Microwave-assisted methanolysis of green coffee oil

Microwave-assisted extraction in closed vessel in food analysis

Microwave-assisted extraction (MAE) is an important technique in analytical chemistry. It offers several advantages over traditional extraction methods, such as improved extraction efficiency, shorter extraction times, reduced solvent consumption, and enhanced analyte recovery. Using microwaves, heat is directly applied to the sample, leading to rapid and efficient extraction of target compounds by enhancing the solubility and diffusion of the target compounds, thus requiring lower solvent volume. Therefore, MAE can be considered a more environmentally friendly and cost-effective option facilitating the transition toward greener and more sustainable analytical chemistry workflows. This contribution systematically reviews the application of MAE to a selection of target compounds/compounds classes of relevance for food quality and safety assessment. As inclusion criteria, MAE active temperature control and molecularly-resolved characterization of the extracts were considered. Contents include a brief introduction of the principles of operation, available systems characteristics, and key parameters influencing extraction efficiency and selectivity. The application section covers functional food components (e.g., phenols, diterpenes, and carotenoids), lipids, contaminants (e.g., polycyclic aromatic hydrocarbons and mineral oil hydrocarbons), pesticides, veterinary drug residues, and a selection of process contaminants and xenobiotics of relevance for food safety.

An In Vitro and In Vivo Assessment of Antitumor Activity of Extracts Derived from Three Well-Known Plant Species

One of the objectives of this study consists of the assessment of the antitumor activity of several extracts from three selected plant species: Xanthium spinosum L., Trifolium pratense L., and Coffea arabica L. and also a comparative study of this biological activity, with the aim of establishing a superior herbal extract for antitumor benefits. The phytochemical profile of the extracts was established by HPLC-MS analysis. Further, the selected extracts were screened in vitro for their antitumor activity and antioxidant potential on two cancer cell lines: A549-human lung adenocarcinoma and T47D-KBluc-human breast carcinoma and on normal cells. One extract per plant was selected for in vivo assessment of antitumor activity in an Ehrlich ascites mouse model. The extracts presented high content of antitumor compounds such as caffeoylquinic acids in the case of X. spinosum L. (7.22 µg/mL-xanthatin, 4.611 µg/mL-4-O-caffeoylquinic acid) and green coffee beans (10.008 µg/mL-cafestol, 265.507 µg/mL-4-O-caffeoylquinic acid), as well as isoflavones in the case of T. pratense L. (6806.60 ng/mL-ononin, 102.78 µg/mL-biochanin A). Concerning the in vitro results, the X. spinosum L. extracts presented the strongest anticancerous and antioxidant effects. In vivo, ascites cell viability decreased after T. pratense L. and green coffee bean extracts administration, whereas the oxidative stress reduction potential was important in tumor samples after T. pratense L. Cell viability was also decreased after administration of cyclophosphamide associated with X. spinosum L. and T. pratense L. extracts, respectively. These results suggested that T. pratense L. or X. spinosum L. extracts in combination with chemotherapy can induce lipid peroxidation in tumor cells and decrease the tumor viability especially, T. pratense L. extract.

Extraction of Diterpene-Phytochemicals in Raw and Roasted Coffee Beans and Beverage Preparations and Their Relationship

Cafestol and kahweol are expressive furane-diterpenoids from the lipid fraction of coffee beans with relevant pharmacological properties for human health. Due to their thermolability, they suffer degradation during roasting, whose products are poorly studied regarding their identity and content in the roasted coffee beans and beverages. This article describes the extraction of these diterpenes, from the raw bean to coffee beverages, identifying them and understanding the kinetics of formation and degradation in roasting (light, medium and dark roasts) as the extraction rate for different beverages of coffee (filtered, Moka, French press, Turkish and boiled). Sixteen compounds were identified as degradation products, ten derived from kahweol and six from cafestol, produced by oxidation and inter and intramolecular elimination reactions, with the roasting degree (relationship between time and temperature) being the main factor for thermodegradation and the way of preparing the beverage responsible for the content of these substances in them.

New trends in coffee diterpenes research from technological to health aspects

The coffee oil is rich in diterpenes, mainly cafestol and kahweol, which are predominantly present in the esterified form with different fatty acids. Despite their beneficial effects including anti-angiogenic and anti-carcinogenic properties, they have been also associated with negative consequences such as elevation of blood cholesterol. Considering the coffee, it is an important human beverage with biological effects, including potentially health benefits or risks. Therefore, it may have important public health implications due to its widespread massive consumption, with major incidence in the varieties Arabica and Robusta. According to literatures, cafestol (182-1308 mg/100 g), kahweol (0-1265 mg/100 g) and 16-O-methycafestol (0-223 mg/100 g) are the main diterpenes in green and roasted coffee beans. Nevertheless, the coffee species, genetic background, and technological parameters like roasting and brewing have a clear effect on coffee diterpene content. Besides that, bibliographic data indicated that limited studies have specifically addressed the recent analytical techniques used for determination of this class of compounds, being HPLC and GC the most common approaches. For these reasons, this review aimed to actualize the occurrence and the profile of diterpenes in coffee matrices, focusing on the effect of species, roasting and brewing and on the other hand, introduce the current state on knowledge regarding coffee diterpenes determination which are nowadays highly regarded and widely used. In general, since diterpenes exhibit different health effects depending on their consumption dosage, several parameters needs to be carefully analyzed and considered when comparing the results.

Reduction of βN-alkanoyl-5-hydroxytryptamides and diterpenes by yeast supplementation to green coffee during wet processing

Coffee is one of the most consumed non-alcoholic beverages in the world. It is well known that some compounds present in coffee beans have important biological activities. In this study, evidence was turned to ^βN-alkanoyl-5-hydroxytryptamides (C-5HTs) and to the furokaurane diterpenes cafestol and kahweol, associated with gastric irritation and increasing of blood cholesterol, respectively. Fermentation in coffee post-harvest wet process was induced by three Saccharomyces cerevisiae yeasts (for bakery, white and sparkling wines) as starter cultures. Variations in mass, time, temperature and pH (56 experiments under fractional factorial and mixture experimental designs) were tested. Substantial reductions for C-5HTs (up to 38% reduction for C20-5HT and 26% for C22-5HT) as well as for diterpenes (54% for cafestol and 53% for kahweol) were obtained after treating green coffee beans with 0.6 g of a 1:1:1 mixture the three yeasts for 12 h at 15 °C and pH 4. Caffeine and 5-CQA content, monitored in the green coffee beans, did not change. Therefore, the use of starter cultures during coffee post-harvest wet process has influence on the amount of some important compounds related to health and improves the sensory quality of the beverage.

A brief understanding of process optimisation in microwave-assisted extraction of botanical materials: options and opportunities with chemometric tools

INTRODUCTION

Extraction forms the very basic step in research on natural products for drug discovery. A poorly optimised and planned extraction methodology can jeopardise the entire mission.

OBJECTIVE

To provide a vivid picture of different chemometric tools and planning for process optimisation and method development in extraction of botanical material, with emphasis on microwave-assisted extraction (MAE) of botanical material.

METHODS

A review of studies involving the application of chemometric tools in combination with MAE of botanical materials was undertaken in order to discover what the significant extraction factors were. Optimising a response by fine-tuning those factors, experimental design or statistical design of experiment (DoE), which is a core area of study in chemometrics, was then used for statistical analysis and interpretations.

RESULTS

In this review a brief explanation of the different aspects and methodologies related to MAE of botanical materials that were subjected to experimental design, along with some general chemometric tools and the steps involved in the practice of MAE, are presented. A detailed study on various factors and responses involved in the optimisation is also presented.

CONCLUSION

This article will assist in obtaining a better insight into the chemometric strategies of process optimisation and method development, which will in turn improve the decision-making process in selecting influential extraction parameters.