Antônio Fernandes de Carvalho

Políticas de saúde e alegações de propriedades funcionais e de saúde para alimentos no Brasil

O trabalho estabelece a relacao entre as diretrizes das politicas publicas de saude brasileiras e os criterios adotados pela Anvisa para aprovacao das alegacoes de propriedades funcionais e, ou, de saude para alimentos e para substâncias bioativas e probioticos isolados. Comenta a legislacao brasileira sobre alimentos com alegacoes de propriedades funcionais e, ou, de saude, novos alimentos e substâncias bioativas e probioticos isolados, evidenciando a obrigatoriedade de registro destes produtos junto aos orgaos competentes. Apresenta as diretrizes da Politica Nacional de Alimentacao e Nutricao, Politica Nacional de Promocao da Saude, Guia Alimentar para a Populacao Brasileira e Estrategia Global sobre Dieta, Atividade Fisica e Saude da Organizacao Mundial de Saude. Ressalta a convergencia das diretrizes destas politicas que objetivam a reducao das doencas cronicas nao-transmissiveis na populacao atraves da promocao da alimentacao saudavel e da atividade fisica. Destaca as orientacoes direcionadas aos governos e a industria para a implementacao dessas medidas. Apresenta criterios de avaliacao da base cientifica das alegacoes propostos por orgaos internacionais. Objetiva oferecer subsidios para o entendimento da influencia da tecnologia de alimentos sobre a saude publica e para o entendimento dos criterios adotados pela Anvisa, na avaliacao das alegacoes de propriedades funcionais e de saude.

FT-Raman and chemometric tools for rapid determination of quality parameters in milk powder: Classification of samples for the presence of lactose and fraud detection by addition of maltodextrin

FT-Raman spectroscopy has been explored as a quick screening method to evaluate the presence of lactose and identify milk powder samples adulterated with maltodextrin (2.5-50% w/w). Raman measurements can easily differentiate samples of milk powder, without the need for sample preparation, while traditional quality control methods, including high performance liquid chromatography, are cumbersome and slow. FT-Raman spectra were obtained from samples of whole lactose and low-lactose milk powder, both without and with addition of maltodextrin. Differences were observed between the spectra involved in identifying samples with low lactose content, as well as adulterated samples. Exploratory data analysis using Raman spectroscopy and multivariate analysis was also developed to classify samples with PCA and PLS-DA. The PLS-DA models obtained allowed to correctly classify all samples. These results demonstrate the utility of FT-Raman spectroscopy in combination with chemometrics to infer about the quality of milk powder.

Glucose slows down the heat-induced aggregation of β-lactoglobulin at neutral pH.

The behavior of β-lactoglobulin (β-Lg) during heat treatments depends on the environmental conditions. The influence of the presence or absence of a reducing sugar, namely, glucose, on the modification of the protein during heating has been studied using fluorescence, polyacrylamide gel electrophoresis (PAGE), size-exclusion chromatography (SEC), and transmission electron microscopy. Glycated products were formed during heating 24 h at 90 °C and pH 7. The fluorescence results revealed an accumulation of the advanced Maillard products and the formation of aggregates during heating. PAGE and SEC data suggested that the products in the control samples were essentially composed of covalently linked fibrillar aggregates and that their formation was faster than that for glycated samples. We showed that glucose affected the growing step of covalent aggregates but not the initial denaturation/aggregation step of native protein. Glucose-modified proteins formed a mixture of short fibrils and polydisperse aggregates. Our results revealed that β-Lg forms fibrils at neutral pH after heating and that glucose slows the formation of these fibrils.

Microbiota of Minas cheese as influenced by the nisin producer Lactococcus lactis subsp. lactis GLc05.

Minas cheese is a popular dairy product in Brazil that is traditionally produced using raw or pasteurized cow milk. This study proposed an alternative production of Minas cheese using raw goat milk added of a nisin producer Lactococcus lactis subsp. lactis GLc05. An in situ investigation was carried on to evaluate the interactions between the L. lactis subsp. lactis GLc05 and the autochthonous microbiota of a Minas cheese during the ripening; production of biogenic amines (BAs) was assessed as a safety aspect. Minas cheese was produced in two treatments (A, by adding L. lactis subsp. lactis GLc05, and B, without adding this strain), in three independent repetitions (R1, R2, and R3). Culture dependent (direct plating) and independent (rep-PCR and PCR-DGGE) methods were employed to characterize the microbiota and to assess the possible interferences caused by L. lactis subsp. lactis GLc05. BA amounts were measured using HPLC. A significant decrease in coagulase-positive cocci was observed in the cheeses produced by adding L. lactis subsp. lactis GLc05 (cheese A). The rep-PCR and PCR-DGGE highlighted the differences in the microbiota of both cheeses, separating them into two different clusters. Lactococcus sp. was found as the main microorganism in both cheeses, and the microbiota of cheese A presented a higher number of species. High concentrations of tyramine were found in both cheeses and, at specific ripening times, the BA amounts in cheese B were significantly higher than in cheese A (p<0.05). The interaction of nisin producer L. lactis subsp. lactis GLc05 was demonstrated in situ, by demonstration of its influence in the complex microbiota naturally present in a raw goat milk cheese and by controlling the growth of coagulase-positive cocci. L. lactis subsp. lactis GLc05 influenced also the production of BA determining that their amounts in the cheeses were maintained at acceptable levels for human consumption.

ASPECTOS COLOIDAIS DA ADESÃO DE MICRO-ORGANISMOS

The ability of bacteria to attach to surface and develop into a biofilm has been of considerable interest to food industry. Electrostatic, Lifhistz-van der Waals and Lewis acid-base forces are usually considered responsible for the interactions at the interface of the bacterial adhesion. The study of microbial adhesion thermodynamic is important because it represents the reflection of microbial surface and food processing surface physicochemical characteristics. This review examines the most important aspects involved in bacterial attachment to a surface with emphases in thermodynamics of adhesion process.

Recent advances in spray drying relevant to the dairy industry: A comprehensive critical review

ABSTRACT Milk is extremely perishable, and yet it has to be preserved for later consumption. In this view, membrane filtration, vacuum concentration lactose crystallization, homogenization, and spray-drying dehydration are valuable techniques to stabilize most dairy ingredients. Considering the increasing development of dairy trade, there is a need for the dairy industry to improve its understanding of how these concentration and spray-drying processes affect the quality of the resulting dairy powders, so to control it. However, the residence time of the droplet and the powder in the spray dryer is so short that it is very difficult to implement studies on the mechanisms of the structural changes in the protein without fundamental research into the process/product interactions. Moreover, several authors have reported the crucial and specific role of dairy components in the mechanisms of water transfer during drying and rehydration. The aim of this paper is to review the present and recent advances in knowledge and innovations, on the properties of spray-dried dairy products, on the modeling and simulation of water transfer processes (drying and rehydration), and on spray-drying equipment and energy consumption.

Technical note: enumeration of mesophilic aerobes in milk: evaluation of standard official protocols and Petrifilm aerobic count plates.

Enumeration of mesophilic aerobes (MA) is the main quality and hygiene parameter for raw and pasteurized milk. High levels of these microorganisms indicate poor conditions in production, storage, and processing of milk, and also the presence of pathogens. Fifteen raw and 15 pasteurized milk samples were submitted for MA enumeration by a conventional plating method (using plate count agar) and Petrifilm Aerobic Count plates (3M, St. Paul, MN), followed by incubation according to 3 official protocols: IDF/ISO (incubation at 30 degrees C for 72 h), American Public Health Association (32 degrees C for 48 h), and Brazilian Ministry of Agriculture (36 degrees C for 48 h). The results were compared by linear regression and ANOVA. Considering the results from conventional methodology, good correlation indices and absence of significant differences between mean counts were observed, independent of type of milk sample (raw or pasteurized) and incubation conditions (IDF/ISO, American Public Health Association, or Ministry of Agriculture). Considering the results from Petrifilm Aerobic Count plates, good correlation indices and absence of significant differences were only observed for raw milk samples. The microbiota of pasteurized milk interfered negatively with the performance of Petrifilm Aerobic Count plates, probably because of the presence of microorganisms that poorly reduce the dye indicator of this system.

egc characterization of enterotoxigenic Staphylococcus aureus isolates obtained from raw milk and cheese

Genes encoding staphylococcal enterotoxins (SEs) are carried by mobile genetic elements, and enterotoxin gene clusters (egc) are pathogenicity island-borne structures comprising several SE genes, which are frequently found among clinical Staphylococcus aureus isolates. In the present study, we investigated the distribution and the genetic variability of egc loci in S. aureus strains isolated from raw milk and soft cheese in Minas Gerais, Brazil. Ninety-two isolates were submitted to PCR detection of individual egc-borne SE genes (seg, sei, sem, sen, seo, seu), and egc loci were typed using PCR-RFLP. PCR products of egc positive isolates were sequenced. Ninety-one isolates harbored at least one SE gene, which generated 14 different genotypes. The sei gene was the most widely distributed (97.8%), and was found in combination with seg in 49 isolates (53.3%). Altogether, a complete set of individual egc genes was detected in 37 isolates (40%). However, egc loci were detected by PCR-RFLP in only 4 isolates, and classified as egc1 (n=2), egc3 (n=1), and egc4 (n=1). This investigation demonstrated the low occurrence of the egc in S. aureus isolated from dairy products. However, the frequency of complete sets of individual egc-borne genes reflects either the presence of these SE genes outside egc or the existence of new egc types in these strains.

UFV-P2 as a member of the Luz24likevirus genus: a new overview on comparative functional genome analyses of the LUZ24-like phages.

BackgroundPhages infecting spoilage microorganisms have been considered as alternative biocontrol agents, and the study of their genomes is essential to their safe use in foods. UFV-P2 is a new Pseudomonas fluorescens-specific phage that has been tested for its ability to inhibit milk proteolysis.ResultsThe genome of the phage UFV-P2 is composed of bidirectional modules and presented 75 functionally predict ORFs, forming clusters of early and late transcription. Further genomic comparisons of Pseudomonas-specific phages showed that these viruses could be classified according to conserved segments that appear be free from genome rearrangements, called locally collinear blocks (LCBs). In addition, the genome organization of the phage UFV-P2 was shown to be similar to that of phages PaP3 and LUZ24 which have recently been classified as a Luz24likevirus.ConclusionsWe have presented the functional annotation of UFV-P2, a new Pseudomonas fluorescens phage. Based on structural genomic comparison and phylogenetic clustering, we suggest the classification of UFV-P2 in the Luz24likevirus genus, and present a set of shared locally collinear blocks as the genomic signature for this genus.

Binding of Folic Acid Induces Specific Self-Aggregation of Lactoferrin: Thermodynamic Characterization.

In the study presented here, we investigated the interaction at pH 5.5 between folic acid (FA) and lactoferrin (LF), a positively charged protein. We found a binding constant Ka of 10(5) M(-1) and a high stoichiometry of 10 mol of FA/mol of LF. The size and charge of the complexes formed evolved during titration experiments. Increasing the ionic strength to 50 mM completely abolished the isothermal titration calorimetry (ITC) signal, suggesting the predominance of electrostatic interactions in the exothermic binding obtained. We developed a theoretical model that explains the complex triphasic ITC profile. Our results revealed a two-step mechanism: FA/LF interaction followed by self-association of the complexes thus formed. We suggest that 10 FA molecules bind to LF to form saturated reactive complexes (FA10/LF) that further self-associate into aggregates with a finite size of around 15 nm. There is thus a critical saturation degree of the protein, above which the self-association can take place. We present here the first results that provide comprehensive details of the thermodynamics of FA/LF complexation-association. Given the high stoichiometry, allowing a load of 55 mg of FA/g of LF, we suggest that FA/LF aggregates would be an effective vehicle for FA in fortified drinks.