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Context: Currently, there is a great tendency in cosmetic area to use natural extracts. Coffee silverskin (CS) is the most abundant solid by-product generated during roasting of coffee processing. Objectives: To evaluate different CS extracts as promising cosmetic ingredients, regarding antioxidant, antimicrobial, and cytotoxic properties. Materials and methods: Aqueous, hydroalcoholic and ethanolic CS extracts were obtained by an environmentally friendly procedure considering costs and pollution. Extracts were characterized for total phenolic and flavonoid contents (TPC and TFC, respectively), antioxidant activity by 1,1-diphenyl-2-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), antimicrobial activity expressed as minimal inhibitory concentration (MIC) and cytotoxicity using the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) and lactate dehydrogenase (LDH) assays in two skin cell lines (fibroblasts and keratinocytes). Results: The TPC of extracts was 18.33-35.25 mg of gallic acid equivalents per g of material on a dry basis (mg GAE/g db). The TFC of extracts was 1.08-2.47 mg cathechin equivalents per g dry material (mg CE/g db). The antioxidant activity was high, with values ranging between 95.95 and 216.40 mmol Fe 2+ /g for aqueous and alcoholic samples, respectively. Preliminary assays for antimicrobial potential showed that extracts display antibacterial activity. The MIC varied from 31.3 to 250 mg/mL for Gram-positive, and from 31.3 to 1000 mg/mL for Gram-negative. Extracts did not affect in vitro cell viability, with values near 100% in all concentrations tested. Conclusion: Results seem show that CS is a safe source of natural antioxidants with antifungal and antibacterial activity and no cytotoxicity, with potential usefulness for cosmetic applications.

Twenty-four coffee samples of different botanical and geographical origins were analyzed for their FA composition, including trans isomers. The analysis used high-resolution GC/FID/CP Sil 88 capillary column to separate FAME obtained by esterification with BF 3 /methanol. The purpose of this work was to verify whether this parameter could be applied in the discrimination of arabica and robusta coffees, either in green or in roasted stage. Statistical approaches were applied to check the efficiencies of some univariate and multivariate procedures, and the results permitted the conclusion that the FA profile can be used as a coffee variety marker and may inform on the historical background, mainly in terms of heat-processing conditions. Paper no. J9895 in JAOCS 80, 511-517 (June 2003).Of all the species of Coffea available, two have acquired high commercial value, namely, C. arabica Linn. and C. canephora Pierre ex Froehner var. robusta, and are used to prepare coffee drinks. The beans of the preferred species are easily identified by their macroscopic characteristics when in the green stage. After roasting, this distinction is still possible with whole beans, but after milling, when the anatomic characteristics are lost, identification becomes extremely difficult. Since C. arabica and C. robusta display different appeals and have different commercial values, the discrimination of these species is essential to be able to avoid adulteration and to prevent unfair commercial practices (1).To guarantee the authenticity of coffees, several chemical and physical parameters have been tried, namely, hydroxycinnamic acid derivatives (2), unsaponifiable lipid fractions (3,4), furanic aldehydes (5), trace element profiles (6), stable isotope ratios (7), aroma profiles (8), and spectroscopic techniques (9-11).With regard to the FA composition of the two coffee varieties, an unambiguous position among authors is not yet available, especially when roasted beans are considered (12-16).Therefore, the approach presented in this paper is (i) a new attempt to verify the utility of FA profiles in the discrimination between arabica and robusta coffee varieties, both in the green and roasted stage, (ii) a study of the possible role played by trans isomers of unsaturated FA in the discrimination of the roasted coffees, and (iii) an attempt to develop a statistical model for green and roasted arabica and robusta coffee varieties for use as a starting point for the development of a database. EXPERIMENTAL PROCEDURES Samples.A total of 16 samples of coffee beans from C. canephora Pierre ex Froehner var. robusta and 8 samples of C. arabica Linn., before and after roasting, were studied. The 16 C. robusta samples in the green stage were identified as RG01-RG16, and the same 16 samples after roasting were identified as RR01-RR16. These samples had several geographical origins (India, Vietnam, Uganda, Amboim/Angola, Angola, Cameroon, and the Ivory Coast). Like the C. robusta samples, the 8 C. arabica samples were prepared in green and roasted st...

This study focused on the development of a sensitive enzymatic biosensor for the determination of pirimicarb pesticide based on the immobilization of laccase on composite carbon paste electrodes. Multi-walled carbon nanotubes (MWCNTs) paste electrode modified by dispersion of laccase (3%, w/w) within the optimum composite matrix (60:40%, w/w, MWCNTs and paraffin binder) showed the best performance, with excellent electron transfer kinetic and catalytic effects related to the redox process of the substrate 4-aminophenol. No metal or anti-interference membrane was added. Based on the inhibition of laccase activity, pirimicarb can be determined in the range 9.90 × 10(-7) to 1.15 × 10(-5) mol L(-1) using 4-aminophenol as substrate at the optimum pH of 5.0, with acceptable repeatability and reproducibility (relative standard deviations lower than 5%). The limit of detection obtained was 1.8 × 10(-7) mol L(-1) (0.04 mg kg(-1) on a fresh weight vegetable basis). The high activity and catalytic properties of the laccase-based biosensor are retained during ca. one month. The optimized electroanalytical protocol coupled to the QuEChERS methodology were applied to tomato and lettuce samples spiked at three levels; recoveries ranging from 91.0 ± 0.1% to 101.0 ± 0.3% were attained. No significant effects in the pirimicarb electroanalysis were observed by the presence of pro-vitamin A, vitamins B1 and C, and glucose in the vegetable extracts. The proposed biosensor-based pesticide residue methodology fulfills all requisites to be used in implementation of food safety programs.

This paper describes an adequate procedure of reversed-phase HPLC/diode-array detector to be used in quality control to simultaneously quantify three nitrogen compounds: trigonelline, nicotinic acid, and caffeine, in coffee samples either in the green or roasted states. The chromatographic separation was achieved using a reversed-phase column (Spherisorb ODS2) with gradient elution of 0.01M phosphate buffer pH 4.0 (A) and methanol (B). The effluent was monitored by a diode-array detector and the chromatograms were recorded at 265 nm. The sample preparation was quite simple involving only boiling water extraction and filtration.A linear relationship was found between peak area and concentration range of 0.15-450 pg/mL, 0.10-500 pglmL, and 0.05-500 pg/mL for trigonelline (at 268 nm), nicotinic acid (at 264 nm), and caffeine (at 276 nm), respectively. 3187 3188 CASAL ET AL.Extensive quality assurance of the proposed method was performed by the standard addition method in both green and roasted coffee.The precision in green coffee samples was better than 1.3,5.8, and 1.1% and, for roasted coffee, better than 0.5, 2.4, and 1.2% for trigonelline, nicotinic acid, and caffeine, respectively. Also, for green coffee, the mean recovery values were 98 f 1%, 84 f 5%, and 99 f 1% and for roasted coffee, these were 101 f 1%, 98 f 1%, and 99 f 1 % for trigonelline, nicotinic acid, and caffeine, respectively.The proposed method appears to be an adequate method for quality control in the coffee industry.

A bi-enzymatic biosensor (LACC-TYR-AuNPs-CS/GPE) for carbamates was prepared in a single step by electro-deposition of a hybrid film onto a graphene doped carbon paste electrode (GPE). Graphene and the gold nanopar-ticles (AuNPs) were morphologically characterized by transmission electron microscopy, X-ray photoelectron spectroscopy, dynamic light scattering and laser Doppler velocimetry. The electrodeposited hybrid film was composed of laccase (LACC), tyrosinase (TYR) and AuNPs entrapped in a chitosan (CS) polymeric matrix. Exper-imental parameters, namely graphene redox state, AuNPs:CS ratio, enzymes concentration, pH and inhibition time were evaluated. LACC-TYR-AuNPs-CS/GPE exhibited an improved Michaelis-Menten kinetic constant (26.9 ± 0.5 M) when compared with LACC-AuNPs-CS/GPE (37.8 ± 0.2 M) and TYR-AuNPs-CS/GPE (52.3 ± 0.4 M). Using 4-aminophenol as substrate at pH 5.5, the device presented wide linear ranges, low detection limits (1.68 × 10 −9 ± 1.18× 10 −10 -2.15 × 10 −7 ± 3.41 × 10 −9 M), high accuracy, sensitivity (1.13 × 10 6 ± 8.11 × 10 4 -2.19 × 10 8 ± 2.51× 10 7 %inhibition M −1 ), repeatability (1.2-5.8% RSD), reproducibility (3.2-6.5% RSD) and stability (ca. twenty days) to determine carbaryl, formetanate hydrochloride, propoxur and ziram in citrus fruits based on their inhibitory capacity on the polyphenoloxidases activity. Recoveries at two fortified levels ranged from 93.8 ± 0.3% (lemon) to 97.8 ± 0.3% (orange). Glucose, citric acid and ascorbic acid do not interfere signifi-cantly in the electroanalysis. The proposed electroanalytical procedure can be a promising tool for food safety control.

The present study was aimed to assess the macronutrient composition and the amino acid and vitamin E profiles of Castanea sativa shell from different production regions of Portugal (Minho, Trás-os-Montes and Beira-Alta). The nutritional composition was similar for all samples, with a high moisture content and low fat amounts. Arginine and leucine were the predominant essential amino acids (EAA) accounting for 3.55-7.21% and 1.59-2.08%, respectively, for samples of the different production zones. All the shells presented high contents of vitamin E (481.5 mg per 100 g sample, 962.8 mg per 100 g sample and 567.5 mg per 100 g sample, respectively, for Minho, Trás-os-Montes and Beira-Alta). The predominant vitamer was γ-tocopherol (670 mg per 100 g sample for Trás-os-Montes). The antimicrobial and antioxidant activities of C. sativa shell were also determined. Trás-os-Montes extracts displayed the highest antioxidant activity (EC50 = 31.8 ± 1.3 μg mL(-1) for DPPH; 8083.5 ± 164.8 μmol per mg db for FRAP). The total phenolic content (TPC) varied from 241.9 mg to 796.8 mg gallic acid equivalents (GAE) per g db sample, the highest TPC being obtained for Trás-os-Montes. The total flavonoid content (TFC) varied from 31.4 to 43.3 mg of catechin equivalents (CEQ) per g db sample. No antimicrobial activity was observed. The results showed the potentialities of C. sativa shell extracts.

It is possible to suggest that this formulation is stable under extreme conditions and safe for topical use.