Fontes vegetais naturais de antioxidantes

Growing knowledge on the health-promoting impact of antioxidants in everyday foods, combined with the assumption that a number of common synthetic preservatives may have hazardous side effects has led to increased investigations in the field of natural antioxidants, principally those found in plants. Food industries normally discard plant residues that could benefit the human health and diminish undesirable environmental impact. Once estimated the content of antioxidants in these residues, advantageous economical and social alternatives to the discard are possible, for example, their use for preparation of nutraceuticals to be offered to low-income populations. We present here a broad, although not complete, account of the continuously growing knowledge on the antioxidant capacity of whole fruits, seeds and peels, cereals, vegetal oils and aromatic plants, at several physical forms, as well as a description of the usual methods for evaluating their antioxidant capacity and examples of agroindustrial processes that could be harnessed for the production of antioxidant supplement food, along with research perspectives in the area.

Resíduos de agrotóxicos em alimentos: uma preocupação ambiental global - Um enfoque às maçãs

This paper describes the use of pesticides in agriculture. Research has shown that significant quantities of pesticide residues have been found in many types of foods. Thus, an overview is given of pesticide residue determinations in fruits and vegetables, with special attention to apples. The toxicity and the adverse effects possibly caused by the exposure of these compounds are alerting the scientific community to develop studies about the validation of analytical methods for multiresidue pesticide determination in these samples. This review shows that pesticide-residue determination in apples is becoming a very important and challenging issue.

Tocoferois e tocotrienois em óleos vegetais e ovos

The distribution and content of vitamin E isomers was investigated in vegetable oils and raw and cooked egg yolk in commercial restaurants. The analysis of the eight vitamin E isomers was carried out by High Performance Liquid Chromatography (HPLC) with fluorescence detection. The tocopherol and tocotrienol composition of foods varied considerably. Tocopherols were detected in greater quantity and frequency. The α-tocopherol predominated in egg yolks and olive oil while γ-tocopherol was found in high quantities in soybean and canola oils. Cooking did not cause major losses for most of the vitamin E isomers in egg yolks.

O valor energético dos alimentos: exemplo de uma determinação experimental, usando calorimetria de combustão

The energies involved in the combustion, under atmosphere of oxygen, of breakfast cereals and dehydrate powdered whole milk samples, were determined by combustion calorimetry. This practical work, in the field of human nutrition, involved the characterization of the nutritional composition and the combustion of samples of the two foods that are part of the alimentary diet, namely, at breakfast. The obtained results allowed to assess the energy value printed in the foods labels and discuss the way those values are estimated.

Um método verde, rápido e simples para determinar o valor energético de farinhas e cereais matinais

The Energy Value (EV) corresponds to the sum of the energetic contributions from food macronutrients (proteins, carbohydrates and fats) and is required on the labels of pre-packaged foods. The determinations of these parameters are based on distinct analytical procedures, each one being time-consuming, laborious and producing residues. This work presents multivariate models to determine the EV contents of industrialized foods for human consumption by using X-ray fluorescence spectra of samples with known parameters, determined through conventional methods. The proposed method is an alternative to conventional analytical methods and does not require any reagent, given the demands of the "green chemistry".

Foam-forming properties of Ilex paraguariensis (mate) saponin: foamability and foam lifetime analysis by Weibull equation

Saponins are natural soaplike foam-forming compounds widely used in foods, cosmetic and pharmaceutical preparations. In this work foamability and foam lifetime of foams obtained from Ilex paraguariensis unripe fruits were analyzed. Polysorbate 80 and sodium dodecyl sulfate were used as reference surfactants. Aiming a better data understanding a linearized 4-parameters Weibull function was proposed. The mate hydroethanolic extract (ME) and a mate saponin enriched fraction (MSF) afforded foamability and foam lifetime comparable to the synthetic surfactants. The linearization of the Weibull equation allowed the statistical comparison of foam decay curves, improving former mathematical approaches.

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.

Aspectos analíticos da resposta do detector de ionização em chama para ésteres de ácidos graxos em biodiesel e alimentos

The analysis of fatty acid (FA) esters by gas chromatography and flame ionization detector (FID) normally uses the normalization method. However, if one FA is wrongly estimated, the results could be greatly affected. In this study, methodologies using internal standards and correction factors for the FID response are described. The results show that by using theoretical correction factors associated to the internal standardization, the quantitative analyses of the FAs are expressed in mass, increasing the accuracy and facilitating the interpretation and comparison of the results for foods and biodiesels.

Estimativa da incerteza de medição: estudo de caso no ensaio de migração de ε-caprolactama com determinação por CG-DIC

The estimation of measurement uncertainty of an analytical result is an important tool to be applied for compliance to ISO IEC 17025. Through the available guides it is possible to establish procedures and criteria for the estimation of measurement uncertainty. This paper presents a case study on the estimation of measurement uncertainty in migration the test of ε-caprolactam from the polyamide 6 packages to fatty foods with determination by GC-FID. The calculation methodology used for the estimation of measurement uncertainty for the migration test was developed based on the guides EURACHEM / CITAC and ISO GUM, taking into account relevant aspects of the migration test. The expanded uncertainty estimated was approximately 23% of the concentration of migration.

Compósitos biodegradáveis de amido de mandioca e resíduos da agroindústria

The objectives of this work were to produce biodegradable composites using starch and different agro-industrial wastes (coconut fiber, soy bran and sugarcane bagasse) using a baking process, and to study the effects of these components on the resultant composite properties. The addition of different residues yielded trays with different properties. Samples manufactured with soy bran showed the highest density and water uptake at relative humidities ≥ 60%. The addition of sugarcane bagasse resulted in less dense and resistant samples whereas coconut fiber composites showed the highest breaking stress. The samples fabricated in this study represent an alternative packaging option for foods with low water content.

O estado da arte na determinação de resíduos de medicamentos veterinários em alimentos de origem animal empregando técnicas cromatográficas acopladas à espectrometria de massas

The determination of veterinary drug residues in foods of animal origin is an important issue because of the risk these compounds pose to human health in addition to their persistence and tendency to bioaccumulate. In recent years, significant progress has been made in the area and this review presents the state of the art in sample preparation procedures associated with chromatographic techniques coupled to mass spectrometry for multiresidue determination of veterinary drugs in food of animal origin at concentration levels suitable for the control of residues and contaminants in food.

Resíduos de medicamentos veterinários em leite e ovos

The use of veterinary drugs in food producing animals may result in the presence of residues in foods, including milk and eggs. Immunoassay or microbiological tests are used to screen for residues, but chromatographic methods are needed to confirm positive results. In most methods, the sample is extracted with acetonitrile, submitted to clean up or directly analyzed by LC-MS/MS. Results of the Brazilian governmental monitoring programs from 2006 to 2011 have shown that the antiparasitic ivermectin was the drug most frequently found in milk. Residues in eggs are only monitored by one of the programs, and few studies have reported the incidence of veterinary drugs in this matrix in Brazil.

Determinação da atividade antitríptica em proteínas de produtos do amendoim isoladas por cromatografia de afinidade

The peanut is an oleaginous plant of high nutritional value, a source of protein and a trypsin inhibitor. Trypsin inhibitors are proteins present in the vegetable kingdom, considered anti-nutritional factors for animals. However, there have been several recent reports about their heterologous and beneficial effects on human health. These important effects have been the focus of studies investigating these inhibitors in foods. The aim of the present study was to isolate and determine the estimated molecular mass and specific inhibitory activity, for trypsin in the Japanese peanut, peanut butter, and peanut nougat using the techniques of precipitation with ammonium sulfate and affinity chromatography on trypsin - Sepharose CNBr 4B. The techniques used in this study were efficient for isolating the protein inhibitors with antitryptic specific activity of 694 UI mg-1, 823 UI mg-1 and 108 UI mg-1 for the Japanese peanut, peanut nougat, and peanut butter, respectively. The techniques featured high selectivity of the adsorbent, with consequent efficiency in isolation, given the low amount of dosed proteins and specific antitryptic activity presented by the products studied. The various health-related benefits show the importance of detecting and isolating efficient trypsin inhibitors in foods, taking into account the health claims attributed to the vegetable and its high consumption by humans.

O Estado da arte da cromatografia líquida bidimensional: conceitos fundamentais, instrumentação e aplicações

The constant evolution of science and the growing demand for new technologies have led to new techniques in instrumentation that can improve detection, separation, resolution, and peak capacity. Comprehensive two-dimensional liquid chromatography (LC×LC) is presented as a powerful tool in complex sample analyses. During an analysis, a sample is subjected to two independent separation mechanisms that are combined, resulting in increased resolving power. For appropriate application of LC×LC, understanding the influence of parameters that require optimization is necessary. The main purpose of optimization is to predict the combination of stationary phases, separation conditions, and instrumental requirements to obtain the best separation performance. This review discusses theoretical, intrumental, and chemometric aspects of LC×LC and focuses on its applications in foods. It aims to provide a clear understanding of the aspects that can be used as strategies in the optimization of this analytical method.

COMPARAÇÃO DE MÉTODOS POR CROMATOGRAFIA LÍQUIDA NA DETERMINAÇÃO DE MULTIRRESÍDUOS DE AGROTÓXICOS EM MORANGOS

Liquid chromatography is often used for the determination of pesticide multiresidues in foods. In Brazil, the strawberry crop is an example of a food with high levels of irregularities because of the application of pesticides. This is a major concern from the perspective of food safety, environmental protection, and certification for food export. The purpose of this study is to evaluate and compare chromatographic separation and detection methods in relation to a newly developed and validated method using ultra high performance liquid chromatography (LC) coupled with tandem mass spectrometry (MS/MS) for the analytical determination of pesticides in strawberries. The comparisons were based on evaluations of the analysis time, consumption of the solvent in the mobile phase, injection volume, detectability, matrix effect, and recovery. The results showed that the LC–MS/MS and UHPLC–MS/MS techniques were both extremely efficient at analyzing pesticide residues with different physico-chemical parameters that were present at low concentrations in a complex matrix. The UHPLC separation method provided better chromatographic performance and productivity, which contributed favorably to routine analytical determinations. Detection by MS/MS had better detectability and selectivity compared with the diode array detector.