Manuela Cristina Pessanha de Araújo Santiago

Microscale extraction method for HPLC carotenoid analysis in vegetable matrices

In order to generate simple, efficient analytical methods that are also fast, clean, and economical, and are capable of producing reliable results for a large number of samples, a micro scale extraction method for analysis of carotenoids in vegetable matrices was developed. The efficiency of this adapted method was checked by comparing the results obtained from vegetable matrices, based on extraction equivalence, time required and reagents. Six matrices were used: tomato (Solanum lycopersicum L.), carrot (Daucus carota L.), sweet potato with orange pulp (Ipomoea batatas (L.) Lam.), pumpkin (Cucurbita moschata Duch.), watermelon (Citrullus lanatus (Thunb.) Matsum. & Nakai) and sweet potato (Ipomoea batatas (L.) Lam.) flour. Quantification of the total carotenoids was made by spectrophotometry. Quantification and determination of carotenoid profiles were formulated by High Performance Liquid Chromatography with photodiode array detection. Microscale extraction was faster, cheaper and cleaner than the commonly used one, and advantageous for analytical laboratories.

Identification and quantification of anthocyanins in fruits from Neomitranthes obscura (DC.) N. Silveira an endemic specie from Brazil by comparison of chromatographic methodologies.

Neomitranthes obscura (DC.) N. Silveira is a Brazilian fruit belonging to the Myrtaceae family that contains anthocyanins in the peel and was studied for the first time in this work. Delphinidin-3-O-galactoside, delphinidin-3-O-glucoside, cyanidin-3-O-galactoside, cyanidin-3-O-glucoside, cyanidin-3-O-arabinoside, petunidin-3-O-glucoside, pelargonidin-3-O-glucoside, peonidin-3-O-galactoside, peonidin-3-O-glucoside, cyanidin-3-O-xyloside were separated and identified by LC/DAD/MS and by co-elution with standards. Reliable quantification of anthocyanins in the mature fruits was performed by HPLC/DAD using weighted linear regression model from 0.05 to 50mg of cyaniding-3-O-glucoside L(-1) because it gave better fit quality than least squares linear regression. Good precision and accuracy were obtained. The total anthocyanin content of mature fruits was 263.6 ± 8.2 mg of cyanidin-3-O-glucoside equivalents 100 g(-1) fresh weight, which was in the same range found in literature for anthocyanin rich fruits.

Chemical characterization of Myrciaria floribunda (H. West ex Willd) fruit

M. floribunda fruit was studied to characterize its chemical composition. The chemical composition, bioactive compounds, antioxidant activity and volatiles of the fruit were determined. The chemical composition was determined according to AOAC and AOCS, the bioactive compounds by HPLC, the volatiles by GCMS and the antioxidant activity by ABTS+ and DPPH methods. The chemical composition of the freeze-dried fruit was 1.89 g·100 g-1, 2.43 g·100 g-1, 4.78 g·100 g-1 and 90.89 g·100 g-1 of ashes, lipids, proteins and total carbohydrates on a dry base, respectively. The concentration of the carotenoids was 52.22 mg·100 g-1 and for the flavonoid rutin was 78.56 mg·100 g-1. The gallic and ellagic acid contents were 5.45 mg·g-1 and 2.21 mg·g-1, respectively. The cis-β-ocimene corresponded to 50.90% of the volatiles. The antioxidant activity by ABTS+ method was 550.14 µmol Trolox·g-1 and by the DPPH method the EC50 was 85.68 g·g-1. The fruits presented relevant antioxidant activity, a high concentration of carotenoids and of rutin.

Overview of Currently Applied Techniques for Detection of Adulterants in Coffee and Potential Use of DNA-Based Methods as Promising New Analytical Tools

Reports on coffee adulteration with cheaper materials date from over a century. Along with this illicit practice, a number of methods have been developed for the analysis of coffees authenticity. Among the most commonly applied techniques for this purpose are optical and electronic microscopy, liquid and gas chromatography, spectroscopy, and, most recently, molecular biology. This chapter presents a brief overview on the methods proposed in the literature for detection of adulterants in coffee, with emphasis on molecular biology, which is known as the most sensitive and specific method among all the existing ones. The authors hope to provide reference material to support the development of significant future works.