The objective of this study was to determine whether soybeans without the Kunitz trypsin inhibitor and lectins could be fed effectively to young chicks and pigs. Specifically, we compared the growth performance of chicks and pigs fed diets containing modified soybeans: Kunitz trypsin inhibitor-free (KF), lectin-free (LF), lectin and Kunitz trypsin inhibitor-free (LFKF), conventional soybeans (CSB), and commercially obtained, dehulled, solvent-extracted soybean meal (SBM). A 7-d chick experiment was conducted to evaluate the nutritional value of CSB, KF, LF, LFKF, and SBM. The experiment was conducted as a completely randomized design, with four replicates, five treatments, and six male chicks per pen (n = 120). The five treatments consisted of 23% CP dextrose-soybean-based diets containing KF, LF, LFKF, CSB, or SBM as the source of dietary protein. A 28-d pig experiment was conducted to evaluate the nutritional value of CSB, LF, LFKF, and SBM. Pens of four pigs were assigned randomly to a control, corn-SBM, or one of six corn-soybean diets containing raw or extruded soybean varieties as a 2 x 3 factorial arrangement of treatments in a randomized complete block design with five blocks per treatment (n = 140). Chicks fed diets containing any of the raw soybean varieties gained less weight (P < 0.05) than chicks fed SBM (22.81 g/d for SBM vs. 14.17 g/d for the raw soybeans combined). Among the raw soybean treatments, there was a greater effect on growth performance (P < 0.05) by removing both lectins and Kunitz trypsin inhibitor (ADG of 16.56 g for LFKF) than by removing each antinutritional factor separately (ADG of 14.38 and 14.11 g for KF and LF, respectively). Pig growth performance was different (P < 0.001) for SBM (ADG of 409 g) and all the varieties when extruded (ADG of 450 g for CSB, 417 g for LF, and 408 g for LFKF) compared with the raw soybean treatments (ADG of 101 g for CSB, 165 g for LF, and 266 g for LFKF). Among the raw soybean treatments, growth performance improved (P = 0.003) as the antinutritional factor, lectin, was removed from the soybean and improved further (P = 0.045) when both lectins and Kunitz trypsin inhibitor were removed. The growth-inhibiting effect of feeding modified soybeans to young animals was more detrimental for pigs than for chicks in our experiments. Soybeans without the Kunitz trypsin inhibitor and lectins cannot be fed successfully to young chicks and pigs without heating.

Recebido em 17/8/07; aceito em 14/3/08; publicado na web em 26/8/08The moisture sorption isotherms of Chilean papaya were determined at 5, 20, and 45 ºC, over a relative humidity range of 10-95%. The GAB, BET, Oswin, Halsey, Henderson, Smith, Caurie and Iglesias-Chirife models were applied to the sorption experimental data. The goodness of fit of the mathematical models was statistically evaluated by means of the determination coefficient, mean relative percentage deviation, sum square error, root-mean-square error, and chi-square values. The GAB, Oswin and Halsey models were found to be the most suitable for the description of the sorption data. The sorption heats calculated using the Clausius-Clapeyron equation were 57.35 and 59.98 kJ·mol -1 , for adsorption and desorption isotherms, respectively.Keywords: Chilean papaya; sorption isotherms; isosteric heat. INTRODUCTIONThe Chilean papaya, Vasconcellea pubescens, which grows in a temperate climate regime, is a distant relative of the tropical papaya Carica papaya L.1,2 Most of the Chilean papayas come from the (irrigated) region around La Serena, Chile (ca.30 ºS) which has a Mediterranean-type climate, typically overcast mornings and evenings, and an annual relative humidity normally over 80%.3 The Chilean papaya is very different from the tropical papaya in that it is much smaller, and is consumed whole, only after cooking, with the seeds removed. It has an edible yield of 46%, a sugar content of about 5% and is high in papain content. 4 Exogenous sugar is usually added to its commercialized products, since this papaya is commercialized mainly in canned and dried (candied) forms.Water activity within a food is the amount of water available for chemical and biochemical reactions (i.e. lipid oxidation, enzymatic, and Maillard reactions), its participation in microbial development, and as a parameter useful in predicting the shelf life of the product. 5 In addition, water activity (a w ) measured within a product provides a good indicator of its shelf-life. The isotherm of a product, for a constant temperature, relates the equilibrium moisture content to the thermodynamic water activity, since in equilibrium, the latter is equal to the relative humidity of the air around the product. 6 The isotherms are important for the analysis and design of various food transformation processes such as drying, mixing, and storage; and to predict changes in food stability and aid in the selection of suitable packaging materials. 7Various empirical and semi-empirical equations have been proposed to predict the behaviour of sorption isotherms of foods and foodstuffs. The equation proposed by Guggenheim, Anderson and de Boer usually called GAB, is very useful for foods and has been recommended by the European project COST 90. 8 The GAB equation is based on the Brunauer, Emmett and Teller usually called BET adsorption theory, 9 which gives a physical explanation for the parameters of the equation. 10The monolayer moisture content (X m ) for the GAB and BET models is related to f...

The objective of this study was to determine whether soybeans without the Kunitz trypsin inhibitor and lectins could be fed effectively to young chicks and pigs. Specifically, we compared the growth performance of chicks and pigs fed diets containing modified soybeans: Kunitz trypsin inhibitor-free (KF), lectin-free (LF), lectin and Kunitz trypsin inhibitor-free (LFKF), conventional soybeans (CSB), and commercially obtained, dehulled, solvent-extracted soybean meal (SBM). A 7-d chick experiment was conducted to evaluate the nutritional value of CSB, KF, LF, LFKF, and SBM. The experiment was conducted as a completely randomized design, with four replicates, five treatments, and six male chicks per pen (n = 120). The five treatments consisted of 23% CP dextrose-soybean-based diets containing KF, LF, LFKF, CSB, or SBM as the source of dietary protein. A 28-d pig experiment was conducted to evaluate the nutritional value of CSB, LF, LFKF, and SBM. Pens of four pigs were assigned randomly to a control, corn-SBM, or one of six corn-soybean diets containing raw or extruded soybean varieties as a 2 x 3 factorial arrangement of treatments in a randomized complete block design with five blocks per treatment (n = 140). Chicks fed diets containing any of the raw soybean varieties gained less weight (P < 0.05) than chicks fed SBM (22.81 g/d for SBM vs. 14.17 g/d for the raw soybeans combined). Among the raw soybean treatments, there was a greater effect on growth performance (P < 0.05) by removing both lectins and Kunitz trypsin inhibitor (ADG of 16.56 g for LFKF) than by removing each antinutritional factor separately (ADG of 14.38 and 14.11 g for KF and LF, respectively). Pig growth performance was different (P < 0.001) for SBM (ADG of 409 g) and all the varieties when extruded (ADG of 450 g for CSB, 417 g for LF, and 408 g for LFKF) compared with the raw soybean treatments (ADG of 101 g for CSB, 165 g for LF, and 266 g for LFKF). Among the raw soybean treatments, growth performance improved (P = 0.003) as the antinutritional factor, lectin, was removed from the soybean and improved further (P = 0.045) when both lectins and Kunitz trypsin inhibitor were removed. The growth-inhibiting effect of feeding modified soybeans to young animals was more detrimental for pigs than for chicks in our experiments. Soybeans without the Kunitz trypsin inhibitor and lectins cannot be fed successfully to young chicks and pigs without heating.

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