Antioxidant activity and phenolic profile of selected organic and conventional honeys from Poland

Honey is a natural food product hypothesized to have significant health-beneficial value. The results of recent studies indicate that the biological activity of honey can also be ascribed to phenolic compounds and their antioxidant activity. The aims of this study were: To determine the phenolic profiles of several varieties of Polish honey and their correlation with various factors influencing the quality of honey, plus to verify the impact of production method (organic/conventional) and the pollen content on these profiles. In total, 11 organic and 11 conventional honey samples from Poland were investigated. The botanical origin of the samples was identified through melissopalynological analysis, whereas individual phenolic compounds were determined by the LC/MS analysis. The Folin-Ciocalteau assay was used for the determination of the total phenolic content (TPC). Moreover, the CIE L*a*b* color values were measured and matched with the above-mentioned parameters. The results of the study contribute to the discussion on the health benefits of organic farming. It was found that chrysin may act as a potential indicator compound. The study confirms the existence of the link between TPC and color, and it shows that there is a correlation between pinocembrin and galangin, two compounds that are reported to ameliorate insulin resistance

An online NP-HPLC-DPPH method for the determination of the antioxidant activity of condensed polyphenols in cocoa

In PressUnroasted cocoa beans are rich in monomeric flavanols and particularly epicatechin-based proanthocyanidin oligomers, with the latter making up to 60% of the total polyphenol content. Although the antioxidant activity of cocoa polyphenols is well known, it is still a challenging analytical field, especially, when it comes to the determination of condensed polyphenols and the evaluation of their single contribution to the overall activity. Therefore, an online NP-HPLC-DPPH assay was developed to separate the homologous series of condensed polyphenols for assessing their antioxidant capacity in relation to their degree of polymerization (DP), simultaneously. In this context, normal-phase chromatography allows separation of polyphenols based on their degree of polymerization. This study showed that an unroasted cocoa extract contains condensed polyphenols with a DP of up to 10 monomer units. By means of the online post-column derivatisation with 2,2-diphenyl-1-picrylhydrazyl (DPPH), the antioxidant capacity of the separated condensed polyphenols was assessed. It could be shown that, with the exception of the dimers, the contribution to the total antioxidant activity decreased from monomers to decamers. However, from the single proanthocyanidins identified, nonameric and decameric proanthocyanidins were found to have the highest values for the antioxidant capacity. The degree of polymerization associated with each molecular weight fraction was further confirmed using electrospray ionization mass spectrometry coupled with reverse-phase liquid chromatography. The online NP-HPLC-DPPH method can be used as qualitative and quantitative analysis of condensed proanthocyanidins and the simultaneous elucidation of the biological activity of proanthocyanidins in complex mixtures

Characterization of phenolic compounds and their contribution to sensory properties of olive oil

Olive oil is not only known for its pungent, bitter, and fruity taste, but also for its health potential, which is often hypothesized to depend on its phenolic compounds. One hundred extra virgin olive oil samples (monocultivaric as well as blends of varieties) were assessed with regard to their sensory properties and phenolic compound composition. Nineteen phenolic compounds have been determined and correlated with sensory data. In all olive oil samples, oleocanthal and oleacein were the most abundant phenolic compounds, with average amounts of 77.9 mg/kg and 41.8 mg/kg, respectively. The highest correlation coefficient between a sensory descriptor and the phenolic compounds was found for the bitter taste sensation and the total phenolic content with r = 0.72 and in particular, for 3,4-DHPEA-EA, with r = 0.57. Intensity plots were assessed for the three main sensory descriptors fruitiness, bitterness, pungency, and for the quality factor harmony, which is associated with the degree of ripeness aroma of olive oil. Positive correlations for the aroma descriptors freshly cut grass, leaves, and nuts, and the phenolic compounds were especially observed for oleoside 11-methylester and vanillic acid. The present study provides a comprehensive database of phenolic compounds in olive oils from six different varieties and seven countries

Evolution of the polyphenol and terpene content, antioxidant activity and plant morphology of eight different fiber-type cultivars of Cannabis sativa L. cultivated at three sowing densities

The chemical composition of the inflorescences of eight different fibre-type Cannabis sativa L. cultivars grown in Switzerland was monitored for different sowing densities over the season 2019. HPLC-MS, GC-MS and GC-FID, as well as spectrophotometric techniques were used to measure the total phenolic content (TPC) and the antioxidative activity of the inflorescence extracts, and to characterise and quantify the flavonoids and terpenes produced by the different cultivars over different sowing densities from July to September 2019. The main finding of the present study is that the TPC, as well as the individual flavonoids and terpenes, were mainly influenced by the harvest period and the phenological stage of the plant. The content of polyphenols and flavonoids decrease during the flower development for all cultivars studied. The terpene content increased with maturation. The monoterpenes/sesquiterpenes ratio also changed between the early flowering (majority of sesquiterpenes) and the end of flowering (majority of monoterpenes). The sowing density showed an impact on plant morphology, a low density such as 30 seeds/m2 influencing the production of bigger flowers, thus increasing the yield of polyphenols and terpenes production. Therefore, hemp inflorescences can be regarded as valuable by-products of fibre production, for their valorisation in the food and beverage industry in addition to cosmetics and perfumery

HPTLC fingerprint profile analysis of coffee polyphenols during different roast trials

Coffee beans are a rich source of bioactive phytochemicals such as chlorogenic acids (CGA). During the roasting process, the CGA content changes dramatically. An effective HPTLC method was developed which allows a fast characterization of the eight main CGA present in green and roasted coffee beans and their distribution during roasting trials. The method was optimized with regard to three caffeoylquinic acids (CQA), two feruloylquinic acids (FQA) and three dicaffeoylquinic acids (di-CQA). The best separation for a fingerprint consisting of eight phenolic compounds as markers was achieved on silica gel 60 F254 HPTLC plates with a solvent mixture of diethyl ether, formic acid, acetic acid, water, acetophenone and heptane (30:3:9:50:30:10) (v/v/v/v/v/v). Staining with natural product reagent A enabled visualization and quantitative evaluation. Principal component analysis can help to visualize the evolution of the chlorogenic acids throughout the process also with the aim of controlling the roasting degree

On-farm examination of sainfoin supplementation effects in dairy cows in a roughage-based feeding system: Indicators of protein utilisation

A case study was conducted with the objective to determine the effects of the tanniferous legume sainfoin (Onobrychis viciifolia) on protein utilisation of dairy cows, which were exposed to excessive dietary crude protein during autumn pasture grazing in a zero-concentrate feeding system. The study was conducted under practical conditions, deliberately accepting a certain lack of controllable variables. In order to assess a system applicable in practice, relatively small amounts of sainfoin were offered, and graded supply levels were compared by varying the duration of offer instead of dietary concentration. Within one dairy herd of 60 Swiss Fleckvieh cows, 30 individuals were chosen and randomly allocated to three groups balanced for milk yield, milk urea concentration, days in milk and parity. Over a period of 5 weeks, 2 kg per cow and day of sainfoin pellets were provided either intermittently, for 2 × 5 days (SST) in weeks 3 and 5 of the experiment or continuously over 35 days (SLT). A control group (CON) received 2 kg per cow and day of ryegrass pellets during the 5 weeks. The entire herd grazed on a protein-rich natural sward and was kept overnight in an open-space barn receiving fresh grass and hay ad libitum. Experimental pellets were offered individually twice per day in buckets. Feed, milk, faeces and urine samples were collected in weeks 0 (baseline), 3 and 5. Milk was analysed for fat, protein and urea, urine for purine derivatives, creatinine and nitrogen, and faeces for protein, fibre and particle fractions. During three sampling weeks, chewing activity was recorded by sensor halters. Treatment SST increased rumination time in the first half of the day, which was the only treatment effect on intake and rumination behaviour. Milk fat and protein yields were greater in SST compared to CON, but no treatment effect on concentration and yield of milk urea was found. The proportion of particle fractions in faeces was smaller in both sainfoin treatments compared to CON. In urine, the ratio of purine derivatives to creatinine tended to be higher in SST than in CON, and total urinary nitrogen excretion was lower, indicating a slightly better protein efficiency in SST. In summary, the study revealed small positive effects on protein metabolism and yield when sainfoin was applied short-term over two short periods, whereas long-term application had no effect

Extraction of cocoa proanthocyanidins and their fractionation by sequential centrifugal partition chromatography and gel permeation chromatography

Erworben im Rahmen der Schweizer Nationallizenzen (http://www.nationallizenzen.ch)Cocoa beans contain secondary metabolites ranging from simple alkaloids to complex polyphenols with most of them believed to possess significant health benefits. The increasing interest in these health effects has prompted the need to develop techniques for their extraction, fractionation, separation, and analysis. This work provides an update on analytical procedures with a focus on establishing a gentle extraction technique. Cocoa beans were finely ground to an average particle size of <100 μm, defatted at 20°C using n-hexane, and extracted three times with 50 % aqueous acetone at 50°C. Determination of the total phenolic content was done using the Folin-Ciocalteu assay, the concentration of individual polyphenols was analyzed by electrospray ionization high performance liquid chromatography-mass spectrometry (ESI-HPLC/MS). Fractions of bioactive compounds were separated by combining sequential centrifugal partition chromatography (SCPC) and gel permeation column chromatography using Sephadex LH-20. For SCPC, a two-phase solvent system consisting of ethyl acetate/n-butanol/water (4:1:5, v/v/v) was successfully applied for the separation of theobromine, caffeine, and representatives of the two main phenolic compound classes flavan-3-ols and flavonols. Gel permeation chromatography on Sephadex LH-20 using a stepwise elution sequence with aqueous acetone has been shown for effectively separating individual flavan-3-ols. Separation was obtained for (-)-epicatechin, proanthocyanidin dimer B2, trimer C1, and tetramer cinnamtannin A2. The purity of alkaloids and phenolic compounds was determined by HPLC analysis and their chemical identity was confirmed by mass spectrometry

Characterization of Phenolic Compounds and Their Contribution to Sensory Properties of Olive Oil

Olive oil is not only known for its pungent, bitter, and fruity taste, but also for its health potential, which is often hypothesized to depend on its phenolic compounds. One hundred extra virgin olive oil samples (monocultivaric as well as blends of varieties) were assessed with regard to their sensory properties and phenolic compound composition. Nineteen phenolic compounds have been determined and correlated with sensory data. In all olive oil samples, oleocanthal and oleacein were the most abundant phenolic compounds, with average amounts of 77.9 mg/kg and 41.8 mg/kg, respectively. The highest correlation coefficient between a sensory descriptor and the phenolic compounds was found for the bitter taste sensation and the total phenolic content with r = 0.72 and in particular, for 3,4-DHPEA-EA, with r = 0.57. Intensity plots were assessed for the three main sensory descriptors fruitiness, bitterness, pungency, and for the quality factor harmony, which is associated with the degree of ripeness aroma of olive oil. Positive correlations for the aroma descriptors freshly cut grass, leaves, and nuts, and the phenolic compounds were especially observed for oleoside 11-methylester and vanillic acid. The present study provides a comprehensive database of phenolic compounds in olive oils from six different varieties and seven countries

Sensory-driven substitution of acrylate polymers with natural alternatives

Environmentalists are increasingly concerned about microplastics in the environment and are also critical of the use of liquid plastic in cosmetics putting the industry under pressure to find acceptable alternatives. Since liquid plastic gel formers greatly influence the sensorial characteristics and the stability of a product, it is important that such gels are replaced with polymers derived from natural products (biopolymers) or a blend of such polymers having similar performance characteristics. The researchers responsible for developing such products are also interested in a time-saving and reproducible "pre-screening tool" to support their product assessment, which is necessarily subjective, before the final formulations are profiled by an appropriately trained expert panel. The aim of this study was to apply rheological, frictiometric measurement protocols and sensory profiling enabling both a comprehensive characterization of the raw materials and identification of an appropriate replacement. Furthermore, the transferability of the concept of predictive modelling to polymers in general was to be tested