Influence of pH and salt concentration on protein solubility,emulsifying and foaming properties of sesame protein concentrate

The effects of pH and NaCl concentration on protein solubility, emulsification, and foamability of sesame protein concentrate from dehulled seeds were investigated. The protein content of the concentrate was 70.7%. Protein solubility, emulsion, and foaming capacities varied with pH and ionic strength. Protein solubility, which was least at pH 4, (2.1%) ranged from 6.6% at pH 2 to 13.1% at pH 10. The solubility increased with increase in ionic strength, ranging from 9.8% at 0.0 M to 16.1% at 1.0 M concentration. The emulsion capacity ranged from 6.2 mL oil/g sample at pH 2 to 19.4 mL oil/g sample at pH 10. The emulsion capacity increased from 11.5 mL oil/g sample at 0.0 M to 20.9 mL oil/g sample at 1.0 M salt concentration. Stability of the emulsion increased with increase in NaCl concentration, ranging from 42% at 0.0 M concentration to 70% at 1.0 M concentration, but 0.5 M NaCl produced the most stable foam after 120 min of whipping while the least stable was at 1.0 M.     

The Isolation of Yellow Mustard Oil Using Water and Cyclic Ethers

An aqueous extraction process (AEP) was developed for dehulled yellow mustard flour with the aim of producing yellow mustard oil for industrial applications, as a by-product of food protein production. During AEP, most of the oil extracted was bound in a stable oil-in-water emulsion that must be destabilized to recover free oil. The oil distribution after aqueous extraction and the composition of the emulsion produced were determined. The emulsion was solubilized in organic solvents including tetrahydrofuran (THF) and 1,4-dioxane to fully recover the oil in a single-phase oil–solvent-water miscella. Over 97 and 95% of the oil in the emulsion was successfully recovered using 4:1 THF:oil and 9:1 dioxane:oil weight ratios, respectively. The oil recovery from the emulsion was optimized, based on experimentally prepared ternary phase diagrams of THF/oil/water and dioxane/oil/water. The results suggest that this technically viable approach can successfully recover essentially all of the oil from the emulsion, equivalent to an overall free oil recovery of ~63% from dehulled yellow mustard flour.     

Functional properties and protein concentrate of Pigeon pea (Cajanus cajan (I.) Millsp) flour

The objective of this investigation was to study the functional properties of Pigeon pea (Cajanus cajan (L.) Millsp) flour and protein concentrate. The solubility of both samples were superior than 70% at pH above 6.7 and below 3.5. The water and oil absorption were 1.2 and 1.07 ml/g of sample and 0.87 and 1.73 ml/g of flour and protein concentrate samples, respectively. The minimum concentration of flour and protein concentrate needed for gelation was 20% and 12%, respectively. The emulsifying capacity of flour and concentrate was 129.35 g and 191.66 g oil/g of protein and the emulsion stability 87.50 and 97.97%, respectively, after 780 minutes. The foam capacity and stability of flour foam were 36.0% and 18.61, while of the concentrate were 44.70% and 78.97% after 90 minutes. These properties indicate that the flour as well as the concentrate could have application in various food systems.     

Functional properties of dehulled sesame (sesamum indicum L.) seed flour

Certain functional properties of sesame seed flour were obtained after oil extraction from dehulled seed meal was investigated. The protein content in the flour was 69.7% and the least gelation concentration was 6.0%. Water and oil absorption capacities at room temperature (31 ± 2°C) were 2.3 g H₂O/g sample and 3.0 g oil/g sample, respectively. The values were higher at 100°C. The emulsification capacity, which was more stable at alkaline conditions, ranged from 25.0 mL oil/g sample at pH 4 to 66.0 mL oil/g sample at pH 10. The foaming capacity was more stable at pH 4 but lower (205.0%). The highest foaming capacity (315.0%) was at pH 2 whereas at pH 10 it was 310.0%. Protein solubility, which was least at pH 4, ranged from 7.9% at pH 2 to 14.2% at pH 10. The viscosity of the flour dispersion ranged from 2.5 cps at 1% concentration to 7.0 cps at 10% concentration. The findings show that sesame flour could impart desirable characteristics when incorporated into products such as ice cream, frozen dessert, sausages, baked food and confections.     

Enzymatic modification of soy protein concentrates by fungal and bacterial proteases

Solubility, foaming capacity and foam stability of denatured soy protein concentrate obtained from toasted flour were improved by proteolysis with fungal or bacterial proteases. Emulsifying capacity was unchanged, but emulsion stability decreased; bacterial protease highly improved oil absorption. Also, the bacterial protease was able to solubilize more protein and gave products which foamed more than those obtained with the fungal enzyme. However, the stabilizing properties of the bacterial modified soy protein concentrate at the air/water or oil/water interface were inferior. By limited hydrolysis up to degree of hydrolysis 10% most functional properties were improved without greatly reducing emulsion stability and water absorption.     

Yield and functional properties of air-classified protein and starch fractions from eight legume flours

Eight legumes were pin-milled and air-classified into protein (fine) and starch (coarse) fractions and their functional properties compared with those of soybean and lupine flours. The fine material which represented 22.5 to 29% of the original flours contained from 29 to 66% protein as well as a high proportion of the flour lipids and ash. The coarse material contained 51 to 68% starch and much of the crude fiber which was dense and concentrated in the starch fraction. Generally legumes which showed highly efficient starch fractionation gave lower recoveries of protein in the fine material. High values for oil absorption, oil emulsification, whippability and foam stability were characteristics of the protein fractions, while starch fractions gave high water absorptions, peak and cold viscosities. Gelation occurred in both air-classified fractions. Pea and northern bean, chickpea and lima bean flours, and airclassified fractions gave generally higher values in the functional property tests, while fababean, field pea, mung bean and lentil gave high protein fractionation in the air classification process.     

Sweet lupine (Lupinus luteus, var. Aurea/Weico and Lupinus albus, var. Multolupa) proteins. I. Extraction and filtration by Sephadex

Samples of Lupinus luteus, var. Aurea/Weico and Lupinus albus var. Multolupa flours were analyzed. The flour proteins were extracted and fractionated by gel filtration, and the per cent pattern for both globulins and albumins was then determined. The dehulled seeds, previously analyzed for composition, were ground, defatted and consecutively extracted with distilled water (pH 5.0) and phosphate buffer (0.05 M, pH 8.5). The extracted protein content was measured by the Lowry simplified method. Globulins (pH 8.5 fraction) from both species were filtered through Sephadex G-100; besides, Lupinus albus globulins were filtered through Sephadex G-150, and absorbance of the collected fractions was measured at 280 nm. The dehulled seed (DS) of L. luteus and L. albus revealed a good protein content (58.2 and 41.0%, respectively). The protein extracted from L. luteus was constituted by 17% albumins and 58.4% globulins. In contrast, L. albus presented a higher albumin content (55.6%) than globulins (31.5%). The elution pattern for the Sephadex G-200 gel filtration showed for both lupine species analyzed a preponderant peak I corresponding in L. luteus to 55.0% and in L. albus to 84.1% of the total globulins content. From these results, it may be concluded that the dehulled seed protein content is 42.0% higher for the L. luteus sample than for the L. albus. The applied methodology indicated a predominant content of globulins above albumins in L. luteus, while in the case of L. albus, the albumin content was the highest.     

Destabilization of Yellow Mustard Emulsion Using Organic Solvents

An aqueous extraction process was developed consisting of aqueous contact with dehulled yellow mustard flour to recover protein followed by dissolution of the released emulsion in dimethylformamide (DMF) or isopropyl alcohol (IPA) to recover the released oil in the form of single-phase oil–solvent miscellae suitable for industrial applications. Only some 38 ± 3 % of the oil in the yellow mustard emulsion was extracted using DMF even at high weight ratios since DMF is widely miscible with water, preventing separation of the oil from the emulsion. A ternary phase diagram of DMF/oil/water was prepared and confirmed the limited solubility of the oil in DMF in the presence of water. The use of 31:1 IPA:oil weight ratio could effectively recover over 94 % of the oil in the emulsion; however, multiple-stage treatment of the emulsion was proven to be more efficient with lower volumes of IPA required to achieve high oil extraction yields. The results suggest that the optimal conditions for multiple-stage process were four stages using 2:1 IPA:oil weight ratio, with 96 ± 1 % oil recovery from the emulsion.     

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.     

Functional properties of a protein product from Caryodendron orinocense (Barinas nut)

The functional properties of Caryodendron orinocense protein product were investigated and compared with those of soybean (Glycina maxima). The product protein content was 24.47 g/100 g (Nx6.25). Solubility increased at both sides of the isoelectric point (pH 4.0) and with increased NaCl concentration up to 0.5M. Compared with soybean flour (50% protein), the protein product exhibited higher water and oil absorption, but lower emulsifying activity, emulsion stability, foaming capacity, and foam stability, the last one increase at higher pH. Emulsifying activity, foaming capacity, and foam stability were ionic strength dependent. C. orinocense protein product increased its emulsifying activity steadily from 0.05M to 0.75M NaCl, while it remained almost constant for soybean flour. Foaming capacity increased drastically at pH 10. The minimum time and concentration to form a gel was 20% in 4 min and 10% in 8 min for the Caryodendron protein product and soybean flour, respectively. The bulk density was 0.5056+/-0.0041 g/mL.     

Biodiesel Feedstock from Emulsions Produced by Aqueous Processing of Yellow Mustard

The multi-stage treatment of stable oil-in-water emulsions produced during non-enzymatic aqueous processing of dehulled yellow mustard flour with cyclic ethers [tetrahydrofuran (THF) and 1,4-dioxane] was investigated to produce a single-phase oil-solvent-water miscella suitable for biodiesel production. While the single-stage treatment of yellow mustard emulsion recovered 97 % and 95 % of the oil by using 4:1 THF:oil and 9:1 dioxane:oil weight ratios, respectively, miscella phases containing more than 7 % water formed, which made them unsuitable as biodiesel feedstock. Multi-stage treatments of the emulsion using lower THF:oil and dioxane:oil weight ratios were further developed to produce oil-solvent-water miscella phases with low water content. While three-stage extraction of emulsions using 0.5:1, 1:1, 1.5:1, and 2:1 dioxane:oil weight ratios did not destabilize the emulsion, three-stage extraction using 0.5:1 and 0.75:1 THF:oil weight ratios effectively recovered over 97 % of the oil, resulting in the production of oil-rich miscella phases containing only 1 % and 1.5 % water, respectively. These miscella phases were analyzed for free fatty acid and phosphorus contents and proved to be excellent feedstocks for the preparation of high-purity methyl esters through single-phase base-catalyzed transmethylation.     

Effect of the addition of wood flours on the properties of rigid polyurethane foam

The objective of this study is to investigate an appropriate process to fabricate the wood‐polyurethane hybrid composites [wood‐polyurethane foam (PUF)]. Rigid PUFs that contain up to 20% wood flours were successfully fabricated from polymeric 4,4‐diphenylmethane diisocyanate, polyols, silicone surfactant, dibutin dilaurate/dimethylethanolamine catalysts, and distilled water (chemical blowing agent). The effects of hydroxyl value of polyols, wood flour particle size, wood flour content, isocyanate index, and water amount on the compressive property of foam were investigated. The morphology of the cell was observed with a scanning electron microscope. Wood‐PUF with different densities were prepared at different water contents in the wood flours. The relationship between the compressive property and density was established following the Power law. The incorporation of wood flour improved the compressive property of PUF, whereas its tensile and flexural properties were reduced. The thermal stability of the PUF was improved with the addition of wood flour. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Effect of moisture and temperature on the phosphorus content of crude soybean oil extracted from fine flour

Analysis of total oil content in soybeans is usually done by extracting flours, whereas commercial extraction for recovery of oil is done by extracting flakes. It has recently become apparent that phosphorus content of crude soybean oil extracted from flours can vary depending on extraction temperature and flour moisture. In this study, flour moistures below 6% yielded crude oil with low phosphorus (15 ppm), but phosphorus in the oil increased rapidly to 260 ppm at 9% moisture. When temperature of the extraction was increased from 25 to 60°C, the phosphorus in extracted oil also increased for moisture contents of 6.6% and 8.3%, but not for moisture contents of 5% and 3%. In addition to the effects of extraction temperature, it was found that preheating whole soybeans at various temperatures affected phosphorus in oil from extracted flour. Preheating at 130°C caused high phosphorus content regardless of how dry the flour was, whereas preheating at 100°C or below caused phosphorus content that increased with increased moisture. The response of phosphorus content in crude oil to temperature and moisture may be useful in improving the quality of commercially extracted soy oil.     

Technical news feature

Hull-free kernels from confectionary-type sunflower seed were prepressed with two levels of heat treatment and two levels of severity of pressing. Cakes were solvent extracted, desolventized in a continuous, pilot size extractor, and ground into flour. For comparison, kernels were also pressed into flour using direct solvent extraction and desolventizing at room temperature. Qualities of oil and of flour from different treatments were compared. Oils were all of good quality with no differences among treatments. Flours showed no distinct differences in dispersible nitrogen at pH values between 2 and 12, indicating that processing conditions did not damage the solubility of the protein. All cake and flour samples were high in residual hexane, showing the need for a deodorizer in the pilot plant. Treatments did not affect particle size distribution in flours. The flour samples all fell within the range for satisfactory microbiological quality, although bacteria count increased considerably during grinding of cake into flour. Treatments affected dry color but not wetted color of flour, with the more intense heating and pressing producing slightly darker flours. Amino acid compositions were not affected by process treatments.     

Food uses of sunflower proteins

Commerical use of sunflower meal as a food product is dependent on the development of low chlorogenic acid cultivars and efficient procedures for dehulling the high oil cultivars and hybrids. Laboratory defatted sunflower flours have high protein contents, bland flavors, white colors at acid pH levels, and contain no antinutritive factors. Functional test data show that sunflower flours and protein concentrates have high salt solubility, oil absorption and oil emulsification. In rat feeding trials, the low lysine level in sunflower proteins has resulted in low protein efficiency ratios for sunflower diets and blends with cereals including bakery products. High weight gains are obtained for sunflower blends with legume and animal proteins, suggesting applications in milk and meat extenders and in soybean-based infant, formulas. Heat treatments, mechanical agitation, and emulsifiers were effective in solubilizing 80% of sunflower proteins in extended milk formulations, and the product was given high ratings in taste panel evaluations. Sunflower flour slurries show excellent whippability and foam stability, comparable to that of soybean protein isolate, but lack the ability to form a firm gel. Wieners supplemented with sunflower products have low shrinkage and cooking losses, but rate poorly in organoleptic tests. Texturization of sunflower flour by extrusion cooking gave fibrous chunks which were greyish in appearance, but had a chewy texture, a meat-like flavor, and gave low cooking losses in beef pattie formulations. Spun sunflower protein/casein (1:1) blends are superior to other vegetable proteins in shear strength, swellability and firmness. Sunflower flours are particularly deleterious to bread loaf characteristics. This effect can be partially overcome by autoclaving the flour, concentration of the protein, or addition of gluten, but the protein nutritive value of the supplemented bread is only marginally improved.     

Endogenous antioxidants and stability of sesame oil as affected by processing and storage

The effect of processing of coated and dehulled sesame seeds on the content of endogenous antioxidants, namely sesamin, sesamolin, and γ-tocopherol in hexane-extracted oils, was studied over 35 d of storage under Schaal oven test conditions at 65°C. Seeds examined were Egyptian coated (EC) and dehulled (ED) and Sudanese coated (SC) varieties. Processing conditions of raw (RW) seeds included roasting at 200°C for 20 min (R), steaming at 100°C for 20 min (S), roasting at 200°C for 15 min plus steaming for 7 min (RS) and microwaving at 2450 MHz for 15 min (M). The sesamin content in fresh oils from EC, ED, and SC raw seeds was 649, 610, and 580 mg/100 g oil, respectively. Corresponding values for the content of sesamolin in oils tested were 183, 168 and 349 mg/100 g oil, respectively. Meanwhile, the content of γ-tocopherol, the only tocopherol present in the oils, ranged from 330 to 387 mg/kg sample. The effect of processing on changes in the sesamin content in oils from coated seeds was low and generally did not exceed 20% of the original values. On the other hand, oils from dehulled seeds underwent a more pronounced decrease in their sesamin content than the oil from coated seeds after 35 d of storage at 65°C. The corresponding changes in sesamolin and γ-tocopherol contents were more drastic. The RS treatment, which would be the optimal to prepare sesame oil with better quality, was found to retain 86, 80 and 60% of the sesamin, sesamolin and γ-tocopherol, respectively, originally present in the seeds after the storage period. The loss in the content of endogenous antioxidants present in the oils paralleled an increase in their hexanal content.     

Study oil/water separation property of PE foam and its improvement by in situ synthesis of zeolitic–imidazolate framework (ZIF‐8)

Herein, the oil/water separation property of four polyethylene (PE) foams with two different volume expansion ratios including 15 and 30 times was studied. We found that the PE‐30‐1 foam was the best absorbent materials among these four samples, which was also superior to the commercially available products. It demonstrated high oil absorption capacities, as well as high oil/water selectivity, which was due to its small average pore size and high porosity. In addition, this work also reports two rapid and straightforward methods to fabricate PE‐30‐1‐ZIF‐8 composite with enhanced compressive property, an encouraging absorption capacity for different organic solvents, reaching 59 times of its own weight for chloroform, as well as increased oil–water selectivity of the system. Comparing with the PE foam, the organic solvent absorption capacities for PE‐ZIF‐8‐sono composite foams were improved by 6.4%, 29%, 9.1%, and 12% for chloroform, acetone, toluene and oleic acid, respectively, while the corresponding improvement for PE‐ZIF‐8‐Me(OH) was about 7.5%, 28%, 14%, and 15%, respectively. These PE‐ZIF‐8 foams could reach the requirement for oil spill cleanup, suggesting its great potential for this type of application. POLYM. ENG. SCI., 59:1354–1361 2019. © 2019 Society of Plastics Engineers     

月桂醛和琥珀酸酐接枝改性天然胶原所得产物的表面活性

以月桂醛与琥珀酸酐接枝改性具有三股螺旋结构的天然胶原,得到了一种保留了天然胶原结构的生物表面活性剂(胶原基生物表面活性剂,简称BCB)。研究了BCB的基本表面活性,结果表明,BCB具有较好的泡沫膨胀和泡沫稳定性,其乳化活性(284.08 m2/g)与天然胶原(32.23 m2/g)相比有显著的提高,乳化稳定性和吸油能力也有所提升。BCB的润湿能力随着其浓度的增加而提高,表面张力随存放时间的延长而降低,在质量浓度为5.0×10-3g/L时,表面张力在3 000 s时达到平衡,为52.58 m N/m。研究表明,BCB和天然胶原的乳液类型均为O/W型。     

Toxic Compound, Anti-Nutritional Factors and Functional Properties of Protein Isolated from Detoxified Jatropha curcas Seed Cake

Jatropha curcas is a multipurpose tree, which has potential as an alternative source for biodiesel. All of its parts can also be used for human food, animal feed, fertilizer, fuel and traditional medicine. J. curcas seed cake is a low-value by-product obtained from biodiesel production. The seed cake, however, has a high amount of protein, with the presence of a main toxic compound: phorbol esters as well as anti-nutritional factors: trypsin inhibitors, phytic acid, lectin and saponin. The objective of this work was to detoxify J. curcas seed cake and study the toxin, anti-nutritional factors and also functional properties of the protein isolated from the detoxified seed cake. The yield of protein isolate was approximately 70.9%. The protein isolate was obtained without a detectable level of phorbol esters. The solubility of the protein isolate was maximal at pH 12.0 and minimal at pH 4.0. The water and oil binding capacities of the protein isolate were 1.76 g water/g protein and 1.07 mL oil/g protein, respectively. The foam capacity and stability, including emulsion activity and stability of protein isolate, had higher values in a range of basic pHs, while foam and emulsion stabilities decreased with increasing time. The results suggest that the detoxified J. curcas seed cake has potential to be exploited as a novel source of functional protein for food applications.     

Flaking and extrusion as mechanical treatments for enzyme-assisted aqueous extraction of oil from soybeans

Flaking and extruding dehulled soybeans were evaluated as a means of enhancing oil extraction efficiency during enzyme-assisted aqueous processing of soybeans. Cellulase, protease, and their combination were evaluated for effectiveness in achieving high oil extraction recovery from extruded flakes. Aqueous extraction of extruded full-fat soy flakes gave 68% recovery of the total available oil without using enzymes. A 0.5% wt/wt protease treatment after flaking and extruding dehulled soybeans increased oil extraction recovery to 88% of the total available oil. Flaking and extruding enhanced protease hydrolysis of proteins freeing more oil. Treating extruded flakes with cellulase, however, did not enhance oil extraction either alone or in combination with protease. Discrepancies in oil extraction recoveries were encountered when merely considering crude free fat because some oil became bound to denatured protein during extrusion and/or sample drying. Bound fat was unavailable for determination by using the hexane extraction method, but was accounted for by using the acid hydrolysis method for total oil determination. Oil extraction recovery from extruded soybean flakes was affected by oil determination methods, which was not the case for unextruded full-fat soy flour.