Marco A. Z. Santos

Ultrasound-assisted synthesis of aliphatic acid esters at room temperature.

This work describes the ultrasound-assisted synthesis of saturated aliphatic esters from synthetic aliphatic acids and either methanol or ethanol. The products were isolated in good yields after short reaction times under mild conditions.

Antarctic red macroalgae: a source of polyunsaturated fatty acids

The n-3 and n-6 series of polyunsaturated fatty acids (PUFAs) are important for numerous metabolic functions that reduce the risk of inflammation, cancer, and heart diseases. These fatty acids (FAs) have been detected in high concentrations in some species of algae. The amount of the n-3 and n-6 PUFAs is closely associated with abiotic factors, such as solar radiation intensity, salinity, and temperature variation. However, abiotic influence on PUFA levels, along with the physiological function of these molecules in algae, remains inconclusive. In the present study, the quantities of the n-3 and n-6 in Antarctic red algae species Iridaea cordata, Palmaria decipiens, Plocamium cartilagineum, and Pyropia endiviifolia were determined. The lipids were extracted from the macroalgae according to the method followed by Bligh and Dyer (1959) and converted to methyl esters for further analysis using gas chromatography. The main n-6 PUFA identified and quantified in this study of Antarctic red algae were linoleic acid (18:2n-6), dihomo-γ-linolenic acid (20:3n-6), and arachidonic acid (20:4n-6). The eicosapentaenoic acid was detected at high concentrations in all species, with approximately 62.8% of total FA in P. endiviifolia, 75.4% in P. decipiens, 50.4% in I. cordata, and 20.1% in P. cartilagineum. The results corroborate those of the literature and show that PUFAs increased in red algae environments, with increased production of n-3 and n-6 PUFAs.

Cultivation of algae in photobioreator and obtention of biodiesel

In this work we described the cultivation of Chlorella vulgaris in a photobioreactor to algal biomass production. The dried biomass was used as feedstock for biodiesel production, it presented 26% lipids and via sonocatalysis stage of the methodology resulted in 60% of fatty acid methyl esters (FAME). The FAME content was confirmed by Gas Chromatography (GC).

Synthesis of Biodiesel from Grape Seed Oil Using Ultrasound Irradiation

Biodiesel is a mixture of fatty esters obtained by transesterification of triglycerides with low molecular weight alcohols, such as methanol and ethanol. The transesterification reaction is slow at room temperature and therefore require the use of catalysts. In this work, conventional heating sources were replaced by ultrasound in the presence of KOH and methanol. The oil was obtained from grape seed, a byproduct of the wineries. The biodiesel was obtained in 97% yield, at the time of 30 minutes and the fatty acids of grape oil were characterized by gas chromatography and evaluated the parameters viscosity, iodine, and acidic saponification.

Hydroxychalcones: Synthetic Alternatives to Enhance Oxidative Stability of Biodiesel

In this chapter, the main aspects about biodiesel synthesis and established quality parameters are reviewed and discussed in the perspective of oxidative stability. First, the characteristics, which define biodiesel as a promising, renewable green fuel, are listed. On the other hand, the propensity of biodiesel to oxidation is explained as one of the limitations to its application. Along this line of thought, the majority of natural and synthetic antioxidants usually applied in the industry are discussed, in which it can be noted that phenolic compounds are very representative. Chalcones containing hydroxyl groups in its structure are phenolic compounds, and so, their origins, sources, and synthetic approaches to obtain these types of molecules are presented. Antioxidant effects of hydroxychalcones already reported in the literature are pointed, and then an experimental topic shows the influence of two synthetic hydroxychalcones, namely (E)-1-(2-hydroxyphenyl)-3-phenylprop-2-en-1-one and (E)-1-(2-hydroxyphenyl)-3-(3-hydroxyphenyl) prop-2-en-1-one, on the oxidative stability of biodiesel obtained from frying soybean oil. The effects assessed by calorimetric analysis revealed interesting effects on the enhancement of biodiesel oxidative stability.

Diets Rich in Polyunsaturated Fatty Acids With Different Omega-6/Omega-3 Ratio Decrease Liver Content of Saturated Fatty Acids Across Generations of Wistar Rats

Our study evaluated how the consumption of diets with low (LOW group - 0.4/1) or high (CON group - 13.6/1) omega-6/omega-3 ratio across generations (F1 and F2) can modulate liver fatty acid (FA) profile and blood biomarkers. Liver content of α-linolenic acid was higher in animals always fed with LOW diet than animals that changed from CON to LOW diet, which by your time was higher than animals always fed with CON diet. Liver saturated FA concentration decreased in both groups from F1 to F2. In conclusion, both diets were efficient in decreasing the saturated FA liver content across generations, the LOW ratio diet was more effective in reducing blood triglycerides and non-esterified fatty acids, and there was a multigenerational effect of the LOW ratio diet, improving the FA profile even when the offspring start receiving the CON diet.