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- Mead production: tradition versus modernityPublication . Ramalhosa, Elsa; Gomes, Teresa; Pereira, Ana Paula; Dias, Teresa; Estevinho, Leticia M.Honey is a natural product with recognized physical and chemical properties, which contribute to its biological activity. However, honey is currently being sold at low prices, making it imperative to find alternatives to make apiculture a viable national enterprise. One of these alternatives could be mead production. Despite the excellent properties of honey, mead production faces several problems, namely, delays and “pouts” fermentations, lack of product uniformity, and production of yeast off-flavors. Many factors might be related with these problems, such as honey variety, temperature, medium composition (vitamin and nitrogen content), fermentative yeast, and pH. Due to all these factors, mead production has decreased over the years. To overcome this situation, more research is needed to optimize the production of this beverage. This chapter presents a comprehensive review of previous research on mead production. It will focus on honey characterization and mead production. The first section covers honey composition and the way this affects honey properties, as well as important parameters that are indicators of honey quality. The second section discusses mead production, including fermentative microorganisms, fermentation conditions, and required postfermentation adjustments and maturation conditions. The final section focuses on the problems that must be surpassed and what the future holds for mead production.
- Mead and Other Fermented BeveragesPublication . Pereira, Ana Paula; Oliveira, José M.; Ferreira, Alexandra Mendes; Estevinho, Leticia M.; Faia, Arlete MendesThis chapter introduces the production of mead, a traditional alcoholic fermented beverage. It starts with an introduction to mead that includes historical aspects of production and a description of some styles and derivative products. Then, the raw material in mead production, the honey, is characterized in terms of its physicochemical composition and microbiota. Next, we focus on some aspects of mead production, such as the steps involved, the problems associated with the fermentation (the yeast inoculation and the nutrient supplementation of must), and the application of immobilized yeasts to the production. At the end is presented a detailed description of honey and fermentation-derived volatiles, the main contributors to mead aroma. Finally, we present an approach to the sensory evaluation of mead, an indispensable method to assess the beverage quality.
- Antioxidant and antimicrobial effects of phenolic compounds extracts of Northeast Portugal honeyPublication . Estevinho, Leticia M.; Pereira, Ana Paula; Moreira, Leandro; Dias, L.G.; Pereira, ErmelindaPhenolic compounds of dark and clear honeys from Trás-os-Montes of Portugal were extracted with Amberlite XAD-2 and evaluated for their antioxidant and antimicrobial activities. The antioxidant effect was studied using the in vitro test capacity of scavenge the 2,2-diphenyl-1-picryhydrazyl (DPPH) free radical and of reducing power of iron (III)/ferricyanide complex. The antimicrobial activity was screened using three Gram-positive bacteria (Bacillus subtilis, Staphylococcus aureus, Staphylococcus lentus) and three Gram-negative bacteria (Pseudomonas aeruginosa, Klebsiella pneumoniae and Escherichia coli). The results obtained from the partial identification of honey phenolic compounds by high-performance liquid chromatography with a diode array detector showed that p-hydroxibenzoic acid, cinnamic acid, naringe- nin, pinocembrin and chrysin are the phenolic compounds present in most of the samples analyzed. Anti- oxidant potential was dependent of honey extract concentration and the results showed that dark honey phenolic compounds had higher activity than the obtained from clear honey. In the biological assays, results showed that S. aureus were the most sensitive microrganisms and B. subtilis, S. lentus, K. pneumo- niae and E. coli were each moderately sensitive to the antimicrobial activity of honey extracts. Neverthe- less, no antimicrobial activity was observed in the test with P. aeruginosa.
- Qualidade microbiológica de azeitonas de mesa comercializadas em PortugalPublication . Pereira, Ana Paula; Pereira, J.A.; Bento, Albino; Estevinho, Leticia M.As azeitonas de mesa são um componente importante da dieta mediterrânica sendo consumidas em larga escala no mundo inteiro. São vários os métodos utilizados 110 seu processamento, sendo os mais comuns a fermentação ao natural, o método Sevilhano e o método Californiano. Os diferentes tipos de tratamento tem por objectivo produzir no fruto uma serie de transformações , consequência de processos físico-químicos e microbiológicos, que 0 fazem adquirir as características organolépticas de cor, sabor e textura, permitindo por outro lado a sua conservação. Neste trabalho pretendeu-se proceder a caracterização microbiológica de azeitonas de mesa comercializadas em Portugal, no que respeita a sua segurança microbiológica, de acordo com os diferentes métodos usados na sua produção. Para tal, em 35 amostras, de diferentes tipos e métodos de tratamento, nomeadamente azeitona da cultivar Galega de fermentação natural (AGFN) , azeitona mista de fermenta9ao natural (AMFN), azeitona verde (A V), azeitona preta oxidada (APO) e azeitona mista de fermentação natural, proveniente de produtores tradicionais e do Comercio Tradicional da Região de Trás-os-Montes (ACT), procedeu-se 11 analise microbiol6gica da polpa da azeitona e do molho de cobertura. Determinou-se também pH da polpa e do molho de cobertura e identificaram-se as leveduras isoladas nas amostras. Procedeu-se ainda a verifica9ao da conformidade da informação dos rótulos com a legislação em vigor.
- Estudo preliminar da actividade antifúngica e efeito quelante de iões do própolisPublication . Moreira, Leandro; Pereira, Ana Paula; Morais, Margarida; Estevinho, Leticia M.O própolis é uma substância resinosa produzida pelas abelhas e tem sido utilizado na medicina não convencional durante muito tempo, no tratamento e prevenção de inúmeras doenças, devido às suas propriedades biológicas, tais como antitumoral, antioxidante, antimicrobiana, anti-inflamatória e efeito imunomodelador, entre outros. O estudo preliminar da actividade antifúngica foi realizado testando o própolis (5mg/mL, 10mg/mL e 20mg/mL) em três leveduras patogénicas: Candida albicans, Candida krusei e Cryptococcus neoformans, usando a Sacharomyces cerevisiae como referência. Os resultados demonstraram que o crescimento de todos os microrganismos foi afectado pela presença de própolis no meio extracelular, sendo que à concentração de 20mg/mL foi possível reduzir em 48h o número de unidades formadoras de colónias em cerca de 90%. Para avaliar a actividade quelante de iões utilizaram-se dois própolis Portugueses, seguindo o método descrito por Decker and Welch. Os resultados demonstram que ambos os própolis evidenciam efeito quelante nos iões, sendo que o de Bornes - Trásos- Montes se mostrou mais eficaz quando comparado com o de Fundão - Beira Interior. Dada a importância destes resultados, principalmente, devido ao aumento de doenças provocadas por leveduras resistentes a antibióticos. Em estudos posteriores proceder-seá à quantificação das concentrações mínimas inibitórias, bem como à identificação dos compostos envolvidos nesta propriedade, e à elucidação dos mecanismos de acção. Relativamente à actividade quelante de iões esta pode ter interesse noutras funções a abordar em estudos posteriores, nomeadamente à utilização deste produto como anticoagulante.
- Levels of hygiene and safety quality indicators along the processing stages of a Portuguese traditional dry-fermented sausage (Linguiça)Publication . Gonzales-Barron, Ursula; Pereira, Ana Paula; Gomes, Aline; Lopes-da-Silva, M.F.; Rodrigues, Paula; Estevinho, Leticia M.; Cadavez, Vasco; Dias, TeresaWhile Portuguese fermented sausages are highly appreciated, research has shown that their microbiological quality is inconsistent due to the high variability in the production process and insufficient hygiene quality. Linguica is a dryfermented sausage, which has been found to harbour food-borne pathogens. Hence, the objective of this study was to investigate the changes in the levels of total viable counts (TVC), Enterobacteriaceae, L. monocytogenes and S. aureus at the key production stages of Linguica (raw meat, maceration, stuffing and smoking/drying). A microbiological survey followed a batch throughout production, extracting samples of raw meat (n=3), batter before maceration (n=3), batter after 3- or 4-day maceration (n=3) and sausages after curing/drying (n=5). Samples were taken from a total of three batches from each of the two factories under examination. Overall, TVC counts did not change considerably from raw meat to stuffing (5.5-5.9log CFU/g, 95% Cl: 5.15-5.82 log CFU/g), yet it increased significantly up to the end of drying (7.83 log CFU/g, 95% Cl: 7.57- 8.09 log CFU/g)- seemingly, because of the multiplication of lactic acid bacteria (LAB). Unlike the Enterobacteriaceae counts, which decreased (p<0.001) from batter before maceration (3.23 log CFU/g, 95% Cl: 2.80-3.66 log CFU/g) to the end of drying (1.56 log CFU, 95 percent Cl: 1.23-1.90 log CFU/g), S. aureus increased significantly between these two processing stages (2.58 log CFU/g; 95% Cl: 2.20-2.93 log CFU/g in the finished product). L. monocytogenes was detected in the products of one of the factories although their counts decreased after batter maceration. Because Linguica is a product that can be consumed without cooking, there is a need to further investigate the risk factors that determine their presence along processing. The presence of these two pathogens should also prompt industries to reinforce good hygiene practices in the processing of traditional sausages.
- Propriedades anti-fúngicas de meis comerciais.Publication . Gomes, Susana Paula Martins; Moreira, Leandro; Pereira, Ana Paula; Rodrigues, Paula; Estevinho, Leticia M.A qualidade do mel é determinada principalmente pelas suas características sensoriais, químicas, físicas e microbiológicas. Este trabalho teve como objectivo a avaliação da actividade anti-fúngica de 5 meis comerciais, adquiridos no mercado português. Procedeu-se também à sua caracterização quanto à qualidade comercial e segurança. Os resultados obtidos nas análises fisico-químicas foram, no geral, satisfatórias, uma vez que praticamente todas as amostras apresentavam valores dentro do permitido por lei para os vários parâmetros analisados. No que diz respeito à actividade antifúngica, verificou-se que os diferentes tipos de meis não variaram na capacidade de limitar o desenvolvimento das várias leveduras analisadas. No que diz respeito à resistência das leveduras aos diferentes meis, Zigosaccharomyces mellis ESA38 e Zigosaccharomyces rouxii ESA56 não foram infuenciadas pela presença de mel no meio extracelular (concentrações até 50%). Saccharomyces cerevisiae ESA1 e Zigosaccharomyces bailii ISA 1307 evidenciaram uma ligeira sensibilidade.
- Effects of high cell density fermentations on the optimisation of mead fermentationPublication . Pereira, Ana Paula; Ferreira, Alexandra Mendes; Estevinho, Leticia M.; Faia, Arlete MendesMead is a traditional drink, containing 8-18% (v/v) of ethanol, which results from the alcoholic fermentation of diluted honey performed by yeasts. It has been reported that mead fermentation is a time-consuming process, often taking several months to complete, depending on the type of honey, yeast strain and honey-must’s composition. An important objective of mead makers is to reduce the fermentation time without decreasing the quality of the end product. It has been shown that significant time can be saved in the fermentation process by increasing the pitching rate, i.e., the amount of suspended yeast cells added to a batch fermenter. Therefore, the aim of this study was to determine the adequate inoculum size of two commercial winemaking strains of Saccharomyces cerevisiae (Lalvin QA23 and Lalvin ICV D47) for the optimisation of mead fermentation. Honey must was prepared according to the recipe developed by our team, supplemented with potassium tartrate, pH adjusted to 3.7 with malic acid and the nitrogen concentration adjusted to 267 mg/L with diammonium phosphate. The appropriate amounts of inoculum were pitched into the honey-must to obtain five different pitching rates. Several parameters were determined during the fermentation to evaluate the effect of the inoculum size on yeast growth, fermentation profile and mead composition. Minor differences between the two strains in respect to growth kinetics were detected. As expected the increasing of the inoculum size resulted in significant increases in cell biomass and CFUs’ numbers but also decreased the yeast net growth. The time required to reach the same stage of fermentation ranged from 24 to 96 hours depending on the inoculum size. In accordance to the results obtained the strain ICV D47 appears to be more suitable for the production of high quality meads, although the strain QA23 provided better fermentation profile. However, sugars were not fully consumed and about 25 mg/L of assimilable nitrogen remained at the end of all fermentations. This is the first study of the effect of inoculum size on the optimisation of mead fermentation, however further research is needed to improve its quality.
- Effect of storage conditions on the quality of the bee pollenPublication . Estevinho, Leticia M.; Rocha, Joana; Pascoal, Ananias; Pereira, Ana Paula; Choupina, AltinoBee pollen (BP), is the result of the agglutination of flower pollens, made by worker honey bees, with nectar and salivary substances and collected at the hive entrance. The collection of AP is a relatively recent development, dependent primarily on the basic concept of scraping pollen of the bees' legs as they enter the hive. The objective of this work was to evaluate the effect of storage conditions in the physical-chemical and microbiological parameters of organic bee pollen.
- Bee propolis effect on protection of RBCs membrane integrityPublication . Moreira, Leandro; Rogão, Mónica; Pereira, Ana Paula; Morais, Margarida; Costa, Bruno; Dias, L.G.; Dias, Teresa; Estevinho, Leticia M.Propolis is a resinous substance collected from plants by bees. The propolis composition depends on the surrounding vegetation, the season, and the area from which derive. This hive product usually contains a variety of chemical compounds such as polyphenols (flavonoids, phenolic acids and esters), steroids, and amino acids. The hereditary spherocytosis (HS) is a congenital hemolytic anemia, with origin in the modification of membrane proteins of erythrocytes, which leads to increased susceptibility to hemolysis and a decrease of the cell over-life.