Probiotic Yogurt Supplemented with Lactococcus lactis R7 and Red Guava Extract: Bioaccessibility of Phenolic Compounds and Influence in Antioxidant Activity and Action of Alpha-amylase and Alpha-glucosidase Enzymes.

The industry has increasingly explored the development of foods with functional properties, where supplementation with probiotics and bioactive compounds has gained prominence. In this context, the study aimed to evaluate the influence of in vitro biological digestion on the content of phenolic compounds, antioxidant activity, and inhibition of α-amylase and α-glucosidase activities of probiotic yogurt supplemented with the lactic acid bacteria Lactococcus lactis R7 and red guava extract (Psidium cattleianum). A yogurt containing L. lactis R7 (0.1%) and red guava extract (4%) was characterized for the content of phenolic compounds, antioxidant activity, and potential for inhibition of digestive enzymes after a simulated in vitro digestion process. After digestion, the caffeic and hydroxybenzoic acids remained, and sinapic acid only in the last digestive phase. Antioxidant activity decreased during digestion by 28.93, 53.60, and 27.97% for DPPH, nitric oxide and hydroxyl radicals, respectively, and the inhibition of the α-amylase enzyme decreased only 4.01% after the digestion process. α-glucosidase was more efficient in intestinal digestion, demonstrating an increase of almost 50% in probiotic yogurt with red guava extract before digestion. Possibly, the phenolics change their conformation during digestion, generating new compounds, reducing antioxidant activity, and increasing the inhibitory activity of α-glucosidase digestive enzymes. It was concluded that the probiotic yogurt formulation supplemented with red guava extract could interfere with the concentration of phenolic compounds and the formation of new compounds, suggesting a positive and effective inhibition of the digestive enzymes, even after the digestive process.

Development of antimicrobial and antioxidant electrospun soluble potato starch nanofibers loaded with carvacrol.

In this study, a method was developed to encapsulated carvacrol in nanofibers from soluble potato starch. The carvacrol was added in starch solutions at various concentrations (0, 20, 30 and 40% v/v) and electrospun into fibers. The morphology, size distribution, thermal stability, FT-IR spectra, relative crystallinity (RC) and antioxidant of the electrospun fibers were analyzed. For mechanical properties and antimicrobial activities evaluation electrospun nonwovens were obtain. The carvacrol-loaded nanofibers showed homogeneous morphology and average diameters ranging from 73 to 95 nm. The carvacrol encapsulated in the nanofibers had greater thermal stability than the free carvacrol. FT-IR analysis showed interactions between starch and carvacrol. The RC of the nanofibers was approximately 40%. The electrospun nonwovens mechanical properties did not present significant differences (p < 0.05). The 40% carvacrol-loaded nanofibers exhibited higher antioxidant activity with 83.1% of inhibition. The electrospun nonwoven loaded with 30% carvacrol resulted in 89.0% reduction of Listeria monocytogenes, 68.0% for Salmonella Typhimurium, 62.0% for Escherichia coli and 49.0% for Staphylococcus aureus. These electrospun nonwovens sustained antimicrobial activity for at least 30 days against S. aureus. The starch nanofibers are promising materials for application as a vehicle for carvacrol release in antimicrobial and antioxidant food packages.

Antibacterial activity, optical, mechanical, and barrier properties of corn starch films containing orange essential oil.

The incorporation of antimicrobial compounds into natural polymers can promote increased shelf life and ensure food safety. The aim of this study was to evaluate the antibacterial activity, morphological, optical, mechanical, and barrier properties of corn starch films containing orange (Citrus sinensis var. Valencia) essential oil (OEO). The corn starch films were prepared using the casting method. OEO and the corn starch films incorporated with OEO showed higher antibacterial activity against Staphylococcus aureus and Listeria monocytogenes. The addition of OEO to the films increased the morphological heterogeneity and contributed to the reduction of the tensile strength and elongation of the films, and it increased the moisture content, water solubility, and water vapor permeability. The water vapor permeability and partial or total solubility of a film in water prior to consumption of a product are of interest when the film is used as food coating or for encapsulation of specific molecules.

Multivariate optimization of Staphylococcus xylosus AD1biomass production using sugarcane molasses plus yeast extract and soybean meal

Staphylococcus xylosusis a microorganism that has important physiological and technological characteristics that make it suitable for use as a starter culture in fermented meat products. For the development of these products in the food industry, it is necessary to produce biomass by the multiplication of starter cultures using low-cost media. This study developed a culture medium based on sugarcane molasses (SCM) supplemented with yeast extract (YE) and soybean meal (SM) to produce S. xylosusAD1 biomass employing a Box Behnken multivariateoptimization design,usingthe best concentrations of the constituents of the culture medium for S. xylosusAD1 growth. By combining the mathematical models by the desirability function, it was possible to establish the optimal condition for the maximum production of viable cells and biomass. The optimal experimental condition was found when the fermentative process medium was composed of 10% SCM, 2% YE and 4% SM. In addition, the results of all experiments, except for the medium formulated with only SCM,presented a better performance than the commercial medium Brain Heart Infusion for the growth of S. xylosusAD1. The culture medium with agro-industrial byproduct (SCM) supplemented with YE and SM is an excellent alternative for producing S. xylosusAD1 biomass.

Action of ginger essential oil (Zingiber officinale) encapsulated in proteins ultrafine fibers on the antimicrobial control in situ.

The ultrafine fibers were produced using a polymeric blend of soy protein isolate (SPI), polyethylene oxide (PEO), and zein at a ratio of 1:1:1 (v/v/v) by electrospinning. The ginger essential oil (GEO) was encapsulated in the ultrafine fibers and the morphology, Fourier-Transform Infrared Spectroscopy (FTIR) analysis, thermal properties and relative crystallinity were evaluated. The antimicrobial activity of ginger essential oil was evaluated against five bacteria (Listeria monocytogenes, Staphylococcus aureus, Escherichia coli 0157:H7, Salmonella typhimurium, and Pseudomonas aeruginosa). Based on the preliminary tests, the concentration of GEO selected to add in the polymer solution was 12% (v/v; GEO/polymer solution). The fiber produced with 12% (v/v) GEO was used for antimicrobial analysis and in situ application (in fresh Minas cheese) against L. monocytogenes by micro-atmosphere. The ultrafine fibers produced, regardless the concentration of the essential oil, presented homogeneous morphology with cylindrical shape without the presence of beads. The application of the active fibers containing 12% GEO showed high potential to be applied in food packaging to reduce microbial contamination.

Antimicrobial electrospun ultrafine fibers from zein containing eucalyptus essential oil/cyclodextrin inclusion complex.

The aim of this study was to produce ultrafine fibers from zein incorporated with a complex of eucalyptus essential oil (EEO) and ß-cyclodextrin (ß-CD) with antimicrobial properties by electrospinning technique. The EEO was characterized by chemical composition and antimicrobial tests against three Gram positive and four Gram negative bacteria. The inclusion complex (IC) was prepared with ß-CD and EEO by co-precipitation technique and added at different concentrations in zein polymer solution using aqueous ethanol as solvent. The morphology, thermal properties, functional groups, and antimicrobial activity against L. monocytogenes and S. aureus of the ultrafine fibers were evaluated. The composite membranes containing 24% IC exhibited a greater reduction of growth as compared to the fibers without addition of IC. For L. monocytogenes the growth reduction was 28.5% and for S. aureus it was 24.3%. The electrospun IC-ß-CD/EEO composite membranes are promising for use in antimicrobial applications, such as food packaging.

Microbiological and physicochemical characterization of the raw milk and the colonial type cheese from the Northwestern Frontier region of Rio Grande do Sul, Brazil / Caracterização microbiológica e físico-química de leite cru e queijo colonial da região Fronteira Noroeste do Rio Grande do Sul, Brasil

This study aimed at evaluating the microbiological and physicochemical characteristics of raw milk and colonial type cheese from Northwestern Frontier region of Rio Grande do Sul, Brazil. For this purpose, the samples were collected in January and July. Microbiological analyses (aerobic mesophilic bacteria, total/thermotolerant coliform, coagulase-positive Staphylococcus, Salmonella spp. and Listeria monocytogenes, lactic acid bacteria) and physicochemical assays (pH, acidity, total solids, protein, fat, aw, moisture, NaCl) were performed. The milk and cheese samples showed low microbiological quality because high counting of aerobic mesophilic bacteria, total/thermotolerant coliform and coagulase-positive Staphylococcus were detected. High counting of lactic acid bacteria was observed. However, neither Salmonella spp. nor Listeria monocytogenes was found. The standard deviations above one (1.0) in the fat, protein, moisture and salt contents indicated that no standard procedure was followed for producing the local cheese. The sample collection period caused differences in the microbiota, total solids of milk and cheese moisture contents, aw and salt. The maturation period did not significantly influenced on the microbial counts, but it provided an increase in protein contents and a decrease in aw value in cheese samples collected in July.

Este estudo avaliou as características microbiológicas e físico-químicas de leite cru e queijo colonial da região Fronteira Noroeste do Rio Grande do Sul, Brasil. Para isto, foram feitas coletas de amostras em janeiro e julho. Análises microbiológicas (bactérias aeróbias mesófilas, coliformes totais e termotolerantes, Staphylococcus coagulase positiva, Salmonella spp. e Listeria monocytogenes, bactérias ácido lácticas) e físico-químicas(pH, acidez, sólidos totais, proteína, lipídeos, Aa, umidade, NaCl) foram realizadas. As amostras de leitee de queijo indicaram baixa qualidade microbiológica, pois houve detecção de altos níveis de bactériasmesófilas, coliformes totais e termotolerantes e Staphylococcus coagulase positiva. Altas contagens de bactérias ácido láticas foram observadas. Entretanto, não foi detectada a presença de Salmonella spp. eListeria monocytogenes. O desvio padrão acima de um (1,0) nos conteúdos de lipídeos, proteínas, umidade e sal indicou que não houve seguimento do procedimento padrão estabelecido na produção local de queijos. O período de coleta de amostras resultou em diferenças nas análises de microbiota, sólidos totais do leitee dos queijos, o teor de umidade, Aa e sal. O período de maturação não causou significativa influênciasobre as contagens microbianas, mas promoveu aumento no conteúdo de proteína e diminuição na Aa dos queijos coletados em julho.

Processamento hidrotérmico em escala industrial sobre parâmetros de qualidade em frações de aveia / Hidrothermal processing on an industrial scale on quality parameters in oat fractions

A aveia destaca-se dentre os cereais por seu teor e qualidade proteica, alta porcentagem de lipídios distribuídos por todo o grão e predominância de ácidos graxos insaturados, além de possuir altos teores de fibra alimentar, minerais e antioxidantes, responsáveis pelos efeitos benéficos à saúde humana. Devido aos seus constituintes, a aveia apresenta forte tendência à rancidez e, por esse motivo, faz-se necessária a inativação enzimática das cariopses. Na indústria, a inativação normalmente é realizada pelo tratamento hidrotérmico. Objetivou-se, com este trabalho, estudar os efeitos do processamento hidrotérmico em escala industrial sobre parâmetros de composição química, atividade enzimática, β-glicanas e compostos fenólicos solúveis totais nas frações de aveia farinha, farelo e integral. O processamento industrial da aveia foi realizado em batelada com temperatura e pressão constantes e tempo de retenção na coluna de 37min e 110min. O experimento foi conduzido em delineamento inteiramente casualizado, sendo os resultados submetidos à análise de variância e as médias comparadas pelo teste Tukey a 5% de significância. Os constituintes químicos das frações farinha, farelo e integral foram pouco afetados nos tempos de retenção estudados. O tempo de retenção de 37min se mostra mais adequado por ser suficiente para inativar as enzimas lipase e peroxidase e preservar os compostos fenólicos solúveis totais em todas as frações de aveia estudadas.

Oat stands out among other cereals because of its quality as high protein content, high percentage of lipids distributed throughout the grain and predominance of unsaturated fatty acids, in addition oat presents high contents of dietary fiber, minerals and antioxidants responsible for the beneficial effects to human health. Due to their constituents oats has a strong tendency to rancidity and because of this reason is necessary to enzymatic inactivation of caryopses. In industry, the inactivation is carried out usually by hydrothermal treatment. The objective of this work was to study the effects of hydrothermal processing on an industrial scale. Parameters of chemical composition, enzyme stability, β-glucan and total soluble phenolic compounds oat fractions (flour, bran and wholemeal) were evaluated. The industrial processing was carried out in batch with constant temperature and pressure and column retention time of 37min and 110min. The experiment was conducted in a completely randomized design and the results were submitted to analysis of variance and means were compared by Tukey test at 5% significance. The chemical constituents of the fractions flour, bran and whole were little affected the retention times studied. The retention time of 37min shown more appropriate for being sufficient to inactivate lipase and peroxidase enzymes and preserve the phenolic total soluble in all oats fractions studied.

Influence of a native strain of Staphylococcus xylosus on the microbiological, physicochemical and sensorial characteristics on milano salami type

In this work, the influence of native starter cultures on the microbiological, physicochemical and sensorial characteristics of Milano salami type was studied. Two batches of Milano salami type were produced: Batch A, with the addition of Staphylococcus xylosus U5 and Batch B (control) without the starter culture. The Milano salami type was characterized by an important microbial activity of coagulase-negative staphylococci (CNS) that resulted in substantial growth in Batch A during the ripening with an initial count of 7.60 log cfu.g-1 and reached 9.84 log CFU.g-1 after 14 days. Bacterial enzymes that showed efficient activity under the conditions found in Milano salami type were catalase, nitrite and nitrate reductase, contributing for sensory and physicochemical properties of the product. There were no significant differences in general free fatty acids composition among the batches, while the color parameters (L *, a * and b *) in the Batch A presented significantly higher values in relation to Batch B. Moreover, batch A had the higher preference in sensorial analysis.

A análise da influência de culturas iniciadoras nativas nas características microbiológicas, físicoquímicas e sensoriais de salame tipo Milano foi o objeto deste estudo. Foram produzidos dois grupos de salame tipo Milano: Grupo A - com aplicação de linhagem Staphylococcus xylosus U5 enquanto o controle, Grupo B, foi produzido sem culturas iniciadoras. O salame tipo Milano foi caracterizado pela importante atividade microbiana de estafilococos coagulase negativo (SCN), que resultou significativo crescimento no Grupo A durante a maturação, com contagem inicial de 7,60 ufc.g-1 e alcançando um crescimento de 9,84 cfu.g-1 depois de 14 dias. As enzimas bacterianas que mostraram eficiente atividade sob as condições encontradas no salame tipo Milano foram catalase, nitrito e nitrato redutase, contribuindo para as propriedades físicoquímicas e sensoriais do produto. Não houve diferenças significativas na composição geral dos ácidos graxos livres entre as amostras, enquanto os parâmetros de cor (L*, a* e b*) obtidos no salame inoculado (Grupo A) diferiram significativamente em relação ao controle (Grupo B) e foi o grupo preferido pelos degustadores.

Aspectos científicos e tecnológicos do emprego de culturas probióticas na elaboração de produtos lácteos fermentados: revisão / Scientific and technological asapects of using probiotic cultures to produce fermented dairy products: review

O presente trabalho, mediante revisão de literatura, teve como objetivo apresentar os efeitos benéficos que a ingestão de probióticos pode oferecer à saúde e os inúmeros aspectos científicos e tecnológicos fundamentais para a elaboração de produto lácteo probiótico. Abordou-se a utilização de bactérias ácido lácticas produtoras de exopolissacarídeos, bem como o desenvolvimento de novas classes de produtos funcionais envolvendo microorganismos probióticos em conjunto com compostos prebióticos (alimentos simbióticos). A seleção de microorganismo com propriedades probióticas exige a observação de três fatores principais: segurança, características funcionais e características tecnológicas. Portanto, a observação desses aspectos possibilitará a obtenção de produtos probióticos com a qualidade necessária e em sua máxima funcionalidade.

Avaliação das condições higiênico-sanitárias em serviços de alimentação / Evaluation of the hygienic-sanitary conditions in food services

Este trabalho apresenta o diagnóstico das condições higiênico-sanitárias dos serviços de alimentação do município de Santa Rosa, RS. Em cada estabelecimento foi aplicado um checklist (lista de verificação) constituído de cinco requisitos fundamentais para a manipulação higiênica dos alimentos. Além disso, foram realizadas análises microbiológicas do ambiente, equipamentos, utensílios e nos manipuladores de alimentos. A avaliação do checklist mostrou que 36% dos itens não estavam em conformidade com a legislação vigente. As análises microbiológicas do ar em dois ambientes demonstraram elevadas contagens de fungos e leveduras e de micro-organismos aeróbios mesófilos. Os equipamentos e utensílios avaliados apresentaram resultados semelhantes, sendo que 100% e 86% das amostras apresentaram, respectivamente, contagemde micro-organismos aeróbios mesófilos e de coliformes totais acima dos padrões estabelecidos pela American PublicHealth Association (APHA), os quais indicam condições higiênicas insatisfatórias. Na avaliação dos manipuladores foram previamente definidas as faixas de contagens para coliformes totais, sendo que 57,1% das amostras apresentaram valores entre 10.001 a 100.000 UFC/mão, a maior faixa de contagem observada, o que indica ineficiência nos procedimentos de higiene pessoal. Assim, os serviços de alimentação de Santa Rosa (RS) apresentam condições higiênico-sanitárias insatisfatórias, que podem colocar em risco os consumidores que frequentam tais estabelecimentos.

Phenotypic and molecular characterization of Staphylococcus xylosus: technological potential for use in fermented sausage

Micrococcaceae strains are applied to fermented sausage as starter cultures, where several members of this family are naturally found. The aim of the present work was to isolate and characterize Staphylococcus xylosus from artisanal sausages produced in South Region of Brazil. From 89 isolates presenting catalase positive and coagulase negative activities, 25 strains were selected for phenotypic characterization. Nine strains identified as Staphylococcus xylosus by API-STAPH were evaluated for their nitrate reduction capacity, which showed satisfactory growth of the strains in the presence of nitrite and sodium chloride, demonstrating their potential for use as starter cultures in fermented sausage. The strains were also evaluated through genus and species-specific PCR, which showed only two as S. xylosus, differing from results found in phenotypic characterization.

Cepas de Micrococcaceae são aplicadas em embutidos cárneos fermentados como culturas iniciadoras, onde vários membros desta família são naturalmente encontrados. O objetivo deste trabalho foi isolar e caracterizar Staphylococcus xylosus de embutidos cárneos artesanais produzidos na região Sul do Brasil. Dos 89 isolados que apresentaram atividades positiva para catalase e negativa para coagulase, 25 cepas foram selecionadas para caracterização fenotípica. Nove cepas identificadas como Staphylococcus xylosus por API-STAPH foram avaliadas para capacidade de redução de nitratos e o crescimento satidfatório das cepas foi verificado na presença de nitrito e NaCl, demonstrando seu potencial para utilização como culturas iniciadoras em embutidos cárneos fermentados. As cepas foram ainda avaliadas quanto ao gênero e espécie através da reação em cadeia da polimerase e apenas duas cepas foram identificadas como S. xylosus, diferindo dos resultados encontrados na caracterização fenotípica.

Viability of Staphylococcus xylosus isolated from artisanal sausages for application as starter cultures in meat products / Viabilidade de Staphylococcus xylosus isoladas de embutidos artesanais para aplicação como cultivos iniciadores em produtos cárneos

Viability of Staphylococcus xylosus isolated from artisanal sausages for application as starter cultures in meat products Viability of Staphylococcus xylosus strains AD1 and U5isolated from natural fermented sausages was investigated as starter cultures in fermented sausages produced in the South Region of Brazil. The study demonstrated that the Staphylococcus xylosus strains AD1 and U5showed significant growth during fermentation, stability over freeze-dried process, negative reaction for staphylococcal enterotoxins and viability for using as a single-strain culture or associated with lactic acid bacteria for production of fermented sausages.

Investigamos a viabilidade de cepas de Staphylococcus xylosus (AD1 e U5) isoladas de embutidos com fermentação natural, para aplicação como cultivos iniciadores em embutidos fermentados produzidos na Região Sul do Brasil. O estudo demonstrou que cepas de Staphylococcus xylosus (AD1 e U5) apresentaram crescimento significativo durante a fermentação, estabilidade no processo de liofilização e conservação, ausência de produção de enterotoxinas e viabilidade para aplicação como cultivo iniciador simples ou associado com bactérias lácticas na elaboração de embutidos fermentados.

Phenotypic characterization and species-specific PCR of promising starter culture strains of Lactobacillus plantarum isolated from naturally fermented sausages

The purpose of the present work was to characterize promising starter culture strains of Lactobacillus plantarum isolated from naturally fermented artisanal sausage manufactured in the northwestern region of Rio Grande do Sul state, Brazil. From 127 isolates of homofermentative, Gram-positive and catalase-negative lactic acid bacteria, ten isolates were randomly selected and the phenotypic characterization and species-specific PCR were performed. Genomic DNA from each isolated strain and from the reference strains L. plantarum ATCC 8014 and L. pentosus ATCC 8041 were amplified using two pairs of L. plantarum species-specific primers (16/Lpl and LbP11/LbP12). The results of the phenotypic characterization and species-specific PCR indicated that five out of ten isolates were Lactobacillus plantarum.

O objetivo do presente trabalho foi caracterizar cepas promissoras como cultivos iniciadores de Lactobacillus plantarum isoladas de embutidos cárneos fermentados naturalmente produzidos na região noroeste do Rio Grande do Sul, Brasil. Das 127 bactérias ácido láctica homofermentativas, Gram-positivo e catalase-negativo isoladas, dez foram aleatoriamente selecionadas e a caracterização fenotípica e a PCR espécie-específica foram realizadas. DNA genômico das cepas isoladas e das cepas de referência L. plantarum ATCC 8014 e L. pentosus ATCC 8041 foram amplificadas utilizando-se dois pares de iniciadores espécie-específicos para L. plantarum (16/Lpl e LbP11/LbP12). Os resultados da caracterização fenotípica e da PCR espécie-específica permitiram a identificação como Lactobacillus plantarum de cinco cepas das dez selecionadas.