Determination of the Phytochemical Composition and Antioxidant Potential of Eugenia copacabanensis and Myrciaria tenella Leaves (Myrtaceae) Using a Saccharomyces cerevisiae Model.

Eugenia copacabanensis and Myrciaria tenella are present in restingas of the Atlantic Forest, but little information is available about their chemical and biological potential. In this context, the hexane, dichloromethane, ethyl acetate and butanol fractions from the leaves of methanolic extract were analyzed by GC/MS and HPLC-DAD and the antioxidant potential was determined by DPPH and ABTS assays and using a Saccharomyces cerevisiae model. Dereplication allowed the identification of 68 compounds, 42 and 41 of which, respectively, are first reported here for E. copacabanensis and M. tenella. In vivo results revealed that the ethyl acetate and butanol fractions showed expressive antioxidant protection in the BY4741 and Δgsh1 strains, with greater impact on glutathione-deficient cells. With a high diversity of phenolic compounds, these polar fractions of E. copacabanensis and M. tenella leaves are potential protectors against intracellular oxidative stress.

Effects of carrot incorporation and high hydrostatic pressure processing on fresh cheese: Antilisterial activity, carotenoid degradation, and sensory characteristics.

This study was carried out to evaluate the antilisterial activity of carrot, and the impact of its incorporation on the carotenoid content in Minas Frescal cheese, combined or not with high hydrostatic pressure processing, as an alternative for the development of healthier fresh cheese free of synthetic preservatives. Cheeses were manufactured with milk added with carrot incorporation (0, 3, and 6%) and pressurized (0; 250 and 500 MPa/10 min). Total carotenoid content, α-carotene, ß-carotene, lutein, consumer acceptance, and sensory characteristics were determined one day after the manufacture while Listeria innocua enumeration was evaluated up to 22 days of storage at 8 ℃. The results showed that although a decrease of over 7 log CFU g-1 in L. innocua counts was observed immediately after fresh cheese processing at 500 MPa/10 min, inactivation was not complete, as the growth of this nonpathogen surrogate during storage was observed. The addition of 6% carrot had a slight bacteriostatic effect, verified on the 15th day of storage, particularly in pressurized cheeses. On the other hand, high pressure treatment at 500 MPa/10 min increased carotenoids degradation in cheeses. Although pressurized cheeses were characterized as "rubbery," high hydrostatic pressure had no significant effect on consumer acceptance.

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-ß-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.

LC-MS based screening and targeted profiling methods for complex plant: coffee a case study.

In the recent years the way of thinking about human health necessarily passes by human food. Recent discoveries are not only concerned about valuable biomolecules but also contaminants. Thus, the screening of substances in animal and vegetable matrices by analytical techniques is focused on the presence and absence of target substance. In both cases, the majority of these substances are present as traces or in very low levels. Contaminants could be naturally present in the food, inserted on it or even developed on it as a consequence of food processing or cooking. Pesticides, mycotoxins, dioxins, acrylamide, Sudan red, melamine and now 4(5)-methylimidazole can be, at present, be listed as some of the world big problems related to food contaminants and adulterants. With the development of liquid chromatography coupled to mass spectrometry (LC-MS-MS), in the last few decades, analysis of some food contaminants in trace levels trace become less laborious, more accurate and precise. The multiple approach of those techniques make possible to obtain many results in one single run. On the other hand, European Union (2002/657/EC) established regulations for analytical methods regarding mass spectrometry as detection tool, showing the importance of this technique in food quality control. The EU criteria uses identification points (IPs) that could be achieved basically with four product ions (including molecular ion) or reduced with the use of high resolution equipments. This kind of mass spectrometers made the IPs criteria more accessible, as the exact mass information is a differential tool. In view of this the aim of this review is to present the actual scenario for mass spectrometry analysis in a complex vegetable food matrix such as roasted coffee, with emphasis on needs and challenges regarding the LC-MS technique in order to meet and contribute to food safety standards in this complex matrix.