Eliane Colla

Potential application of microalga Spirulina platensis as a protein source.

The high protein level of various microalgal species is one of the main reasons to consider them an unconventional source of this compound. Spirulina platensis stands out for being one of the richest protein sources of microbial origin (460-630 g kg-1 , dry matter basis), having similar protein levels when compared to meat and soybeans. The use of S. platensis in food can bring benefits to human health owing to its chemical composition, since it has high levels of vitamins, minerals, phenolics, essential fatty acids, amino acids and pigments. Furthermore, the development of new protein sources to supply the shortage of this nutrient is an urgent need, and protein from S. platensis plays an important role in this scenario. In this sense, extraction processes that allow maximum protein yield and total utilization of biomass is an urgent need, and ultrasonic waves have proven to be an effective extraction technique. The number of scientific papers related to protein fraction from S. platensis is still limited; thus further studies on its functional and technological properties are needed.

Characterization of the spoilage lactic acid bacteria in "sliced vacuum-packed cooked ham".

The lactic acid bacteria are involved with food fermentation and in such cases with food spoilage. Considering the need to reduce the lactic acid bacteria growth in meat products, the aim of this work was to enumerated and investigated the lactic acid bacteria present on sliced vacuum-packed cooked ham stored at 4 °C and 8 °C for 45 days by phenotypic and molecular techniques. The quantification showed that the lactic acid bacteria were present from the first day with mean count of 1.98 log cfu/g for the four batches analyzed. The lactic acid bacteria grew rapidly on the samples, and plate counts around 7.59 log cfu/g and 8.25 log cfu/g were detected after 45 days of storage at 4 °C and 8 °C, respectively; storage temperatures studied showed significant influence on the microorganism in study growth. The predominant lactic acid bacteria associated with the spoilage samples at one day of storage includes Lactobacillus sp., the phenotypic overlap Leuconostoc / Weissella sp. and Enterococcus sp. At 45 days of storage at 4 and 8 °C the mainly specie was Lactobacillus curvatus , following by Lactobacillus sakei and Leuconostoc mesentereoides ; the Enterococcus sp. was not present in the samples.

Growth inhibition of lactic acid bacteria in ham by nisin: a model approach.

Lactic acid bacteria (LAB) have been described as spoilage organisms in vacuum-packed cooked ham. A Fractional Factorial Design was performed to investigate the relative merits of sodium chloride, sodium lactate, sodium tripolyphosphate, sodium erythorbate, nisin and pediocin, in limiting the Lactobacillus sakei growth in broth culture. This allowed rejection of sodium chloride, sodium lactate and sodium erythorbate (no significant effects on growth), and a Central Composite Rotatable Design broth culture study was performed comparing the effects of nisin and pediocin. From this study, nisin was identified as a more important variable for inclusion into a cooked ham model (significant effects on growth parameters: logarithmic increase in the population, exponential microbial growth rate and lag phase extension). The validation of this outcome in a model formulation of vacuum-packed sliced cooked ham (0.001%, 0.007% and 0.013% of nisin) stored for 60days, confirmed the inhibitory effect of nisin on total LAB growth.

The action of probiotic microorganisms on chemical contaminants in milk

Abstract Consumption of milk and its derivatives is an important food habit in the diet of all age groups. However, there has been increasing concern about physical, biological (pathogenic or spoilage microorganisms) and chemical (metals, pesticides and mycotoxins) contaminants in milk and dairy products. Considering the high levels of consumption, it is important that milk and dairy products are free from toxic compounds. Microbial degradation as a strategy for chemical decontamination is an emerging biotechnological approach that is considered a safe and inexpensive practice. The decontaminant activity of probiotic microorganisms is associated with fermentation, antibiosis and the ability of the microbial cell wall to bind to the contaminant. Exploiting the potential of microorganisms for chemical decontamination will further leverage its application in the food industry.

Protein and carbohydrate extraction from S. platensis biomass by ultrasound and mechanical agitation

Spirulina platensis is considered an alternative and excellent source of protein [46-63% dry basis (DB)], having protein levels comparable to meat and soybeans. Thus, it can be considered an adequate ingredient to supply the necessity of this compound in the food industry. Its carbohydrates (8-14% DB) may also be a useful food ingredient or a potential source of bioenergy. Thus, extracting these compounds from the microalgae biomass will maximize its exploitation. Sonication can completely or partially degrade the microalgal cell wall, providing a useful technique to extract the protein and carbohydrate. This study used a sequential strategy of experimental design (fractional factorial design and central composite rotatable design) to evaluate the protein and carbohydrate extraction from S. platensis defatted biomass using ultrasonic waves and mechanical agitation, under alkaline conditions. The optimal conditions for protein and carbohydrate co-extraction were established by selecting and maximizing the variables that significantly influenced the extraction. The optimized percentages recovery from the extraction process yielded 75.76% protein and 41.52% carbohydrate at 33-40min sonication and 40-55min agitation. The protein fraction may be further concentrated and purified for use in food formulations, and the carbohydrates may be a useful feedstock for bioethanol production.

Saccharification of Spirulina platensis biomass using free and immobilized amylolytic enzymes

We aimed to use physical methods of microalgal biomass rupture to study saccharification strategies using free and immobilized amylolytic enzymes. The biomass of Spirulina platensis, which consists of 50-60% carbohydrates, was exposed to physical cell rupture treatments, with better results obtained using freeze/thaw cycles following by gelatinization. In saccharification tests, it was possible to hydrolyze Spirulina biomass with hydrolysis efficiencies above 99% and 83%, respectively, using 1% (v/v) of free enzymes or 1% (m/v) of amylolytic enzymes immobilized together. The use of free and immobilized enzymes yielded high levels of conversion of polysaccharides to simple sugars in Spirulina biomass, showing that these processes are promising for the advancement of bioethanol production using microalgal biomass.

Lactose reduced ice cream enriched with whey powder

Ice cream is a food product that pleases the palate of consumers worldwide. Whey powder (WP) has various technological and functional properties. However, WP increases the lactose content of the final products in which it is incorporated and causes grittiness and intolerance in lactose-sensitive individuals. This study aimed to produce ice cream with milk powder (MP) replaced by WP (MP/WP), decrease the lactose content by enzymatic hydrolysis and verify the physicochemical and microbiological parameters of the final product. Initially, the variables ?-galactosidase concentration and reaction time were studied for the response of the percentage of lactose hydrolysis in a milk ice cream base, using a full 22 factorial design(FFD).With the reaction conditions defined (0.5 g L-1 of ?-galactosidase at 37 C for 4 h)the sucrose concentration and MP/WP replacement variables were then studied in the ice cream formulation for the percentage of lactose hydrolysis and overrun responses using a 22 FFD. The lactose hydrolysis, which ranged between 86.59-97.97%, was not affected by the MP/WP replacement in the ice cream, whilst the overrun was increased by the MP/WP replacement. The physicochemical and microbiological parameters of the ice cream were either not influenced or positively influenced by lactose hydrolysis and MP/WP replacement.

PARÂMETROS DE HIDRÓLISE ENZIMÁTICA DE FARELO DE ARROZ PARA PRODUÇÃO DE ETANOL DE SEGUNDA GERAÇÃO

A importância atribuida aos biocombustiveis aumentou nos ultimos anos em virtude das preocupacoes mundiais com as consequencias do avanco do aquecimento global e da elevacao dos precos do petroleo. Porem, a producao destes biocombustiveis convencionais defronta-se com serias dificuldades para atingir os niveis desejados, pois sao originados, em geral, de plantas que exigem areas de cultivo extensas, limitando a producao de alimentos, o que constitui um forte estimulo a adocao de tecnologias avancadas. Por isso, as pesquisas atuais sinalizam como tecnologia emergente a producao de etanol combustivel a partir de biomassas como alternativa para a utilizacao de combustiveis renovaveis. Sendo assim, a producao de alcool etilico a partir de residuos agroindustriais, como o farelo de arroz, apresenta-se como uma alternativa para transformar o residuo amilaceo em coproduto, gerando para a industria os beneficios de uma industria limpa. Por isso, o objetivo deste trabalho foi avaliar a producao de etanol de segunda geracao a partir do farelo de arroz, que se apresenta como uma fonte amilacea e um residuo agroindustrial, conferindo a importância de agregar valor a este residuo e contribuir com as pesquisas emergentes para a producao de etanol de segunda geracao. Isto foi realizado por meio da investigacao do processo de hidrolise do farelo de arroz desengordurado por via enzimatica aplicando um DCCR para a avaliacao do efeito das variaveis do processo (concentracao da enzima alcalase, tempo de exposicao ao ultrassom, e frequencia utilizada no ultrassom) visando maximizar o processo de liberacao de acucares fermentesciveis para a etapa subsequente de fermentacao alcoolica. As maiores concentracoes de acucares redutores foram alcancadas quando se utilizou a frequencia de 80 kHz no banho de ultrassom, verificando-se que as variaveis do DCCR nao apresentaram diferenca significativa na resposta a 95% de significância, ou seja, a utilizacao de quaisquer valores para ambas as variaveis do DCCR, dentro da faixa estudada, nao apresentaria diferenca na resposta, consideracoes estas tambem observadas para a resposta percentual de etanol. Ainda confirmou-se a importância da agitacao no processo de quebra das moleculas complexas, visto que as maiores concentracoes de acucares redutores foram obtidas atraves da realizacao de ensaios em diferentes condicoes de agitacao.

Mortadella Bologna Type With Reduced Lipid Content by Adding Biomass of Green Bananas, Pectin, Carrageenan and Linseed Flour

Considering the high consumption of meat products and the high fat content of most of them, it is necessary the development of meat products with reduced lipid content, since there is a growing demand for healthier and safer food. The aim of this work was to evaluate the possibility of reduction of the lipid content of a type of Mortadella Bologna by adding biomass of green banana. Four formulations were prepared with 10% of biomass of green banana. In the standard formulation (F1), it was not added brown linseed flour, pectin and carrageenan while in formulations F2, F3 and F4, it was added 1% of brown linseed flour, 0.5%, 0.3% and 0.1% of pectin and carrageenan, respectively. The microbiological, physic-chemical and sensory properties of the four formulations were analyzed. All the samples met the microbiological and physic-chemical criteria established in the legislation. The lipid content was re-

PADRÃO DE IDENTIDADE E QUALIDADE DE QUEIJOS COLONIAL E PRATO, COMERCIALIZADOS NA CIDADE DE MEDIANEIRA - PR

The present study relate the hygienic and sanitary quality of Colonial and Prato cheeses, commercialized in supermarkets and free markets of Medianeira-PR. Microbiological ( Salmonella sp., total and thermo-tolerant coliforms and Staphylococci coagulase-positive), physical-chemical (determination of fat, moisture and fat content on dry extract) and microscopic analyses were conducted in eight samples of Colonial cheese and eight samples of Prato cheese in two separate batches. According to the results, 50% of Colonial cheese samples were in disagreement with the current legislation for thermotolerant coliforms and 12.5% of samples showed Staphylococci coagulase-positive above the standards. Samples of Prato cheese showed heterogeneity among them and were in disagreement with the standard of identity. Colonial cheese presented a large amount of dirtiness, probabily due to the characteristics of the raw material and inadequate processing.