A maceração do milho é uma das etapas mais importantes para seu processamento através da moagem por via úmida. Consiste em uma série de processos que envolvem fermentação e hidrólise química de forma a permitir a separação adequada de seus componentes. Trata-se de uma etapa demorada que requer alto investimento em tanques e utilidades. No presente trabalho buscou-se avaliar o uso de enzimas para auxiliar na redução do tempo de maceração de milho dentado, em escala laboratorial, produzido na região do triângulo mineiro. Para tal, os grãos foram submetidos a diferentes tratamentos com as enzimas xilanase e protease. A ação enzimática foi comparada a padrões de maceração convencionais. Os resultados obtidos mostraram que o uso de enzima permite diminuir o tempo de maceração em torno de 18 horas assim como reduzir a quantidade de SO2 adicionada ao processo de maceração. / Corn steeping is one of the most important stage in the corn wet milling process. It consists of several processes involving fermentation and chemical hidrolysis to enable separation of different fractions of the grain. This process is time and capital investment intense. In the present work it was studied the use of enzymes to reduce the steeping time for dent corn, produced in the southeast of Brazil, in laboratory scale. The evaluated enzymes were xilanase and protease. The enzyme performance was compared with the regular steeping process. The final result has shown that the use of enzymes enabled to reduce steeping time in 18 hours as weel as the amount of added SO2 in the steeping process.

A maceração do milho é uma das etapas mais importantes para seu processamento através da moagem por via úmida. Consiste em uma série de processos que envolvem fermentação e hidrólise química de forma a permitir a separação adequada de seus componentes. Trata-se de uma etapa demorada que requer alto investimento em tanques e utilidades. No presente trabalho buscou-se avaliar o uso de enzimas para auxiliar na redução do tempo de maceração de milho dentado, em escala laboratorial, produzido na região do triângulo mineiro. Para tal, os grãos foram submetidos a diferentes tratamentos com as enzimas xilanase e protease. A ação enzimática foi comparada a padrões de maceração convencionais. Os resultados obtidos mostraram que o uso de enzima permite diminuir o tempo de maceração em torno de 18 horas assim como reduzir a quantidade de SO2 adicionada ao processo de maceração. / Corn steeping is one of the most important stage in the corn wet milling process. It consists of several processes involving fermentation and chemical hidrolysis to enable separation of different fractions of the grain. This process is time and capital investment intense. In the present work it was studied the use of enzymes to reduce the steeping time for dent corn, produced in the southeast of Brazil, in laboratory scale. The evaluated enzymes were xilanase and protease. The enzyme performance was compared with the regular steeping process. The final result has shown that the use of enzymes enabled to reduce steeping time in 18 hours as weel as the amount of added SO2 in the steeping process.

Background and objectives: While alkaline nixtamalization has historically been used for corn, this process may have application in other cereals. Drawbacks to wider use include the lengthy steep time, as well as the volume of alkaline wastewater produced. This study evaluated a novel, waste-effluent-free nixtamalization process for oat (Avena sativa) masa, and compared properties of oat masa and tortillas prepared with 1, 1.5 and 2% lime, with and without steeping. Findings: A minimal water-addition, 45-min, simmering process, without steeping, was effluent-free, and produced oat tortillas comparable to those produced using a traditional overnight steep. The pH increased significantly with increasing lime content (r=0.982). Consumer overall-liking scores did not significantly differ across treatments, though appearance scores were significantly higher for 2% lime samples (p<0.05), which were significantly darker and more yellow, based on L* and b* values. Masa adhesiveness means ranged from 1.49-1.52 N, with no significant differences between the no-steep treatments. Higher lime addition (1.5-2%) in the no-steep process significantly improved tortilla flexibility, based on extensibility and rollability scores, though tortilla rupture force did not vary significantly across treatments. Tortilla rollability scores at 3-days were lowest (x=1.1 + 0.31, indicating less cracking) for the 1.5-2% lime no-steep treatments, which were significantly better than the steeped treatment (x=3.7 + 0.48). Consumers rated the steeped sample as significantly less flexible. B-vitamins were negatively impacted by increasing lime, while calcium increased significantly with lime addition. Conclusions: The no-steep, effluent-free nixtamalization process produced oat tortillas with good masa and tortilla texture, which were not significantly different in consumer liking to tortillas produced via a traditional process. Significance and novelty: This research suggests nixtamalization can be applied to other grains in a shorter, environmentally-friendly process, with broader commercial applicability.

Ce travail s'intéresse au recyclage des rejets d'eaux usées par les malteries, principalement à l'étape de trempe. L'impact négatif de ces eaux sur la qualité des malts a été mis en évidence: leur réutilisation provoque un retard de prise d'eau par le grain et un retard de la germination. Puis, la caractérisation de ces eaux de trempe a permis d'identifier les inhibiteurs de la germination: il s'agit des intermédiaires d'oxydation et de polymérisation des composés phénoliques. Enfin, un procédé de traitement de ces eaux de trempe par bioréacteur à membrane a été mis au point. Testé aux échelles de laboratoire et pilote - avec ou sans couplage à une étape d'osmose inverse ou de charbon actif - ce procédé s'est révélé efficace pour l'épuration de l'eau et l'élimination des inhibiteurs. La réutilisation de ces eaux traitées dans l'étape de trempe n'a pas eu d'impact sur la qualité du procédé de maltage, et les malts ainsi préparés ont permis d'obtenir des bières de qualités équivalentes / This work is focused on the reuse of malting process wastewaters, especially steep-out waters. The negative impact of these waters on malt quality was demonstrated: their reuse results in a water uptake delay and a germination delay. Then, the characterisation of these steep-out waters allowed to identify germination inhibitors: they are intermediates of oxidation and polymerisation reactions of phenolic compounds. Finally, a membrane bioreactor treatment process of steep-out waters was developed. Studied at laboratory and pilot scales - with and without coupling to reverse osmosis or activated carbon step - this process was efficient for water treatment and for the removal of inhibitors. The reuse of these treated waters at the steeping step didn't have any negative impact on the process performances,and malts obtained allowed to prepare beers of comparable qualities

Orientador: José Francisco Lopes Filho / Banca: Javier Telis Romero / Banca: Eduardo Micotti da Gloria / Resumo: Foi monitorada a hidratação dos germes dos grãos de milho macerados a 52ºC e 180 rpm, em 9 soluções formadas pelas combinações de três níveis de SO2 (0,0 ; 0,1 e 0,2%) e três níveis de ácido lático (0,0 ; 0,55 e 1,0%) em intervalos de tempos de 10 minutos até 36 horas. Para determinar os coeficientes efetivos de difusão da água no germe foi utilizada a solução proposta por Crank (1975) para a Segunda Lei de Fick. Os coeficientes de difusão foram da ordem de 10-6 cm2/s, valores até 10 vezes maiores que os reportados na literatura para o grão inteiro. Verificou-se que o ácido lático dificultou a hidratação nas primeiras 2 horas e facilitou em 24 horas de maceração, ao passo que o SO2 dificultou a hidratação em 24 horas de maceração. Numa segunda etapa, macerou-se 1kg de grãos de milho em 4 tratamentos que apresentaram maior hidratação e no tratamento convencional (36 horas, 0,2% SO2 e 0,55% ácido lático), determinando-se o rendimento, a porcentagem de danificação e o teor de óleo nos germes. Foi verificado que a primeira moagem do processo úmido deve ocorrer somente após o germe atingir umidade próxima de 50% b.u. e que o SO2 e o ácido lático são imprescindíveis para se obter germe de boa qualidade. / Abstract: Moisture content was measured at 15 steep times, from 10 minutes to 36 hours at 9 steep solutions made by combination between three levels of SO2 (0,0; 0,1; 0,2%) and three levels of lactic acid (0,0; 0,55; 1,0%). The solution of Fick's Second Law proposed by Crank (1975) was used to find the water effective diffusivity coefficients. The coefficients were in the order of 10-6cm2/s, and were up to 10 times faster them the values reported on the literature for diffusivity in the whole grain. Lactic acid decreased germ hydration during the first two hours of steeping and increased hydration at steeping time of 24 hours. SO2 decreased hydration for steeping time of 24 hours. On the second part of this work, 1kg of corn grains on the four treatments that showed to be of highest hydration and the conventional steeping treatment (36 hours, 0,2% SO2 and 1,0% lactic acid) were wet milled to recovery germ fraction. Percentage of germ yields, damages and oil content were determined and compared. Results showed that the first milling of the corn wet milling processes must occur only after the germ moisture content achieves approximately 50% w. b., and that SO2 and lactic acid are indispensable to obtain a high quality germ. / Mestre

Made available in DSpace on 2014-06-11T19:24:46Z (GMT). No. of bitstreams: 0 Previous issue date: 2003-05-21Bitstream added on 2014-06-13T20:13:02Z : No. of bitstreams: 1 manente_jcpp_me_sjrp.pdf: 685880 bytes, checksum: cb9d50daf3a657ec5c57bcb533adeba6 (MD5) / Foi monitorada a hidratação dos germes dos grãos de milho macerados a 52ºC e 180 rpm, em 9 soluções formadas pelas combinações de três níveis de SO2 (0,0 ; 0,1 e 0,2%) e três níveis de ácido lático (0,0 ; 0,55 e 1,0%) em intervalos de tempos de 10 minutos até 36 horas. Para determinar os coeficientes efetivos de difusão da água no germe foi utilizada a solução proposta por Crank (1975) para a Segunda Lei de Fick. Os coeficientes de difusão foram da ordem de 10-6 cm2/s, valores até 10 vezes maiores que os reportados na literatura para o grão inteiro. Verificou-se que o ácido lático dificultou a hidratação nas primeiras 2 horas e facilitou em 24 horas de maceração, ao passo que o SO2 dificultou a hidratação em 24 horas de maceração. Numa segunda etapa, macerou-se 1kg de grãos de milho em 4 tratamentos que apresentaram maior hidratação e no tratamento convencional (36 horas, 0,2% SO2 e 0,55% ácido lático), determinando-se o rendimento, a porcentagem de danificação e o teor de óleo nos germes. Foi verificado que a primeira moagem do processo úmido deve ocorrer somente após o germe atingir umidade próxima de 50% b.u. e que o SO2 e o ácido lático são imprescindíveis para se obter germe de boa qualidade. / Moisture content was measured at 15 steep times, from 10 minutes to 36 hours at 9 steep solutions made by combination between three levels of SO2 (0,0; 0,1; 0,2%) and three levels of lactic acid (0,0; 0,55; 1,0%). The solution of Fick's Second Law proposed by Crank (1975) was used to find the water effective diffusivity coefficients. The coefficients were in the order of 10-6cm2/s, and were up to 10 times faster them the values reported on the literature for diffusivity in the whole grain. Lactic acid decreased germ hydration during the first two hours of steeping and increased hydration at steeping time of 24 hours. SO2 decreased hydration for steeping time of 24 hours. On the second part of this work, 1kg of corn grains on the four treatments that showed to be of highest hydration and the conventional steeping treatment (36 hours, 0,2% SO2 and 1,0% lactic acid) were wet milled to recovery germ fraction. Percentage of germ yields, damages and oil content were determined and compared. Results showed that the first milling of the corn wet milling processes must occur only after the germ moisture content achieves approximately 50% w. b., and that SO2 and lactic acid are indispensable to obtain a high quality germ.