J. Agric. Food Chem. 2004, 52, 6193−6199 6193 Chemical Composition and Protein Quality Comparisons of Soybeans and Soybean Meals from Five Leading Soybean-Producing Countries LISA K. KARR-LILIENTHAL,† CHRISTINE M. GRIESHOP,† NEAL R. MERCHEN,† DONALD C. MAHAN,‡ AND GEORGE C. FAHEY,JR.*,† Department of Animal Sciences, University of Illinois, Urbana, Illinois 61801, and Department of Animal Sciences, The Ohio State University, Columbus, Ohio 43210 Soybeans (SBs) were obtained from five leading SB-producing countries (Argentina, Brazil, China, India, and the United States), imported to the United States, and processed into soybean meal (SBM) under uniform conditions in the United States. SBs from China had the highest crude protein (CP) content while SBs and the resultant SBM from Argentina had the lowest. Additional differences in the quality of the SB and resultant SBM samples collected were noted. An additional set of SBM produced in these five countries and subjectively evaluated to be of low, intermediate, and high quality also were obtained and evaluated. Overall, SBM quality affected amino acid and mineral concentrations with differences existing both among and within countries. SBM produced in the United States had a higher CP content than SBM produced in other countries. Amino acid concentrations generally increased, and antinutritional factors decreased with increasing subjective quality assessment. KEYWORDS: International; soybeans; soybean meals; protein quality INTRODUCTION Overprocessing of SBM results in a portion of the lysine being rendered unavailable for poultry and swine because of the Soybean meal (SBM) accounts for approximately 62% of the Maillard reaction (4). proteinaceous ingredients used in diets of all food-producing On the basis of increased global competition and variation animals and is the primary protein source used in swine diets in processing methodologies being employed, it is important to worldwide (1). In 2001, the world soybean (SB) crop was valued determine if differences in SBM quality occur both among and at $12.3 billion, with about 42% of the world’s crop being raised within countries. The objective of this research was to determine in the United States (1). SB production in other countries has the compositional and quality differences among select SB and increased in recent years. After the United States, Brazil had SBM samples from five different geographic regions of the the next highest SB production (24% of the world’s crop), world. followed by Argentina (16%), China (8%), and India (3%; 1). Even though the United States is the leading SB producer, it is third in SBM export, contributing 16% toward the world’s MATERIALS AND METHODS supply, behind Argentina (35%) and Brazil (25%; 1). Sources of SBs and SBMs. One 450 kg sample of whole SB was Because of differences in environmental conditions, genetic collected from each of five countries (Argentina, Brazil, China, India, varieties, and processing conditions, SBM chemical composition and the United States) by an American Soybean Association representa- differs among geographic regions and affects the nutritional tive within each country. One sample of high quality SBs was obtained value of these meals (2, 3). SB processing conditions, such as from each country, but both a low and a high quality SB sample were moisture, drying time, and toasting or drying temperature, can obtained from India. The low quality SB was produced in a year with contribute to the differences observed in SBM quality. Over- higher than normal rainfall and was potentially exposed to flooding. These SBs were processed into SBM within the United States under and underprocessing due to improper heating conditions can standardized processing conditions at the TexasA&MUniversity pilot result in the production of poor quality SBM. If SBM is processing plant. Initially, the SBs were cracked using the Ferrel Ross underprocessed, high concentrations of antinutritional factors Cracking Rolls (Ferrel Ross, Oklahoma City, OK) with a gap setting such as trypsin inhibitors and saponins remain and potentially of 0.13 cm. Then, the cracked SBs were dehulled using the Kice decrease the quality of SBM, particularly for nonruminants (4). Aspirator (Kice Industries, Wichita, KS), whereupon they were screened (Smico Vibratory screener, Simco Manufacturing Co., LLC, Oklahoma City, OK) to remove whole beans and large hull particles. After this, * To whom correspondence should be addressed. Tel: 217-333-2361. - ° Fax: 217-244-3169. E-mail: [email protected]. the SBs were heated to 65.6 76.7 C in a French stack cooker and † University of Illinois. flaked using Bauer flaking rolls. Then, the flakes were extracted using ‡ The Ohio State University. a Crown model 2 extractor using hexane as the solvent at ambient 10.1021/jf049795+ CCC: $27.50 © 2004 American Chemical Society Published on Web 09/14/2004 6194 J. Agric. Food Chem., Vol. 52, No. 20, 2004 Karr-Lilienthal et al. temperature. Next, the hexane solvent was removed and toasting was Table 1. Chemical Composition of an Individual Sample of SBs from completed in the Crown desolventizer/toaster (DT; Crown Iron Works Five Geographic Locations Co., Minneapolis, MN) that contained three different trays (top, middle, and bottom), which were at the same bed depth for each SB. Efforts SB source were made to maintain similar temperatures across batches in the Crown Indiaa DT. United item Argentina Brazil China low high States In addition to the SB samples described above, an additional set of three different samples of at least 250 kg of SBM from the same five DM (%) 91.0 90.5 90.6 93.2 91.9 90.1 countries were collected by an American Soybean Association repre- %, DM basis sentative located in that country who subjectively evaluated the SBM OM 94.4 95.1 93.8 94.5 94.8 94.9 to be of high, intermediate, or low quality. Indicators used to determine CP 32.6 39.3 44.9 37.5 39.6 37.1 quality included SBM color, protein content, and (or) processor history. acid-hydrolyzed fat 14.1 13.6 12.9 13.1 12.8 15.1 No data were available on processing conditions used to prepare the NDF 23.3 22.6 23.4 24.9 22.4 22.4 meals or the genetic varieties of the SB sources. As a control, a high essential amino acids quality SBM obtained from a U.S. processor was purchased on the arginine 2.24 2.82 3.42 2.64 2.88 2.79 open market and used as a standard for comparison with the other histidine 0.90 1.05 1.19 1.03 1.08 1.03 SBMs. isoleucine 1.51 1.66 2.06 1.68 1.84 1.80 leucine 2.47 3.04 3.41 2.80 3.09 2.94 Laboratory Analysis. Prior to analysis, all SBs and SBMs were lysine 2.07 2.41 2.69 2.38 2.48 2.37 ground througha2mmscreen using a Wiley Mill, model 4 (Thomas- methionine 0.48 0.54 0.64 0.54 0.54 0.53 Wiley, Swedesboro, NJ). Whole SBs were ground with dry ice to avoid phenylalanine 1.63 2.08 2.33 1.91 2.03 1.95 loss of oil. A subsample of SB and SBM was further ground through threonine 1.25 1.48 1.62 1.44 1.47 1.40 a 0.5 mm screen prior to potassium hydroxide (KOH) protein solubility tryptophan 0.55 0.36 0.53 0.58 0.49 0.44 analysis. Samples of SB were stored at -20 °C, and the SBM was valine 1.70 1.80 2.20 1.74 1.98 1.95 stored at room temperature until later analyses. SBs and all SBMs were nonessential amino acids analyzed for dry matter (DM), organic matter (OM; 5), and crude alanine 1.46 1.70 1.90 1.58 1.71 1.64 protein (CP) by the Kjeldahl method (5). SBMs were analyzed for total aspartate 3.44 4.27 5.00 4.13 4.36 4.10 dietary fiber (TDF; 6) while SBs were analyzed for neutral detergent cystine 0.59 0.57 0.72 0.62 0.57 0.63 fiber (NDF; 7). The fat content of the samples was determined by acid glutamate 5.35 6.86 7.86 6.72 7.28 6.64 hydrolysis (8) followed by ether extraction according to Budde (9). glycine 1.48 1.70 1.88 1.55 1.76 1.68 proline 1.31 1.70 1.95 1.72 1.75 1.67 Analysis of amino acid concentrations was conducted at the University serine 1.31 1.75 1.81 1.65 1.75 1.54 of Missouri Experiment Station Chemical Laboratories using a Beckman tyrosine 1.15 1.46 1.56 1.39 1.42 1.35 6300 amino acid analyzer (Beckman Coulter, Inc., Fullerton, CA) TEAA 14.8 17.2 20.1 16.7 17.9 17.2 according to AOAC (5) procedures. The urease activity (10), KOH TNEAA 16.1 20.0 22.7 19.4 20.6 19.3 protein solubility (4), and protein dispersability index (10) were TAA 30.9 37.3 42.8 37.5 38.5 36.5 determined on all SB and SBM samples. The SBM samples were analyzed for mineral content according to AOAC (5) using inductively a Low ) low quality SB; high ) high quality SB. coupled plasma (ICP) spectroscopy (model 137, Applied Research Laboratories, Valencia, CA) at Star Labs [Ohio Agricultural Research data are more robust as multiple samples from individual and Development Center (OARDC), Wooster, OH]. countries were collected and evaluated as compared to the single The particle size was determined on all SBM samples according to sample analysis reported here.