Arianna Binello

Determination of phenolic diterpene antioxidants in rosemary (Rosmarinus officinalis L.) with different methods of extraction and analysis

The extraction from rosemary (Rosmarinus officinalis L.) of the phenolic diterpene antioxidants (PDAs), carnosic acid and carnosol, by sonication or Soxhlet extraction with acetone (with or without active charcoal bleaching) are compared with fractionated SFE extraction obtained by varying the dissolving power of supercritical carbon dioxide through the addition of methanol. For the further analysis of the PDAs, the results obtained by reversed-phase HPLC linked to a UV detector are compared with those produced when an evaporative light scattering detector or a particle beam interface linked to an MS were employed. Copyright

Cyclodextrins as Food Additives and in Food Processing

This review deals with the applications of cyclodextrins (CDs) to food manufacture, focusing on the technical advantages of their use in food processing and as food additives. Their beneficial effects essentially derive from the ability to form stable inclusion complexes with sensitive lipophilic nutrients and constituents of flavor and taste. Toxicological data are examined and an assessment of CDs from the standpoint of safety for human consumption is made. Regulations are covered, showing a general trend towards a wider acceptance of CDs as food additives. The growing health consciousness of consumers and expanding market for functional foods and nutraceutical products are opening up to CDs a promising future in food industry.

Ultrasound-Promoted Copper-Catalyzed Azide-Alkyne Cycloaddition

†Dipartimento di Scienza e Tecnologia del Farmaco, Universita di Torino, Via Giuria 9, 10125Torino, Italy, and Department of Chemistry, The Scripps Research Institute, 10550 North TorreyPines Road, La Jolla, California 92037The 1,3-dipolar cycloaddition reaction of azides and alkynes has been known for over 100years and was studied extensively by Huisgen and co-workers in the 1960s.

Innovative “Green” and Novel Strategies for the Extraction of Bioactive Added Value Compounds from Citrus Wastes—A Review

Citrus is a major processed crop that results in large quantities of wastes and by-products rich in various bioactive compounds such as pectins, water soluble and insoluble antioxidants and essential oils. While some of those wastes are currently valorised by various technologies (yet most are discarded or used for feed), effective, non-toxic and profitable extraction strategies could further significantly promote the valorisation and provide both increased profits and high quality bioactives. The present review will describe and summarize the latest works concerning novel and greener methods for valorisation of citrus by-products. The outcomes and effectiveness of those technologies such as microwaves, ultrasound, pulsed electric fields and high pressure is compared both to conventional valorisation technologies and between the novel technologies themselves in order to highlight the advantages and potential scalability of these so-called “enabling technologies”. In many cases the reported novel technologies can enable a valorisation extraction process that is “greener” compared to the conventional technique due to a lower energy consumption and reduced utilization of toxic solvents.

Click Chemistry Under Microwave or Ultrasound Irradiation

The copper-catalyzed azide-alkyne cycloaddition (CuAAC) is generally recognized as the most striking example of “click reaction”. CuAAC fit so well into Sharpless’ definition that it became almost synonymous with “click chemistry” itself. The most common catalyst systems employ Cu(II) salt in the presence of a reducing agent (i.e. sodium ascorbate) to generate the required Cu(I) catalyst in situ or as an alternative the comproportionation of Cu(II)/Cu(0) species. Although, Cu(I) catalyzes the reaction with a rate enhancement of 10 7 even in the absence of ligands and provides a clean and selective conversion to the 1,4-substituted triazoles, some bulky and scantily reactive substrates still require long reaction times and often few side products are formed. Outstanding results have been achieved by performing CuAAC under microwave (MW) irradiation. Several authors described excellent yields, high purity and short reaction times. In few cases also power ultrasound (US) accelerated the reaction, especially when heterogeneous catalysts or metallic copper are employed. The aim of this review is to summarize and highlight the huge advantages offered by MWand US-promoted CuAAC. In the growing scenario of innovative synthetic strategies, we intend to emphasize the complementary role played by these nonconventional energy sources and click chemistry to achieve process intensification in organic synthesis.

Hydrodistillation and in situ microwave-generated hydrodistillation of fresh and dried mint leaves: a comparison study.

BACKGROUND Hydrodistillation (HD) has been used since ancient times for the extraction of essential oils (EO). Despite the intrinsic limitations of this technique, it remains the most common method both in the laboratory and on an industrial scale. The main drawbacks are the long extraction time involved and the risk of thermal degradation. Over the last decade, microwave-assisted extraction (MAE) and in situ microwave-generated hydrodistillation (MGH) have been shown to be the most promising techniques in improving plant extraction and hydrodistillation. RESULTS In this study we compare HD with MGH in the extraction of several mint species cultivated in Piedmont: Mentha spicata L. var. rubra, Mentha spicata L. var. viridis and Mentha piperita L. MGH requires either fresh plant or rehydrated material, it is extremely fast and allows a reduction in energy consumption and overall cost. All the EO have been analyzed by gas chromatography-mass spectrometry. A mechanism of microwave-generated essential oil extraction has been proposed to explain the differences in the composition of the oil obtained from this environmentally friendly technique. CONCLUSIONS The yields and composition percentages of the EO obtained by HD and in situ MGH of fresh and dried mint leaves lie in a relatively narrow range, although MGH is faster. MW polarization effects and the water solubility of the components influence extract composition.

Extraction of kiwi seed oil: Soxhlet versus four different non-conventional techniques

Kiwi seed oil has a nutritionally interesting fatty acid profile, but a rather low oxidative stability, which requires careful extraction procedures and adequate packaging and storage. For these reasons and with the aim to achieve process intensification with shorter extraction time, lower energy consumption and higher yields, four different non-conventional techniques were experimented. Kiwi seeds were extracted in hexane using classic Soxhlet as well as under power ultrasound (US), microwaves (MWs; closed vessel) and MW-integrated Soxhlet. Supercritical CO2 was also employed and compared to the other techniques in term of yield, extraction time, fatty acid profiles and organoleptic properties. All these non-conventional techniques are fast, effective and safe. A sensory evaluation test showed the presence of off-flavours in oil samples extracted by Soxhlet and US, an indicator of partial degradation.

Recent Applications of Cyclodextrins as Food Additives and in Food Processing

Nowadays the application of cyclodextrin-assisted molecular encapsulation in foods offers many advantages. Cyclodextrins, their derivatives and their cross-linked polymers can all improve the quality of food in storage, remove specific components and stabilize and increase the presence of components that are important for a healthy diet. The application of cyclodextrins and their complexes in packaging materials can help not only transport of previously nontransportable foods, but may also prevent, or at least decelerate, the spread of microbial infections. The number of publications, particularly analytical papers, on this matter is constantly increasing. Although the application of modern analytical methods and equipment allows for the quantitation of previously subjectively characterized parameters, bio-sensory methods are still important. The application of cyclodextrins in the nutraceutical industry has many advantages; however, some side effects connected with the inclusion complexation ability of these carbohydrates should lead scientists to study cases on an individual basis. Recent developments in the major fields of cyclodextrin related food research are herein summarized.

Efficient mechanochemical complexation of various steroid compounds with α-, β- and γ-cyclodextrin.

Mechanochemical technology enables solvent-free micronized solid dispersions and efficient molecular host-guest inclusion complexes to be formed in matrices which contain cyclodextrins (CDs). This type of complexation has been studied using α-, β- and γ-cyclodextrin with the dual aims of improving overall solubility and enhancing the bioavailability of common steroid compounds, such as cholic acids and β-sitosterols or lowering cholesterol content in products of animal origin. Several parameters have been studied and optimized: CD/compound molar ratio (1:1, 1:2, 2:1 and 3:1) in function of the cavity sizes of the three different CDs, milling time (from 5 to 40 min) and rotation speed (from 100 to 300 rpm). DSC (differential scanning calorimetry) analyses have revealed that inclusion complexes were efficiently formed after 40 min milling (200 rpm) for β-CD/cholesterol and β-CD/ugrsodeoxycholic acid (encapsulation efficiency 96% and 77% respectively). Besides steroid encapsulation/vehiculation, the mechanochemical technique may pave the way for new ideas in solventless steroid extraction from vegetal matrices with CDs.

Packed column SFC/UV versus HPLC/UV analysis of valerenic acids and valepotriates in extracts of Valeriana officinalis L.

Valerenic acids and valepotriates are considered among the constituents responsible for the sedative effect of roots and rhizomes of Valeriana species. Packed column SFC/UV (p-SFC) was applied to the analysis of valerenic acids and valepotriates extracted from the underground parts of Valeriana officinalis. The separation of these compounds by p-SFC was optimized by varying the conditions (i.e. columns, column coupling and stationary phase coupling, density programmes, types of modifiers and modifier programmes). A CN-stationary phase using supercritical carbon dioxide modified with methanol:water (95:5) as mobile phase was successful in separating both valerenic acids and valepotriates. The qualitative and quantitative results of p-SFC are comparable to HPLC for both valerenic acids and valepotriates, but analyses are faster with p-SFC than with HPLC. Copyright