Pea and lentil protein extraction and functionality

These studies have demonstrated that peas and lentils can be used as protein sources for flours, concentrates and isolates. Less research attention has been devoted to lentil protein extraction, probably because of the greater cost of lentils as compared to peas. Pin-milling and air classification is well adapted to extracting pea flours to produce pea protein concentrates. Apparently, air-classification can be applied successfully to starch rich legumes, but will not give satisfactory results with lipid rich legumes. Wet processes, including alkaline and salt and acid solubilization, together with isoelectric precipitation or ultrafiltration, have been developed. The pea and lentil protein extracts of these processes exhibit comparable and complementary functionality to homologous soybean products. Air-classified pea protein concentrates are different from soy protein concentrates because of residual starch which can be useful for particular functional applications. Pea isolates appear to exhibit better foaming properties and more solubility than soy isolates, but pea isolates have to be more concentrated than soy isolates to produce viscous dispersions. The economic feasibility of pea and lentil protein extracts is related directly to protein content of the flour, unique functionality of the extracts, marketability of the by-products of extraction and the cost of peas or lentils. Presented at the 78th American Oil Chemists' Society Annual Meeting, May 17–21, 1987, New Orleans, LA.     

Fate of Phytic Acid in Producing Soy Protein Ingredients

Phytic acid (myo-inositol hexaphosphate) is present in soybeans and soy protein products at 1–2% dry matter. Phytate causes poor absorption of essential electrolytes and minerals, and binds to proteins and co-precipitates with isoelectric soy protein isolates. We determined how phytic acid partitioned during different procedures to prepare soy protein ingredients. Procedure and soybean variety significantly affected phytic acid content and recovery. High-sucrose/low-stachyose (HS/LS) soybeans contained significantly (P < 0.05) less phytate than did a typical variety of commodity soybeans (IA2020). In addition, phytate was more readily extracted from the commodity soybeans than from HS/LS soybeans. Among all procedures studied, ethanol-washed soy protein concentrate had the highest phytate contents and yields in the protein products for both soybean varieties (~80 mg/g and 99%, respectively). When protein extraction was carried out at room temperature the protein products had significantly lower phytate yields (60–78%) than when extraction was at 60 °C (80–99%). The protein products obtained from normal soybeans had significantly higher phytate contents than the same products made from HS/LS soybeans. When fractionating soy proteins, the glycinin-rich fraction contained significantly less phytate than the β-conglycinin fraction except for the fractionation procedure performed at room temperature instead of 4 °C.     

Peanut proteins as food supplements: A compositional study of selected Virginia and Spanish peanuts

Three peanut cultivars (Virginia, red-skinned, and white-skinned Spanish) were analyzed and compared as potential protein supplements for food uses. The seeds were solvent-extracted in the laboratory to yield defatted flours with 9–10% nitrogen contents. Protein isolates were prepared from the flours by subsequent extraction with dilute salt solutions buffered at pH 7.0. Various parameters were compared, such as total protein contents, soluble proteins, amino acid compositions of flours and protein isolates, free amino acids and free sugars of defatted flours, and certain trace minerals in flours and soluble proteins. The application of these results to the selection of certain types of peanuts for potential uses as protein supplements in food products is discussed. Presented in the Symposium, Oilseed Proteins, 66th Annual AOCS Meeting, Dallas, Texas, April 27–30, 1975.     

Lupin protein concentrates by extraction with aqueous alcohols

In order to remove the toxic quinolizidine alkaloids and other nonprotein constituents, hexane-defatted flakes of lupin (Lupinus mutabilis) were extracted under various conditions with ethanol, methanol or their aqueous solutions. Lupin protein concentrates containing more than 70% protein and 0.1–0.2% alkaloids were obtained in high yields by consecutive extractions, countercurrent extraction or semicountercurrent extraction of the defatted lupin flakes with either 80% ethanol or 80% methanol.     

Composition of polar lipids in rapeseed

Phosphatidylcholine, -inositol and -ethanolamine represented 48, 18 and 8%, respectively, of the total phospholipids in medium and low erucic acid rapeseed. Oleic acid was the principal fatty acid in phosphatidylcholine and -ethanolamine but all components contained high levels of linoleic and saturated acids. There were eight components in the glycolipid fraction of which digalactosyl diglyceride, monogalactosyl diglyceride, sterol glycoside, esterified sterol glucoside and cerebrosides were identified. Defatted flours contained 2.0–3.5% of bound lipid which was composed primarily of phospholipids and glycolipids whereas neutral lipids were also a major component in the bound lipids of protein concentrates. The storage properties of these protein products would be adversely affected by the polyunsaturated fatty acids in these bound fractions.     

Effects of processing on the functional properties of canola/rapeseed protein

Canola rapeseed is a major oilseed in Canada, Europe and Japan. Recently, Generally Recognized As Safe (GRAS) status was granted to low erucic acid rapeseed oil for use in the U.S. market. Commercial oil extraction of the seed results in a meal that contains 44% protein and which has been subjected to considerable heat. The meal is presently utilized as livestock feed supplement. A number of processes for the preparation of protein concentrates and isolates from canola/rapeseeds and meal have been proposed, although none have proven commercially viable. In addition to protein concentration, a successful process must reduce the levels of glucosinolates, phenolics, phytates and fiber. These antinutrients present a barrier to the use of canola/rapeseed protein materials in foods. Processes to produce protein concentrates have included water extraction of undesirable compounds from heat denatured, dehulled seed followed by solvent extraction for oil recovery and the isopropanol washing of dehulled, defatted flours. Isolates have been prepared by traditional alkaline extraction, and by acid or water extractions followed by isoelectric, heat or polyelectrolyte precipitation of the protein. Isolates have been chemically and enzymatically modified to improve fooduse properties. In this paper, the effects of various processing methods on the functional properties of solubility, color and flavor of canola protein products are reviewed. Presented at the 78th American Oil Chemists' Society Annual Meeting, May 17–21, 1987, New Orleans, LA.     

Characteristics and utilization of dry roasted air-classified navy bean protein fraction

Navy beans,Phaseolus vulgaris, were dry roasted in a particle-to-particle heat exchanger, dehulled by air aspiration, pin-milled and air-classified to yield a high protein fraction. Proximate analyses, nitrogen solubility indices and oligosaccharide contents of this high protein fraction as influenced by processing parameters which affected final product temperature were determined. Farinograms of wheat/bean protein fraction composite flours were run. A high-protein bean flour fraction was selected from these dry and roasted treatments and used in product development. Quality characteristics and consumer acceptability of high-protein prototype products were evaluated. Results of this research indicate that the dry roasting process influences the characteristics of the air-classified protein fraction. Flour color, nitrogen solubility and dough mixing properties were most greatly influenced by roasting time and temperature. Increased roasting resulted in increased browning and decreased nitrogen solubility and dough mixing stability. Wheat flour bread products, substituted with low levels of high-protein bean flour, were of high quality. Presented at the 73rd AOCS annual meeting, Toronto, 1982.     

Tissue culture of cocoa bean (Theobroma cacao L.): changes in lipids during maturation of beans and growth of cells and calli in culture

Callus cultures ofTheobroma cacao L., initiated from explants of immature cocoa bean cotyledons, contained 5.3%–6.4% lipids (dry wt basis). The major fatty acids were palmitic, oleic and linoleic acids. Cell suspensions contained 5.7–7.7% total lipids which had a higher polyunsaturated fatty acid content than total lipids of the calli. Phospholipids and glycolipids were the predominant lipid classes of calli and cell suspensions. Immature cocoa beans at early stages of development contained much higher polyunsaturated fatty acids, higher polar lipids and lower triglycerides than did mature ripe beans. Ripe cocoa beans contained 54% total lipids of which 96.8% where triglycerides. The fatty acid composition of total lipids of calli and cell suspensions were similar to those of the immature cocoa beans.     

Fractionation and characterization of proteins from <Emphasis Type="Italic">Gevuina avellana</Emphasis> and <Emphasis Type="Italic">Rosa rubiginosa</Emphasis> seeds

Gevuina avellana and Rosa rubiginosa proteins were evaluated for their potential food use. The proteins were sequentially separated into five fractions according to their solubilities in deionized water, 0.5 M NaCl, 70% (vol/vol) isopropyl alcohol, 50% (vol/vol) glacial acetic acid, and 0.1 M NaOH. The five fractionated protein groups were then characterized by SDS-PAGE and gel filtration chromatography to determine their M.W. profiles. Ninety-six percent of G. avellana total protein was solubilized in three extraction stages, and 88% of R. rubiginosa total protein was solubilized in one extraction stage. Albumins were the major protein fraction in G. avellana and glutelins-1 the most abundant in R. rubiginosa. The protein solubility profile determined over the pH range 1–12 showed minimal solubilities at pH 3–5 and pH 3–7 for G. avellana and R. rubiginosa, respectively. Electrophoretic studies revealed the existence of proteins composed of two major kinds of polypeptides linked together via disulfide bonds and with molecular masses ranging from 13 to 119 kDa. Gel filtration chromatography profiles of globulins and albumins were studied for both seeds. Isoelectric focusing showed an isoelectric point in the ranges of 4.5–6 and 3–6.5 for G. avellana and R. rubiginosa proteins, respectively.     

Application of urea complexes in the purification of fatty acids,esters, and alcohols. III. Concentrates of natural linoleic and linolenic acids

Summary Concentrates of natural linoleic acid (linoleic acid content, 85–95%) have been prepared in 50–72% yields from corn oil fatty acids by preferential precipitation of the saturated and monounsaturated fatty acids at room temperature as their urea complexes. By a similar procedure, concentrates of natural linolenic acid (linolenic acid content, 87–89%) have been prepared in 55–61% yields from perilla oil fatty acids by preferential precipitation of the saturated, monounsaturated, and diunsaturated fatty acids. Although concentrates of natural linolenic acid containing only 66–70% linolenic acid were obtained from linseed oil fatty acids, yields were 87–90%. A levelling-off effect has been observed in the use of the preferential precipitation technique in raising the purity of concentrates of linoleic and linolenic acid. This parallels the experience in the purification of these acids by low-temperature crystallization. The preceding papers in this series are references 12 and 13. Presented at the Fall Meeting of the American Oil Chemists' Society, Cincinnati, O., Oct. 20–22, 1952. One of the laboratories of the Bureau of Agricultural and Industrial Chemistry, Agricultural Research Administration, U. S. Department of Agriculture.     

Evaluation of Simple and Inexpensive High-Throughput Methods for Phytic Acid Determination

High‐throughput/low‐cost/low‐tech methods for phytic acid determination that are sufficiently accurate and reproducible would be of value in plant genetics, crop breeding and in the food and feed industries. Variants of two candidate methods, those described by Vaintraub and Lapteva (Anal Biochem 175:227–24, 1988 ; “VL” methods) and Huang and Lantzsch (J Sci Food Agric 34:1423–1426, 1983 ; “HL” methods), were evaluated. The primary concern with these methods is that, due to interference of matrix constituents including inorganic P, they can overestimate phytic acid and are ineffective at low levels of phytic acid. Twelve seed flours, representing lines of soybean, maize, barley and dry bean, containing a wide range of phytic acid levels, were analyzed by a minimum of eight cooperating laboratories using three variants of the VL method and two variants of the HL method. No method had consistently acceptable (?2.0”) “Horwitz ratios”, a measure of reproducibility, although some treatments approached that. For example, one variant of the VL method when used to assay a soybean flour with a “standard” level of phytic acid had a Horwitz ratio of 2.15. Some variants of the VL method were adequate for analyses of cereal grains regardless of phytic acid level but none accurately measured phytic acid when at low levels in soybean flours. One variant of the HL method in which the 0.2 N HCl extraction media is modified to contain 10% Na₂SO₄, did accurately measure phytic acid levels in both cereal and legume flours regardless of endogenous phytic acid levels or matrix constituents.     

The role of soybeans in food systems

Technological advances have made it possible to have soybean protein available in various forms: as whole seeds and flours, protein concentrates and protein isolates. These products differ in functional properties as well as in fat and protein content; however, amino acid patterns on a protein basis are essentially the same. Nutritionally, these products have in common a highly digestible protein with ample amounts of lysine and a relatively good essential amino acid pattern. Soybeans have contributed to food systems as sources of calories, as supplementary protein, and as complementary protein because of their good essential amino acid pattern. Furthermore, soybean protein products have made significant contributions to food systems because of their functional properties, which are essential to derive benefit from the nutritional or economic enhancement they impart to other foods. Many examples of this are found in the literature and in practice. Whole soybeans have been used to extend common beans, providing higher energy concentration and higher protein content and quality. Full-fat flour or protein concentrates added in variable amounts to cereal grain flours have introduced higher energy and higher protein content and quality into foods based on maize, rice or wheat. Finally, the amino acid pattern of soybean protein products has allowed them to be used as extenders for cow’s milk and meat products, without altering the protein quality or acceptability of the food product.     

Lipid Classes,Fatty Acid Distributions and Triacylglycerol Molecular Species of Broad Beans (<Emphasis Type="Italic">Vicia faba</Emphasis>)

Seed oils from four legume cultivars of Vicia faba, grown in Japan, were extracted and classified by thin-layer chromatography (TLC) into eight fractions. The major lipid components were triacylglycerols (TAG: 48.8–50.1%) and phospholipids (PL: 47.5–50.5%), while hydrocarbons (HC), steryl esters (SE), free fatty acids (FFA), diacylglycerols (1,3- and 1,2-DAG) and monoacylglycerols (MAG) were present in minor proportions (1.8–2.4%). All lipid samples had high amounts of total unsaturated FA, representing 79.7–82.8% and 77.6–79.7% for TAG and PL, respectively. Molecular species and FA distributions of TAG, isolated from the total lipids in the broad beans, were analyzed by a combination of argentation-TLC and GC. Fourteen different molecular species were detected. With a few exceptions, the main TAG components were S₂D (6.1–8.9%), SD₂ (7.8–10.5%), SMT (6.3–8.5%), M₂D (4.5–6.2%), MD₂ (18.9–21.8%), D₃ (21.0–23.9%) and MDT (8.1–10.2%) (where S, M, D, and T denote a saturated fatty acid, a monoene, a diene, and a triene, respectively). These results suggest that the lipid classes, FA distributions and TAG molecular species of broad beans are not dependent on the cultivation areas during the growing season.     

Effect of feeding soy products with varying trypsin inhibitor activities on growth of shrimp

Six isonitrogenous, isocaloric diets containing commercially defatted, toasted and lightly toasted soy flours (SF) (diets 1 and 2) and four soy protein concentrates (SPC) (diets 3–6) as replacements for 40% of animal protein were fed to satiation to juvenile shrimp (Penaeus vannamei) for 10 weeks. The SPCs used in diets 3 and 5 were chemically modified products with reduced trypsin inhibitor (TI) content. The chemical modification of SF in diet 2, which resulted in an SPC for diet 3, and of SPC in diet 4 consisted of heating at 70°C for 1 hr with 50 mM Na₂S₂O₅, followed by dialysis to remove salt residues. To keep all diets isocaloric, cornstarch was added to replace the oli-gosaccharides lost during processing to an SPC. The TI contents, in mg TI/g diet, were 0.77, 6.14, 0.64, 1.40, 0.92 and 1.72 for diets 1–6, respectively. Shrimp fed lightly toasted SF had the highest weight gain, which was significantly higher than shrimp fed SPC diets 4, 5 and 6, but not significantly higher than shrimp fed diets 1 and 3. No significant difference was observed in survival rates. Shrimp fed diet 3 (with lowest TI) had the highest body percentages of crude protein, while toasted soy flour diet 1, also with low TI, had the lowest content of this constituent. In general, a high body protein reflects good health of the animal and excellent utilization of the feed. At the replacement levels of soy evaluated, TI content did not affect overall weight gain. Presented at the 1991 AOCS Meeting, May 12–15, 1991, Chicago, IL.     

Aqueous Enzymatic Extraction of Oil and Protein Hydrolysates from Roasted Peanut Seeds

To evaluate the effects of the roasting process on the extraction yield and oil quality, peanut seeds were roasted at different temperatures (130–220 °C) for 20 min prior to the aqueous extraction of both oil and protein hydrolysates with Alcalase 2.4 L. Roasting temperatures did not significantly affect the yields of free oil, whereas the temperature of 220 °C led to a reduced recovery of protein hydrolysates. The color and acid values of peanut oils did not change significantly with roasting temperatures. The enzyme-extracted oil with roasting at 190 °C had a relatively low peroxide value, a strong oxidative stability, and the best flavor score. Using the same seed-roasting temperature (190 °C), quality attributes such as color, acid and peroxide values, phosphorus content and oxidative stability of the enzyme-extracted oil were better than those of the oil obtained by an expeller. After the peanut seeds were roasted at 190 °C for 20 min, with a seeds-to-water ratio of 1:5, an enzyme concentration of 2%, and an incubation time of 3 h, the yields of free oil and protein hydrolysates were 78.6 and 80.1%, respectively. After demulsification of the residual emulsion by a freezing and thawing method, the total free oil yield increased to 86–90%.     

Twin-screw extrusion texturization of extruded-expelled soybean flour

Texturized soy proteins (TSP) have been produced from hexane-extracted soy flours having a narrow range of characteristics. The objective of this study was to determine the influence of protein dispersibility index (PDI) and residual oil content on extrusion texturization of partially defatted soy flours produced by extruding-expelling (E-E). Ten E-E processed soy flours having residual oil contents and PDI values of 5.5–12.7% and 35.3–69.1%, respectively, were texturized using a twin-screw extruder. Water-holding capacities were greater for TSP prepared from E-E processed soy flours with lower residual oil contents. Bulk densities were significantly lower for TSP prepared from E-E processed soy flours compared with a commercial product made from hexane-extracted soy flour. The texture characteristics of extended ground beef patties containing texturized E-E processed soy flour were similar to that of 19% fat ground beef. Flavor acceptability was directly correlated (R=0.761) with residual oil content of the E-E processed soy flours. However, lower residual oil and higher PDI flours exhibited better texturization and extrudate qualities.     

γ-Linolenic acid concentrates from borage and evening primrose oil fatty acidsvia lipase-catalyzed esterification

γ-Linolenic acid (GLA, all-cis 6,9,12-octadecatrienoic acid) has been enriched from fatty acids of borage (Borago officinalis L.) seed oil to 93% from the initial concentration of 20% by lipase-catalyzed selective esterification of the fatty acids withn-butanol in the presence ofn-hexane as solvent. The immobilized fungal lipase preparation, Lipozyme, used as biocatalyst, preferentially esterified palmitic, stearic, oleic and linoleic acids and discriminated against GLA, which was thus concentrated in the unesterified fatty acids fraction. In the absence of hexane, concentrate containing about 70% GLA was obtained. When the reaction conditions, optimized for borage oil fatty acids, were applied to fatty acids of evening primrose (Oenothera biennis L.) oil, concentrates containing 75% GLA were obtained. From both oils, GLA concentrates were prepared efficiently in short reaction times (1–3 h) at 30–60°C. The process can be applied for the production of GLA concentrates for dietetic purposes.     

Effects of soybean pretreatments on crude oil quality

The effects of soybean pretreatments, including infrared (IR) radiation, oven toasting, microwave heating and live steam treatment on crude oil quality were investigated. Free fatty acid, oxidation value, carbonyl value and tocopherol content were used to monitor crude soybean oil quality. All soybean pretreatments were effective in improving the quality of oils from 15 and 18% moisture beans. Based on the analyses, recommended treatments are 3–4 min for IR at 220V–250W; 1 min for microwave heating at 650 W–2450 mHz; 1–1.5 min for steam heating; and 100–120°C, 30 min for oven toasting. Heat treatment of high-moisture soybeans before extraction yielded crude oil with a lower content of phosphatidic acid as compared to that of the untreated beans.     

Fatty Acid Composition and Oil Yield in Fruits of Five <Emphasis Type="Italic">Arecaceae</Emphasis> Species Grown in Cuba

The present study targeted the whole-fruit oil yield and fatty acid composition from five of the most abundant Arecaceae species grown in Cuba. The oil yields (% dry weight), determined by the Soxhlet extraction technique with hexane, were 25.5, 5.3, 6.9, 5.4, and 6.4% for Roystonea regia, Colpothrinax wrightii, Sabal maritima, Sabal palmetto and Thrinax radiata, respectively. The free fatty acid (FFA) content varied from 2.7 to 6.8%. Fatty acid (FA) profiles of the oils indicated that lauric acid (13.7–44.4%), myristic acid (9.4–22.4%) and palmitic acid (9.2–17.1%) as major saturated FA; whereas oleic acid (9.6–42.7%) and linoleic acid (9.3–17.0%) as major unsaturated FA. R. regia fruit seemed the most promising among Arecaceae grown in Cuba because of its high oil yield and low oil FFA content.     

Microwave roasting effects on the physico-chemical composition and oxidative stability of sunflower seed oil

The purpose of the present study was to explore the influences of microwave heating on the composition of sunflower seeds and to extend our knowledge concerning the changes in oxidative stability, distribution of FA, and contents of tocopherols of sunflower seed oil. Microwaved sunflower seeds (Helianthus annuus L.) of two varieties, KL-39 and FH-330, were extracted using n-hexane. Roasting decreased the oil content of the seeds significantly (P<0.05). The oilseed residue analysis revealed no changes in the contents of fiber, ash, and protein that were attributable to the roasting. Analysis of the extracted oils demonstrated a significant increase in FFA, p-anisidine, saponification, conjugated diene, conjugated triene, density, and color values for roasting periods of 10 and 15 min. The iodine values of the oils were remarkably decreased. A significant (P<0.05) decrease in the amounts of tocopherol constituents of the microwaved sunflower oils also was found. However, after 15 min of roasting, the amount of α-tocopherol homologs was still over 76 and 81% of the original levels for the KL-39 and FH-330 varieties, respectively. In the same time period, the level of σ-tocopherol fell to zero. Regarding the FA composition of the extracted oils, microwave heating increased oleic acid 16–42% and decreased linoleic acid 17–19%, but palmitic and stearic acid contents were not affected significantly (P<0.05).