Granulometria da matéria prima e configuração da extrusora sobre os parâmetros de processo, características do extrusado e digestibilidade de rações para gatos
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Data
2016-08-03
Autores
Gonçalves, Karina Nogueira Venturelli [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
A maior parte dos alimentos industrializados destinados à gatos são secos e extrusados. A aplicação de energia termomecânica durante a extrusão promove mudanças físico-químicas e nutricionais nos ingredientes com eficiência e baixo custo relativo. Por outro lado, ela também pode promover efeitos indesejáveis, incluindo destruição de vitaminas, oxidação de lipídeos, destruição e redução na disponibilidade da proteína e aminoácidos, principalmente a lisina. Não foram encontradas na literatura as implicações do tamanho da partícula da matéria prima e o efeito de diferentes configurações de extrusora em alimentos para gatos sobre a formação dos “kibbles” e aspectos nutricionais. O presente estudo teve como objetivo estudar as implicações nutricionais, à macroestrutura de extrusados e aos parâmetros de processo de alimentos para gatos produzidos a partir de diferentes graus de moagem da matéria prima e configurações de extrusora. Para tanto foram conduzidos dois experimentos. O primeiro avaliou o efeito do tamanho da partícula da matéria-prima e área aberta da matriz da extrusora sobre os parâmetros de processamento, gelatinização do amido (GA), digestibilidade in vitro da matéria orgânica, macroestrutura dos “kibbles”, digestibilidade in vivo dos nutrientes (DIV) e teor de lisina. O experimento seguiu um arranjo fatorial 6 x 2 (6 áreas abertas e 2 tamanhos de partículas), totalizando 12 tratamentos. Uma dieta para gatos adultos foi formulada e moída em moinho de martelo em duas aberturas de peneira (0,5 e 1,2mm), as quais geraram diâmetro geométrico médio (DGM) de 195 e 254 μm respectivamente. O material foi extrusado a partir das seguintes áreas abertas (AA) alvo: 59, 118, 177, 236, 294, 353 mm2/ton/h. Todos os outros parâmetros de software e de hardware da extrusora não foram alterados. A DIV feita pelo método de coleta total de fezes, nas dietas com 195 μm e 59 mm2/ton/ h, 195 μm e 353 mm2/ton/h, 254 μm e 59 mm2/ton/h, 254 μm e 353 mm2/ton/h, usando 6 gatos por dieta. A lisina total, ligada e reativa foi analisada em 5 tratamentos: mistura dos ingredientes não extrusada e nos 4 tratamentos escolhidos para a DIV. Os dados foram submetidos à análise de variância considerando os efeitos de DGM e AA e suas interações e as médias foram comparadas por contrastes polinomiais (P<0,05). Para a DIV interação foi considerada significativa quando P<0,15. Os resultados de lisina foram comparados pelo teste de Dunnet (P<0,05), sendo a mistura não extrusada considerado como referência. Com relação aos parâmetros de processo interação entre DGM e AA foi observada na pressão e na temperatura da última camisa da extrusora, sendo que os menores valores foram observados no menor DGM. Os valores de flash off foram semelhantes entre ambos DGM e diminuíram linearmente com aumento da AA. A energia mecânica específica (EME) e a energia térmica específica (ETE) foram influenciadas pela interação entre DGM e AA. Em ambos DGM houve redução quadrático na EME e aumento ETE com o aumento da AA. Todos os parâmetros da macroestrutura dos “kibbles” foram influenciados pela interação. As dietas com maiores DGM apresentaram maior densidade aparente e específica, comprimento específico e menor expansão radial. A GA e digestibilidade in vitro da matéria orgânica não foram influenciados pela AA, apenas pelo DGM. Foi verificada uma interação (P<0,15) para a digestibilidade da proteína bruta e da matéria seca e orgânica. Os menores resultados foram vistos no menor DGM e área mais restrita. Houve aumento da lisina total e reativa em todas as dietas extrusadas, mas não na lisina ligada. O efeito conjunto do DGM e da AA influenciaram fortemente os parâmetros do processo, a transferência de EM e as características dos “kibbles”. O segundo estudo avaliou o efeito de diferentes configurações de extrusão sobre os parâmetros de processamento, GA, digestibilidade in vitro da matéria orgânica, macroestrutura dos “kibbles” e DIV. O experimento seguiu um arranjo fatorial 4 x 2 (4 áreas abertas e 2 restrições após rosca da extrusora), totalizando 8 tratamentos. A mesma dieta usada no primeiro experimento foi extrusada com uma combinação de 60 ou 90% de restrição após a rosca da extrusora (RAR) e quatro AA alvo: 59, 118, 236 e 353 mm2/ton/h). Todos os outros parâmetros de software e de hardware da extrusora não foram alterados. A DIV foi feita pelo método de coleta total de fezes, nas dietas com 90% de restrição e 353 mm2/ton/h e restrição de 60% e 59 mm2/ton/h, usando 6 gatos por dieta. Os dados foram submetidos à análise de variância, considerando os fatores RAR e AA e suas interações. As médias foram comparadas por contrastes polinomiais (P<0,05). A amperagem do motor foi influenciada pela interação, sendo que as maiores médias foram observadas nas dietas com 90% de RAR e foi notado redução com aumento AA. A umidade no canhão da extrusora foi semelhante entre os tratamentos. A pressão da massa medida antes da matriz alterou somente com AA. Houve redução no flash off apenas nas dietas com 90% de RAR e diminuiu com aumento AA. Houve redução na temperatura média da quarta camisa com aumento da AA. A EME não sofreu influência da interação e foi maior para as dietas com 90% RAR. A ETE foi semelhante entre os tratamentos e a energia total aplicada foi semelhante para todas AA nas dietas com 60% de RAR, mas reduziu com o aumento da AA nas extrusadas com 90% de RAR. Foi observado efeito (P<0,05) de AA para todas as características dos “kibbles”. Houve interação para a densidade aparente e específica e aumento nas maiores AA. A expansão mais elevada foi verificada nas dietas com 90% RAR. Gelatinização do amido e digestibilidade in vitro não foram influenciadas pela interação. A digestibilidade in vitro foi alterada de acordo com AA, mas a DIV não mudou (P>0,05) entre os tratamentos. A RAR e AA exercem forte impacto sobre os parâmetros de processos, transferência de EME e formação dos “kibbles”. A DIV não foi influenciada pela expansão dos “kibbles”
Most processed foods intended for cats are dried and extruded. Application of thermomechanical energy during extrusion promotes physical-chemical and nutritional changes in the ingredients in an efficient and relatively low cost. Moreover, it can also promote undesirable effects, including the destruction of vitamins, lipid oxidation, destruction and reduction in the availability of protein and amino acids, especially lysine. The author was not able to found scientific literature on the implication of the raw material particle size and extruder configuration on kibble formation and the nutritional aspects of extruded foods for cats. Taken these considerations, this study aimed to evaluate the implications of two raw particle size and changes in extruder configuration on the extrusion traits, kibbles, starch gelatinization (SG) degree and digestibility of cat food formulation. It was conducted two experiments. The first evaluated the effect of raw material particle size and extruder open area (Eoa) on the processing parameters, SG, in vitro digestibility of organic matter, kibble macrostructure, in vivo nutrient digestibility (IVND) and content of lysine. The experiment followed a factorial 6 x 2 (6 Eoa and 2 raw particle size), totaling 12 treatments. A diet was formulated for adult cats and ground in a hammer mill in two sieve openings (0.5 and 1.2) which generated mean geometric diameter of raw material (MGD) of 195 and 254 μm respectively. The material was extruded with these Eoa target: 59, 118, 177, 236, 294, 353 mm2/ton/h. All other software parameters and extruder hardware have not changed. The IVND was conducted by the method of total collection of feces, in the diets of 195 μm and 59 mm2/ton/h, 195 μm and 353 mm2/ton/h, 254 μm and 59 mm2/ton/h, 254 μm and 353 mm2/ton/h, using 6 cats per diet. The results of total, linked and reactive lysine were measured at 5 treatments: raw material and four treatments chosen for IVND. Data were submitted to analysis of variance considering the MGD and Eoa effects and their interactions, and means were compared by polynomial contrasts (P <0.05). The digestibility interaction was considered significant when P<0.15. Lysine results were compared by the Dunnett test (P<0.05) and raw material was considered as the reference. Regarding the process parameters interaction between MGD and Eoa were observed in die pressure and temperature of the last extruder jacket, and the lowest values were observed in the diets with 195 μm MGD. Flash off values were similar between MGD and decreases linearly with increasing Eoa. Specific mechanical energy (SME) and specific thermal energy (STE) were influenced by the interaction. In both MGD there was a reduction in quadratic SME, and STE increased with increasing Eoa. All macrostructure parameters of kibbles were influenced by interaction. Diets with larger MGD presented higher bulk and piece density, specific length and less radial expansion rate. The SG and in vitro digestibility of organic matter were not affected by Eoa, only by MGD. For digestibility a significant interaction (P<0.15) between MGD and Eoa was observed on crude protein and dry and organic matter. The lower results were seen in the smaller MGD and more restricted area (195 μm and 59 mm2/ton/h). There was increase in total and reactive lysine in all extruded diets, but not on lysine linked. The combined effect of DGM and Eoa strongly influence the process parameters, the transference of SME and kibbles traits. The second experiment evaluated the effect of different extruder configuration on the processing parameters, SG, in vitro digestibility of organic matter, kibble macrostructure, and IVND of extruded cat foods. The experiment followed a 4 x 2 factorial arrangements of treatments, with 4 Eoa and 2 restrictions after extruder screw (RASc), a total of 8 treatments. A single food was formulated for cat maintenance, and processed in a single screen extruder with a combination of 60% or 90% RASc, and 4 Eoa target: 59, 118, 236, 353 mm2/ton/h. All other extruder software and hardware parameters was unchanged during the study. IVND was measured by the total collection of feces method on the diets processed with 90% RASc and 353 mm2/ton/h, and 60% RASc and 59 mm2/ton/h, using 6 cats per diet. Data were submitted to analysis of variance considering RASc and Eoa effects, as well their interactions. Means were compared by polynomial contrasts (P < 0.05). For motor amperage was verified an interaction between RASc and Eoa, with greater means for the 90% RASc diets and a reduction with increase Eoa. In barrel moisture was similar among treatments. Die pressure did not change according to RASc, only Eoa, it decreased. Flash off was different only in diets with 90% of RASc and decreased with the increase Eoa. There was a reduction in mean temperatures of forth extruder jacket with increase Eoa. SME application did not suffer influence of the interaction between RASc and Eoa, but was higher for 90% RASc diets. STE was similar among treatments. Total specific energy application was similar for all Eoa on 60% RASc, but decreased with the increase on Eoa for 90% RASc. A significant effect of Eoa was observed for all analyzed kibble traits. There was an interaction for bulk and piece density and both item showed an increase with increase on Eoa. Higher expansion were verified for 90% RASc diets. SG and in vitro digestibility were not influenced by the interaction of RASc and EOA. In vitro digestibility changed according to Eoa, but IVND was similar (P> 0.05) between treatments and did not suffer influence of bulk density. RARs and Eoa have a strong impact on the process parameters, transference of SME and kibble traits.
Most processed foods intended for cats are dried and extruded. Application of thermomechanical energy during extrusion promotes physical-chemical and nutritional changes in the ingredients in an efficient and relatively low cost. Moreover, it can also promote undesirable effects, including the destruction of vitamins, lipid oxidation, destruction and reduction in the availability of protein and amino acids, especially lysine. The author was not able to found scientific literature on the implication of the raw material particle size and extruder configuration on kibble formation and the nutritional aspects of extruded foods for cats. Taken these considerations, this study aimed to evaluate the implications of two raw particle size and changes in extruder configuration on the extrusion traits, kibbles, starch gelatinization (SG) degree and digestibility of cat food formulation. It was conducted two experiments. The first evaluated the effect of raw material particle size and extruder open area (Eoa) on the processing parameters, SG, in vitro digestibility of organic matter, kibble macrostructure, in vivo nutrient digestibility (IVND) and content of lysine. The experiment followed a factorial 6 x 2 (6 Eoa and 2 raw particle size), totaling 12 treatments. A diet was formulated for adult cats and ground in a hammer mill in two sieve openings (0.5 and 1.2) which generated mean geometric diameter of raw material (MGD) of 195 and 254 μm respectively. The material was extruded with these Eoa target: 59, 118, 177, 236, 294, 353 mm2/ton/h. All other software parameters and extruder hardware have not changed. The IVND was conducted by the method of total collection of feces, in the diets of 195 μm and 59 mm2/ton/h, 195 μm and 353 mm2/ton/h, 254 μm and 59 mm2/ton/h, 254 μm and 353 mm2/ton/h, using 6 cats per diet. The results of total, linked and reactive lysine were measured at 5 treatments: raw material and four treatments chosen for IVND. Data were submitted to analysis of variance considering the MGD and Eoa effects and their interactions, and means were compared by polynomial contrasts (P <0.05). The digestibility interaction was considered significant when P<0.15. Lysine results were compared by the Dunnett test (P<0.05) and raw material was considered as the reference. Regarding the process parameters interaction between MGD and Eoa were observed in die pressure and temperature of the last extruder jacket, and the lowest values were observed in the diets with 195 μm MGD. Flash off values were similar between MGD and decreases linearly with increasing Eoa. Specific mechanical energy (SME) and specific thermal energy (STE) were influenced by the interaction. In both MGD there was a reduction in quadratic SME, and STE increased with increasing Eoa. All macrostructure parameters of kibbles were influenced by interaction. Diets with larger MGD presented higher bulk and piece density, specific length and less radial expansion rate. The SG and in vitro digestibility of organic matter were not affected by Eoa, only by MGD. For digestibility a significant interaction (P<0.15) between MGD and Eoa was observed on crude protein and dry and organic matter. The lower results were seen in the smaller MGD and more restricted area (195 μm and 59 mm2/ton/h). There was increase in total and reactive lysine in all extruded diets, but not on lysine linked. The combined effect of DGM and Eoa strongly influence the process parameters, the transference of SME and kibbles traits. The second experiment evaluated the effect of different extruder configuration on the processing parameters, SG, in vitro digestibility of organic matter, kibble macrostructure, and IVND of extruded cat foods. The experiment followed a 4 x 2 factorial arrangements of treatments, with 4 Eoa and 2 restrictions after extruder screw (RASc), a total of 8 treatments. A single food was formulated for cat maintenance, and processed in a single screen extruder with a combination of 60% or 90% RASc, and 4 Eoa target: 59, 118, 236, 353 mm2/ton/h. All other extruder software and hardware parameters was unchanged during the study. IVND was measured by the total collection of feces method on the diets processed with 90% RASc and 353 mm2/ton/h, and 60% RASc and 59 mm2/ton/h, using 6 cats per diet. Data were submitted to analysis of variance considering RASc and Eoa effects, as well their interactions. Means were compared by polynomial contrasts (P < 0.05). For motor amperage was verified an interaction between RASc and Eoa, with greater means for the 90% RASc diets and a reduction with increase Eoa. In barrel moisture was similar among treatments. Die pressure did not change according to RASc, only Eoa, it decreased. Flash off was different only in diets with 90% of RASc and decreased with the increase Eoa. There was a reduction in mean temperatures of forth extruder jacket with increase Eoa. SME application did not suffer influence of the interaction between RASc and Eoa, but was higher for 90% RASc diets. STE was similar among treatments. Total specific energy application was similar for all Eoa on 60% RASc, but decreased with the increase on Eoa for 90% RASc. A significant effect of Eoa was observed for all analyzed kibble traits. There was an interaction for bulk and piece density and both item showed an increase with increase on Eoa. Higher expansion were verified for 90% RASc diets. SG and in vitro digestibility were not influenced by the interaction of RASc and EOA. In vitro digestibility changed according to Eoa, but IVND was similar (P> 0.05) between treatments and did not suffer influence of bulk density. RARs and Eoa have a strong impact on the process parameters, transference of SME and kibble traits.
Descrição
Palavras-chave
Gato, Extrusão, Moagem, Configuração da extrusão, Cat, Extrusion, Grind, Extruder configuration