Validação de métodos cromatográficos por clae para análise das vitaminas B1, B2, B6 e niacina naturalmente presentes em farinha de cereais

Complex B vitamins are present in some cereal foods and the ingestion of enriched products contributes to the recommended dietary intake of these micronutrients. To adapt the label of some products, it is necessary to develop and validate the analytical methods. These methods must be reliable and with enough sensitivity to analyze complex B vitamins naturally present in food at low concentration. The purpose of this work is to evaluate, with validated methods, the content of vitamins B1, B2, B6 and niacin in five cereal flours used in food industry (oat, rice, barley, corn and wheat).

Folatos em brócolis convencional e orgânico e perdas no processo de cocção em água

Broccoli is a vegetable consumed in many countries and a possible source of folates, which are water-soluble vitamins active during DNA synthesis. The folates found in the samples analyzed were 5-methyltetrahydrofolate and 5-formyltetrahydrofolate. The vitamin content varied between 413.7 and 742.2 µg/100 g for 5-methyltetrahydrofolate and from 4.8 to 12.8 µg/100 g for 5-formyltetrahydrofolate. In organic broccoli the amount of 5-methyltetrahydrofolate was significantly higher than in the same vegetable cultivated by traditional methods, for the commercial samples analyzed. The losses of these folates after cooking in water were of approximately 68%, most of it (53%) found in the cooking water.

Sensory and Non-sensory Factors Behind the Liking and Choice of Healthy Food Products

A healthy and balanced diet can reduce health problems, such as overweight and metabolic syndrome. In general, people have a considerably good knowledge of what constitutes a healthy diet and how they could achieve it with their food choices. Besides, people argue that health is among their top five food choice motives. Nevertheless, the prevalence of overweight is increasing and other food choice motives, such as taste, seem to conflict with the health. Liking for food does not necessarily determine acceptance alone, thus several non-sensory factors, such as brand, country of origin and nutrition claim, can also influence. Moreover, consumers are individuals in how they prioritize sensory and nonsensory factors of foods, but e.g. increasing age, female gender and health concern have been connected to a more health-oriented dietary behaviour. To sum up, identifying different factors that can increase the liking and consumption of healthy food is essential in order to develop more attractive healthful food products. Adding vitamins, minerals, fibre or other ingredients to a food product can be used to enrich the nutritional quality of the products. However, this may be difficult in practice as regards the sensory quality and pleasantness of the foods. Generally, consumers are not willing to compromise on taste in food. On the other hand, consumers are very heterogeneous in their likings, and their personal values and attitudes may interact with preferences for specific sensory characteristics. The aims of this study were to investigate the effects of intrinsic product characteristics on sensory properties and hedonic responses; to determine the impact of few non-sensory factors; and to examine the interaction between sensory and non-sensory factors with consumers’ demographics, values and attitudes in liking of healthy model foods. The results showed that product composition influenced sensory quality and had an effect on hedonic responses. Adding flaxseed to bakery products showed a significant improvement in the nutritional quality without negative effects on sensory properties. On the other hand, the fortification of wellness beverages with vitamins and minerals may impart off-flavours. In general, sweetness of yoghurts, freshness of wellness beverages and low intensity of rye bread flavour appealed to consumers. Information about the domestic origin of yoghurts and claiming a specific function for wellness beverages enhanced liking. However, consumers who were more concerned about their health and considered natural content as an important food choice motive, rated sourer and less sweet yoghurts and wellness beverages as more pleasant. In addition, interest in health increased the consumption of rye breads and other whole grain breads among adolescents. The results showed that the optimal product quality in terms of intrinsic and extrinsic factors differs between individual consumers, and personal values and food choice motives can be connected to preferences for specific sensory characteristics of foods. This indicates that each food product needs to be considered in relation to its specific market niche, and to which segment of consumer will respond most positively to its characteristics.

NADPH-Dependent Thioredoxin System In Regulation of Chloroplast Functions

Photosynthesis, the process in which carbon dioxide is converted into sugars using the energy of sunlight, is vital for heterotrophic life on Earth. In plants, photosynthesis takes place in specific organelles called chloroplasts. During chloroplast biogenesis, light is a prerequisite for the development of functional photosynthetic structures. In addition to photosynthesis, a number of other metabolic processes such as nitrogen assimilation, the biosynthesis of fatty acids, amino acids, vitamins, and hormones are localized to plant chloroplasts. The biosynthetic pathways in chloroplasts are tightly regulated, and especially the reduction/oxidation (redox) signals play important roles in controlling many developmental and metabolic processes in chloroplasts. Thioredoxins are universal regulatory proteins that mediate redox signals in chloroplasts. They are able to modify the structure and function of their target proteins by reduction of disulfide bonds. Oxidized thioredoxins are restored via the action of thioredoxin reductases. Two thioredoxin reductase systems exist in plant chloroplasts, the NADPHdependent thioredoxin reductase C (NTRC) and ferredoxin-thioredoxin reductase (FTR). The ferredoxin-thioredoxin system that is linked to photosynthetic light reactions is involved in light-activation of chloroplast proteins. NADPH can be produced via both the photosynthetic electron transfer reactions in light, and in darkness via the pentose phosphate pathway. These different pathways of NADPH production enable the regulation of diverse metabolic pathways in chloroplasts by the NADPH-dependent thioredoxin system. In this thesis, the role of NADPH-dependent thioredoxin system in the redox-control of chloroplast development and metabolism was studied by characterization of Arabidopsis thaliana T-DNA insertion lines of NTRC gene (ntrc) and by identification of chloroplast proteins regulated by NTRC. The ntrc plants showed the strongest visible phenotypes when grown under short 8-h photoperiod. This indicates that i) chloroplast NADPH-dependent thioredoxin system is non-redundant to ferredoxinthioredoxin system and that ii) NTRC particularly controls the chloroplast processes that are easily imbalanced in daily light/dark rhythms with short day and long night. I identified four processes and the redox-regulated proteins therein that are potentially regulated by NTRC; i) chloroplast development, ii) starch biosynthesis, iii) aromatic amino acid biosynthesis and iv) detoxification of H₂O₂. Such regulation can be achieved directly by modulating the redox state of intramolecular or intermolecular disulfide bridges of enzymes, or by protecting enzymes from oxidation in conjunction with 2-cysteine peroxiredoxins. This thesis work also demonstrated that the enzymatic antioxidant systems in chloroplasts, ascorbate peroxidases, superoxide dismutase and NTRC-dependent 2-cysteine peroxiredoxins are tightly linked up to prevent the detrimental accumulation of reactive oxygen species in plants.

Evaluation of protein extraction methods to obtain protein concentrate from cassava leaf

The cassava leaf, waste generated in the harvest of the roots, is characterized by high content of protein, vitamins and minerals; however, its use is limited due to the high fiber content and antinutritional substances, which can be removed by obtaining protein concentrates. In this context, the objective of this study was to evaluate protein extraction processes, aiming the use of cassava leaves (Manihot esculenta Crantz) as an alternative protein. Four methods were tested: 1) Coagulation of Proteins by Lowering the Temperature, 2) Extraction by Isoelectric Precipitation, 3) Solubilization of Proteins and 4) Fermentation of Filter Leaf Juice. To obtain the concentrates, the use of fresh or dried leaves and extraction in one or two steps were also evaluated. The solubilization of proteins (method 3) showed a higher extraction yield; however, with concentrate of low quality. The fermentation of the juice (method 4) produced concentrates with higher quality and lower costs and the isoelectric precipitation (method 2) promoted the obtention of concentrates in less time, both with good prospects for use. The use of two extraction steps was not advantageous to the process and there was no difference between the use of fresh or dried leaf, and the use of fresh leaves is presented as a good option for the simplicity of the method.

Antinociceptive effects of Cremophor EL orally administered to mice

Surfactants are frequently used to improve solubilization of lipophilic drugs. Cremophor EL (CrEL) is a polyoxyethylated castor oil surfactant used to solubilize water-insoluble drugs such as anesthetic, antineoplastic, immunosuppressive and analgesic drugs, vitamins and new synthetic compounds, including potential analgesics. The antinociceptive effect of CrEL (3.2, 6.4 and 10.6 g/kg, in 10 ml/kg body weight, by gavage) on the abdominal writhing response induced by intraperitoneal administration of acetic acid (0.8%, 10 ml/kg body weight) and on the tail immersion test was investigated in mice. Control animals received castor oil (10 ml/kg body weight) or saline (0.9% NaCl, 10 ml/kg body weight). CrEL reduced nociception in a dose-dependent manner in both tests. At 10.6 g/kg, CrEL caused antinociception similar to that induced by dipyrone (300 mg/kg, by gavage) in the abdominal writhing test, and antinociception similar to that induced by morphine (20 mg/kg, by gavage) in the tail immersion test. The effect of castor oil was similar to that of saline in both assays. These data indicate that the appropriate controls should be used when evaluating the effects of potential antinociceptive agents dissolved in CrEL.

Vitamin B1 and B6 in the malaria parasite: requisite or dispensable?

Vitamins are essential compounds mainly involved in acting as enzyme co-factors or in response to oxidative stress. In the last two years it became apparent that apicomplexan parasites are able to generate B vitamers such as vitamin B1 and B6 de novo. The biosynthesis pathways responsible for vitamin generation are considered as drug targets, since both provide a high degree of selectivity due to their absence in the human host. This report updates the current knowledge about vitamin B1 and B6 biosynthesis in malaria and other apicomplexan parasites. Owing to the urgent need for novel antimalarials, the significance of the biosynthesis and salvage of these vitamins is critically discussed in terms of parasite survival and their exploitation for drug development.

Modulation of extracellular matrix by nutritional hepatotrophic factors in thioacetamide-induced liver cirrhosis in the rat

Nutritional substances associated to some hormones enhance liver regeneration when injected intraperitoneally, being denominated hepatotrophic factors (HF). Here we verified if a solution of HF (glucose, vitamins, salts, amino acids, glucagon, insulin, and triiodothyronine) can revert liver cirrhosis and how some extracellular matrices are affected. Cirrhosis was induced for 14 weeks in 45 female Wistar rats (200 mg) by intraperitoneal injections of thioacetamide (200 mg/kg). Twenty-five rats received intraperitoneal HF twice a day for 10 days (40 mL·kg-1·day-1) and 20 rats received physiological saline. Fifteen rats were used as control. The HF applied to cirrhotic rats significantly: a) reduced the relative mRNA expression of the genes: Col-α1 (-53%), TIMP-1 (-31.7%), TGF-β1 (-57.7%), and MMP-2 (-41.6%), whereas Plau mRNA remained unchanged; b) reduced GGT (-43.1%), ALT (-17.6%), and AST (-12.2%) serum levels; c) increased liver weight (11.3%), and reduced liver collagen (-37.1%), regenerative nodules size (-22.1%), and fibrous septum thickness. Progranulin protein (immunohistochemistry) and mRNA (in situ hybridization) were found in fibrous septa and areas of bile duct proliferation in cirrhotic livers. Concluding, HF improved the histology and serum biochemistry of liver cirrhosis, with an important reduction of interstitial collagen and increased extracelullar matrix degradation by reducing profibrotic gene expression.

Yam (Discorea sp) drying with different cuts and temperatures: experimental and simulated results

The yam (Discorea sp) is a tuber rich in carbohydrates, vitamins and mineral salts, besides several components that serve as raw material for medicines. It grows well in tropical and subtropical climates and develops well in zones with an annual pluvial precipitation of around 1300mm, and with cultural treatments, its productivity can exceed 30t/ha. When harvested, the tubers possess about 70% of moisture, and are merchandised "in natura", in the atmospheric temperature, which can cause its fast deterioration. The present work studied the drying of the yam in the form of slices of 1.0 and 2.5cm thickness, as well as in the form of fillets with 1.0 x 1.0 x 5.0cm, with the drying air varying from 40 to 70°C. The equating of the process was accomplished, allowing to simulate the drying as a function of the conditions of the drying air and of the initial and final moisture of the product. Also investigated was the expense of energy as function of the air temperature. The drying in the form of fillets, with the air in a temperature range between 45 and 50°C, was shown to be the most viable process when combining both the quality of the product and the expense of energy.

Antinutrients in the cassava (Manihot esculenta Crantz) leaf powder at three ages of the plant

In Brazil, the cassava leaf meal (CLM) has been used to strive against undernourishment because it is a high source of vitamins and minerals. However, the wide variation in the chemical composition of the different cultivars, as well as their antinutritional substances may be a restriction to their uses. The levels of some antinutrients in CLM from five cultivars at three ages of the plant (TAP) were investigated, in order to select the cultivars and plant ages that would be more appropriate for human consumption. The lowest contents of antinutrients were observed in the 12-month old plants, except for nitrate and hemagglutinin from which the lowest contents were found for the 17 month old ones. The cultivar IAC 289-70 had the lowest antinutrient levels, except for saponin and oxalate. Thus, the cultivar IAC 289-70 at 12 months is the most appropriate for human consumption.

Contents of folates in edible mushrooms commercialised in the city of Campinas, São Paulo, Brazil

In this study, folates were evaluated in the main species of mushroom cultivated in Brazil. The species analysed were Agaricus bisporus (button mushroom), Lentinula edodes (shiitake) and Pleorotus ostreatus (shimeji). The five main forms of folate found in foods were determined: tetrahydrofolic acid (THFA), 10-methyl folic acid (10MFA), 5-methyl tetrahydrofolic acid (5MTHFA), 10-formyl folic acid (10FFA) and 5-formy tetrahydrofolic acid (5FTHFA). The methodology employed used extraction with phosphate buffer, clean up with trichloroacetic acid and separation of the vitamins by high-performance liquid chromatography, with simultaneous ultraviolet and fluorescence detection. The results obtained for total folate were 551 to 1404 µg.100 g -1 for the button mushroom, 606 to 727 µg.100 g -1 for shiitake and 460 to 1325 µg.100 g-1 for shimeji. The data showed that mushrooms could be considered as sources of folates and that their contribution of these vitamins to the diet was meaningful.

Microbial profile of a kefir sample preparations: grains in natura and lyophilized and fermented suspension

Probiotics are supplementary foods developed by microbial strains that improve animal health beyond basic nutrition. Probiotics are consumed orally, regardless of being considered as normal inhabitants of the intestines, able to survive in enzimatic and biliary secretions. Kefir is a probiotic originated from the old continent, fermented by several bacteria and yeasts, encapsulated in a polyssacharide matrix, and resembles jelly grains. Kefir is also presented as its sourish product both in sugary or milky suspensions containing vitamins, aminoacids, peptides, carbohydrates, ethanol, and volatile compounds. Kefir is known to have a diverse microbial content depending on the country and fermentative substrates, which cause distinct probiotic effects. In this sense, the purpose of this work was to isolate, identify, and quantify the microbial content of a native sugary kefir sample (fermented suspension and lyophilized natural grains). Serial dilutions were plated on Rogosa agar (AR) and De Man, Rogosa and Sharpe (MRS), for Lactobacillus; Brain Heart Infusion (BHI), for total bacteria; Sabouraud-Dextrose-Agar (SDA), for yeasts and filamentous fungi; Thioglycolate Agar (TA), for Streptococcus, Acetobacteria and Leuconostoc; and Coconut Water Agar (CWA), and CWA supplemented with yeast extract (CWAY), for various genera. Genera and species for all strains were identified through biochemical reactions and specific API systems. The microbial profile of kefir was different from other sources of grains despite the presence of similar microorganisms and others which have not been reported yet. The data obtained with the CWA and CWAE media suggest that both substrates are alternative and salutary media for culture of kefir strains.

Chemical and physicochemical characteristics changes during passion fruit juice processing

Passion fruit is widely consumed due to its pleasant flavour and aroma acidity, and it is considered very important a source of minerals and vitamins. It is used in many products such as ice-cream, mousses and, especially, juices. However, the processing of passion fruit juice may modify the composition and biodisponibility of the bioactive compounds. Investigations of the effects of processing on nutritional components in tropical juices are scarce. Frequently, only losses of vitamin C are evaluated. The objective of this paper is to investigate how some operations of passion fruit juice processing (formulation/homogeneization/thermal treatment) affect this product's chemical and physicochemical characteristics. The results showed that the chemical and physicochemical characteristics are little affected by the processing although a reduction in vitamin C contents and anthocyanin, large quantities of carotenoids was verified even after the pasteurization stage.

Investigation of cytotoxic and mutagenic effects of Malpighia glabra L. (barbados cherry) fruit pulp and vitamin C on plant and animal test systems

Fruits are important sources of nutrients in human diet, and Barbados Cherry (Malpighia glabra L.) is of particular interest due to its high content of antioxidants. Diets rich in fruits and vegetables protect individuals against diseases and cancer, but excessive intake of vitamins may act as pro-oxidant and generate changes in DNA. To evaluate the effect of different in natura (BAN) and frozen (BAF) Barbados Cherry pulp concentrations and synthetic vitamin C in liquid form (VC) on the chromosome level and the cell cycle division, root meristeme cells of Allium cepa L. and bone marrow cells of Wistar rats Rattus norvegicus, were used as test system. In Allium cepa L., BAN, at the highest concentration (0.4 mg.mL-1) and BAF, at the lowest concentration (0.2 mg.mL-1), inhibited cell division, and there was recovery of cell division after the recovery period in water only for BAN. In the Wistar rats, all treatments with Barbados Cherry, either acute or subchronic, were not cytotoxic or mutagenic; only the highest concentration of VC increased significantly the rate of chromosomal abnormalities. The data obtained are important to reinforce the use of Barbados Cherry fruit in the diet.

Chemical composition and antioxidant activity of jatobá-do-cerrado (Hymenaea stigonocarpa Mart.) flour

The Brazilian Savannah, known as "Cerrado," has an extensive biodiversity, but it is under explored. Among the native vegetables is the jatobá-do-cerrado (Hymenaea stigonocarpa Mart.), a legume with great potential for exploration for its content of dietary fiber. Legumes are an important source of nutrient compounds, such as phenolic compounds and vitamins that have antioxidant properties. This study aimed at determining the chemical composition and antioxidant activity of the jatobá flour. The jatobá flour showed high fiber content (insoluble and soluble fiber 47.8 and 12.8 g.100 g- 1, respectively), significant amounts of carotenoids such as beta-carotene and lutein, and some minerals such as calcium: 145 mg.100 g- 1, magnesium: 125 mg.100 g- 1, and potassium: 1352 mg.100 g- 1. The jatobá flour extracted with different solvents (water, methanol, and acetone) exhibited antioxidant activity by the DPPH, FRAP, and ORAC methods. The solvent used in the extraction affected the total phenolic content and antioxidant activity. Acetone extraction produced the best results. Therefore, the jatobá flour is an ingredient that can be used to develop new products with properties that promote health.