Davor Valinger

Determination of histamine in fish by Surface Enhanced Raman Spectroscopy using silver colloid SERS substrates

This study was focused on development of a rapid and sensitive method for histamine determination in fish based on Surface Enhanced Raman Spectroscopy (SERS) using simple and widely available silver colloid SERS substrate. Extraction of histamine with 0.4M perchloric acid and purification with 1-butanol significantly shortened sample preparation (30min) and provided clear SERS spectra with characteristic Raman bands of histamine. Principal component analysis effectively distinguished SERS spectra of fish samples with different histamine content. Partial least square (PLS) regression models confirmed reliability of detection and spectral analysis of histamine with SERS. In histamine concentration range 0-200mgkg-1, significant in legislative and fish quality control aspects, PLS regression model based on spectral range 1139.9-1643.7cm-1 showed linear trend with R2pred=0.962, RPD=7.250. Presented protocol for histamine extraction and purification followed by SERS analysis coupled with chemometric approach, enabled development of rapid and inexpensive method for histamine determination in fish.

Multi-criteria Decision Analysis: Linear and Non-linear Optimization of Aqueous Herbal Extracts

This chapter is aimed to present the multi-criteria decision analysis: Linear and non-linear optimization of aqueous herbal extracts. Modelling is an indispensable part of food production, from “farm to fork”, where it is used to optimize the initial production of food and feed as well as in the food and feed processing. Different particle sizes of olive leaves were used in extraction of biologically active components using water as a solvent. Experiment conditions varied in mixing times (5, 10, 15 min), heating treatments (40 °C, 60 °C, 80 °C), Revolutions per minute: rpm (250, 500, 750 min−1) and particle sizes (100, 300, 500 μm). Based on the measured bioactive compounds (pH, total dissolved solids, conductivity, dry matter, total polyphenols and the antioxidant capacity by ABTS method, DPPH method and FRAP method). Aim was to develop models to support the optimization of this decision-making process—find the best experiment conditions for extraction of a certain bioactive compound. Two approaches; linear and nonlinear approaches were investigated. Linear optimization is presented with two models: Response Surface Methodology and using linear programing based on the Simplex method while the nonlinear approach is presented by developing membership functions using fuzzy logic approach. Final results showed that, simple or complex, i.e. linear or nonlinear approach(es) in the search for optimal experiment conditions in extraction of bioactive compounds from olive leaves, will lead to an optimal solution, but the engineer will decide which approach is suitable for further application. Linear optimization and application of fuzzy logic resulted with the best possible offer per set limitations. But each approach resulted with other optimal extraction conditions. However, the application of fuzziness allowed the extension of the set of acceptable experiment combinations to achieve the best extraction of a bioactive component.

Integrated approach for bioactive quality evaluation of medicinal plant extracts using HPLC-DAD, spectrophotometric, near infrared (NIR) spectroscopy and chemometric techniques

ABSTRACT To establish a universal analytical tool that could be used as a bioactive quality determination procedure on medicinal plant extracts, a range of spectrophotometric assays, HPLC, near infrared reflectance spectroscopy and chemometric analysis were employed for determination of the bioactive quality of 16 widely spread medicinal plants. Macro-constituents (total carbohydrates, soluble polysaccharides, proteins, amino acids) and secondary plant metabolites (total phenols, flavonoids, hydroxycinnamic acids, flavons, and flavonols) were determined, and HPLC method for the simultaneous determination of phenolic acids and flavonoids was developed, and its linearity, limits of detection and quantification, precision, and accuracy were validated. The evaluated medicinal plant extracts were characterised by a marked protein (marigold – 4.22 g/kg dw), amino acid (marigold – 61.14 g/kg dw), and carbohydrate content (dandelion – 113.5 g/kg dw), while Lamiaceae plants were distinguished as the predominant sources of polyphenolic bioactives (<2.26 g GAE/L). The developed HPLC method enabled separation of 24 polyphenolic compounds within a short analysis time (30 min) and revealed rosmarinic and chicoric acids as the prevalent polyphenolic constituents. NIR spectroscopy coupled with chemometric analysis of all determined analytical parameters indicated the suitability of NIR analysis for amino acids, carbohydrates, and polyphenols determination in medicinal plant extracts.

Properties of medicinal plants related to NIR spectroscopy

The aim of the study on Big Data in Public Health, Telemedicine and Healthcare is to identify applicable examples of the use of Big Data in Health and develop recommenda-tions for their implementation in the European Union. Examples of Big Data in Health were identified by a systematic literature review, after which the added value of twenty selected examples was evaluated. Based on the as-sessment of the added value and the quality of the evidence, ten priority examples were selected. Furthermore, potential policy actions for the implementation of Big Data in Health were identified in the literature, and a SWOT analysis was conducted to check the feasibility of the proposed actions. Based on this analysis, and with the help of renowned experts, the study team developed ten policy recommendations in the field. These recommendations were validated through public consultations at three relevant conferences in Europe and were again reviewed by the Expert Group. The recommendations aim to benefit European citizens and patients in terms of strengthening their health and improving the performance of Member State’s health systems. They should be seen as suggestions for the European Union and its Member States on how to utilise the strengths and exploit the opportunities of Big Data for Public Health without threatening privacy or safety of citizens. Recommendations were developed for ten relevant fields: awareness raising, education and training, data sources, open data and data sharing, applications and purposes, data analysis, governance of data access and use, standards, funding and financial resources, as well as legal aspects and privacy regulation.P molecules found in plants are utilized currently for improving prostate health. The botanicals with the highest recognized profiles are Resveratrol and the isoflavonoids. Prostate health is compromised with aging, especially beginning in the mid-40s, when testosterone levels decline and estrogenic hormonal actions increase along with enhanced expression of the prostatic 5α-reductase enzyme that result in prostate enlargement commonly known as benign prostatic hyperplasia (BPH). There is a linear increase in BPH incidence with increasing age in men over 60 years old. Approximately 1 in 5 men with BPH had a clinical event (prostatectomies), within 1 year of initiating treatment for BPH. The symptoms of BPH include nocturia, incomplete emptying, urinary hesitancy, weak stream, frequency and urgency that negatively impact the quality of life. Current pharmaceuticals are somewhat effective, but can have serious side effects. Interest in complementary and alternative medicines (CAM) for BPH has increased during the last two decades. CAM agents include polyphenolic compounds such as Resveratrol and the isoflavonoids. Resveratrol is effective in vitro, but, in vivo administration presents efficacious challenges. Genistein was first thought to be responsible for improved prostate health, however, since the equal hypothesis was proposed in the late1990s, there has been increased focus on this isoflavonoid molecule. This presentation will briefly review Resveratrol and some isoflavonoid molecules where clinical studies have shown improvement of BPH symptoms in men using standardized laboratory biomarkers and survey indexing parameters. Clearly there is an opportunity for an efficacious and cost-effective approach for the treatment of BPH with botanicals.

Stereoselective synthesis of (1S,2S)-1-phenylpropane-1,2-diol by cell-free extract of Lactobacillus brevis

Abstract In this study Lactobacillus brevis cells were cultivated and then disrupted using various cell disruption methods to obtain maximal nicotinamide adenine dinucleotide phosphate (NADP(H))-dependent alcohol dehydrogenase (ADH) activity in cell-free extract. Evolutionary operation (EVOP) technique was used to find the optimal cell disruption method. The released ADH in cell-free extract was then used for biotransformation of (S)-2-hydroxypropiophenone ((S)-2-HPP) to (1S, 2S)-1-phenylpropane-1,2-diol ((1S, 2S)-1-PPD). Due to high coenzyme cost, the possibility of NADPH regeneration was considered by examining two substrate-coupled regeneration systems, and for that isopropanol and (R)-1-phenylethanol were used. The enzyme was kinetically characterized, and kinetics of all reactions were determined. Based on kinetic results, mathematical models were developed and were validated in batch reactor. Both regenerating systems successfully shifted the reaction in the desired direction; without coenzyme regeneration, obtained substrate equilibrium conversion was 27.5%, while with coenzyme regeneration by isopropanol oxidation was 99.0% and by (R)-1-phenylethanol was 70.1%.