Marília Oetterer

Characterization of chestnut (Castanea sativa, mill) starch for industrial utilization

Studies were conducted to characterize the chestnut and its starch. Chemical composition of the chestnuts showed high level of starch. Moisture level in the raw nuts was around 50g/100g in wet basis and starch content, around 80g/100g in dry basis; other nut flour components were protein (5.58 g/100g), lipid (5.39 g/100g), crude fiber (2.34 g/100g) and ash (2.14 g/100g). Starch fraction was chemically characterized in order to identify the granule quality as compared with those of cassava and corn. This fraction showed more lipids and proteins than the other starches. Chestnut starch granules showed peculiar shape, smaller than the control starches and low amount of damaged units. Chemical composition concerning amylose : amylopectin ratio was intermediate to that presented by cassava and corn starch granules. Water absorption at different temperatures as well as solubility were also intermediate but closer to that presented by cassava granules. The same behavior was observed in the interaction with dimethyl-sulfoxide. Native starch granules and those submitted to enzymatic treatment with commercial a-amylase and also with enzymes from germinated wheat were observed by scanning electronic microscopy. Water suspensions of chestnut starch granules were heated to form pastes that were studied comparatively to those obtained with cassava and corn starches. Viscographic pattern of chestnut starch pastes showed a characteristic profile with high initial viscosity but peak absence, high resistance to mechanical stirring under hot conditions and high final viscosity. There was no way to compare it with the paste viscographic profiles obtained with the control starches. Chestnut starch pastes were stable down to pH 4 but unstable at pH 3. The water losses observed in the chestnut starch pastes after freeze-thaw cycles showed more similarity to the pattern observed in corn starch pastes as well as clarity and strength of the gel. In general the results showed that chestnut pastes functional properties are intermediate to those of the cassava and corn starch pastes.

Use of fish waste as silage: a review

The use of fish silage as a substitute for protein ingredients in rations for aquatic organisms is an alternative to solve sanitary and environmental problems caused by the lack of adequate disposition for the waste from the fish industry. Besides, it is also a way of decreasing feeding costs, and, consequently, fish production costs, since feeding corresponds to about 60% of the overall expenses with production. The objective of this review was to discuss the use of fish waste, the elaboration of chemical silage and the use of this ingredient in feed for aquaculture.

Ionizing radiation effects on food vitamins: a review

Ionizing radiation has been widely used in industrial processes, especially in the sterilization of medicals, pharmaceuticals, cosmetic products, and in food processing. Similar to other techniques of food processing, irradiation can induce certain alterations that can modify both the chemical composition and the nutritional value of foods. These changes depend on the food composition, the irradiation dose and factors such as temperature and presence or absence of oxygen in the irradiating environment. The sensitivity of vitamins to radiation is unpredictable and food vitamin losses during the irradiation are often substantial. The aim of this study was to discuss retention or loss of vitamins in several food products submitted to an irradiation process.

Seafood as functional food

Functional food presents specific physiological properties, supplies nutrients and can be naturally found in formulated food or added to it. Seafood plays an important role in human diet, representing the largest stock available of w-3 polyunsaturated fatty acids, especially eicosapentaenoic (EPA) and docosahexaenoic (DHA). Scientific researchers have intensified their studies on fatty acids due to their importance in preventing and/or curing diseases, especially cardiovascular and inflammatory ones. This review describes the most important aspects of w-3 fatty acids found in fish, as well as their roles in the mechanism involved in the prevention and control of diseases.

Characterization and Frozen Storage Stability of Minced Nile Tilapia (Oreochromis niloticus) and Red Tilapia (Oreochromisspp.)

Abstract The mechanical separation of flesh from fish, i.e., mechanical deboning, is an economical and efficient process, which results in a higher yield than the filleting process. The process permits mincing fish from different size classes and weight classes. Nile tilapia (Oreochromis niloticus) and red tilapia (Oreochromis spp.) were mechanically deboned under industrial conditions. Mince average yield and the chemical composition of fillet, washed mince and unwashed mince were determined. Monthly evaluations were made on the physicochemical and microbiological stability of frozen mince stored at -16°C for 180 days. The results indicated that mince was physically stable and in good condition for consumption after 180 days.

Saxitoxins accumulation by freshwater tilapia (Oreochromis niloticus) for human consumption

The accumulation of saxitoxins (STXs) in fish from freshwater aquaculture was investigated for the first time in the present study. Cyanotoxins have been monitored in liver and muscle samples of Oreochromis niloticus by chromatographic methods, both before and after the depuration process. The results show that tilapia can accumulate STXs. Our findings suggest that depuration with clean water is an alternative process to eliminate STXs from fish and, therefore, improve the safety of tilapia for consumers.

Shelf life of minimally processed carrot and green pepper

As perdas pos-colheita de alimentos horticolas justificam a adocao de tecnicas de conservacao. Uma vez beneficiados, esses produtos permitem agregar valor a producao primaria e se tornam de conveniencia ao consumidor. Este trabalho teve como objetivo definir as metodologias do processamento minimo de cenoura e pimentao quanto ao tipo e intensidade de adocao das tecnicas de barreiras e monitorar os produtos apos o processamento, atraves de analises microbiologica, fisico-quimica e nutricional. As hortalicas foram lavadas e sanificadas com hipoclorito de sodio, 100 mg L-1 de cloro livre, durante 15 min em agua refrigerada (7oC), e a seguir centrifugadas por 5 min. O produto foi acondicionado em sacos plasticos com filme BOPP/PEBD (polipropileno biorientado/polietileno de baixa densidade), selados sob ar atmosferico, vacuo e atmosfera modificada (2% O2, 10% CO2 e 88% N2), e a seguir armazenados a 1oC±1oC. A composicao centesimal das hortalicas permaneceu estavel durante o periodo de armazenamento, nos tres tratamentos testados. Os teores de vitamina C, para as amostras de cenoura e pimentao minimamente processados, nao apresentaram diferencas entre os tratamentos. Os teores de b-caroteno diminuiram ligeiramente durante o periodo de armazenamento para a cenoura e pimentao minimamente processados. Apos o processamento, a cenoura e o pimentao obtiveram contagens para psicrotroficos de 102-105 e 103-106 UFC g-1, respectivamente. Foram constatados anaerobios mesofilos e coliformes totais em pimentoes, da ordem de 1,6x103 a 7,4x105 e <10/g a 7,4x105, respectivamente. Nas cenouras, nao foram detectados coliformes totais e fecais, anaerobios mesofilos e Salmonella em nenhum dos tratamentos. Salmonella nao foi detectada nos pimentoes.

Effects of Irradiation and Refrigeration on the Nutrients and Shelf-Life of Tilapia (Oreochromis niloticus)

Abstract The objective of this study was to enhance the shelf life of processed fish, combining ionizing radiation and refrigeration with minimal processing. The physical, chemical, nutritional and microbiological characteristics of the species Tilapia nilotica (Oreochromis niloticus) were studied in eviscerated samples and in commercial cuts. The fish were separated into samples irradiated with 0, 1.0, 2.2 and 5 kGy. They were stored at temperatures ranging from 0.5°C to −2°C for 20 and 30 days. During storage, the level of moisture in the non-irradiated samples decreased and the levels of protein and lipid increased while the irradiated samples remained stable. The levels of TVB-N and NPN increased in the non-irradiated samples but tended to remain stable in the irradiated fish samples. The irradiated samples had a microbiological content below the levels established by the Brazilian seafood legislation, whereas the non-irradiated samples had a higher microbiological content and were not in conformity with the officially permitted levels. The levels of amino acids in muscles and fatty acids in oil remained stable in the irradiated fish stored samples but decreased in the non-irradiated ones. Lipid-oxidation, measured by the TBARS test, showed a tendency to increase when the dose of irradiation increased.

Nutritional aspects of nile tilapia (Oreochromis niloticus) silage

One third of the world’s fishing produce is not directly used for human consumption. Instead, it is used for making animal food or is wasted as residue. It would be ideal to use the raw material thoroughly and to recover by-products, preventing the generation of residues. With the objectives of increasing the income and the production of the industry, as well as minimizing environmental and health problems from fish residue, chemical silage from Tilapia (Oreochromis niloticus) processing residues was developed after homogenization and acidification of the biomass with 3% formic acid: propionic, 1:1, addition of antioxidant BHT and maintenance of pH at approximately 4.0. Analyses to determine the moisture, protein, lipids and ash were carried out. The amino acids were examined in an auto analyzer after acid hydrolysis, except for the tryptophan which was determined through colorimetry. The tilapia silage presented contents that were similar to or higher than the FAO standards for all essential amino acids, except for the tryptophan. The highest values found were for glutamic acid, lysine and leucine. The results indicate a potential use of the silage prepared from the

Produções de ácido acético, etanol e dos isômeros óticos do ácido lático por linhagens de Lactobacillus isoladas de fermentações alcoólicas industriais

Avaliaram-se no presente trabalho, as producoes de etanol e dos acidos acetico e latico, bem como das proporcoes dos isomeros oticos D(-) e L(+) desse ultimo, por 17 linhagens de Lactobacillus isoladas de fermentacoes industriais de producao de etanol. As linhagens foram crescidas a 32oC por 24 horas, em meio contendo 1% de glucose, 1% de frutose, 1% de extrato de levedura, sais nutrientes (K, Mg e Mn) e tampao fosfato. Foram estimados os teores de acido latico, acido acetico e etanol mediante cromatografia liquida de alta eficiencia, assim como dos isomeros oticos D(-) e L(+) do acido latico mediante espectrofotometria ao ultra-violeta, empregando desidrogenases laticas estereoespecificas. O crescimento bacteriano foi inferido pela absorvância a 600 nm. Os resultados obtidos mostraram, pelos perfis de excrecao dos metabolitos, a presenca de 8 linhagens homofermentativas obrigatorias (produzindo unicamente acido latico), 8 linhagens heterofermentativas obrigatorias (com producoes de acidos latico, acetico e etanol) e 1 linhagem supostamente heterofermentativa facultativa. Observou-se tambem, em relacao a formacao dos estereoisomeros, que 12 linhagens foram incluidas no grupo DL, 4 no grupo L e 1 no grupo D. Os resultados permitem concluir que os Lactobacillus que contaminam processos fermentativos industriais de producao de etanol, podem se apresentar nos 3 biotipos fermentativos e produzindo as mais variadas proporcoes dos dois estereoisomeros do acido latico, com relevantes implicacoes biotecnologicas. Este e o primeiro relato sobre as producoes dos isomeros oticos do acido latico por bacterias do genero Lactobacillus isoladas de fermentacoes industriais baseadas na cana-de-acucar.