of plant metabolomics to support preharvest fruit development studies can provide important insights into the biochemical mechanisms involved and lately support producers on harvesting management. A metabolomic-based strategy for fingerprinting of volatile terpenoids and norisoprenoids from Sambucus nigra L. berries from three cultivars, through ripening, was established. From 42 monoterpenic, 20 sesquiterpenic, and 14 norisoprenoid compounds, 48 compounds are reported for the first time as S. nigra berries components. Chemometric tools revealed that ripening was the factor that influenced more the volatile fraction profile and physicochemical parameters (pH, TS, and TSS), followed by cultivar. For the unripe stages, a higher overall content of the studied metabolites was observed, which gradually decreased over the ripening stages, being consistent for the three cultivars. These trends were mainly ruled by limonene, p-cymene, aromadendrene, β-caryophyllene, and dihydroedulan, which might therefore be used by producers as an additional simple decision making tool in conjunction with physicochemical parameters.

Unveiling elderflowers (Sambucus nigra L.) volatile terpenic and norisoprenoids profile: Effects of different postharvest conditions

The volatile terpenic and norisoprenoids profile from elderflowers (Sambucus nigra L.) was established for two cultivars by multidimensional gas chromatography. From 47 monoterpenic, 13 sesquiterpenes and 5 norisoprenoids components, 38 are reported for the first time on elderflowers. Elderflower seasonality implies proper handling and storage conditions, for further processing, thus the impact of freezing, freeze-drying, air drying and vacuum packing, was evaluated on these potential aroma metabolites. The most suitable preservation methods, regarding the total metabolites content, were vacuum packing and freezing for intermediary storage times (24-32weeks) with a reported overall decrease of the volatile terpenic and norisoprenoids of up to 58.6%; and freezing, for longer period (52weeks), with a decrease of up to 47.4% (compared to fresh elderflowers). This study presents the most detailed terpenic and norisoprenoids elderflower profiling, and linalool oxides were proposed as markers for a more expedite assess to the impact of postharvest conditions.

Effect of Elderberry (Sambucus nigra L.) Extract Supplementation in STZ-Induced Diabetic Rats Fed with a High-Fat Diet

Elderberry (Sambucus nigra L.) lipophilic and polar extract dietary supplementation effects were evaluated according to diabetes management indices, using an in vivo model. A research pipeline was constructed, that ranged from extract preparation, partial chemical characterization and toxicity evaluation, to examining the elderberry extract dietary supplementation effects on biofluid and tissues. Extracts toxicity was screened using an Aliivibrio fischeri bioluminescence model. A concentration of up to 60 mg/L was selected, and rat doses for oral supplementation were computed applying the interspecies correlation between A. fischeri and rats. Wistar type 2 diabetic rats, induced by streptozotocin (STZ), were fed a high-fat diet and supplemented for 4 weeks at doses of 190 and 350 mg/kg body weight/day of lipophilic and polar extract, respectively. As far as we know, lipophilic elderberry extract supplementation was assessed for the first time, while polar extract was administrated at higher doses and for a shorter period compared to previous studies, aiming to evaluate subacute supplementation effects. The polar extract modulated glucose metabolism by correcting hyperglycemia, while the lipophilic extract lowered insulin secretion. Both extracts lowered insulin resistance, without remarkable alterations to hematological indices, sera lipids and sera and tissular trace element homeostasis. In conclusion, elderberries are a potential source of bioactive compounds for formulations to be used as co-adjuvants in diabetes management.

Bioactive Phytochemicals from Wild Arbutus unedo L. Berries from Different Locations in Portugal: Quantification of Lipophilic Components

The lipophilic composition of wild Arbutus unedo L. berries, collected from six locations in Penacova (center of Portugal), as well as some general chemical parameters, namely total soluble solids, pH, titratable acidity, total phenolic content and antioxidant activity was studied in detail to better understand its potential as a source of bioactive compounds. The chemical composition of the lipophilic extracts, focused on the fatty acids, triterpenoids, sterols, long chain aliphatic alcohols and tocopherols, was investigated by gas chromatography–mass spectrometry (GC–MS) analysis of the dichloromethane extracts. The lipophilic extractives of the ripe A. unedo berries ranged from 0.72% to 1.66% (w/w of dry weight), and consisted mainly of triterpenoids, fatty acids and sterols. Minor amounts of long chain aliphatic alcohols and tocopherols were also identified. Forty-one compounds were identified and among these, ursolic acid, lupeol, α-amyrin, linoleic and α-linolenic acids, and β-sitosterol were highlighted as the major components. To the best of our knowledge the current research study provides the most detailed phytochemical repository for the lipophilic composition of A. unedo, and offers valuable information for future valuation and exploitation of these berries.

Effect of high pressure on cod (Gadus morhua) desalting

The effect of high pressure on salt and water diffusion in the desalting process of cod was studied. Under pressure, up to 300 MPa, the osmotic equilibrium is reached much faster, compared to desalting at atmospheric pressure. Water (D ew) and salt (D es) effective diffusion coefficients reached a maximum at 200 MPa, increasing 500- and 160-fold, respectively, compared with desalting at atmospheric pressure. Increasing pressure up to 300 MPa causes a reduction in both effective diffusion coefficients, although they were still about 70-fold higher than at atmospheric pressure. Up to 200 MPa, a linear correlation was found between D ew and D es and pressure. However, the total diffused amounts of water and salt, when the osmotic equilibrium was reached, were lower under pressure. At atmospheric pressure cod water content increased 1.65-fold, but under pressure the increment was on average 1.25-fold, while salt content decreased to 0.51-fold the initial value at atmospheric pressure and to around 0.75-fold under pressure.