Antonio Joaquim de Oliveira

Conservation of Brazil nut extract

Pasteurization of a Brazil nut extract with and without addition of chemical preservatives and the storage of this product under refrigeration was performed to evaluate the conservation of this extract. The product was monitored during 180 days by microbiological, physical and chemical analysis including titratable acidity and pH. Treatments with chemical preservatives were microbiologically stable and titratable acidity and pH were equilibrated. Absence of total and fecal coliforms demonstrated the pasteurization efficiency. It is concluded that the pasteurization is only a viable method for preservation of the Brazil nut extract when associated with chemical preservatives and refrigeration.

Uso de leite reconstituído na fabricação de queijo mussarela

Nowadays the Mozzarella cheese is the most produced in Brazil. However, due to the problem of the seasonal production of milk, in a certain period of the year, there is a shortage of the milk offer and than the cheese price rises. For this reason, the usage of reconstituted dry milk blended with fresh milk could be an alternative for the stabilization of the offer of the product in the market. In this experiment, Mozzarella cheeses were produced with fresh milk and with fresh milk added of 10% and 20% of reconstituted dry milk (obtained from medium-heat dry milk). The physico-chemical and slicing properties of the cheeses made with fresh milk and with fresh milk added of reconstituted milk (10% and 20%) were compared. The statistical analysis of data permited withdraw the following conclusions: the Mozzarella cheese may be produced by adding 10% of reconstituted milk to the fresh milk without affecting its physico-chemical characteristics nor the property of slicing; on the other hand, that one produced by addition of 20% of reconstituted milk to the fresh milk showed a poor property of slicing.

Elaboração do queijo mozarela de leite de búfala pelos métodos tradicional e da acidificação direta

The study was purpose to evaluate the processing of buffalos milk Mozzarella cheese of elaborated by traditional method and by direct acidification method with citric acid. Acidification pH ranged from 5,1 to 5,2. There was a reduction from 8 to 3 hours in the total time of cheese production by utilization of direct acidification method in relation to the traditional method. This reduction occurred due to a decrease on coagulation time from 50 to 5 minutes and the absence of fermentation stage. Fermentation stage lasted 4 hours in the traditional method. The cheese elaborated by direct acidification method presented higher yield than those obtained with the traditional method, with values of 18,0 and 17,3%, respectively. Considering dry basis yield both processing methods did not differ. The cheese elaborated by the acidification method presented lower protein and higher humidity contents and, consequently, lower contents of total solids in relation to the traditional one. There were no significantly differences between the two types of cheeses on fat, ash and calcium levels. For the acceptance test, 50 non-trained tasters evaluated the samples using a 9 points hedonic scale. Results showed no significant difference (p<0,05) in the acceptance of the samples, with means of 6,68 and 6,26 for the direct acidification method and traditional method, respectively.

Influência das culturas láticas no índice de proteólise do queijo minas frescal

The influence of lactic cultures in the ripening index of Minas Frescal cheese was studied, utilizing pasteurized and not pasteurized milk. The use of lactic cultures for Minas Frescal cheese can be recomended, since the ripening index had good correlation only with storage time.

Mozzarella cheese of buffalo's milk elaborated by traditional and direct acidification methods

The study was purpose to evaluate the processing of buffalos milk Mozzarella cheese of elaborated by traditional method and by direct acidification method with citric acid. Acidification pH ranged from 5,1 to 5,2. There was a reduction from 8 to 3 hours in the total time of cheese production by utilization of direct acidification method in relation to the traditional method. This reduction occurred due to a decrease on coagulation time from 50 to 5 minutes and the absence of fermentation stage. Fermentation stage lasted 4 hours in the traditional method. The cheese elaborated by direct acidification method presented higher yield than those obtained with the traditional method, with values of 18,0 and 17,3%, respectively. Considering dry basis yield both processing methods did not differ. The cheese elaborated by the acidification method presented lower protein and higher humidity contents and, consequently, lower contents of total solids in relation to the traditional one. There were no significantly differences between the two types of cheeses on fat, ash and calcium levels. For the acceptance test, 50 non-trained tasters evaluated the samples using a 9 points hedonic scale. Results showed no significant difference (p<0,05) in the acceptance of the samples, with means of 6,68 and 6,26 for the direct acidification method and traditional method, respectively.

APROVEITAMENTO DO SORO DE QUEIJO PARA PRODUÇÃO DE METANO

SUMMARY The objective was to study the viability of methane production through the utilization of whey from cheese manufacture and, also, to evaluate the behaviour of methanogenic bacteria. Biodigestors were FED with cheese whey (proportions of 1%, 5% and 10% of the nominal volume), and mantained at 35° C. Five retention times and four feeding systems were used for different times of substract addition. In the first and second retention times, biodigestors were FED at intervals of 24 hours. In the third retention time, the load was dividid in three parts and put into biodigestors every eight hours. In the fourth retention time, biodigestors received 8 feeding daily, at regular intervals of 2 hours. For the fifth retention time, the organic load was divided in to five daily feeding that were put into biodigestors at intervals of 3 hours and 36 minutes. Results of this work showed that the anaerobic conditions were affected by the feeding systems of biodigestors, but it was possible to treat the residues from dairy plants, since as cheese whey, by using anaerobic digestion with production of biogas. The maximum methane production was obtained at the 5% concentration and three daily feedings system, althought, there was not a statisticaly significative difference among the feedings systems.

A microflora de derivados do leite como índice de qualidade: II. Leites desidratados e manteigas

O presente trabalho teve por objetivo o isolamento e a caracterizacao de microrganismos patogenicos e deterioradores em leites desidratados (integral e desnatado) e manteigas (com e sem sal). Amostras comerciais foram tomadas e analisadas para: Contagem Total, Coliformes Totais, Coformes Fecais, Staphylococcus, Psicrotroficos, Termofilos, Proteoliticos, Lipoliticos, Enterococos, Salmonella, Fungos e Leveduras e Esporulados Aerobicos (somente para as amostras de leites desidratados). As altas contagens verificadas para Contagem Total, Coliformes Totais, Coliformes Fecais, S. aureus, Enterococos, Proteoliticos , Lipoliticos e Psicrotroficos na maioria das amostras de manteigas analisadas neste trabalho, e a presenca de Salmonella em algumas delas, revelam que as mesmas devem ser consideradas improprias ao consumo humano, uma vez que, a maiorias das contagens de microrganismos patogenicos esta acima dos padroes estabelecidos pela Comissao Nacional de Normas e Padroes para Alimentos (1978). Ja as amostras de leites desidratados analisadas se enquadram nos padroes nacionais existentes para microrganismos patogenicos.

A microflora de derivados do leite como índice de qualidade: I. Queijos

Foram isolados e identificados microrganismos patogenicos e deterioradores em tres diferentes tipos de queijos, a saber, Prato, Minas Frescal e Provolone, adquiridos junto ao comercio de Piracicaba. As analises realizadas foram para Contagem Total, Coliformes Totais, Coliformes Fecais, Staphylococcus, Psicrotroficos, Termofilos, Proteoliticos, Lipoliticos, Enterococos, Salmonella, Fungos e Leveduras. As altas contagens verificadas para Contagem Total, Coliformes Totais, Coliformes Fecais, S. aureus, Enterococos, Proteoliticos, Lipoliticos e Psicrotroficos na maioria das amostras analisadas neste trabalho, e a presenca de Salmonella em algumas delas, revelam que as mesmas devem ser consideradas improprias ao consumo humano, uma vez que, a maioria das contagens de microrganismos patogenicos, esta acima dos padroes estabelecidos pela Comissao Nacional de Normas e Padroes para Alimentos (1978).