Estimative of the nutritional value of agroindustrial byproducts by using in vitro gas production technique Estimativa do valor nutricional de subprodutos agroindustriais pelo uso da técnica de produ o de gás

The objective of this work was to determine the total carbohydrates fractions and to estimate the digestion rate of non-fibrous carbohydrates of agroindustrial byproducts by using the gas production technique. The agroindustrial byproducts evaluated were the following: cashew, passion fruit, pineapple, barbados cherry, annatto and melon, and each sample was incubated in quadruplicate. After mixing all contents thoroughly, the bottles were placed in an incubator at 39oC, and connecting the lid of each bottle to a pressure sensitive switch, a solenoid valve and a vent stem connector. Gas pressure measurements were made at 0, 3, 6, 12, 15, 18, 22, 26, 30, 34, 40, 48, 60, 72, 96 e 120 hours post-inoculation. Blanks and an internal standard were included to enable adjustments in variation among readings. There was a high variation in nutritional composition of agroindustry byproducts, that cashew and annato presented the highest protein contents (159.3 and 135.3 g/kg of dry matter, respectively). Mellon and cashew presented the lowest values of total gas production (9.60 and 12.85 mL, respectively); and annato, pineapple and passion fruit presented highest gas volume (32.80; 28.16 and 22.54 mL, respectively), being the greatest percentages of phases from B2 fraction (64.27; 81.25 and 67.49%, respectively). Among the byproducts, pineapple and annatto stand out for the highest contribution of fibrous carbohydrate for total gas production, being B2 the main energy source for microbial growth, which is degraded at a slower rate than non-fibrous carbohydrate. Os objetivos deste trabalho foram determinar as fra es de carboidratos totais e estimar a taxa de digest o dos carboidratos n o-fibrosos de subprodutos agroindustriais, utilizando a técnica de produ o de gás. Os subprodutos agroindustriais avaliados foram: caju, maracujá, abacaxi, acerola, urucum e mel o, sendo cada amostra incubada em quadriplicata. Após mistura minuciosa de todos os conteúdos, as garrafas foram colocadas em estufa a 39oC e foram conectadas a um interruptor sensível à press o, com uma válvula solenóide e uma haste de ventila o. As medi es de press o do gás foram feitas a 0, 3, 6, 12, 15, 18, 22, 26, 30, 34, 40, 48, 60, 72, 96 e 120 horas após a incuba o. Espa os em branco e um padr o interno foram incluídos para permitir ajustes na varia o entre as leituras. Houve grande varia o na composi o nutricional dos subprodutos agroindustriais, sendo que caju e urucum apresentaram os maiores teores de proteína (159.3 e 135.3 g/kg de matéria seca, respectivamente). Mel o e caju apresentaram o