Investigation and dynamic profiling of oligopeptides, free amino acids and derivatives during Pu-erh tea fermentation by ultra-high performance liquid chromatography tandem mass spectrometry

 Food Chem. 371, 131176, 2022

Microbial fermentation is the critical step of Pu-erh tea manufacture, which will induce dramatic changes in the chemical composition and content of tea. In this research, we applied multi-methods based on UHPLC-Q-TOF/MS to profile the dynamic changes of oligopeptides, free amino acids, and derivatives (OPADs) during Pu-erh fermentation and predicted the potential bioactivities in silico. A total of 60 oligopeptides, 18 free amino acids, and 42 amino acid derivatives were identified, and the contents of most of them decreased after fermentation. But several N-acetyl amino acids increased 7–36 times after fermentation, and they might be the potential inhibitors of neurokinin-1 receptor. Moreover, the results of metamicrobiology showed Aspergillus niger and Aspergillus luchuensis were more prominent to metabolize protein, oligopeptides, and amino acids. Overall, these findings provide valuable insights about dynamic variations of OPADs during Pu-erh tea fermentation and are beneficial for guiding practical fermentation and quality control of Pu-erh tea.

Starch-digesting product analysis based on the hydrophilic interaction liquid chromatography coupled mass spectrometry method to evaluate the inhibition of flavonoids on pancreatic α-amylase

 Food Chem. 372, 131175, 2022

An accurate hydrophilic interaction liquid chromatography coupled mass spectrometry (HILIC-MS) method is presented to characterize starch digestion by α-amylase and measure the inhibition properties of flavonoids against α-amylase in vitro. Eleven products were found as 1 → 4 linkage glucose oligosaccharides with different degrees of polymerization (DPs) from 2 to 12. The products with DPs of 2, 3, 6, 7, and 9 had higher yields. The product with DP of 9 had the highest yields, which first increased and then decreased with the reaction time. Pelargonidin has the best inhibition activity on all enzyme products. The 3′-hydroxyl of B-ring enhanced the inhibition activity of flavonol and flavone but weakened that of anthocyanin. The C-ring 3-hydroxyl increased the inhibition effect of flavonol on maltose but decreased that on the products with higher DPs than flavone. The HILIC-MS method can provide more detailed information on enzyme products for the study of flavonoids inhibiting α-amylase.

A new HPLC-MS/MS method for the simultaneous determination of 36 polyphenols in blueberry, strawberry and their commercial products and determination of antioxidant activity

 Food Chem. 367, 130743, 2022

Berry fruits consumption has increased in recent years because they are rich sources of polyphenols with reported health benefits. The aim of the present work was to develop a new comprehensive and fast HPLC-MS/MS method for simultaneous determination of 36 phenolic compounds (7 anthocyanins, 9 flavonols, 4 flavan-3-ols, 2 dihydrochalcones, 2 flavanones and 12 phenolic acids) present in blueberry, strawberry, and their fruit jam. Blueberry fruits showed higher contents of anthocyanins, flavonols and phenolic acids, while strawberry fruits exhibited higher contents of flavan-3-ols, dihydrochalcones and flavanones. Anthocyanins were the main phenolic constituents in both berries. Furthermore, the higher total phenolic content in the blueberry fruit and jam justified their greater antioxidant capacity measured by DPPH free radical assay, compared to strawberry. In conclusion, this new HPLC-MS/MS method is useful and reliable for quality control and authentication analyses of blueberry and strawberry fruits and their commercial food products, such as jams.

Active sites of peptides Asp-Asp-Asp-Tyr and Asp-Tyr-Asp-Asp protect against cellular oxidative stress

 Food Chem. 366, 130626, 2022

The protective effects of the peptides Asp-Asp-Asp-Tyr (DDDY) and Asp-Tyr-Asp-Asp (DYDD) against AAPH-induced HepG2 cells are unclear. Our objective was to investigate the active sites of these peptides and their cellular antioxidant mechanism. DDDY and DYDD show a direct free radical scavenging effect in reducing ROS levels and maintained cellular antioxidant enzymes at normal levels. The quantum chemistry analysis of the electronic properties of antioxidant activity showed that DYDD has a greater energy in the highest occupied molecular orbital than DDDY, and O58-H59 and N10-H12 were identified as the active antioxidant sites in DYDD and DDDY, respectively, indicating that the inconsistent arrangement of amino acids affects the distribution of the highest occupied orbital energy as well as the active sites; thus, influences the antioxidant activity of peptides. It provide valuable insights into the antioxidant active sites of peptides.

Molecular Recognition by Pillar[5]arenes: Evidence for Simultaneous Electrostatic and Hydrophobic Interactions

 Pharmaceutics 2022, 14(1), 60

The formation of inclusion complexes between alkylsulfonate guests and a cationic pillar[5]arene receptor in water was investigated by NMR and ITC techniques. The results show the formation of host-guest complexes stabilized by electrostatic interactions and hydrophobic effects with binding constants for the guest with higher hydrophobic character. Structurally, the alkyl chain of the guest is included in the hydrophobic aromatic cavity of the macrocycle while the sulfonate groups are held in the multicationic portal by ionic interactions.

Delineation of molecular interactions of plant growth promoting bacteria induced β-1,3-glucanases and guanosine triphosphate ligand for antifungal response in rice: a molecular dynamics approach

Mol Biol Rep 49, 2579–2589 (2022)

Background

The plant growth is influenced by multiple interactions with biotic (microbial) and abiotic components in their surroundings. These microbial interactions have both positive and negative effects on plant. Plant growth promoting bacterial (PGPR) interaction could result in positive growth under normal as well as in stress conditions.

Methods

Here, we have screened two PGPR’s and determined their potential in induction of specific gene in host plant to overcome the adverse effect of biotic stress caused by Magnaporthe grisea, a fungal pathogen that cause blast in rice. We demonstrated the glucanase protein mode of action by performing comparative modeling and molecular docking of guanosine triphosphate (GTP) ligand with the protein. Besides, molecular dynamic simulations have been performed to understand the behavior of the glucanase-GTP complex.

Results

The results clearly showed that selected PGPR was better able to induce modification in host plant at morphological, biochemical, physiological and molecular level by activating the expression of β-1,3-glucanases gene in infected host plant. The docking results indicated that Tyr75, Arg256, Gly258, and Ser223 of glucanase formed four crucial hydrogen bonds with the GTP, while, only Val220 found to form hydrophobic contact with ligand.

Conclusions

The PGPR able to induce β-1,3-glucanases gene in host plant upon pathogenic interaction and β-1,3-glucanases form complex with GTP by hydrophilic interaction for induction of defense cascade for acquiring resistance against Magnaporthe grisea.

Molecular characterization and genetic diversity studies of Indian soybean (Glycine max (L.) Merr.) cultivars using SSR markers

 Molecular Biology Reports 49, 2129–2140 (2022)

Background

The genetic base of soybean cultivars in India has been reported to be extremely narrow, due to repeated use of few selected and elite genotypes as parents in the breeding programmes. This ultimately led to the reduction of genetic variability among existing soybean cultivars and stagnation in crop yield. Thus in order to enhance production and productivity of soybean, broadening of genetic base and exploring untapped valuable genetic diversity has become quite indispensable. This could be successfully accomplished through molecular characterization of soybean genotypes using various DNA based markers. Hence, an attempt was made to study the molecular divergence and relatedness among 29 genotypes of soybean using SSR markers.

Methods and results

A total of 35 SSR primers were deployed to study the genetic divergence among 29 genotypes of soybean. Among them, 14 primer pairs were found to be polymorphic producing a total of 34 polymorphic alleles; and the allele number for each locus ranged from two to four with an average of 2.43 alleles per primer pair. Polymorphic information content (PIC) values of SSRs ranged from 0.064 to 0.689 with an average of 0.331. The dendrogram constructed based on dissimilarity indices clustered the 29 genotypes into two major groups and four sub-groups. Similarly, principal coordinate analysis grouped the genotypes into four major groups that exactly corresponded to the clustering of genotypes among four sub-groups of dendrogram. Besides, the study has reported eight unique and two rare alleles that could be potentially utilized for genetic purity analysis and cultivar identification in soybean.

Conclusion

In the present investigation, two major clusters were reported and grouping of large number of genotypes in each cluster indicated high degree of genetic resemblance and narrow genetic base among the genotypes used in the study. With respect to the primers used in the study, the values of PIC and other related parameters revealed that the selected SSR markers are moderately informative and could be potentially utilized for diversity analysis of soybean. The clustering pattern of dendrogram constructed based on SSR loci profile displayed good agreement with the cultivar’s pedigree information. High level of genetic similarity observed among the genotypes from the present study necessitates the inclusion of wild relatives, land races and traditional cultivars in future soybean breeding programmes to widen the crop gene pool. Thus, hybridization among diverse gene pool could result in more heterotic combinations ultimately enhancing genetic gain, crop yield and resistance to various stress factors.

Machine Learning Applied to the Oxygen-18 Isotopic Composition, Salinity and Temperature/Potential Temperature in the Mediterranean Sea

 Mathematics 2021, 9(19), 2523

This study proposed different techniques to estimate the isotope composition (δ18O), salinity and temperature/potential temperature in the Mediterranean Sea using five different variables: (i–ii) geographic coordinates (Longitude, Latitude), (iii) year, (iv) month and (v) depth. Three kinds of models based on artificial neural network (ANN), random forest (RF) and support vector machine (SVM) were developed. According to the results, the random forest models presents the best prediction accuracy for the querying phase and can be used to predict the isotope composition (mean absolute percentage error (MAPE) around 4.98%), salinity (MAPE below 0.20%) and temperature (MAPE around 2.44%). These models could be useful for research works that require the use of past data for these variables.

Production of a Potentially Probiotic Product for Animal Feed and Evaluation of Some of Its Probiotic Properties

 Int. J. Mol. Sci. 2021, 22(18), 10004

Nowadays, probiotics have been proposed for substituting antibiotics in animal feed since the European Union banned the latter compounds in 2006 to avoid serious side effects on human health. Therefore, this work aimed to produce a probiotic product for use in animal feed by fed-batch fermentation of whey with a combination of kefir grains, AGK1, and the fermented whole milk used to activate these kefir grains. The probiotic culture obtained was characterized by high levels of biomass (8.03 g/L), total viability (3.6 × 108 CFU/mL) and antibacterial activity (28.26 Activity Units/mL). Some probiotic properties of the probiotic culture were investigated in vitro, including its survival at low pH values, under simulated gastrointestinal conditions, after freezing in skim milk at −20 °C, and in the commercial feed during storage at room temperature. The viable cells of lactic and acetic acid bacteria and yeasts exhibited higher tolerance to acidic pH and simulated gastrointestinal conditions when the cells were protected with skim milk and piglet feed, compared with washed cells. The results indicated the feasibility of producing a probiotic product at a low cost with a potential application in animal feed.

Metal and metalloid profile as a fingerprint for traceability of wines under any Galician protected designation of origin

 Journal of Food Composition and Analysis, 102, 104043, 2021

Effective and cheap methods for detecting fraud and, guaranteeing wine authenticity, are of paramount importance in the sector. In this sense, three different kinds of prediction models (random forest, artificial neural networks, and support vector machines) were developed to classify wines, according to their element contents (metals and metalloids, obtained using an inductively coupled plasma with a quadrupole mass spectrometer, and an optic emission spectrophotometer). One models were developed using 45 inputs variables, and then the models were subjected to a process of reducing variables to simplify models and save material and time costs. A total accuracy was reached in all phases for the white wines-random forest models. From a practical point of view, the accuracy and the errors obtained by the selected models (except for red wines-artificial neural network developed using reduced variables) are acceptable. The models developed with fewer variables, can make the prediction task easier.

Modelling and Prediction of Monthly Global Irradiation Using Different Prediction Models

 Energies 2021, 14(8), 2332

Different prediction models (multiple linear regression, vector support machines, artificial neural networks and random forests) are applied to model the monthly global irradiation (MGI) from different input variables (latitude, longitude and altitude of meteorological station, month, average temperatures, among others) of different areas of Galicia (Spain). The models were trained, validated and queried using data from three stations, and each best model was checked in two independent stations. The results obtained confirmed that the best methodology is the ANN model which presents the lowest RMSE value in the validation and querying phases 1226 kJ/(m2∙day) and 1136 kJ/(m2∙day), respectively, and predict conveniently for independent stations, 2013 kJ/(m2∙day) and 2094 kJ/(m2∙day), respectively. Given the good results obtained, it is convenient to continue with the design of artificial neural networks applied to the analysis of monthly global irradiation.

Assessment of Glyphosate Impact on the Agrofood Ecosystem

 Plants 2021, 10(2), 405

Agro-industries should adopt effective strategies to use agrochemicals such as glyphosate herbicides cautiously in order to protect public health. This entails careful testing and risk assessment of available choices, and also educating farmers and users with mitigation strategies in ecosystem protection and sustainable development. The key to success in this endeavour is using scientific research on biological pest control, organic farming and regulatory control, etc., for new developments in food production and safety, and for environmental protection. Education and research is of paramount importance for food and nutrition security in the shadow of climate change, and their consequences in food production and consumption safety and sustainability. This review, therefore, diagnoses on the use of glyphosate and the associated development of glyphosate-resistant weeds. It also deals with the risk assessment on human health of glyphosate formulations through environment and dietary exposures based on the impact of glyphosate and its metabolite AMPA—(aminomethyl)phosphonic acid—on water and food. All this to setup further conclusions and recommendations on the regulated use of glyphosate and how to mitigate the adverse effects.

Main Applications of Cyclodextrins in the Food Industry as the Compounds of Choice to Form Host–Guest Complexes

 Int. J. Mol. Sci. 2021, 22(3), 1339

Cyclodextrins (CDs) are cyclic oligomers broadly used in food manufacturing as food additives for different purposes, e.g., to improve sensorial qualities, shelf life, and sequestration of components. In this review, the latest advancements of their applications along with the characteristics of the uses of the different CDs (α, β, γ and their derivatives) were reviewed. Their beneficial effects can be achieved by mixing small amounts of CDs with the target material to be stabilized. Essentially, they have the capacity to form stable inclusion complexes with sensitive lipophilic nutrients and constituents of flavor and taste. Their toxicity has been also studied, showing that CDs are innocuous in oral administration. A review of the current legislation was also carried out, showing a general trend towards a wider acceptance of CDs as food additives. Suitable and cost-effective procedures for the manufacture of CDs have progressed, and nowadays it is possible to obtain realistic prices and used them in foods. Therefore, CDs have a promising future due to consumer demand for healthy and functional products. 

Enhancing the saccharification of pretreated chestnut burrs to produce bacteriocins

 Journal of Biotechnology, 329, 13-20

The present study aims to valorize chestnut burrs, an important lignocellulosic waste, through a biorefinery concept. A solid residue rich in glucan (41.36 ± 0.59 %) and lignin (39.06 ± 0.01 %) obtained from a previous process of pre-hydrolysis was subjected to four treatments with water or NaOH to enhance enzymatic hydrolysis. Saccharification was performed using different ratios of commercial cellulases and β-glucosidases and at controlled pH 4.8 or 6.0 (with citrate buffer) or uncontrolled pH. Carbohydrate-rich solutions with or without nutrients were used to produce bacteriocins by Lactobacillus plantarum CECT 211. The use of NaOH at high temperatures (120 and 130 °C) was the most suitable treatment to improve saccharification. Regarding the production of bacteriocins, the best result was obtained using the enzymatic solution obtained at controlled pH 6.0, supplemented with MRS broth nutrients (except glucose). Thus, the concentrations of bacteriocins obtained in this culture medium (9.21 BU/mL) was 1.22 and 1.98 times higher than those obtained in the nutrient supplemented medium buffered at pH 4.8 (7.56 BU/mL) and in the commercial MRS broth (4.65 BU/mL), respectively. These results highlight the feasibility of the technology developed in this work.

Essential Oils as Antimicrobials in Crop Protection

 Antibiotics 2021, 10(1), 34

At present, organic crops have reached an important boom in a society increasingly interested in the conservation of the environment and sustainability. It is evident that a part of the population in the Western world focuses their concern on how to obtain our food and on doing it in a way that is as respectful as possible with the environment. In this review, we present a compilation of the work carried out with the use of essential oils as an alternative in the fight against different bacteria and fungi that attack crops and related products. Given the collected works, the efficacy of essential oils for their use as pesticides for agricultural use is evident. 

HCR 2020

Cuatro investigadores vinculados a nuestro grupo de investigación [AA1] (Grupo de Investigaciones Agro-ambientales y Alimentarias de la Universidad de Vigo)   -Jesús Simal, Francisco J. Barba, Seid Mahdi Jafari e Jian Bo Xiao - han sido reconocidos como HCR (High Cited Researcher) por Clarivate.

Esta mención como HCR implica un reconocimiento a los investigadores como los más influyentes del mundo, como lo demuestra la producción de varios artículos altamente citados citados que se ubican en el primer percentil según las citas por campo en el último decenio (2011-2020) según Web of Science™.

Este hecho situaría a la Universidade de Vigo en el terceiro lugar en el ranking correspondiente, solamente por detrás de la Universidad de Barcelona, la Universidad de Granada, y pondría al grupo de investigación como uno de los referentes en materia de investigaciones agroalimentarias.

Recordemos que la Universidad de Vigo, también aparece en el Ranking de Shanghai, dentro del apartado de Ciencia y Tecnología de los Alimentos (en el que se encuentra encuadrada la actividad investigadora de nuestro grupo) en el rango 51-75 del mundo. Así la Ciencia y Tecnología de los Alimentos es el ámbito de conocimiento mejor situado en todo el Sistema Universitario de Galicia este año 2020.

Up4Health

El proyecto Europeo Up4Health se basa en el aprovechamiento de biomasa generada en procesos que se llevan a cabo en la industria, por ejemplo en bodegas, almazaras, o plantas de procesamiento de frutos secos, de los que se obtienen ingredientes funcionales que pueden usarse en otras industrias de diversa índole, como pueden ser la alimentaria, nutracéutica o cosmética.

En Up4Health, además de aprovechar esta materia prima residual rica en compuestos bioactivos, se optimiza la cadena de valor de las industrias productivas del sector alimenticio persiguiendo el objetivo de “residuo cero”, lo que hace que además de ser un proyecto innovador, sea sostenible.

Los ingredientes funcionales de los que hablamos son los siguientes: agua de fruta natural rica en polifenoles, fibra dietética rica en polifenoles, extractos oleosos naturales de frutas y xilooligosacáridos prebióticos. Las aplicaciones en las que se podrán utilizar estos compuestos bioactivos van desde los alimentos funcionales, como productos cárnicos, barritas snack saludables, alimentos suaves para personas mayores, soluciones bebibles en forma de gel, aceite de oliva, bebidas naturales, yogurt, hasta los suplementos nutracéuticos e incluso los cosméticos.

En este proyecto, financiado por el programa H2020, colaboran nueve organizaciones de cinco países distintos  se realiza en colaboración con la empresa AMEREX, que aplicará diversos polifenoles extraídos de harina de fibra de oliva y uva en algunos productos de la industria alimentaria, con el objetivo de retrasar los procesos oxidativos y aumentar la vida útil del producto final.

(blog del proyecto aqui)

Jesús Simal, medalla de la Real Academia Galega de Ciencias

Una das Medallas de Investigación que a Real Academia Galega de Ciencias terá como destinatario o coordinador do grupo AA1,  Jesús Simal, en particular na sección de Química e Xeoloxía. A entrega das medallas será lugar o día 8 de octubre no Colexio de Fonseca (USC) 

Poderá seguirse a retransmisión da entrega de premios en directo a través de @RAGalegaCiencia en Twiter ou ben a través de este enlace

Enlaces de Prensa:

• Diario da Universidade de Vigo
• GCiencia
• El Faro de Vigo
• Atlántico Diario
• La Región
• Galicia Press
• Galicia Conficencial
• Vigo Hoy

Extraction, Properties, and Applications of Bioactive Compounds Obtained from Microalgae

 Current Pharmaceutical Design, 2020, 26, 1929-1950

DOI: 10.2174/1381612826666200403172206

With the increase in the global population, getting new sources of food is essential. One of the solutions can be found in the oceans due to algae. Microalgae are aquatic photosynthetic organisms used mainly due to their variety of bioactive compounds. The consumption of microalgae has been carried out for centuries and is recommended by organizations, such as OMS and FAO, due to its nutritional value and its properties. Based on the existing literature, there is substantial evidence of the nutritional quality of the algae as well as their functional elements. However, much quantification is still necessary, as well as studying possible adverse effects. The present review describes the compounds of alimentary interest present in these algae as well as different extraction techniques assisted by different energetic mechanisms (such as heat, supercritical-fluid, microwave, ultrasound, enzymes, electric field, high hydrostatic pressure, among others). The most challenging and crucial issues are reducing microalgae growth cost and optimizing extraction techniques. This review aimed a better understanding of the uses of microalgae for new researches in nutrition. Since the use of microalgae is still a field in which there is much to discover, it is likely that more benefits will be found in its consumption.

Main bioactive phenolic compounds in marine algae and their mechanisms of action supporting potential health benefits

 Food Chemistry, 2020, 341, 128262

DOI:10.1016/j.foodchem.2020.128262

Given the growing tendency of consumers to choose products with natural ingredients, food industries have directed scientific research in this direction. In this regard, algae are an attractive option for the research, since they can synthesize a group of secondary metabolites, called phenolic compounds, associated with really promising properties and bioactivities. The objective of this work was to classify the major phenolic compounds, compare the effectiveness of the different extractive techniques used for their extraction, from traditional systems (like heat assisted extraction) to the most advance ones (such as ultrasound, microwave or supercritical fluid extraction); the available methods for identification and quantification; the stability of the enriched extract in phenolic compounds and the main bioactivities described for these secondary metabolites, to offer an overview of the situation to consider if it is possible and/or convenient an orientation of phenolic compounds from algae towards an industrial application.