Antibacterial Activity Potential of Industrial Food Production Waste Extracts against Pathogenic Bacteria: Comparative Analysis and Characterization.

The Food and Agricultural Organization estimates a 17% loss in the food production chain, making it imperative to adopt scientific and technological approaches to address this issue for sustainability. Industrial food production waste and its value-added applications, particularly in relation to a wide variety of pathogenic microorganisms and the health-related effects have not been thoroughly investigated. This study explores the potential of food production waste extracts-lemon peel (LP), hot trub (HT), and coffee silverskin (CSS) as sources of bioactive compounds. Extraction was conducted using hydro-methanolic extraction with yields in LP (482 mg/1 g) > HT (332 mg/1 g) > CSS (20 mg/1 g). The agar diffusion assay revealed the substantial antibacterial activity of all three extracts against Erwinia Amylovora, Escherichia coli, Bacillus subtilis, and Bacillus aquimaris. All extracts demonstrated activity against Gram-positive and Gram-negative bacteria, displaying minimum inhibitory concentrations effective against pathogenic bacteria like Listeria monocytogenes, Staphylococcus aureus, Vibrio parahaemolyticus, and Salmonella enterica. Total phenolic content (TPC in mg GAE/1g) was 100, 20, and 100 for CSS, HT, and LP, respectively. Antioxidant activity by ABTS indicated IC50 of 3.09, 13.09, and 2.61 for LP, HT, and CSS, respectively. Also, the antioxidant activity of the extracts was further confirmed by DPPH assay with the best activity in CSS (9.84 GAEg-1) and LP (9.77 mg of GAEg-1) rather than in HT (1.45 GAEg-1). No adverse cytotoxic effects on HaCaT cells were observed. Pancreatic amylase inhibition demonstrated antidiabetic potential, with LP showing the highest levels (92%). LC-MS characterization identified polyphenols as the main compounds in CSS, prenylated compounds in HT, and flavanols in LP. The findings imply the potential sustainable use of food production waste in industry.

Chemotaxis increases metabolic exchanges between marine picophytoplankton and heterotrophic bacteria.

Behaviours such as chemotaxis can facilitate metabolic exchanges between phytoplankton and heterotrophic bacteria, which ultimately regulate oceanic productivity and biogeochemistry. However, numerically dominant picophytoplankton have been considered too small to be detected by chemotactic bacteria, implying that cell-cell interactions might not be possible between some of the most abundant organisms in the ocean. Here we examined how bacterial behaviour influences metabolic exchanges at the single-cell level between the ubiquitous picophytoplankton Synechococcus and the heterotrophic bacterium Marinobacter adhaerens, using bacterial mutants deficient in motility and chemotaxis. Stable-isotope tracking revealed that chemotaxis increased nitrogen and carbon uptake of both partners by up to 4.4-fold. A mathematical model following thousands of cells confirmed that short periods of exposure to small but nutrient-rich microenvironments surrounding Synechococcus cells provide a considerable competitive advantage to chemotactic bacteria. These findings reveal that transient interactions mediated by chemotaxis can underpin metabolic relationships among the ocean's most abundant microorganisms.

Exploring cocoa bean fermentation mechanisms by kinetic modelling.

Compared with other fermentation processes in food industry, cocoa bean fermentation is uncontrolled and not standardized. A detailed mechanistic understanding can therefore be relevant for cocoa bean quality control. Starting from an existing mathematical model of cocoa bean fermentation we analyse five additional biochemical mechanisms derived from the literature. These mechanisms, when added to the baseline model either in isolation or in combination, were evaluated in terms of their capacity to describe experimental data. In total, we evaluated 32 model variants on 23 fermentation datasets. We interpret the results from two perspectives: (1) success of the potential mechanism, (2) discrimination of fermentation protocols based on estimated parameters. The former provides insight in the fermentation process itself. The latter opens an avenue towards reverse-engineering empirical conditions from model parameters. We find support for two mechanisms debated in the literature: consumption of fructose by lactic acid bacteria and production of acetic acid by yeast. Furthermore, we provide evidence that model parameters are sensitive to differences in the cultivar, temperature control and usage of steel tanks compared with wooden boxes. Our results show that mathematical modelling can provide an alternative to standard chemical fingerprinting in the interpretation of fermentation data.

Cocoa bean fingerprinting via correlation networks.

Cocoa products have a remarkable chemical and sensory complexity. However, in contrast to other fermentation processes in the food industry, cocoa bean fermentation is left essentially uncontrolled and is devoid of standardization. Questions of food authenticity and food quality are hence particularly challenging for cocoa. Here we provide an illustration how network science can support food fingerprinting and food authenticity research. Using a large dataset of 140 cocoa samples comprising three cocoa fermentation/processing stages and eight countries, we obtain correlation networks between the cocoa samples by computing measures of pairwise correlation from their liquid chromatography-mass spectrometry (LC-MS) profiles. We find that the topology of correlation networks derived from untargeted LC-MS profiles is indicative of the fermentation and processing stage as well as the origin country of cocoa samples. Progressively increasing the correlation threshold firstly reveals network clusters based on processing stage and later country-based clusters. We present both, qualitative and quantitative evidence through network visualization, network statistics and concepts from machine learning. In our view, this network-based approach for classifying mass spectrometry data has broad applicability beyond cocoa.

Lignin and Its Pathway-Associated Phytoalexins Modulate Plant Defense against Fungi.

Fungi infections cause approximately 60-70% yield loss through diseases such as rice blast, powdery mildew, Fusarium rot, downy mildew, etc. Plants naturally respond to these infections by eliciting an array of protective metabolites to confer physical or chemical protection. Among plant metabolites, lignin, a phenolic compound, thickens the middle lamella and the secondary cell walls of plants to curtail fungi infection. The biosynthesis of monolignols (lignin monomers) is regulated by genes whose transcript abundance significantly improves plant defense against fungi. The catalytic activities of lignin biosynthetic enzymes also contribute to the accumulation of other defense compounds. Recent advances focus on modifying the lignin pathway to enhance plant growth and defense against pathogens. This review presents an overview of monolignol regulatory genes and their contributions to fungi immunity, as reported over the last five years. This review expands the frontiers in lignin pathway engineering to enhance plant defense.

LC-MS based metabolomic approach for the efficient identification and relative quantification of bioavailable cocoa phenolics in human urine.

This study was designed to investigate the rate and extent of urinary excretion of cocoa phenolic metabolites after human intake using metabolomics approach. In this context, a feeding trial was conducted where urine samples were collected at different time points over 48-h period. Several biomarkers were highlighted in LC-MS based chemometrics using principal component (PCA) and partial least squares discriminant analysis (PLS-DA), which revealed the presence of both epicatechin and gut microbial phenyl-γ-valerolactones (PVLs) conjugated analogues. The presences of these metabolites segregated and grouped the samples based on cocoa and non-cocoa ingestion. Furthermore, semi quantification of major bioavailable metabolites was performed to determine the interindividual differences and assess the relative bioavailability of cocoa compounds in the human body. Our approach presented here is unique in displaying a combination of LC-MS based chemometrics visualization strategies, which revealed and identified significant biomarkers that could reduce the problems associated with data screening complexity.

Cocoa origin classifiability through LC-MS data: A statistical approach for large and long-term datasets.

Classification of food samples based upon their countries of origin is an important task in food industry for quality assurance and development of fine flavor products. Liquid chromatography -mass spectrometry (LC-MS) provides a fast technique for obtaining in-depth information about chemical composition of foods. However, in a large dataset that is gathered over a period of few years, multiple, incoherent and hard to avoid sources of variations e.g., experimental conditions, transportation, batch and instrumental effects, etc. pose technical challenges that make the study of origin classification a difficult problem. Here, we use a large dataset gathered over a period of four years containing 297 LC-MS profiles of cocoa sourced from 10 countries to demonstrate these challenges by using two popular multivariate analysis methods: principal component analysis (PCA) and linear discriminant analysis (LDA). We show that PCA provides a limited separation in bean origin, while LDA suffers from a strong non-linear dependence on the set of compounds. Further, we show for LDA that a compound selection criterion based on Gaussian distribution of intensities across samples dramatically enhances origin clustering of samples thereby suggesting possibilities for studying marker compounds in such a disparate dataset through this approach. In essence, we show and develop a new approach that maximizes, avoiding overfitting, the utility of multivariate analysis in a highly complex dataset.

Investigating time dependent cocoa bean fermentation by ESI-FT-ICR mass spectrometry.

A cocoa bean fermentation series, comprising bean samples taken every 24 h of a seven-day cocoa fermentation was analyzed by ultra-high-resolution mass spectrometry using the ESI-FT-ICR technique. Data were acquired in both positive and negative ion mode. At early fermentation times around 2000 signals could be resolved raising to a maximum of 8000 signals in each ion mode towards the end of the fermentation. Molecular formulae were assigned to a large number of observed peaks leading to ion statistics classifying cocoa constituents according elemental composition. Time dependent van Krevelen diagrams were constructed allowing the tracking of chemical changes in bean composition. In particular, the number of CHON compounds assigned to short peptides and their derivatives were shown to undergo significant chemical transformations. Theoretical MS data bases were constructed containing all possible peptides up to a length of ten amino acids and putative derivatives expected to be formed during microbial fermentation. Experimental m/z values were compared to these databases and conclusions drawn with respect to the composition of fermenting beans with tentative fermentation products suggested.

Tetra-(p-tolyl)antimony(III)-Containing Heteropolytungstates, [{(p-tolyl)SbIII}4(A-α-XW9O34)2]n- (X = P, As, or Ge): Synthesis, Structure, and Study of Antibacterial and Antitumor Activity.

We have synthesized and structurally characterized three tetra-(p-tolyl)antimony(III)-containing heteropolytungstates, [{(p-tolyl)SbIII}4(A-α-XW9O34)2]n- [X = PV (1-P), AsV (1-As), or GeIV (1-Ge)], in aqueous solution using conventional, one-pot procedures. The polyanions 1-P, 1-As, and 1-Ge were fully characterized in the solid state and in solution and were shown to be soluble and stable in aqueous medium at pH 7. Biological studies demonstrated that all three polyanions possess significant antibacterial and antitumor activities. The minimum inhibitory concentrations of 1-P, 1-As, and 1-Ge were determined against four kinds of bacteria, including the two pathogenic bacteria strains, Vibrio parahaemolyticus and Vibrio vulnificus. The three novel polyanions also showed high cytotoxic potency in the human cell lines A549 (non-small cell lung cancer), CH1/PA-1 (ovarian teratocarcinoma), and SW480 (colon carcinoma).

Experimentally modelling cocoa bean fermentation reveals key factors and their influences.

Cocoa bean fermentation still remains a rather empirical process. The research presented here employed an artificial system of fermentation, using controlled incubations, in order to achieve greater control over the external influences that cocoa beans are exposed to, with the aim of experimentally modelling changes to bean components (responses). Experimental design was used, in a first-ever attempt, to study the effects of five factors and their interactions on the profiles of pH, peptides, and flavanols in the bean during the incubations. Temperature, incubation time and the concentration of acetic acid were the main factors influencing the three responses. Moreover, there was a significant amount of factor interaction, revealing the process to be more complex than initially thought, especially with respect to the role of ethanol. Using the model, one was also able to accurately predict the response of the bean to the exposure to specific factors.

Comparative lipidomic studies of Scenedesmus sp. (Chlorophyceae) and Cylindrotheca closterium (Bacillariophyceae) reveal their differences in lipid production under nitrogen starvation.

Microalgae are a promising resource for the highly sustainable production of various biomaterials (food and feed), high-value biochemicals, or biofuels. However, factors influencing the valued lipid production from oleaginous algae require a more detailed investigation. This study elucidates the variations in lipid metabolites between a marine diatom (Cylindrotheca closterium) and a freshwater green alga (Scenedesmus sp.) under nitrogen starvation at the molecular species level, with emphasis on triacylglycerols using liquid chromatography-electrospray ionization mass spectrometry techniques. A comprehensive analysis was carried out by comparing the changes in total lipids, growth kinetics, fatty acid compositions, and glycerolipid profiles at the molecular species level at different time points of nitrogen starvation. A total of 60 and 72 triacylglycerol molecular species, along with numerous other polar lipids, were identified in Scenedesmus sp. and C. closterium, respectively, providing the most abundant triacylglycerol profiles for these two species. During nitrogen starvation, more triacylglycerol of Scenedesmus sp. was synthesized via the "eukaryotic pathway" in the endoplasmic reticulum, whereas the increase in triacylglycerol in C. closterium was mainly a result of the "prokaryotic pathway" in the chloroplasts after 96 h of nitrogen starvation. The distinct responses of lipid synthesis to nitrogen starvation exhibited by the two species indicate different strategies of lipid accumulation, notably triacylglycerols, in green algae and diatoms. Scenedesmus sp. and Cylindrotheca closterium could serve as excellent candidates for the mass production of biofuels or polyunsaturated fatty acids for nutraceutical purposes.

Forcing fermentation: Profiling proteins, peptides and polyphenols in lab-scale cocoa bean fermentation.

This study encompassed the lab-scale fermentation of cocoa beans in 300-g heaps under controlled laboratory conditions, in order to replicate the microbial dynamics and metabolomic changes that usually occur in large-scale spontaneous fermentations. Growth profiles of yeast and acetic acid bacteria (AAB) with the native assortment of microbes as well as with the use of a starter culture were very similar to those observed in literature. Greater production of acetic acid by AAB not only led to more acidic-tasting liquor but also contributed to bitterness, due to polyphenol preservation. It also brought about a drastic drop in pH leading to greater proteolytic activity. Peptides generated through proteolysis also showed incredible similarity to those reported in literature, in particular, those speculated to be involved in cocoa-specific flavour. A closer look at the naturally occurring peptide repertoires of our fermentation trials, generated by the breakdown of cocoa storage protein, pointed to a potential peptide responsible for cocoa-specific aroma.

A mathematical model of cocoa bean fermentation.

Cocoa bean fermentation relies on the sequential activation of several microbial populations, triggering a temporal pattern of biochemical transformations. Understanding this complex process is of tremendous importance as it is known to form the precursors of the resulting chocolate's flavour and taste. At the same time, cocoa bean fermentation is one of the least controlled processes in the food industry. Here, a quantitative model of cocoa bean fermentation is constructed based on available microbiological and biochemical knowledge. The model is formulated as a system of coupled ordinary differential equations with two distinct types of state variables: (i) metabolite concentrations of glucose, fructose, ethanol, lactic acid and acetic acid and (ii) population sizes of yeast, lactic acid bacteria and acetic acid bacteria. We demonstrate that the model can quantitatively describe existing fermentation time series and that the estimated parameters, obtained by a Bayesian framework, can be used to extract and interpret differences in environmental conditions. The proposed model is a valuable tool towards a mechanistic understanding of this complex biochemical process, and can serve as a starting point for hypothesis testing of new systemic adjustments. In addition to providing the first quantitative mathematical model of cocoa bean fermentation, the purpose of our investigation is to show how differences in estimated parameter values for two experiments allow us to deduce differences in experimental conditions.

Origin and varietal based proteomic and peptidomic fingerprinting of Theobroma cacao in non-fermented and fermented cocoa beans.

It is well known that the development of chocolate flavor is initiated during cocoa bean fermentation. Storage proteins undergo the most intensive breakdown yielding peptides and free amino acids, which both serve as flavor precursors. A comprehensive analysis of cocoa proteins and oligopeptides of non-fermented and fermented beans from various geographic origins allows the assessment of systematic differences with respect to their origin as well as fermentation status. Protein quantities as well as their profiles derived from two-dimensional gel electrophoresis, showed striking differences for non-fermented beans depending on their geographical origin. From fermented beans, oligopeptides were relatively quantified by utilizing UHPLC-ESI-Q-q-TOF and annotated based on their characteristic fragmentation pattern in the positive-ion mode. With >800 unique oligopeptides, excluding di- and tri-peptides, across 25 different samples, we are herein reporting on the largest collection of cocoa oligopeptides ever observed and identified. The detected diversity of peptides could not be correlated to the geographical origin but rather to the degree of fermentation. Our findings suggest that the variability in peptide patterns depends on the fermentation method applied in the country of origin ultimately indicating diversified proteolytic activities. Furthermore, our results showed that well-fermented and fair-fermented beans can be differentiated from partially fermented and under-fermented ones by higher numbers and total amounts of oligopeptides.

Variation of triacylglycerol profiles in unfermented and dried fermented cocoa beans of different origins.

Fermentation and drying are the two crucial processing steps required to produce cocoa beans with desired properties, especially taste and flavor. To understand their impact on the lipid profile of cocoa, the lipid composition of unfermented raw and fermented dried beans from six different origins was investigated using high-performance liquid chromatography-mass spectrometry methods. While the comparison of triacylglycerol profiles across the different origins showed only small variations in individual compound concentrations, the comparison along the fermentation status showed major differences regarding the occurrence of polar lipids. These compounds may serve as biomarkers for the fermentation status of the beans and a simple analytical method suitable for field trials is proposed. Finally, a hypothesis identifying key unsaturated triacylglycerols contributing to the hardness and softness of cocoa butter is presented.

Changes in the fucoxanthin production and protein profiles in Cylindrotheca closterium in response to blue light-emitting diode light.

BACKGROUND: Marine diatoms have a higher fucoxanthin content in comparison to macroalgae. Fucoxanthin features many potent bioactive properties, particularly anti-obesity properties. Despite the great potential for harvesting larger amounts of fucoxanthin, the impacts of light quality (light source, intensity, and photoperiod) on fucoxanthin production and the essential proteins involved in fucoxanthin biosynthesis in marine diatoms remain unclear. RESULTS: In the present study, Cylindrotheca closterium was selected from four different species of diatoms based on its high fucoxanthin content and productivity. Optimal light conditions (light source, intensity, and regime) were determined by a "Design of Experiment" approach (software MODDE Pro 11 was used). The model indicated that an 18/6 light/darkness regime increased fucoxanthin productivity remarkably as opposed to a 12/12 or 24/0 regime. Eventually, blue light-emitting diode light, as an alternative to fluorescent light, at 100 µmol/m2/s and 18/6 light/darkness regime yielded maximum fucoxanthin productivity and minimal energy consumption. The fucoxanthin production of C. closterium under the predicted optimal light conditions was assessed both in bottle and bag photobioreactors (PBRs). The high fucoxanthin content (25.5 mg/g) obtained from bag PBRs demonstrated the feasibility of large-scale production. The proteomes of C. closterium under the most favorable and unfavorable fucoxanthin biosynthesis light/darkness regimes (18/6 and 24/0, respectively) were compared to identify the essential proteins associated with fucoxanthin accumulation by matrix-assisted laser desorption/ionization-time of flight-mass spectrometry. Six proteins that were up-regulated in the 18/6 regime but down-regulated in the 24/0 were identified as important chloroplastic proteins involved in photosynthesis, energy metabolism, and cellular processes. CONCLUSIONS: Blue light-emitting diode light at 100 µmol/m2/s and 18/6 light/darkness regime induced maximum fucoxanthin productivity in C. closterium and minimized energy consumption. The high fucoxanthin production in the bag photobioreactor under optimal light conditions demonstrated the possibility of commercialization. Proteomics suggests that fucoxanthin biosynthesis is intimately associated with the photosynthetic efficiency of the diatom, providing another technical and bioengineering outlook on fucoxanthin enhancement.

Dithallium(III)-Containing 30-Tungsto-4-phosphate, [Tl2Na2(H2O)2(P2W15O56)2]16-: Synthesis, Structural Characterization, and Biological Studies.

Here we report on the synthesis and structural characterization of the dithallium(III)-containing 30-tungsto -4-phosphate [Tl2Na2(H2O)2{P2W15O56}2]16- (1) by a multitude of solid-state and solution techniques. Polyanion 1 comprises two octahedrally coordinated Tl3+ ions sandwiched between two trilacunary {P2W15} Wells-Dawson fragments and represents only the second structurally characterized, discrete thallium-containing polyoxometalate to date. The two outer positions of the central rhombus are occupied by sodium ions. The title polyanion is solution-stable as shown by 31P and 203/205Tl NMR. This was also supported by Tl NMR spectra simulations including several spin systems of isotopologues with half-spin nuclei (203Tl, 205Tl, 31P, 183W). 23Na NMR showed a time-averaged signal of the Na+ counter cations and the structurally bonded Na+ ions. 203/205Tl NMR spectra also showed a minor signal tentatively attributed to the trithallium-containing derivative [Tl3Na(H2O)2(P2W15O56)2]14-, which could also be identified in the solid state by single-crystal X-ray diffraction. The bioactivity of polyanion 1 was also tested against bacteria and Leishmania.

Degradation of cocoa proteins into oligopeptides during spontaneous fermentation of cocoa beans.

Degradation products of proteins produced during fermentation are believed to be the key precursors of a range of Maillard reactions that deliver the characteristic flavor and aroma of cocoa and chocolate. We have utilized UPLC-ESI-Q-q-TOF to identify and relatively quantify the largest collection of cocoa oligopeptides during a spontaneous fermentation time series using Ivory Coast cocoa beans. Peptides were identified, sequenced by tandem mass spectrometry and annotated based on their characteristic fragmentation pattern in the positive-ion mode. This enabled us to quantitatively trace the sequential degradation of the two main cocoa storage proteins, namely, albumin and vicilin. We observed sequential proteolytic degradation forming longer peptides in the early stages of fermentation and an increasing number of shorter peptides at the latter stages of fermentation. Protein degradation is mediated by both endo- and exopeptidases degrading at either peptide termini. In excess of 800 fermentation peptides could be unambiguously identified, providing unprecedented mechanistic details of cocoa fermentation.

Tea and coffee time with bacteria - Investigation of uptake of key coffee and tea phenolics by wild type E. coli.

Dietary phenolic compounds are often transformed by gut microbiota prior to absorption. This transformation may modulate their biological activities. Many fundamental questions still need to be addressed to understand how the gut microbiota-diet interactions affect human health. Herein, a UHPLC-QTOF mass spectrometry-based method for the quantification of uptake and determination of intracellular bacterial concentrations of dietary phenolics from coffee and tea was developed. Quantitative uptake data for selected single purified phenolics were determined. The specific uptake from mixtures containing up to four dietary relevant compounds was investigated to assess changes of uptake parameters in a mixture model system. Indeed, perturbation of bacteria by several compounds alters uptake parameter in particular tmax. Finally, model bacteria were dosed with complex dietary mixtures such as diluted tea or coffee extracts. The uptake kinetics of the twenty most abundant phenolics was quantified and the findings are discussed. For the first time, quantitative data on in-vitro uptake of dietary phenolics from food matrices were obtained indicating a time-dependent differential uptake of nutritional compounds.