The nutritive value of soybean oil meal prepared by the different methods of oil extraction

This article is primarily a review of the literature pertaining to the subject. Solvent extracted, hydraulic, and expeller soybean oil meals all contain, if properly cooked, protein of high biological value, similar to that of milk protein. Solvent extracted meal has a higher percentage of protein. Since expeller and hydraulic meals contain more oil than solvent extracted soybean oil meal, they naturally have a slightly higher vitamin A and D potency, but the amounts of these vitamins contained in any type of soybean meal or even in the whole soybean are not significant. Levine’s assays reveal that solvent process soybean oil meal contains roughly 2.8 I.U. of vitamin B per gram of solids compared to 1.0 I.U. for hydraulic meal. According to results of Cornell experiments, the vitamin G content of soybeans is not materially affected by any of the common methods of processing. Kraybill reports that expeller and hydraulic pressed soybean oils contain more “lecithin” (total phospholipins) than hexane extracted soybean oil. Therefore his results indicate that our domestic solvent extracted meal contains slightly more “lecithin” than expeller meal. “Lecithin” in soybean oil meal may be valuable as an antioxidant to stabilize the vitamin A contained in mixed feeds.     

Estimating the processed value of soybeans

Interest in marketing soybeans on the basis of protein and oil content is increasing. Producers, breeders, handlers and buyers of soybeans need a method of evaluating soybean lots of different composition. A model is presented that predicts, given soybean composition and processing conditions, the yield of crude soybean oil and soybean meal from the processing of soybeans in a solvent extraction plant. From these yields, an estimated processed value (EPV) was calculated. For one set of price conditions, the EPV of typical soybeans had a range of $0.93 per bushel if premiums were paid for meal protein in excess of specifications and a range of $0.53 per bushel if meal protein premiums were not paid. Trading rules established by the National Oilseed Processors Association for domestic meal markets have a significant effect on the value and composition of soybean meal.     

The comparative value of heated ground unextracted soybeans and heated dehulled soybean flakes as a source of soybean oil and energy for the chick

Experiments were conducted to evaluate heated unextracted soybean fractions as sources of soybean oil and protein for the growing chick. Heated dehulled unextracted soybean flakes produced growth rate and feed efficiency equal to that obtained with the combination of soybean oil meal and degummed soybean oil while heated ground unextracted soybeans were less satisfactory in this respect. The poorer results obtained with ground unextracted soybeans were shown to be related to a poorer absorbability of the oil in them. Flaking the soybeans markedly improved the absorbability of the oil by the chick, probably by causing a greater disruption of cellular structure than was obtained by the grinding of the soybeans. The metabolizable energy of ground unextracted soybeans was substantially less than that of unextracted soybean flakes. Most of the differences in metabolizable energy were accounted for by differences in absorbability of the oil. Soybean hulls at a level equivalent to that contained in soybeans were found to have no effect on growth rate and only a slight effect on feed efficiency. Autoclaving soybean oil did not lower its value for the chick. The relationship between the poorer growth obtained with ground unextracted soybeans and the low absorbability of the oil in them was discussed. To obtain maximum efficiency in the use of unextracted soybean products in chick rations, some such means as flaking must first be employed to increase the availability of the oil.     

The nutritive value of the Brazil nut oil

The chemical composition of the decorticated Brazil nut in the natural and fat-free state was determined, and the results confirm that this seed contains significant amounts of oil and protein. In three growth experiments carried out in rats, the Brazil nut oil had a nutritive value comparable to that of butterfat and the common table oils, olive oil, cottonseed oil, and corn oil. The use of levels of the Brazil nut oil up to 20% of the diet did not reduce growth or food consumption of rats. Heat treatment of the oil up to 120 min. at 140°C. did not reduce its nutritive value. The coefficient of digestibility of the Brazil nut oil was similar to that of the other oils, fresh and heated. The digestibility of the Brazil nut oil averaged 98% and was not affected by the heat treatment. The data indicate that Brazil nut oil is comparable to other animal and vegetable fats and oils in common use for human consumption. International Cooperation Administration fellow and Research Assistant. INCAP Publication I-150.     

Functional properties of extruded-expelled soybean flours from value-enhanced soybeans

The functional properties (protein solubility, emulsification characteristics, foaming characteristics, water- and fatbinding capacities) of extruded-expelled (EE) soy flours originating from six varieties of value-enhanced soybeans (high-sucrose, high-cysteine, low-linolenic, low-saturated FA, high-oleic, and lipoxygenase-null) and two commodity soybeans were determined. The soy flours varied in protein disperisibility index (PDI) and residual oil (RO), with PDI values ranging from 32 to 50% and RO values ranging from 7.0 to 11.7%. Protein solubility was reduced at pH values near the isoelectric region and was higher at both low and high pH. There were no significant differences for water-holding capacity, fat-binding capacity, emulsification activity, or emulsification stability. Only the high-oleic soy flour had significantly lower emulsification capacity. In general, the PDI and RO values of EE soy flours originating from value-enhanced and commodity soybeans had the greatest influence on protein functionality. The genetic modifications largely did not affect functional properties.     

Quality characterization of several bolognas in Mexico. II. Evaluation of the nutritive value of their proteins

Bologna is the most widely consumed processed meat product in the State of Sonora, Mexico. In the study herein described, the nutritive value of the protein in each brand was evaluated by means of the protein efficiency ratio (PER). Additionally, protein apparent digestibility (Cr2O3) and protein digestibility, both in vivo and in vitro, were determined, as well as apparent digestible energy in the same products. Results revealed significant differences in PER (p less than 0.05) among the commercial bologna brands with respect to ANRC casein. Nevertheless, when tested against the specific contrast, no significant PER differences were detected among the six bologna brands, and the control. Neither was there any difference detected in regard to apparent digestible energy consumption, or protein digestibility in vitro or in vivo.     

Rheological study of dispersions prepared with modified soybean protein isolates

Structural modifications of modified soy protein isolates (SPI) were distinguished by rheological behavior. SPI were prepared by acidic (pH 2.5) and thermal-acidic treatment without (pH 1.6) and with neutralization (pH 8.0). Dynamic properties of dispersions were determined through the variation of storage and loss moduli with frequency, and loss tangent behavior was analyzed. Changes in viscoelastic parameters with protein concentration (10–12% wt/vol) and time of heating (15–60 min) were also determined. Flow properties of dispersions were estimated through apparent viscosity and flow and consistency index measurements. Rheological behavior of dispersions was compared with those found by experiment with commercial mayonnaise, mustard, and salad dressing. The analysis of rheological parameters showed that thermally treated isolates formed dispersions with high elastic modulus and consistency index with a structure mainly stabilized by hydrophobic interactions, although no gelation process after cooling was observed. From the rheological point of view, it was deduced that thermally treated isolates could be used as ingredients in the formulation of salad dressings. The alkaline sample would be more versatile because, depending on protein concentration and thermal treatment, the consistency of its dispersions was like that in salad dressing, or similar to those of mustard and mayonnaise.     

Compositional characteristics of protein ingredients prepared from high-sucrose/low-stachyose soybeans

High-sucrose/low-stachyose (HS/LS) soybeans contained lower total concentrations of free sugars (13.3%), less stachyose (0.7%), and more galactinol (0.7%) (galactopyranosylmyo-inositol) than the control normal soybeans (14.9, 5.1, and 0.2%, respectively). A low-fiber soybean protein concentrate (LFSPC) process was developed, which is especially suited to HS/LS soybeans, by which defatted soy flour is merely extracted with alkali to remove fiber and then neutralized and dried to produce the protein-rich soluble fraction. Two different pH values (7.5 and 8.5) were used in extracting protein, and these LFSPC were compared with traditional ethanol-washed soy protein concentrate (EWSPC) and soy protein isolate (SPI) prepared from both normal and HS/LS soybeans. The LFSPC had slightly lower yields of solids and protein (∼70 and ∼81%, respectively) than conventional FWSPC (∼77 and ∼93%, respectively) but much higher than conventional SPI (∼42 and ∼70%, respectively). The LFSPC prepared from HS/LS soybeans contained significantly (P<0.05) more protein (∼66% protein content) than LFSPC prepared from normal soybeans (∼63%). Total isoflavone contents of the LFSPC (∼12 μmol/g) were significantly higher than for EWSPC (∼1.5 ìmol/g) or SPI (∼10 μmol/g). The LFSPC prepared from HS/LS soybeans contained higher sugar contents (∼15%) than either traditional EWSPC (∼2.5%) or SPI (∼1.5%); but the sums of stachyose and raffinose were only ∼1% for the LFSPC compared with ∼1% for EWSPC and 0.5% for SPI prepared from normal soybeans.     

Functional properties of protein ingredients prepared from high-sucrose/low-stachyose soybeans

High-sucrose/low-stachyose (HS/LS) soybeans were used to prepare ethanol-washed soy protein concentrate (EWSPC), soy protein isolate (SPI), and a new low-fiber soy protein concentrate (LFSPC) in which the protein was extracted with alkali to remove fiber and the protein extract was neutralized and freeze-dired. LFSPC prepared from HS/LS soybeans contained significantly higher ratios of β-conglycinin to glycinin (1∶1.32) than did EWSPC (1∶1.75) or SPI (1∶1.69), which may have affected functional properties. The LFSPC were also high in soluble sugars (14.7%) and low in fiber (0.3%) compared with traditional EWSPC (2.9 and 3.4%, respectively) and SPI (1.8 and 0.3%, respectively). For both normal and HS/LS soybean varieties, the LFSPC, especially when extracted at pH 7.5 as opposed to pH 8.5, had higher denaturation enthalpies than did EWSPC and SPI, indicating less denaturation had occurred. Water solubilities, surface hydrophobicities, and emulsification properties were highest for the LFSPC and lowest for EWSPC. The LFSPC also had good foaming properties and low viscosities. These desirable functional properties of the LFSPC make them unique among alternative soy protein ingredients and highly suitable for industrial applications as food additives and ingredients.     

A bibliography on the solvent extraction of soybeans and soybean products 1944–1968

This bibiliography covers the effect of several solvents on oil removal, toxicity, color, texture or flavor of soybean flakes, flour and protein. The literature search included processes, principles and apparatus.     

A comparative study of the nutritive value of thermally oxidized oils

Summary Thermal oxidation of corn oil under laboratory conditions, at 200°C., led to the formation of an oil exhibiting definite growth-depressing action under bothad libitum and paired feeding conditions. Under similar conditions margarine base stock gave only slight growth depression, and none was noted with butter oil. The effect was not a permanent one as animals that were changed to a normal diet quickly recovered and grew to maturity. It appeared that the products formed during the thermal treatment were related to the unsaturated or polyunsaturated portions of the oil. The growth-depressing effect appeared to be multiple in nature, it had an irritant or diarrhea effect and possibly an enzyme-inhibiting or vitamin-destroying effect. Funds for partial support of these studies were made available by the American Dairy Association and research grant No. C-1932 from the National Institute of Health, Public Health Service.     

Effect of lactose on the evaluation of the nutritive value of casein

The biological evaluation of protein from dairy products such as normal and modified powdered milks where lactose is present, poses difficulties. It is known that when this sugar is contained in high concentrations, and due to its osmotic effect, it causes serious intestinal disorders in rats, thus obstructing the determination of the protein nutritional quality. In the study described herein, efforts were made to determine how lactose affects determination of the nutritional value of casein when this is evaluated by the Net Protein Utilization (NPU) procedure, and by the Relative Net Protein Ratio (RNPR) method. Thirty, and 21-day-old rats were fed with diets containing 10% and 8% of casein respectively, and lactose concentrations varying from 20% to 50%. All experiments lasted 10 days. The results demonstrated that casein's nutritional value did not differ significantly (p greater than 0.05) with lactose concentrations up to 40% in any of both methods, even though intestinal disorders were observed with more frequency and duration as lactose concentration increased.     

Formulation and nutritive value of 2 milk substitutes based on sweet lupine (Lupinus albus, var. multolupa)

Two protein mixtures, A and B, based on sweet lupine, wheat flour and dried skim milk powder were formulated, bearing in mind the chemical and nutritional standards set by the National System of Health Services for protein mixtures used through the National Program of Complementary Feeding (PNAC) for preschool children. Both formulas contained 12% of sweet lupine flour, but they differed in their skim milk content, which was 15% in mixture A, and 10% in mixture B. Taking as reference value a content of 2% moisture, formula A contains 17.6% protein and mixture B, 16.4%, with a caloric content of 420 kcal/100 g for both of them. The amino acid score was 0.80 for both mixtures. The biological quality of the proteins of A and B, measured as protein efficiency ratio (PER), was 2.2 and 2.1, respectively. These values are not statistically different, although they are lower than the value of 2.5 obtained for casein (p less than 0.01).     

Role of polyphenols in the low nutritive value of Vicia faba

The inclusion of field bean (Vicia faba) in diets for growing experimental animals, reduced their growth performance in a similar way as compared with controls fed a casein diet, with 0.2% tannic acid. Hydroalcoholic extracts or isolated tannins obtained from Vicia faba seeds, decreased the intestinal transport of D-glucose. The addition of 0.05, 0.1 or 0.2% of tannic acid to the perfusion solutions containing D-glucose proportionally diminished the intestinal uptake of sugar according to its poliphenolic content. It has been postulated that polyphenols reduce, at least partially, the nutritive value of legumes, by altering monosaccharide absorption. Other constituents, however, could also be involved.     

Chemical composition and nutritive value of the protein of Amaranthus quintensis

An account is given of some considerations concerning the chemical recognition and evaluation by biological methods of the quality of the flour obtained from Amaranthus quitensis seeds, submitted to grinding and sifting. The protein content of the flour (21.70g/100g) can be considered as very important, as well as that of the available lysine (5.20g/16gN). The calcium content was also remarkable (500mg/100g), and the starch ratio reached 45.00g/100g. The amount of nitrates found was 20.00mg/100g, which is an acceptable limit. The research for organic nitro compounds was negative. As for the biologic quality of the protein, the experiments revealed that it has quite an acceptable availability, as demonstrated by the following values: NPU = 42.50 +/- 6.10, D = 68.50 +/- 5.30, VB = 62, NPR = 2.10 +/- 1.80 and RNPR = 42.     

Influence of microwave-treated G coal in the batch on the coke quality

The factors that affect the heating of poorly clinkering G coal in microwave treatment are identified. Mathematical models describing their influence on the thermoplastic characteristics of the treated coal and the resulting coke quality are developed. Recommendations are made regarding the composition of batch containing microwave-treated coal.     

The nutritive value of refined rapeseed oils: A review

Recent findings on the nutritive value of rapeseed oil (RSO) with high erucic acid content have been compared to those of canbra oil (CO), an oil extracted from newly bred Canadian rapeseed with no erucic acid. Erucic acid in diets retards animal growth even if food consumption is not altered. Growth performances of CO are as good as olive or peanut oil. The unbalanced ratio of palmitic acid to monoethylenic acids of CO does not affect rat growth rate. Because of its glyceride structure and high content of erucic acid, RSO has a lower digestibility (81%) than CO (96%) in the rat. Unabsorbed erucic acid is not preferentially excreted as calcium soaps. Interesterification of RSO which converts 31.7% of the erucic chains to the 2 position improves digestibility of erucic acid. 2-Monoerucin is more efficiently absorbed than the free acid. In vivo metabolic conversion of erucic to oleic acid has been proved in the rat. β-oxidation of injected 14-¹⁴C labeled erucic acid proceeded at the same rate as oleic acid but the over-all yield of the reaction was lower. Fatty acid composition of tissues in animals fed RSO or CO is influenced on one hand by erucic and gadoleic (C_20∶1) acids of RSO, and on the other hand by the unbalanced ratio of palmitic-monoethylenic acids and the linolenic acid content of both oils. Nonnegligible amounts of erucic acid are deposited in the body fats of rats, chickens, turkeys, lambs and found in the milk of female rats fed RSO. Almost no erucic acid is incorporated in liver and testicles in the rat and it is not recovered in chicken egg yolk. The effect of RSO on rat reproduction has been re-examined. Dietary lipid and vitamin levels are of great importance in the results obtained. RSO induces myocarditis in several animal species. Similar lesions, although less frequent and severe, have been observed also with CO in the rat. Some authors have reported that erucic acid of RSO was responsible for the effect on heart muscle. Common fatty acid patterns to both RSO and CO have to be further investigated to explain the persisting effect of CO. One of 9 papers presented at the Symposium, “Cruciferous Oil-seeds,” ISF-AOCS World Congress, Chicago, September 1970.