Natural Deep Eutectic Solvents (NADES) represent a green chemistry alternative to utilization of common hazardous organic solvents. They were introduced by Abbott et al. [1], and were found to have a wide range of compositions and favorable properties. NADES are typically obtained by mixing hydrogen-bond acceptors (HBA), with hydrogen bond donors (HBD), leading to a significant depression of the melting point. The availability of components, simple preparation, biodegradability, safety, re usability and low cost are the significant advantages that call for research on their analytical applications. Three methods are most commonly used for preparing NADES: a) heating and stirring: the mixture until a clear liquid is formed; b) evaporating solvent from components solution with a rotatory evaporator; c) freeze drying of aqueous solutions.The common solvents for the extraction of anthocyanins are acidified mixtures of water with ethanol, methanol, or acetone. The anthocyanins extracts are susceptible to degradation due to high temperature, and the solvent properties (e.g. high pH) and the whole process can often be time-consuming. Extraction of anthocyanins from red cabbage by four NADES was investigated. It was demonstrated that NADES have comparable extraction efficiencies with conventional method with 0.1 M water solution of HCl. This indicates a possibility of utilization the Green chemistry extraction processes as a promising new green-extraction technology with low cost efficiency and environment friendly technology for production of safe food additives.
• Our research suggest that anthocyanins are promising anti-bacterial agents • The antimicrobial effects are highly dependent on the source of the anthocyanin-extract • Rose-anthocyanins appear to posses the strongest anti-bacterial effects • Gram-positive strains appear to be more sensitive compared to gram-negative strains • Future research efforts should focus on different anthocyanin entities
To treat microbial infections, antibiotics are life-saving but the increasing antimicrobial resistance is a World-wide problem. Therefore, there is a great need for novel antimicrobial substances. Fruit and flower anthocyanins have been recognized as promising alternatives to traditional antibiotics. How-ever, for future application as innovative alternative antibiotics, the full potential of anthocyanins should be further investigated. The antimicrobial potential of anthocyanin mixtures against different bacterial species has been demonstrated in literature. Preliminary experiments performed by our laboratories, using grape, rose and red cabbage anthocyanins against S. aureus and E. coli confirmed the antimicrobial potential of these substances. Hundreds of different anthocyanin entities have been described. However, which of these entities hold antimicrobial effects is currently unknown. Our preliminary data show that an-thocyanins extracted from grape, rose and red cabbage contain different collections of anthocyanin entities with differential antimicrobial efficacies. Our focus is on the extraction and characterization of anthocyanins from various crop residues. Grape peels are residues in the production of wine, while red rose and tulip leaves are residues in the production of tulip bulbs and regular horticulture. The presence of high-grade substances for pharmacological purposes in these crops may provide an innovative strategy to add value to other-wise invaluable crop residues. This project will be performed by the collaborative effort of our institute together with the Medi-cal Microbiology department of the University Medical Center Groningen (UMCG), 'Wijnstaete', a small-scale wine-producer (Lemelerveld) and Imenz Bioengineering (Groningen), a company that develops processes to improve the production of biobased chemicals from waste products. Within this project, we will focus on the antimicrobial efficacy of anthocyanin-mixtures from sources that are abundantly and locally available as a residual waste product. The project is part of a larger re-search effect to further characterize, modify and study the antimicrobial effects of specific anthocy-anin entities.
Bij elke kilo koffiebonen wordt een kilo pulp geproduceerd. De pulp van de koffiebes is rijk aan verschillende waardevolle biologische verbindingen, die momenteel in de koffieproducerende landen niet benut worden. Vaak wordt de pulp in het natuur gedumpt, met milieu problemen als gevolg. Pectcof heeft een innovatieve bioraffinage technologie ontwikkeld om van de koffiepulp waardevolle grondstoffen te winnen. In deze, in 2015 voor de Food Valley Award genomineerd proces, wordt van de koffiepulp een pectineproduct verzuiverd. Deze product is volledig ontwikkeld en wordt naar de markt gebracht onder de naam Dutch Gum. Het huidige Pectcof raffinage proces is gericht naar het isoleren van de Dutch Gum, waarbij naast het product ook twee zijstromen ontstaan: een vaste pulp zijstroom en een water zijstroom. Het doel is deze reststromen volledig te benutten. Allereerst wordt de aandacht gericht op de isolatie van de hoogwaardige polyfenolen. Een deel van de koffiepulp polyfenolen zijn natuurlijke kleurstoffen vooral anthocyanen. Deze kunnen interessante valorisatie mogelijkheden bieden in food en non-food toepassingen. Kennis van de samenstelling, de zuiverheid en de concentratie van deze stoffen in de koffiepulp zijstroom is noodzakelijk om mogelijke valorisatie potentieel van de kleurstoffen te bepalen. N-Chroma is een innovatief bedrijf dat zich richt op de productie van natuurlijke kleurstoffen. Pectcof en N-Chroma hebben gezamenlijke interesse om de kleurstoffen in de koffiepulp te isoleren en te onderzoeken en hebben Avans/CoeBBE benaderd om hen hierbij te helpen. De Biobased Products groep, onder leiding van Dr. Dorien Derksen bezit de expertise in natuurlijke kleurstoffen die noodzakelijk is voor het onderzoek dat de MKB-bedrijven kan helpen om de processen en toepassingsmogelijkheden verder te definiëren. In het project worden de aanwezigheid en samenstelling van de kleurcomponenten in Pectcof zijstromen getest. Op basis van de onderzoek kunnen Pectcof en N-Chroma de valorisatie van de kleurstoffen goed onderbouwd plannen.
