Luiz C. Trugo

Chemical composition of acerola fruit (Malpighia punicifolia L.) at three stages of maturity

Abstract The effect of stage of maturity on the chemical composition and volatile components of acerola (Malpighia punicifolia L. ) was investigated in three different stages. Stage of maturation was characterized by different indicators such as color, vitamin C, soluble solids, protein, ash, moisture, titrable acidity, pH and sugars. Titrable acidity, sugars and soluble solids increased and vitamin C and protein decreased with the progress of maturation. The volatile fraction was analysed by GC–MS. It was possible to identify 31 compounds in the mature (red) fruits, such as acethyl-methyl-carbinol, 2-methyl-propyl-acetate, limonene, E-Z-octenal, ethyl hexanoate, isoprenyl butirate and acetofenone; 23 in the intermediate (yellow), such as, methyl hexanoate, 3-octen-1-ol and hexyl butirate; and 14 in the immature (green) fruit, such as methyl-propyl-ketone, E-Z-hexenyl-acetate and 1-octadecanol.

Effect of dietary lipid level on nutritional performance of the surubim, Pseudoplatystoma coruscans

Abstract Four diets were formulated to contain a constant protein level (46%) and four different lipid levels (6%, 10%, 14% and 18%). The diets were fed to surubim, a Brazilian native carnivorous freshwater fish. Gross energy of the diets were 4440, 4650, 4840, and 5140 (kcal/kg). Surubim fingerlings (average weight: 2.72 g/fish) were randomly assigned to treatments and fed the test diets twice a day to apparent satiation for 62 days. The study was conducted in triplicate with 13 fish distributed in 60-l net-cages set up in 1000-l plastic tanks (three cages per tank), equipped with a flow through freshwater system and water temperature of 27±1 °C. The diet with 6% lipid gave the poorest performance, while fish fed the highest lipid level showed the best nutritional performance. Feed conversion ratio and daily feed consumption showed a marked decrease ( P P P

Performance and fatty acid composition of surubim (Pseudoplatystoma coruscans) fed diets with animal and plant lipids

Four isonitrogenous (46% crude protein) and isolipidic (18.5%) diets were formulated using four different lipid sources: lard (diet 1); corn oil (diet 2); soybean oil (diet 3); and linseed oil (diet 4) to evaluate the performance and body composition of surubim . Ten fingerlings (mean weight, 2.75±0.2 g) were randomly assigned to net cages (60-l capacity). Triplicate groups were fed each test diet twice a day to apparent satiation for 63 days. No difference (P>0.05) was observed for feeding performance. On the other hand, fatty acid composition of carcass lipids was affected (P<0.05) by dietary lipid source. Palmitic (16:0) and oleic (18:1n−9) acids were the major saturated and monoene fatty acids in the carcass and in the polar lipid fraction of liver lipids, independently of dietary lipid source. The total amount of saturated fatty acids was higher (P<0.05) in the carcass of fish fed diet 1, which also showed higher levels of palmitic and oleic acids. Fish fed diets 2 and 3, showed the highest (P<0.05) amount of n−6 fatty acids in their carcass and in the liver polar lipid fraction. Fish fed diet 4 showed the highest level of n−3 fatty acids in the carcass and of n−3 highly unsaturated fatty acids in the liver polar lipid fraction. The results indicated that both animal and plant lipids are well metabolized by this species and that it is possible to improve the n−3/n−6 ratio of surubim meat by feeding various lipid sources.

Determination of non-volatile compounds of different botanical origin Brazilian honeys

The levels of water, HMF, free proline, total acidity, diastase activity, fructose and glucose in 74 different floral type honeys from four Brazilian regions are reported. The majority of the samples showed adequate water and HMF contents indicating the use of good practices by beekeepers in Brazil. Large variation in the contents of proline (389–520 mg/kg) was found in the honeys from the four regions studied. These findings are presumably due to the more intensive labor of the bees on the collected nectar by adding gland secretions. The high amount of diastase (40–120°G) found in some honeys from the northeast region could be due to the visit of the bees to Manhiot sp. (cassava) flour factories to collect starch-rich food, consequently increasing the diastase activity in the honey. Xerotolerant yeasts may be responsible for higher total acidity and ratios below 1 for fructose/glucose found in some samples. The majority of the analysed honeys (82%) were within the limits of the European Codex Honey Standards and Brazilian legal regulations.

Composition of green coffee water-soluble fractions and identification of volatiles formed during roasting

Flavour precursors from water-soluble green coffee low molecular weight (B) and high molecular weight (C) fractions were investigated and the volatiles formed during roasting were identified by high resolution gas chromatography/mass spectrometry (HRGC/MS). Roasting promoted extensive degradation of trigonelline, sucrose and amino acids in fraction (B) and of arabinogalactan in fraction (C). The analyses of the roasted isolated fractions showed that furans are not only formed by sucrose degradation but also by arabinogalactan pyrolysis. Also, pyrazines appear to be mainly formed by pyrolysis of hydroxy amino acids from fraction (C). The results also showed that pyridine found in roasted coffee is not exclusively formed by trigonelline degradation but also by protein pyrolysis.

Composition of green coffee fractions and their contribution to the volatile profile formed during roasting

Abstract A sequential fractionation method to isolate water-soluble fractions of green Arabica coffee is described. Low- and high-molecular-weight fractions were obtained by treating the dried water extract with aqueous ethanol (80%, v/v). High-performance gel filtration chromatography was used to show some differences in molecular weight distribution between fractions. Flavour precursors were detected in both fractions. Arabinogalactan was the main polysaccharide found in the water-soluble high-molecular-weight fraction, together with large amounts of protein. Important flavour precursors such as sucrose, trigonelline and chlorogenic acid were detected in the low-molecular-weight fraction. A simple and rapid headspace method was developed to obtain the volatile profiles produced by the roasted fractions. Volatiles were immediately collected after roasting in a sealed tube and submitted to gas chromatography. The chromatographic profiles obtained showed considerable differences between fractions and revealed an important contribution to aroma formation.

Determination of oligosaccharides in Brazilian honeys of different botanical origin

The levels of 10 oligosaccharides in 70 genuine Brazilian honeys of different floral types are reported. The contents of sucrose and isomaltose were broad, ranging from mean values of 0.07–0.77 and 0.18–0.71%, respectively. The mean values for maltose were in the range 1.58 to 3.77%. The level of turanose (0.78–2.03%) was similar to that of nigerose (1.11–2.81%). Low amounts of melibiose (0.05–0.15%) and panose (0.03–0.08%) were found in Brazilian honeys. Maltotriose, melezitose and raffinose, were present with mean values of 0.24–1.03, 0.21–0.37 and 0.10–0.25%, respectively. Between Brazilian states, honeys from Sao Paulo had mean values for melibiose significantly (P<0.05) lower than those from the Minas Gerais and Rio de Janeiro. The mean values for maltose and nigerose found in the Mato Grosso do Sul and Goias states were significantly higher than from the Mato Grosso state. Honey samples from the Parana state showed a mean value for maltotriose significantly higher than that from the Rio Grande do Sul state. The contents of maltose, nigerose, turanose and maltotriose proved to be useful for the differentiation of honey samples from different geographical regions and also may be valuable for testing the authenticity of Brazilian honeys.

Comparison of three different methods for trehalose determination in yeast extracts

Trehalose is a disaccharide widely distributed in nature with great potential for application in different fields. Determination of trehalose has been carried out for many years using the anthrone colorimetric method, which may be subject to interferents. Alternatives to this problem seem to be the use of HPLC techniques or specific enzymatic assays. In the present work, a simple normal-HPLC procedure was applied to the analysis of different yeast extract samples and the results compared either to the conventional anthrone method or by an enzymatic assay based on the cleavage of trehalose by trehalase. Each method showed correlations over 0.97 with the others; however, only HPLC and the enzymatic method were statistically identical (p <0.05). In addition, the HPLC method showed good linearity (r = 0.995) and recovery (98%), producing trehalose results in the range of 8.3-83 mg g -1 of cells. The results showed that in some cases the anthrone method may in fact produce inflated results although presenting consistency within the set of data.

Effect of Subadequate Maternal Vitamin-A Status on Placental Transfer of Retinol and Beta-Carotene to the Human Fetus

The placental transfer of retinol and beta-carotene was assessed based on maternal serum, cord serum and placental levels at term parturition in women with adequate (n = 15; serum retinol > 20 micrograms/dl) and subadequate (n = 16; serum retinol < or = 20 micrograms/dl) vitamin-A status. There was no difference in retinol and beta-carotene levels in placenta and cord serum between these groups. However, differences in the relation of maternal, placental and cord blood components were observed between women with adequate and subadequate vitamin-A status. In women with subadequate status, circulating fetal retinol levels correlated with placental retinol levels, and maternal serum beta-carotene correlated with placental retinol. Within this group, maternal serum beta-carotene and cord serum retinol correlated significantly in women with serum retinol levels lower than 15 micrograms/dl. These results suggest that beta-carotene may be a precursor of retinol in placenta and that this conversion may depend on the nutritional status of the mother, being particularly effective in a more depleted state.

Determinação de compostos bioativos em amostras comerciais de café torrado

Coffee is a product consumed all around the world, Brazil being the biggest exporter. However, little is known about the difference in composition of the different brands in terms of bioactive substances. In the present study, ten of the most consumed brands of coffee in Rio de Janeiro were analyzed. Caffeine contents, trigonelline and total chlorogenic acid varied from 0.8 g/100g to 1.4 g/100g; 0.2 g/100g to 0.5 g/100g and from 3.5 g kg-1 to 15.9 g kg-1, respectively. The large heterogeneity observed in the amounts of the bioactive compounds can be attributed to different formulations of the various brands, as well as to different roasting conditions.