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.     

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.     

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.     

Protein concentrate of African oil palm (Elaesis guineensis, Jacquin), extraction process and functional properties

A study was carried out for the purpose of obtaining and characterizing a protein concentrate obtained from defatted oil palm cake using alkaline extraction, and compare it with a commercial soy meal. The oil palm cake came from a national industry as a subproduct of the oil extraction of the palm kernels. The moisture, protein, fat, crude fiber and ash content of the oil palm was then determined. The optimum conditions for extraction and precipitation of the proteins were selected. These were the following: extraction at pH, 11.4; adding NaOH 0.06 M solvent; a meal/solvent relation of 1:20 g/ml and extraction time, 20 minutes with magnetic agitation, and precipitation at pH 5.3. The protein concentrate obtained contained: 66.50% protein; 0.07% fat, 0.90% crude fiber, and 3.20% ashes. Then the following functional properties were analyzed: solubility, according to the pH; water absorption (250); oil absorption (175); emulsion activity (27.2), and stability (13.6). The author concludes that the protein concentrate has good water and oil absorption when compared to soymeal; the emulsion, however, was found to be unstable to heat.     

Interfacial and foaming characteristics of milk whey protein and polysaccharide mixed systems

Protein‐polysaccharide (PS) interactions find many applications in food engineering and new foam formulations. In this article, we have studied the effect of anionic nonsurface active PSs [sodium alginate (SA) and lambda‐carrageenan (λ‐C)] in aqueous solution on interfacial and foaming characteristics of milk whey proteins [whey protein concentrate (WPC) and whey protein isolate (WPI)]. Whey protein concentration (1.0% wt), temperature (20°C), pH (7), and ionic strength (0.05 M) of the aqueous media were kept constant, while PS influence was evaluated within a 0.0–1.0% wt concentration range. The dynamic properties (dynamics of adsorption and surface dilatational properties) of WPC/PS and WPI/PS adsorbed films were considered in order to correlate the foaming characteristics of the biopolymer mixed systems. Foaming characteristics of the biopolymer mixed systems depended on the PS relative concentration in the aqueous phase and on the whey protein‐PS interactions in solution and at the air–water interface. Dynamic surface properties of the adsorbed films at short adsorption time had a significant effect on foaming capacity. For a particular system, the overall foam destabilization (foam half‐life time) and the individual destabilization processes (drainage, disproportionation, and bubble coalescence) depend on the nature of the PS, its relative bulk concentration, and whey protein‐PS interactions in the vicinity of the air–water interface. The viscosity of the aqueous phase has an effect on the rate of drainage while the rate of disproportionation/collapse is more dependent on the interfacial characteristics of the adsorbed film. © 2009 American Institute of Chemical Engineers AIChE J, 2010     

Functionality, in Vitro Digestibility and Physicochemical Properties of Two Varieties of Defatted Foxtail Millet Protein Concentrates

Two varieties of foxtail millet protein concentrates (white and yellow) were characterized for in vitro trypsin digestibility, functional and physicochemical properties. Millet protein concentrate was easily digested by trypsin in vitro. Essential amino acids were above the amounts recommended by the Food Agricultural Organization/World Health Organization (FAO/WHO/UNU) for humans. Yellow millet protein concentrate (YMPC) possessed the highest differential scanning calorimetry result (peak temperature of 88.98 °C, delta H = 0.01 J/g), white millet protein concentrate (WMPC) had the lowest (peak temperature 84.06 °C, delta H = 0.10 J/g). The millet protein concentrates had molecular sizes around 14.4 and 97.4 kDa. They have U-shape solubility curves. Water-binding capacity was in the range of 5.0 and 7.0 g/g, while oil absorption capacity ranged between 4.8 and 5.9 g/g. WMPC had higher bulk density (0.22 g/mL) and emulsifying capacity than YMPC and Soy Protein Concentrate (SPC). Foam capacity and foam stability ranged from 137 to 73 g/mL for WMPC, from 124 to 61 g/mL SPC and from 124 to 46 g/mL for YMPC. Millet protein concentrates are potential functional food ingredients.     

Functional properties of protein extracted from flaked,defatted, whole corn by ethanol/alkali during sequential extraction processing

Functional properties (solubility, foaming capacity and stability, emulsifying capacity, emulsion stability, heat coagulability, heat gelation and film formation) of protein extracted by 45% ethanol/55% 0.1 M NaOH from flaked, defatted, undergermed corn during the Sequential Extraction Process (SEP) were evaluated and compared with those of a laboratory-prepared soy protein concentrate. SEP is a new approach to corn fractionation that recycles the ethanol produced from the fermentation of cornstarch to unstream steps of protein extraction and the simultaneous extraction of corn oil and dehydration of the ethanol. Freeze-dried corn protein extracts contained at least 80% crude protein (dry basis), which is indicative of protein concentrates. SEP protein concentrates had solubilities in water of greater than 80% at pH values of 7 or above and were significantly more soluble than the soy protein concentrate at pH above 3. SEP corn proteins also showed better heat stabilities and greater emulsifying capacities and emulsion stabilities. Dilute dispersions (0.1%) of corn protein produced substantial but less stable foams. Corn proteins produced films similar to zein and soy protein films but were unable to form heat-induced gels. These results indicate that SEP produces a protein concentrate with functional properties suitable for food and industrial uses. Paper presented at the session on New Processes: Extractions and Purifications II, 83rd Annual Meeting of the AOCS, Toronto, May 10–14, 1992.     

Protein concentrate and adhesives from meat and bone meal

Defatted meat and bone meal (MBM) was prepared by the removal of extractable fat with isopropyl alcohol. Proteins in the defatted MBM were extracted with 0–4% NaCl concentrations with 0.05% CaCl₂ or 0.05% MgCl₂ at pH 5.5–6.6 for 1 h at 50°C and precipitated at pH 4.0–4.5. By using the salt extraction procedure, MBM protein concentrate (MBMPC) (32 g) was obtained from defatted MBM (100 g). Recovery of protein was dependent on the extraction temperature employed; recovery values ranged from 33.2 to 51.4%. At 4% NaCl concentration, MgCl₂ increased protein solubility by 30%, compared to the control. The adhesiveness of MBMPC at various pH values ranging from 5.0 to 9.0 was investigated. At pH 6.0–8.0, adhesiveness of MBMPC showed the highest value (78.2 kg). The adhesiveness increased linearly as the MBMPC concentration increased up to 20% with respect to temperature for MBMPC adhesiveness, the greatest adhesiveness was in the range of 70 to 90°C. Improved adhesiveness and water resistance were observed with 0.05% glutaraldehyde treatment.     

Extraction and properties of proteins in covercress™, new pennycress varieties developed as cover crop and alternative plant protein source

Pennycress (Thlaspi arvense L.) is a winter oilseed crop that also functions as cover crop, oil feedstock for biofuel, and novel plant-based protein. New pennycress specialty varieties were developed by conventional breeding techniques, but protein chemical and functional traits are still unknown. This research evaluated three new lines (black-seeded B3 and yellow-seeded TTG1/Y1126 and TT8) for protein extractability and functionality. Seeds were ground cryogenically and then hexane-defatted until residual oil content was 0.5%–0.7% dry basis, db. Protein in defatted seed meals was extracted using saline method (1: 10 wt/vol, 0.1 M NaCl, 2 h, 50°C). TT8 and Y1126 had greater protein recoveries (ca. 50%) than those of B3 (36%) and wild-type pennycress (WTP, 40%). TT8 produced higher purity protein isolate (94.3%) than did Y1126 (75.0%) and B3 (71.3%). TT8 and Y1126 protein band patterns were different from WTP and B3, reflecting varietal changes. The new varieties' protein extracts were more soluble than WTP protein in acidic pH, with TT8 showing the highest solubility (81%–93%). TT8, Y1126 and B3 foaming capacities (113–135 ml) were superior to those of WTP (101–107 ml). Emulsification properties (EAI 95–230 m²/g protein, ESI 13–24 min) were similar and increased with pH. B3, Y1126, and TT8 formed heat-induced gels at much lower concentration than did WTP (3% vs. 6%) and their water-holding capacities (pH 7) were two to fivefold greater. This work demonstrated that mutations in the TTG1 or TT8 gene in yellow-seeded lines resulted in improved protein recoveries and functionalities that are desirable in plant-based proteins.     

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.     

Effect of dehulling methods and desolventizing temperatures on proximate composition and some functional properties of sesame (Sesamum indicum L.) seed flour

Sesame seeds were dehulled mechanically and in 10% sodium chloride solution before oil extraction and drying to obtain the flour. The effect of these dehulling methods on the proximate composition, oil and water absorption, emulsification, and foaming properties of the flour was investigated. The effect of desolventizing temperatures (80, 90, and 100°C) on these properties was also investigated. Protein contents of seeds, dehulled mechanically (MDSF) and in 10% NaCl solution (SDSF), were 58.5 and 52.1%, respectively. Carbohydrate and ash contents of both flours also varied. The oil and water absorption capacities of the flours were 268 and 252% for MDSF and 370 and 410% for SDSF, respectively. The emulsion capacity of the MDSF sample was slightly lower (20.0 mL oil/g sample) but more stable than the SDSF sample, whose value was 20.4 mL oil/g sample. The foam capacity of MDSF was, however, higher (48.5%) but less stable than SDSF (33.7%). An increase in desolventizing temperatures of the meal led to increases in oil and water absorption capacities of the flours. Foam and emulsion capacities, on the other hand, decreased with increase in temperature. Desolventizing temperatures had no effect on the stability of the formed emulsion but had a decreasing effect on the stability of the foam.     

Chemical and functional characterization of major protein fractions extracted from nontoxic Jatropha curcas byproduct meals

Jatropha curcas seeds are a suitable source of oil for biofuel, among other use. A protein-rich meal is obtained after oilseed extraction. The goals of this study were to determine the physicochemical and functional properties of a nontoxic genotype of J. curcas defatted meal (JCDM) and the seed storage protein fractions to identify future applications. Both glutelin and globulin were the predominant protein fractions obtained from JCDM (42.03 and 20.17 g/100 g of protein, respectively). Leucine, phenylalanine + tyrosine, and histidine content of JCDM and protein fractions met the Food and Agriculture Organization/World Health Organization recommendation for children. The protein solubility (PS) profiles showed minimum values (5.3%–59.7%) at pH 5–6 and maximum at pH 2 (79.7%–81.6%) and above pH 10 (84.6%–89.8%). These findings suggest that JCDM proteins could be used in the formulation of juice or protein-based beverages. All the proteins showed the highest values for foam expansion (231%–285%) at pH 9. JCDM and the albumin fraction formed highly stable foams at pH 9, while the globulin and glutelin foams were stable at pH 3 and 2, respectively. Protein with stable foams, like those from jatropha are suitable for application in ice cream, mousse, among others. The emulsion activity index had similar behavior as foam expansion, but did not follow a specific trend. Thus, the proteins are suitable for use in salad dressing, sausages, comminuted meats, and mayonnaise. Taken together, JCDM protein and its soluble protein fractions have strong promise as alternative proteins for food structuring.     

极端酸碱pH偏移改善白果蛋白溶解性和乳化性

以白果种子为原料提取蛋白,研究其分离蛋白经历极端酸性(pH 2.0、3.0、4.0)和极端碱性(pH 10.0、11.0、12.0)偏移处理2h后、再将pH恢复至中性后的溶解性和乳化性。基于0.5mol/LNaCl溶液体系,采用物理化学分析、光谱技术及电泳技术等手段表征白果分离蛋白的水化性质、分子组分和结构修饰以及蛋白分子聚集行为和乳化特性,探讨以上极端酸碱pH偏移对蛋白结构和功能性的影响。结果表明,极端酸碱偏移处理致使蛋白疏水性、巯基含量和内源性荧光强度均提高,促进蛋白分子展开、重排和疏水基团的暴露,形成由二硫键调节的分子聚集;显著提高蛋白溶解度(特别是pH10.0处理,溶解度从未处理组的13.42%增加到31.91%)和最高约为未处理组2倍的蛋白乳化活性,但降低蛋白乳化稳定性。     

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.     

Treatment of a Cutting Oil Emulsion by Microwave Irradiation

Abstract

This work investigates the effect of a set of operating variables, including irradiation time, irradiation power, dosage of NaCl, settling time, pH, and the initial oil concentration, on the separation efficiency in the treatment of an oil in water (O/W) type cutting oil emulsion by microwave assisted demulsification. As a result of a series of batch demulsification tests a set of optimum operating conditions was found, consisting of 2 min of microwave irradiation at 280 W, the addition of 14 g/L of NaCl, 1 h settling time, and at a pH of 9.5. A separation efficiency of 93.8% was obtained with these conditions for 50 mL of cutting oil emulsion with an initial oil content of 10 g/L. In addition, data from these tests were treated by a stepwise-regression method which results in a multi-variable equation. This empirical equation was able to describe the separation efficiency fairly well, after excluding those with a separation efficiency less than 40% and temperatures higher than the boiling point. Our principal component analysis (PCA) extracted four principal components with 78% of the total variance explained.     

Protein solubility characteristics of commercial soy protein products

Solubility characteristics of commerical soy protein products (flours, concentrates, and isolates) were determined under various conditions. From the solubility profiles at various pH values and NaCl concentrations, soy protein isolates can be divided into three groups. One group had high solubility near the pl. Another group had low solubility near the pl, but high solubility at pH 11. The third group had low solubility even at pH 11. Except for the hydrolyzed products, the protein solubilities of the soy protein products at various salt concentrations were very low. Temperature did not significantly affect the protein solubility, although a few products showed more than a 20% increase at temperatures >50°C. Soy protein concentrates and soy protein isolates showed similar solubility profiles. The proteins in all commercial products (except flours) tested were denatured, as evident from the solubility profiles in the presence of salt and the enthalpy values from DSC.     

改性凹凸棒土处理垃圾渗滤液中氨氮的实验研究

采用NaCl和煅烧对凹凸棒土进行改性,研究改性凹凸棒土对洛阳市预处理后的垃圾渗滤液中氨氮的去除效果.对100 mL氨氮含量为97 mg/L的垃圾渗滤液的最佳吸附条件为:NaCl溶液浓度为10％,将预处理凹凸棒土在NaCl溶液中浸泡改性1h,干燥,煅烧500℃,调节水样的pH值为6,取改性凹凸棒土3.0g,吸附处理时间为40min,氨氮去除率可达94.8％.     

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.     

Automated measurement of apparent protein solubility to rapidly assess complex parameter interactions

Characterization of protein solubility in downstream processing steps is important to either prevent protein aggregation, e.g. during inclusion body refolding, hydrophobic interaction chromatography and formulation or to decrease solubility, e.g. for selective precipitation or crystallization. In general we distinguish between thermodynamic solubility at equilibrium and kinetically driven apparent solubility.In our study we used a high throughput screening method established on a liquid handling robot to rapidly assess an apparent solubility of lysozyme and its dependence on parameters such as pH, ionic strength and additive concentration. Combinatorial effects were measured in a reasonable amount of time with high data density and low material consumption.Parameter interactions were observed between solvent pH and temperature. With increasing margin of pH from the isoelectric point, the effect of temperature was more pronounced. In addition, we found an influence of ionic strength on the additive induced changes in apparent solubility for all systems. PEG 300 and Tween 20 improved lysozyme apparent solubility at high salt concentrations. For sorbitol and sucrose, two distinct regions of maximum apparent solubility were found depending on the additive concentration. While an explanation for single parameter effects was possible, e.g. for pH by correlating net charge and solubility, this became difficult with increasing number of parameters. By reducing the experimental effort, it was possible to build a solid data basis to elucidate the mechanism of lysozyme aggregation and to find industrial relevant regions of increased solubility. Our approach is thus a powerful tool not only for process optimization but also for an increased understanding of precipitation.     

<Emphasis Type="Italic">Lesquerella fendleri</Emphasis> protein fractionation and characterization

Lesquerella fendleri is a promising new crop whose seed contains hydroxy FATG with potential industrial uses as well as substantial amounts of valuable gums. The defatted L. fendleri seeds also contain more than 30% protein. The objective of this study is to process and characterize this protein component for possible future uses in food. Hexane-defatted seed has more than 30% protein content. Defatted lesquerella meal was extracted sequentially with 0.5 M sodium chloride (2×), water, 70% ethanol, and 0.1 N sodium hydroxide (2×). Each sodium chloride extract was dialyzed against deionized water and centrifuged to separate the water-soluble fraction (albumin) from the salt-soluble fraction (globulin) before freeze-drying. The ethanol extract and the neutralized sodium hydroxide extracts (glutelin) were dialyzed against water and freeze-dried. Albumin had the highest proportion of lysine and sulfur amino acids per 16 g nitrogen among all the fractions analyzed. Glutelin and globulin accounted for the highest amount of protein nitrogen. SDS-PAGE of the reduced albumin, globulin, and glutelin showed the presence of several protein bands with M.W. ranging from 7 to 98 kDa. Nitrogen solubility of defatted lesquerella meal from pH 2 to 12 indicated a solubility minimum of 15% around pH 4.2 and a solubility of 75% at pH 11.5. Nonprotein nitrogen of defatted meal was 12% of total nitrogen. Defatted lesquerella meal has the potential for food use based on good nitrogen solubility and good amino acid composition.