Studies on Amino Acid Contents of Processed Soybean

The influence of heat treatment on defatted soybean flour was studied. The eighteen kinds of amino acids were determined by microbiological assay method.

The heat destruction of the amino acids was found to occur when defatted soybean flour was autoclaved. At 0 Kg/cm² (100°C) for one, two, and four hours, no remarkable destruction was observed on the amino acids. On the other hand, cystine, lysine and arginine were destroyed under following heat conditions at 0.35 Kg/cm² (108°C), 0.7 Kg/cm² (115°C)and 1.4 Kg/cm² (126°C). Especially, heating at 1.4Kg/cm² (126°C) for four hours, a large amount of cystine, lysine and arginine and a small amount of tryptophan and serine were destroyed, but all other amino acids were not destroyed by any heat treatment.

The different types of heat destruction of cystine, lysine and arginine were observed when defatted soybean flour was autoclaved under the systematically specified heating conditions.

The influences of the added water, the period of heating and the temperature on destruction of amino acids of defatted soybean flour were studied. The eighteen amino acids available to the microbiological assay using lactic acid bacteria were assayed with respect to those products treated under different heating conditions in the presence of water 3 and 6 times the weight of the soybean flour, and in the absence of water under the pressure of 0.7 Kg/cm² (115°C) and 1.4 Kg/cm² (126°C) for various heating periods.

Amino acids except for lysine, arginine, cystine, tryptophan and serine were not destroyed in any heat treatment examined. The destruction of lysine and arginine was mainly due to the conditions of the amount of the added water, and those of cystine, tryptophan and serine were chiefly due to the period and the temperature of heat treatment.     

Liver Nonprotein Sulfhydryl and Taurine Concentrations,and Fat Content of Rats Fed a Low Protein Diet Supplemented with Sulfur-containing Amino Acids

The relative excess of some catabolites of sulfur-containing amino acids in the liver of rats fed a low protein diet might be one of the factors which cause the liver fat accumulation. To investigate the possibility were studied relationships between changes in concentrations of some metabolites of sulfur-containing amino acids and those in fat contents of rats fed a low protein diet consisting of heated soybean flour, casein or wheat flour with or without added methionine, threonine or lysine. The addition of 0.6% methionine to the 25% heated soybean flour diet increased the nonprotein-sulfhydryl (NP–SH) concentration and fat content in the liver. These changes were prevented by the further addition of 0.5% threonine to the diet, although the NP–SH concentration was remarkably higher than that of rats fed the unsupplemented diet. The addition of 0.6% cystine HC1 to the 25% heated soybean flour diet containing sufficient choline elevated the NP–SH concentration and fat content in the liver, which were not affected by the further addition of 0.5% threonine. The addition of 0.6% cystine HC1 to the 10% casein diet significantly increased the fat content, and NP–SH and taurine concentrations in the liver. The further addition of 0.5 % threonine completely decreased the fat content, and partially reduced the NP–SH and taurine concentrations. Effects of supplementation of 0.4% lysine HC1 to the 70% wheat flour diet on the fat content and NP–SH concentration in the liver demonstrated the trends similar to those of supplementation of cystine to the 10% casein diet. The further addition of threonine remarkably decreased the fat content, NP–SH and taurine concentrations in the liver.     

Studies on Amino Acid Contents of Processed Soybean

The influence of sugars on the heat destruction of the basic and sulphur containing amino acids of soybean products, soybean protein and also pure amino acids has been investigated.

Amino acids were estimated by microbiological assay procedure. Cystine was also determined chromatographically.

Lysine, arginine and histidine were destroyed in different ways behaved when soybean products, soybean protein or pure amino acids mixed with and without sugars were autoclaved; and the condition of added sugars tended to influence the way of destruction.

Cystine was the most heat-labile amino acid. But the destruction did not appear to be ascribed to added sugars except 50% ethyl alcohol-soluble sugar solution of defatted soybean flour. This finding was also substantiated by the chromatographic analysis.

Methionine, in soybean products and soybean protein or as pure amino acid with and without the addition of sugars, was not influenced by autoclaving.     

Effect of extrusion on trypsin inhibitor activity and nutrient digestibility of diets based on fish meal, soybean meal and white flakes

The effects of moist extrusion processing of diets containing fish meal (FM) and conventional defatted soybean meal (SBM) or untoasted defatted soybean meal (white flakes [WF]) on amino acid composition, trypsin inhibitor activity (TIA), and apparent total tract digestibility of nutrients were studied. Three diets with the nutritional characteristics of feeds for salmonid fish were formulated: one control based on FM as protein source and two others where 40% of total amino acids from FM were substituted by either SBM or WF. Each diet was fed to mink either as an unextruded mixture of the ingredients or as extruded pellets in order to determine the effect of extrusion processing. Extrusion did not change the amino acid composition of the diets significantly, but reduced the TIA of both diets containing soy products by approximately 76%. Intake of the unextruded WF diet was only one-third compared with the other diets. The dry matter concentration in faeces from mink fed diets containing soy products was significantly lower than in mink fed the FM diet. Digestibility of crude protein, all amino acids and fat was lower, but starch higher, in the unextruded WF diet than in the FM and SBM diets, whereas no significant differences were found among the extruded diets. Extrusion of the WF diet increased digestibility of protein and all amino acids. The greatest increase in digestibility after extrusion of the WF diet was observed for cysteine followed by tryptophan. Extrusion of the FM and SBM diets had no significant effect on amino acid digestibility. Digestibility of starch was, in general, increased by extrusion. It is concluded that the heat treatment involved in typical moist extrusion processing used for fish feed may be sufficient to inactivate most of the TIA in unheated soybean meal, and to increase digestibility of the protein in WF to approximately the same level as found for SBM and FM. Still, extrusion is a lenient process with minor effects on nutrient digestibility of diets containing fish meal or toasted soybean meal as major protein sources.     

Effect of extrusion on trypsin inhibitor activity and nutrient digestibility of diets based on fish meal,soybean meal and white flakes

Abstract

The effects of moist extrusion processing of diets containing fish meal (FM) and conventional defatted soybean meal (SBM) or untoasted defatted soybean meal (white flakes [WF]) on amino acid composition, trypsin inhibitor activity (TIA), and apparent total tract digestibility of nutrients were studied. Three diets with the nutritional characteristics of feeds for salmonid fish were formulated: one control based on FM as protein source and two others where 40% of total amino acids from FM were substituted by either SBM or WF. Each diet was fed to mink either as an unextruded mixture of the ingredients or as extruded pellets in order to determine the effect of extrusion processing. Extrusion did not change the amino acid composition of the diets significantly, but reduced the TIA of both diets containing soy products by approximately 76%. Intake of the unextruded WF diet was only one-third compared with the other diets. The dry matter concentration in faeces from mink fed diets containing soy products was significantly lower than in mink fed the FM diet. Digestibility of crude protein, all amino acids and fat was lower, but starch higher, in the unextruded WF diet than in the FM and SBM diets, whereas no significant differences were found among the extruded diets. Extrusion of the WF diet increased digestibility of protein and all amino acids. The greatest increase in digestibility after extrusion of the WF diet was observed for cysteine followed by tryptophan. Extrusion of the FM and SBM diets had no significant effect on amino acid digestibility. Digestibility of starch was, in general, increased by extrusion. It is concluded that the heat treatment involved in typical moist extrusion processing used for fish feed may be sufficient to inactivate most of the TIA in unheated soybean meal, and to increase digestibility of the protein in WF to approximately the same level as found for SBM and FM. Still, extrusion is a lenient process with minor effects on nutrient digestibility of diets containing fish meal or toasted soybean meal as major protein sources.     

Sulphur amino acid requirement of juvenile Asian sea bass Lates calcarifer

The dietary requirement of juvenile Asian sea bass Lates calcarifer Bloch for total sulphur amino acids was studied. Fish (average initial weight of 2.59 ± 0.08 g) were reared in twelve 500 L fibreglass tanks provided with flow-through seawater at 26°C and salinity of 31 p.p.t. for 12 weeks. They were fed semi-purified test diets containing 6.2, 7.2, 8.1, 9.0, 10.8, or 12.6 g methionine kg⁻¹ dry diet and a basal level of 3.1 g cystine kg⁻¹ dry diet. The mean crude protein of the diets (containing defatted Peruvian fishmeal, squid meal, soybean meal, and free amino acid mixture to simulate the pattern of hydrolysed sea bass protein) was 46.02%. The crude fat content of the diets was 10.51% from a 1 : 1 mixture of cod liver oil and soybean oil. Survival was 100% in all treatments. On the basis of the growth response, the total sulphur amino acid requirement of juvenile Asian sea bass was estimated to be 13.4 g kg⁻¹ dry diet (2.9% of protein). Fish fed low levels of l -methionine had significantly lower weight gains and feed efficiency ratios as well as slightly higher hepatosomatic indices. No nutritional deficiency signs were observed other than growth depression in fish fed on diets that were low in methionine. This information is valuable in further refinement of formulations of practical diets for the Asian sea bass.     

The disappearance of dry matter,nitrogen and amino acids in the gastrointestinal tract from Calliandra leaves

The total tract disappearance of dry matter (DM), nitrogen and amino acids in different Calliandra leaves harvested from Kenya and Zimbabwe were measured using the mobile bag technique. In the mobile bag measurements, disappearance was measured in the rumen in sacco, by pepsin–HCl hydrolysis in vitro and in the intestine. The hydrolysis in the pepsin–HCl solution was designed to mimic digestion in the abomasum. The total tract disappearance of DM, nitrogen, and amino acids were generally low. The highest total apparent DM, nitrogen and total amino acid disappearance obtained were 425 (g/kg), 458 (g/kg total nitrogen), and 593 (g/kg amino acid), respectively. There were differences between the leaves in the disappearance of DM, nitrogen and amino acids, and in the proportion of nutrients lost in the rumen, after pepsin–HCl hydrolysis and in the intestine. More DM, nitrogen, and amino acids in the leaves from Kenya disappeared in the intestine in comparison to the disappearance in leaves from Zimbabwe. The reasons for the differences between the nutritive values of the leaves is unclear but appears to be strongly influenced by the stage of growth and conditions in which the plants were grown.     

Effect of various kinds of dietary protein and supplementation with limiting amino acids on growth,haemolymph components and uric acid excretion in the silkworm, Bombyx mori

Effects of various kinds of dietary protein on growth of the silkworm, Bombyx mori, were determined using semi-synthetic diets. Also, the ingestion, digestion and utilization of dry matter and of nitrogen were measured. Nutritive effects of dietary proteins and supplementation of limiting amino acids on haemolymph protein and amino acids pattern were also investigated. Larval growth was largely dependent on the dietary proteins. When the larvae were reared on a diet containing weakly nutritive proteins such as gluten and zein, haemolymph protein was decreased and uric acid excretion was markedly accelerated. The free amino acid composition of the haemolymph manifested characteristic patterns according to the kinds of dietary protein.The supplementation of gluten and zein with their limiting amino acids resulted in a rise of haemolymph protein and a drop in uric acid excretion. The amino acid patterns in the haemolymph were greatly changed according to supplementation.     

近红外光谱技术快速预测大豆氨基酸

为探索近红外光谱技术在大豆氨基酸测试中的应用,寻找一种快速的检测方法,以167份大豆[Glycine max(L.)Merr.]种子为材料,采用傅里叶变换近红外光谱技术(FT-NIRS)对经高效液相色谱法(HPLC)分析的18种氨基酸含量进行模拟。结果显示:天冬氨酸(R2CV=0.85)、谷氨酸(R2CV=0.86)、丝氨酸(R2CV=0.82)、甘氨酸(R2CV=0.89)、酪氨酸(R2CV=0.83)、苯丙氨酸(R2CV=0.78)、异亮氨酸(R2CV=0.86)和色氨酸(R2CV=0.81)及15种氨基酸总和(R2CV=0.82)可利用FT-NIRS准确预测;苏氨酸、精氨酸、丙氨酸、缬氨酸、亮氨酸和胱氨酸检测模型有一定的参考价值,可用来进行相对含量的估测;而对组氨酸、赖氨酸、脯氨酸和蛋氨酸的预测不准确。本研究进一步证明,利用FT-NIRS技术预测大豆主要氨基酸组分是稳定可行的。     

Studies on Rice Glutelin

The complete amino acid analysis of the whole glutelin preparation from rice endosperm was performed. The recoveries were 101.59% for amino acid residues and 101.68% for nitrogen, and the standard deviations for four determinations on the 22 and 70 hr hydrolyzates were very small. The features of the amino acid composition of the protein were as follows; (1) the high contents of dicarboxylic amino acids, particularly glutamic acid, (2) about 60% of these dicarboxylic amino acids was in the amide form, and (3) the significantly low contents of tryptophan, methionine and half cystine. The amino acid analyses of the two kinds of the subunits of glutelin, the neutral major one and the basic minor one, were also carried out. There were some significant differences between the two subunits, for instance, in the contents of glutamic acid, tryptophan, glycine, half cystine, methionine and lysine. However, the composition of whole glutelin seemed to be settled predominantly by that of the major subunit.     

Hydrolysis of Soybean Proteins with Kamchatka Crab Hepatopancreas Enzyme Complex

To perform hydrolysis with the enzyme complex from the hepatopancreas of the Kamchatka crab, a protein mixture was isolated from soybean meal by extraction at alkaline pH values. Extractable low-molecular impurities were removed by ultrafiltration and precipitation of proteins with alcohol. The amino acid composition of the obtained protein extract turned out to be similar to the composition of the fish meal traditionally used in the production of fish feeds. Analysis of the products of fermentolysis by DDS-electrophoresis, HPLC, and mass spectrometry showed a high degree of hydrolysis of soybean proteins. Depending on the time of fermentolysis, the hydrolysates contained up to 60% (18 h of hydrolysis) of free amino acids (the fraction of the weight of the hydrolyzed protein mixture) and short peptides (2–20 amino acid residues).     

Isolation and Characterization of a Proteolipid in Defatted Soybean Meals

A proteolipid was isolated from the chloroform–methanol (2:1, by vol.) extract of defatted soybean meals by a modified Folch method. The proteolipid gave a yield of 0.05% of the defatted meals, and the ratio of protein and lipid was neary 3:4. The complex gave a single band containing both protein and lipid on polyacrylamide gel electrophoresis. TLC analysis of the lipid moiety showed that the major components were glycolipids and phospholipids. The protein moiety contained more hydrophobic amino acids and less acidic amino acids in comparison with the amino acid composition of soybean globulin. The protein moiety contained two kinds of protein component (I and II) which have molecular weights of 13,000 (I) and 15,000 (II) on SDS-urea polyacrylamide gel electrophoresis, and N-terminal amino acids of alanine (I) and glutamic acid (II). The apoprotein is a new protein and different from the whey proteins or globulins of soybean.     

Amino acid analysis: determination of cysteine plus half-cystine in proteins after hydrochloric acid hydrolysis with a disulfide compound as additive

All cysteine and cystine in a protein are derivatized during hydrolysis in hydrochloric acid containing 3,3'-dithiodipropionic acid. The resulting derivative can be separated from other amino acids and used for quantitation of cysteine plus half-cystine. A procedure is presented for accurate determination by ion exchange chromatography and postcolumn derivatization of all amino acids from acid hydrolysis of a protein, including the Cys-derivative.     

The importance of dietary amino acids on the reproduction and longevity of adult Dacus oleae (Gmelin) (Diptera Tephritidae)

When the amino-acid mixture of an effective chemically defined diet was replaced by single amino acids, keeping the total nitrogen at the same level, the egg production of Dacus oleae was minimal with all the 19 amino acids tested. Male survival was adversely affected by the amino acids : alanine, aspartic acid, glutamic acid, glycine, hydroxyproline, lysine, serine and tyrosine, while female survival was shortened when the amino acids : glycine, hydroxyproline and lysine were added. The creation of amino-acid imbalances, by deleting the 19 amino acids individually, from the complete amino-acid mixture, showed that the amino acids : arginine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, serine, threonine, tryptophane and valine were indispensable to the adult Dacus oleae flies, as far as egg production is concerned. Survival of the male flies was significantly shortened when the amino acids : alanine, hydroxyproline and tryptophane were omitted. Significant differences in longevity between males and females were scored, when the amino acids : alanine, aspartic acid, cystine, glycine and tryptophane, were omitted.     

Studies on Flavor Components in Soybean

Aliphatic carbonyl compounds in soybean were studied. Volatile carbonyl compounds in defatted soybean flour were identified as methanal, ethanal, n-hexanal, 2-propanone, 2- pentanone, 2-heptanone, 2-heptenal, and 2,4-decadienal, while those in raw soybean as ethanal, n-hexanal, and 2-propanone. Four kinds of non-volatile carbonyl compounds were found in defatted soybean, two of which seemed to be carbonyl ester and carbonylic acid. It is probable that the compounds in defatted soybean are mostly the secondary products derived from autoxidation of the residual fatty acids and esters in the defatting process and/or during the storage thereafter. n-Hexanal in raw soybean amounts to approximately 10 p.p.m., which is, owing to its extremely low flavoring threshold, likely to be one of the main components of the green bean flavor.     

The utilization of nitrogen for growth in mice fed blends of purified proteins

Reasons for differences in growth of weanling mice fed different blends of purified proteins in diets apparently adequate in indispensable amino acids were investigated. Dietary nitrogen provided at increasing levels from a mixture of casein, gelatin, and zein, or from these plus gliadin and lactalbumin resulted in similar weight gains and efficiency of feed utilization in weanling mice. These responses were always lower (P less than 0.05) than for mice fed the control diet. When diets were based on true digestible nitrogen and amino acids, weight gains and feed efficiency decreased (P less than 0.05) as the dietary nitrogen level increased. High plasma glycine concentrations and high phenylalanine to tyrosine ratios were associated with high dietary glycine levels provided by gelatin. When a mixture of constant proportions of protein sources, predominantly casein, supplied most of the dietary nitrogen, small increases in weight gains and feed efficiency were observed as the nitrogen level in the diet increased. Varying the proportions of sources, which increased the percentage of gelatin, resulted in decreased gains in response to more dietary nitrogen. Replacing the amino acids found in gelatin by crystalline L-amino acids and replacing glycine by glutamic acid improved gains and feed efficiency (P less than 0.05) compared with gelatin-containing diets. These studies demonstrated that glycine at dietary concentrations of approximately 1-2%, either from gelatin or as the free amino acid, inhibited growth and feed utilization of growing mice.     

A new double-labelling procedure for determination of amino acid composition: application to bacteriorhodopsin

A new double-labelling procedure for amino acid analysis which requires only routine chromatographic equipment is described. When 1-fluoro-2,4-dinitro[3H]benzene is reacted with a mixture of 14C-labelled amino acids followed by reaction with the same 14C-labelled amino acid mixture diluted with an unlabelled sample of amino acids, the 3H:14C ratio in the resulting 2,4-dinitrophenyl (DNP) amino acid derivatives of the diluted sample will be increased in proportion to the quantity of unlabelled amino acid in the diluted sample. This procedure gave reliable results when applied to the known proteins insulin and lysozyme. The procedure is most advantageous when applied to amino acids which are unstable during acid hydrolysis or present in low molar fractions. When applied to the analysis of the bacteriorhodopsin in Halobacterium cutirubrum, this procedure showed the presence of one histidine residue and four tryptophan residues per mole protein but no cystine or cysteine; in general, the analyses obtained were consistent with those originally reported by Oesterhelt, D. and Stoeckenius, W. (1971) (Nature (London) New Biol. 233, 149-152) for bacteriorhodopsin of H. halobium.     

Effects of ingestion of thermally oxidized edible oils on plasma lipids, lipoproteins and postheparin lipolytic activity of rats

Acute (after 4 hr) and short-term (after 7 days) effects of ingesting heated and unheated groundnut, coconut and safflower oils on plasma lipids, lipoproteins and postheparin lipopolytic activity (PHLA) were studied in rats. All heated oils were characterized by increases in carbonyl value, peroxide value and free fatty acid (FFA) content, except heated coconut oil which showed a decrease in FFA content. Heating procedure also did not alter to an appreciable extent their fatty acid compositions. Acute and short-term effects of feeding heated and unheated oils showed no significant differences in rat plasma levels of total cholesterol (TC), total triglycerides, total phospholipids, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol + very-low-density lipoprotein cholesterol, TC/HDL-C ratio and PHLA. Inspite of certain changes in some of the indices of thermal alteration of these heated oils, consumption of such heated oils by rats did not have any significant effect on various plasma parameters in these animals.     

An inexpensive medium for production of arachidonic acid by <Emphasis Type="Italic">Mortierella alpina</Emphasis>

The production of arachidonic acid was studied in the fungus Mortierella alpina using an inexpensive medium. Glucose derived from maize starch hydrolysate was the sole carbon source and defatted soybean meal and sodium nitrate were the nitrogen sources. Optimal arachidonic acid yield (1.47 g l^-1) was observed at a glucose concentration of 100 g l^-1. Various treatments of defatted soybean meal to extract soluble nitrogen nutrients were evaluated. Alkali extract was the most effective for arachidonic acid production. A mixture of soybean alkali-extract protein and sodium nitrate was an excellent nitrogen source for fungal growth, lipid accumulation, and arachidonic acid production. A maximum yield of 1.87 g arachidonic acid l^-1 was obtained with a soybean protein concentration of 4.6 g l^-1 and a sodium nitrate concentration of 2.3 g l^-1. Electronic Publication     

Reaction of β-propiolactone with amino acids and its specificity for methionine

1. The reactions of beta-propiolactone with amino acids were investigated under various conditions of pH and temperature to find those under which the reagent acted with specificity. 2. At pH9.0 and 22 degrees , after 15min. of reaction, at least 85% of each amino acid had reacted, methionine and cystine being the most reactive. 3. At pH7.0 and 22 degrees most amino acids reacted; methionine, cystine and histidine reacted almost entirely, and proline and lysine to a significantly smaller extent. 4. At pH3.0 and 22 degrees further specificity was obtained; methionine and cystine were the only reactive amino acids. 5. Reaction at pH3.0 and 0 degrees was specific for methionine; it was the only amino acid modified even after 145hr. of reaction.