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Effect of alcohol extraction and heat treatment of soybean flakes on protein utilization in growing rats and pigs
Abstract
Seven experiments were conducted to determine the effects of combinations of alcohol extraction and heat treatment versus traditional processing methods (heat treatment only) on the nutritional value of soybean meal. In the first two experiments, defatted raw soyflakes were extracted with a 55% ethanol-water mixture and autoclaved for 5 min. Bioevaluation with weanling rats indicated that laboratory-prepared ethanol extracted soyflakes supported greater rate and(or) efficiency of gain than soyflakes which were autoclaved but not ethanol extracted (P $<$.003) and commercially prepared ethanol extracted soyflakes (P $<$.04). The laboratory-prepared ethanol extracted soyflakes were of similar nutritional value to commercially prepared soybean meal. In a third experiment, rats fed soyflakes extracted with methanol, ethanol and n-propanol gained 14% faster (P $<$.03) and were 10% more efficient (P $<$.002) than rats fed soyflakes extracted with water. Rats fed the soyflakes extracted with methanol, ethanol and n-propanol were similar in rate and efficiency of gain. In Exp. 4, 120 weanling barrows and gilts were used in a growth assay and 30 nursery age barrows were used in a nitrogen metabolism experiment. Ethanol extraction of defatted raw soyflakes improved performance and nitrogen utilization, but the extraction process did not improve the nutritional value of soyflakes autoclaved for 20 min. In two subsequent experiments ethanol extraction improved the protein quality of soyflakes heated from 0 to 40 and 5 to 60 min in rats and pigs, respectively. The positive response to ethanol extraction was most pronounced in underprocessed soyflakes (0 and 5 min autoclaving) and overprocessed soyflakes (40 and 60 min autoclaving). A seventh experiment was conducted to determine if a relationship exists between heat treatment and ethanol extraction of soyflakes, and morphological characteristics of the pig small intestine. Soyflake treatment did not result in changes in size or shape of villi in the duodenum or ileum that would help explain differences in performance of pigs fed the various soyflake preparations. Ethanol extraction prior to heat treatment improves nutrient utilization by reducing trypsin inhibitor activity of underprocessed soyflakes and protecting the protein quality of soyflakes from overprocessing.
Subject Area
Livestock
Recommended Citation
Hancock, Joe Dan, "Effect of alcohol extraction and heat treatment of soybean flakes on protein utilization in growing rats and pigs" (1987). ETD collection for University of Nebraska-Lincoln. AAI8810319.
https://digitalcommons.unl.edu/dissertations/AAI8810319