Turkey liver: Physicochemical characteristics and functional properties of protein fractions

Turkey liver is an important edible meat by-product. However, it is generally unprocessed, underutilized and low-priced compared to mammalian livers. The present investigation was conducted to provide information on physicochemical composition and functional characteristics of turkey liver. Proximate composition (%) was: moisture (72.3 ± 1.2), protein (21.9 ± 0.6), fat (2.9 ± 1.6), carbohydrate (1.4 ± 0.7), and total ash (1.5 ± 0.1). Cholesterol, glycogen and total heme pigments (g/kg) in the turkey liver were 2.05 ± 0.06, 5.36 ± 0.01 and 2.3 ± 0.08, respectively. Contents in saturated, monounsaturated and polyunsaturated fatty acids (%) were 42.5, 14.6 and 32.6 respectively. Interestingly, turkey liver fat also contains 5% of camphor (oxygenated monoterpene). Mineral concentrations (mg/kg) in liver were: Na (817 ± 14), K (1390 ± 90), Ca (31.4 ± 0.3), Mg (23 ± 0.4), Fe (161 ± 5), Zn (40 ± 2) and Cu (34 ± 2). Liver proteins extracted at 5 or 10 g/l NaCl showed the highest foaming capacity (P < 0.05). Addition of xanthan (1-3 g/l) to liver proteins improved both foam formation and its stability (P < 0.05). Turkey liver also showed interesting emulsifying properties. The emulsion stability of liver proteins was more pronounced at high NaCl concentration (20 g/l). The highest emulsion stability was obtained at acidic or basic pH values (P < 0.05) and decreased at pH 6.     

Evaluation of the protein quality of legume flours obtained by roasting in heated beds

Roasted flours from cowpea, canavalia and washed lupin were prepared by a thermic treatment in fluid sand beds at 150, 200 and 250 degrees C for 2.0 and 2.5 minutes, followed by dehulling and grinding. A flour produced by pressure cooking at 121 degrees C for 30 min followed by drying was used as reference. The flours were evaluated through residual levels of antitryptic activity, tannin content, available lysine, NPR and protein digestibility. The roasting and the pressure cooking processes increased NPR values. Nevertheless, the NPR values of all legume flours were significantly lower than the NPR casein values. The roasting process carried out under the conditions indicated inactivated trypsin inhibitor activity significantly. A small decrease in tannin content was also observed, with small insignificant changes in available lysine. The protein digestibility of all products was high with lupin, digestibility being equal to that observed for casein. The roasting process in a fluid granular bed allows the production of products of acceptable protein quality with low levels of antiphysiological factors.     

Effect of drying temperatures on starch-related functional and thermal properties of chestnut flours

The use of starchy flours in food systems greatly depends on the related functional properties of starch. The effect of drying temperatures on starch-related functional properties of flours obtained from fruits of the two most common Portuguese Castanea sativa varieties (Martainha and Longal) was evaluated. Flours were analysed for amylose and resistant starch contents, swelling ability, pasting properties and thermal characteristics. Drying temperature is positively correlated with amylose content, resistant starch and viscoamylographic properties, mainly the temperatures higher than 40 °C. Amylograms of fruits dried at 60 °C displayed higher peak viscosity (1370 B.U. and 2260 B.U. respectively for Longal and Martainha) when compared to the other temperatures tested (40 °C, 50 °C and 70 °C). Decreases in transition temperatures and in enthalpy evaluated by thermal analysis were observed with increasing drying temperatures, suggesting modifications in starch structure during the drying process. The effects of drying temperatures were more evident in Longal variety. The flours from the two chestnut varieties and from fruits dried at low temperatures and fruits dried at high temperature showed significant differences between the evaluated properties.     

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.     

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.     

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.     

Effect of extrusion on the activity of anti-nutritional factors and in vitro digestibility of protein and starch in flours of Canavalia ensiformis

The effect of the extrusion (155 degrees C, 20% moisture, screw speed 75 rpm, feed speed 205 g min-1) on antinutritional factors of Canavalia ensiformis was studied. In vitro protein and starch digestibilities were assessed. The extrusion not affect protein content (23%) in the flours, but significantly (P < 0.01) decrease moisture content. The protein digestibility values were improved from 57.5 to 89.5%, these values were lower than casein (98.19%). The digestibility of starch values were improved from 37.7 to 53%. The protease inhibitors activities (trypsin and chymotrypsin) and alpha-amylase inhibitor activity were reduced by 95%. The haemagglutinating activity was eliminated as result of the high temperature employed during the extrusion process. The canavanine content in the flours were not affect by the treatment of extrusion.     

Effects of processing by granular heated beds on the chemical and functional properties of legume grains

The present research compares the effect of cooking cowpea, canavalia and lupine by pressure cooking and by a granular bed roaster, on chemical and physical characteristics. The wet cooking process was carried out by pressure cooking at 121 degrees C for 30 min at 15 psi, using a bean-to-water ratio of 3 to 1. The cooked samples were dried with heated air (60 degrees C). The granular bed roasting was carried out at 200 and 250 degrees C for contact times of 2 and 2.5 minutes, at a 5 to 1 sand:bean ratio. For this process, a granular bed roaster was designed and constructed. This process induced in the grain temperatures which varied from 90-128 degrees C, and thermic efficiencies which fluctuated between 38 and 60%. The wet and the dry processes did not affect protein and fat content, although available lysine values decreased slightly. The two processes did not affect water absorption and water solubility. The nitrogen solubility index, however, decreased as roasting temperatures increased in the case of the granular bed roaster, and it also decreased in the wet-cooking procedure. Both processes affected color of the cooked flours, with a light orange color, suggesting non-enzymatic browning due to the high temperatures used.     

Polyacrylamide-grafted legume starch for wastewater treatment: synthesis and performance comparison

Polyacrylamide as traditional flocculant begins to draw the public awareness because of its non-biodegradable nature which may cause the long-term environmental degradation problems. A new high-efficient flocculant was synthesized by legume starch and acrylamide to satisfy the demand of coalmine wastewater treatment. Grafting acrylamide onto mung bean starch was investigated and the characterizations of elemental analysis, scanning electron microscopy, gel permeation chromatography, Fourier transform infrared, X-ray diffraction, thermogravimetric analysis, differential scanning calorimetry and nuclear magnetic resonance spectrometer were conducted. The characterization results of the new flocculant prove that acrylamide has grafted onto the mung bean starch molecule chains successfully. Experimental results indicate the optimal synthesis parameters of the new flocculant are: mung bean starch 50 g/L (ethanol solvent), acrylamide 100 g/L, ceric ammonium nitrate 12 g/L, gelatinization temperature 70 °C and copolymerization temperature 70 °C. We also measured and evaluated the performance of the new flocculant on wastewater treatment, and the optimal dosage of the new flocculant is 20 mg/L, with a prominent transmittance of 98.1% and turbidity of 7.82. Experimental results have demonstrated the graft copolymer of acrylamide and mung bean starch owns an outstanding flocculation effect than the traditional polyacrylamide and polyaluminum chloride. The new flocculant has a few features such as environmentally friendly, easy to degrade, fasting sedimentation and low cost, which is especially suitable for the occasions of rigorous environmental requirements and is bound to have broad application prospect for coalmine wastewater treatment.     

淀粉基生物质胶粘剂的固化与性能研究

将淀粉在硫酸作用下水解的产物用于替代甲醛与苯酚进行缩聚反应生成淀粉基酚醛树脂,然后以六次甲基四胺为固化剂进行交联固化。研究了淀粉基酚醛树脂的凝胶时间、固化反应表观活化能、冲击强度、热失重性能与断面形貌,并与甲醛基酚醛树脂性能进行比较。结果表明,淀粉基酚醛树脂的固化反应表观活化能为19.8kJ/mol,冲击强度为741J/m2,600℃质量残留率为40%,具有良好的耐热性能,游离甲醛质量分数仅为0.4%,大大低于常规酚醛树脂的甲醛含量。     

甘薯淀粉糖苷表面活性剂的合成及性能研究

以甘薯淀粉、乙二醇、长链醇(C8~10醇、C12醇、C12~14醇)为原料,在2 000 L反应釜中采用转糖苷法合成了系列淀粉糖苷类表面活性剂。该产品25℃时表面张力为32 mN/m左右,并且具有两个cmc值点,第一个cmc值点表面张力约为35 mN/m,第二个cmc值点表面张力为24~28 mN/m。保湿性优于丙三醇及其它市售保湿产品,12 h后失水率低于30%,24 h后失水率为33.35%。具有较好的稳泡性,一定的乳化性。红外、气相色谱表征,该系列产品为淀粉糖苷类表面活性剂。     

Structure and properties of starch nanocrystal‐reinforced soy protein plastics

Pea starch nanocrystals (StNs) were incorporated into a soy protein isolate (SPI) matrix to produce a class of full‐biodegradable nanocomposites. The StN with low loading level (2 wt%) showed a predominant reinforcing function, resulting in an enhancement in strength and Young's modulus. This was attributed to uniform dispersion of StN in the amorphous region of the SPI matrix, as well as maintaining stress of the rigid StN and transfer of stress mediated by interfacial interaction between the active StN surface and the SPI matrix. As a result, the nanocomposite containing 2 wt% StN had the maximum strength and Young's modulus in all the materials. With an increase in StN content, the number and the size of StN domains simultaneously increased due to a strong self‐aggregation tendency of StN. It lowered the effective active StN surface for interaction with the SPI matrix and destroyed the ordered structure in the SPI matrix, resulting in a gradual decrease of strength and Young's modulus. The introduction of relatively hydrophilic StN did not cause an obvious decrease of water resistance for any of the nanocomposites. The water uptake behavior of all the nanocomposites similar to that of neat SPI material was attributed mainly to the strong interfacial interaction between the StN filler and the SPI matrix. POLYM. COMPOS., 2009. Published by the 2008 Society of Plastics Engineers     

Lipid-Derived flavors of legume protein products

Legumes contain unsaturated lipids that are susceptible to oxidative deterioration. Enzymic and non-enzymic deterioration of these lipids results in the development of off-flavors. The primary objective of this review is to summarize what is currently known about lipid-derived flavors of soybeans and underblanched pea seeds(Pisum sativum). Identifying the numerous volatile compounds arising from breakdown of lipid hydroperoxides coupled with organoleptic evaluation defines the flavor problem. Major contributors to the green-beaniness of soybeans were found to be 3-cis-hexenal, 2-pentyl furan, and ethyl vinyl ketone. Oxidized phosphatidylchohnes cause some of the bitter taste. The interaction of lipid breakdown products with proteins, carbohydrates, and other constituents can affect flavor characteristics and also increase the problems of their removal from soy protein products. To prepare bland products, it will be necessary to develop processes that effectively remove bound flavor components and prevent formation of derived flavors. Solvent systems based on alcohol have been used to extract flavor principles from soybeans; aqueous alcohol treatment of the intact seed or blanching with hot water or steam inhibits formation of off-flavors in peas and soybeans. A new approach involving infusion of antioxidants into the intact seed to control lipid deterioration during processing and storage is proposed to minimize flavor formation without subsequent undesirable changes in protein which occur with alcohol treatments. Presented at the AOCS Meeting, New Orleans, April 1976.     

Determination of water-dispersible protein in soybean oil meals and flours

Summary A method is presented for determination of Water-Dispersible Protein, using a Hamilton Beach Drinkmaster #30 modified to accommodate Waring Blendor blades and cups. The probable sources of error in the method are discussed, and the precision of the method is shown, based on the results obtained in three laboratories using six different Modified Hamilton Beach Blendors. Technical Paper 178, Archer-Daniels-Midland Company.     

Mechanical properties of nanocomposites from sorbitol plasticized starch and tunicin whiskers

Nanocomposite materials were obtained using sorbitol plasticized waxy maize starch as matrix and tunicin whiskers as the reinforcement. The effect of filler load (0–25 wt % whiskers) and the relative humidity levels (0–98%) on the mechanical behavior of the films are discussed for linear and nonlinear deformation. The performance of the films is explained, based on the morphology and structural behavior of the composite materials (Mathew and Dufresne, Biomacromolecules 2002, 3, 609). The nanocomposites exhibit good mechanical strength due to the strong interaction between tunicin whiskers, matrix, plasticizer (sorbitol), and water, and due to the ability of the cellulose filler to form a rigid three‐dimensional network. The evolution of T_g as a function of relative humidity level and filler load is studied in detail. A decrease in crystallinity of the amylopectin phase is observed at high filler loads, due to the resistance to chain rearrangement imposed by the whiskers. The mechanical strength increased proportionally with filler loads, showing an effective stress transfer from the matrix to the whiskers. An even distribution of whiskers (as determined by SEM) and plasticizer in the matrix contributes to the mechanical performance. The mechanical properties of the nanocomposites showed a strong dependence on relative humidity conditions. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Functional properties of soy protein fractions produced using a pilot plant-scale process

Soy proteins fractionated by the modified Nagano process (Nagano method) and a simplified pilot-plant process (CCUR method) were studied for their functional properties, including solubility, viscosity, emulsification, and foaming. The functional properties of the three fractions produced by the Nagano method—glycinin (11S), β-conglycinin (7S), and an intermediate fraction (IM)—were studied under a selected range of pH, ionic strengths, and protein concentrations. The 11S fraction was more soluble than the 7S at pH 2–3, whereas the 7S was more soluble than 11S at pH 5–6. Adding NaCl changed the solubility of both fractions at pH 4–5 compared to a neutral pH. Other functional properties were related to solubility in the 7S and 11S fractions. The CCUR method yielded only two fractions, 11S and 7S, and the functionality of those fractions was tested at a neutral pH. The solubility of the CCUR samples was slightly higher at extreme pH levels compared to 11S and 7S fractions from the Nagano method at a neutral pH. The relationship between solubility and other functional properties was clearer in CCUR samples. These results indicate that the simplified pilot-scale CCUR fractionation process can influence the functional properties of the protein fractions.     

Electrophoretic and functional properties of mustard seed meals and protein concentrates

Defatted meals and protein concentrates from five varieties of mustard seeds (four Brassica spp. and one Sinapis alba) were analyzed for polypeptide composition and functional properties. Nonreducing gel electrophoresis showed that Brassica seeds lacked the 135- and 50-kDa polypeptides that were present in the seeds of the S. alba variety. On the other hand, the 29-kDa polypeptide found in the Brassica seeds was absent from the seed of the S. alba variety. Under reducing conditions, the 135 kDa was not detected in the S. alba variety and the intensity of the 50-kDa polypeptide was severely reduced; in contrast, the intensity of the 29-kDa polypeptide in the Brassica seeds was not affected. Meals from yellow seeds had significantly higher (P≤0.05) protein contents than meals from the brown seeds. The emulsifying activity indexes (EAI) of meals and protein concentrates from the Brassica seeds were significantly higher (P≤0.05) than those obtained for similar products from S. alba sees. It was concluded that the disulfide-bonded 50- and 135-kDa polypeptides may have contributed to increased rigidity of S. alba meal proteins, which resulted in poor EAI when compared to the Brassica meals, which do not contain these polypeptides.     

Composition and properties of the fractions of a water-ethanol extract from peat

A water-ethanol extract from cotton grass-sphagnum peat was prepared. Six fractions were separated from the peat extract using sequential extraction with a system of solvents with linearly increasing polarities. The chemical composition of each of the fractions was studied, and the main physicochemical characteristics of these fractions were determined. The biological activity of the initial extract and its individual fractions was examined.     

Chemical,functional, and nutritional properties of sunflower protein products

Sunflower flours and protein concentrates have potential food uses because of their high protein content, white color, bland flavor, and absence of antinutritive factors. Procedures have been developed for removal of chlorogenic acid which forms green and brown colors under alkaline pH, and selection for low chlorogenic acid cultivars is underway in plant breeding programs. Further research is needed on dehulling techniques and possible problems associated with high levels of sugars in sunflower flour. Sunflower flours and concentrates have excellent fat absorption, oil emulsification, and whipping properties. Wieners supplemented with sunflower products showed low shrinkage during the smokehouse treatment and low cooking losses due to high fat and water absorptions. Sunflower-supplemented wieners did score poorly in peelability and organoleptic tests. Sunflower proteins had an excellent amino acid balance except for low lysine content and, in feeding trials with rats, showed high protein efficiency ratios when blended with legume or meat proteins.     

Combined effect of cassava starch nanoparticles and protein isolate in properties of starch-based nanocomposite films

This study aimed to evaluate the effects of incorporation of cowpea protein isolate and cassava starch nanoparticles obtained by ultrasound on the properties of cassava starch:glycerol films. The cowpea bean protein isolate was successfully obtained with 72.5% of protein and solubility about 90%. The cassava starch nanoparticles yielded 97.85%. Increasing protein isolate concentration in starch:glycerol films resulted in a progressive reduction of water vapor permeability up to 27.0%. The cassava starch nanoparticles added films presented expressive increments in tensile strength (283.83%) as well as modulus of elasticity (204.31%), accompanied by decreasing in elongation at break (24.28%). The thermal stabilities of cassava starch films were affected by the addition of both protein isolate and cassava starch nanoparticles. The cassava starch nanoparticles obtained by ultrasound ensured the maintenance of film properties, optimizing the production time, with a higher yield, and without the need for chemical reagents. Thus, it could be useful for substitution of those obtained by acid hydrolysis. Therefore, giving rise to a trend of production of nanocomposite films suitable for reinforced packaging applications.