An innovative green extraction and re-use strategy to valorize food supplement by-products: Castanea sativa bud preparations as case study.

This research takes place in the context of an Alcotra Italy-France trans-frontier project called FINNOVER, which includes among its objectives the "green" innovation of agro-industrial chains. Bud-derivatives are a category of natural products produced macerating meristematic tissues of trees and plants. They are quite expensive compared to other botanicals, since the collection period of their raw materials is extremely limited over the time. Pulsed Ultrasound-Assisted Extraction has been employed to extract further valuable material from the buds by-products remaining after the production of Castanea sativa Glyceric Macerates. UV-Visible spectra coupled with chemometrics were employed, as untargeted phytochemical fingerprints, to quickly screen the best experimental conditions of extraction: a duty cycle of 80%, an extraction time of 15 min and a solvent/ratio of 1/10. Targeted phytochemical fingerprints by HPLC have been used to identify and quantify the main bioactive compounds of the most promising marcs extract comparing it with the corresponding commercial Castanea sativa Glyceric Macerate. An innovative extraction and re-use strategy to obtain value-added products from botanicals by-products was developed in alternative to incineration or composting. It was applied to Castanea sativa buds production as case study, but it could be analogously applied for other herbal preparations.

Optimization of the Ultrasonic-Assisted Extraction of Phenolic Compounds from Oryza Sativa L. 'Violet Nori' and Determination of the Antioxidant Properties of its Caryopses and Leaves.

'Violet Nori' is a new spontaneous growing violet rice variety showing a peculiar violet color in its fresh leaves as well. In this paper, the antioxidant properties and the content of total phenols, radical scavengers, and anthocyanins in 'Violet Nori' caryopses, flour, and leaves are explored and compared. Ultrasonic-Assisted Extraction (UAE) is employed for the extraction of phenolic compounds, improving the extraction conditions by Design of Experiments (DoE). The obtained results show that the Radical Scavenging Activities (RSAs), the Total Phenolic Contents (TPCs), and the anthocyanin amounts (1000-1500 µg/g, expressed as cyanidin-3-glucoside) of 'Violet Nori' caryopses are higher than those in the other analyzed colored rice samples (300-900 µg/g as cyanidin-3-glucoside), with the exception of the cultivars 'Artemide' and 'Nerone', which show comparable values of RSAs and TPCs. The study of 'Violet Nori' leaves at different plant maturation stages shows that their anthocyanin content is 2-3 times higher than in the caryopses and in the flour, reaching the highest levels at about 60 days from seeding. Thus, the estimated extraction yield of 4 kg anthocyanins/t makes fresh leaves very interesting for the extraction of anthocyanins on an industrial scale, whereas violet caryopses are a very interesting dietetic source of valuable anthocyanins and other antioxidant compounds.

Olive fruits and vacuum impregnation, an interesting combination for dietetic iron enrichment.

In this study vacuum impregnation (VI) was employed for the iron enrichment of olive fruits, which are very interesting as food vehicle for VI mineral supplementation for the porosity of their pulp. NaFeEDTA was chosen for olives fortification since it prevents iron from binding with compounds that could hinder it from being efficiently absorbed and since it causes few organoleptic problems. In order to improve the efficiency of the VI process, several parameters of the whole process were studied by design of experiment techniques. First of all D-optimal design was employed for a preliminary screening of the most significant process variables and showed that the concentration of VI solution was by far the most significant process variable, though its time in contact with olives was also significant. A factorial design was then applied to the remaining variables and it showed that the speed of the addition of VI solution was also significant. Finally, the application of a face centered composite design to the three selected variables allowed to detect processing conditions leading to final iron contents of 1.5-3 mg/g, corresponding to an introduction of 10-15 mg Fe with four or five fortified olive fruits. No effect on olive taste was observed at these concentrations. The results showed that olive fruits were the most interesting vehicles for the supplementation of both iron and other minerals.

Determination and speciation of trace and ultratrace selenium ions by energy-dispersive X-ray fluorescence spectrometry using graphene as solid adsorbent in dispersive micro-solid phase extraction.

A dispersive micro-solid phase extraction (DMSPE) with graphene as a solid adsorbent and ammonium pyrrolidinedithiocarbamate (APDC) as a chelating agent was proposed for speciation and detemination of inorganic selenium by the energy-dispersive X-ray fluorescence spectrometry (EDXRF). In developed DMSPE, graphene particles are dispersed throughout the analyzed solution, therefore reaction between Se(IV)-APDC complexes and graphene nanoparticles occurs immediately. The concentration of Se(VI) is calculated as the difference between the concentration of selenite after and before prereduction of selenate. A central composite face-centered design with 3 center points was performed in order to optimize conditions and to study the effect of four variables (pH of the sample, concentration of APDC, concentration of Triton-X-100, and sample volume). The best results were obtained when suspension consisting of 200 µg of graphene nanosheets, 1.2 mg of APDC and 0.06 mg of Triton-X-100 was rapidly injected to the 50 mL of the analyzed solution. Under optimized conditions Se ions can be determined with a very good recovery (97.7±5.0% and 99.2±6.6% for Se(IV) and Se(VI), respectively) and precision (RSD=5.1-6.6%). Proposed DMSPE/EDXRF procedure allowed to obtain low detection limits (0.032 ng mL(-1)) and high enrichment factor (1013±15). The proposed methodology was successfully applied for the determination of Se in mineral, tap, lake and sea water samples as well as in biological materials (Lobster Hepatopancreas and Pig Kidney).

Direct GC-(EI)MS determination of fatty acid alkyl esters in olive oils.

A new analytical method for fatty acid alkyl esters (FAAEs) determination by GC-MS in virgin olive oils is proposed. No sample preparation is required and FAAEs are directly thermo-desorbed and cryo-focalised in the cooled injector of a GC-MS (EI) instrument. The analytical conditions were optimized by Design of Experiment (DoE) techniques (an exploratory Plackett-Burman design followed by a factorial design on three selected variables). After the improvement of method performances, several samples of extra virgin and low quality virgin olive oils were analyzed both by the new method and by the Official EU Method of analysis. The application of Principal Component Analysis to the obtained results confirmed that the ability of the proposed method to discriminate between extra virgin and lower quality olive oils is at least equal to that of the Official Method, but the new method is faster, simpler, requires a much lower amount of organic solvents and significantly enhances method repeatability.

Detection of addition of barley to coffee using near infrared spectroscopy and chemometric techniques.

The current study presents an application of near infrared spectroscopy for identification and quantification of the fraudulent addition of barley in roasted and ground coffee samples. Nine different types of coffee including pure Arabica, Robusta and mixtures of them at different roasting degrees were blended with four types of barley. The blending degrees were between 2 and 20 wt% of barley. D-optimal design was applied to select 100 and 30 experiments to be used as calibration and test set, respectively. Partial least squares regression (PLS) was employed to build the models aimed at predicting the amounts of barley in coffee samples. In order to obtain simplified models, taking into account only informative regions of the spectral profiles, a genetic algorithm (GA) was applied. A completely independent external set was also used to test the model performances. The models showed excellent predictive ability with root mean square errors (RMSE) for the test and external set equal to 1.4% w/w and 0.8% w/w, respectively.

Direct thermal extraction and gas chromatographic-mass spectrometric determination of volatile compounds of extra-virgin olive oils.

The instrumental performances of a Thermo Desorption-Cooled Injection System coupled with a gas chromatography-mass spectrometer (GC-MS) were improved by a Plackett-Burman experimental design for the direct thermal extraction of volatile compounds from extra-virgin olive oils. The obtained experimental conditions were applied to the analysis of samples from West Liguria (cv. Taggiasca > or = 90%) and Spain (cv. Arbequina), which shared such similar sensorial features that Taste Panel did not distinguish them. Principal component analysis (PCA) was then applied to the experimental data. Three linear combinations of the amounts of the lipoxygenase oxidation products proved to be decisive and sufficient in the differentiation of the two groups of samples.