Soy Protein Fiber Research Articles

Soyprotein fibers with high strength and water stability for potential medical applications

Fibers with mechanical properties and water stability suitable for tissue engineering have been developed from soyproteins. Proteins are biocompatible and biodegradable and are preferred over synthetic polymers for medical applications. Although plant proteins are abundant and inexpensive and can be made into various types of scaffolds, very few attempts have been made to understand the suitability of using plant proteins for medical applications, especially as fibrous substrates for tissue engineering. So far, it has not been able to obtain good quality soyprotein fibers without using toxic crosslinking agents or blending soyprotein with synthetic polymers. In this research, we have developed 100% soyprotein fibers with good strength and water stability without using any external crosslinking agents. The soyprotein fibers have better wet strength than collagen fibers and are conducive to the attachment, growth, and proliferation of mouse fibroblasts. Fibers are better substrates than films for growth and orientation of cells and are therefore preferable for tissue engineering applications. Soyprotein fibers show good potential to be novel biomaterials with properties suitable for tissue engineering and other medical applications.

Drug sorption onto and release from soy protein fibers

Drug release in phosphate buffered saline (PBS pH 7.4) and artificial gastric juice (AGJ pH 1.2) and its relationship with kinetic and thermodynamic parameters of drug sorption onto soy protein (SP) fibers have been studied using Diclofenac, 5 Fluorouracil and Metformin as model drugs. Since SP is biodegradable, biocompatible, abundant and annually renewable, it has been widely used in medical applications. To understand drug release from SP fibers using sorption, kinetic and thermodynamic parameters have been investigated. Quantitative relationship between drug release and drug loading concentration, affinity, and activation energy for diffusion was established to predict initial bursts and later drug release. The study showed that Diclofenac had high initial bursts in PBS but more constant release in AGJ. It also has been found that drugs with lower diffusion coefficient and higher affinity (especially van der Waals force) on SP fiber are more suitable for sorption loading to achieve higher loading capacity and more constant releasing rate.

Controlled release of allyl isothiocyanate using soy protein and poly(lactic acid) electrospun fibers

Abstract Electrospun fibers from soy protein isolate (SPI)/poly(ethylene oxide) (PEO) blend and poly(lactic acid) were used for controlled release of a naturally occurring antimicrobial compound, allyl isothiocyanate (AITC). AITC was encapsulated in β-cyclodextrin or added directly into the fiber-forming solutions. Scanning electron micrographs showed that the resulting electrospun SPI/PEO and PLA fibers possessed smooth morphology with diameters ranging from 200 nm to 2 μm. Fiber morphologies were affected by the AITC concentration. The kinetics of AITC release under different relative humidity conditions and fiber morphologies were evaluated. Release of AITC was negligible under dry conditions, but increased dramatically as relative humidity increased. The interactive behaviour of these antimicrobial nanofibers may be promising in active packaging applications for foods.

Alkali‐catalyzed low temperature wet crosslinking of plant proteins using carboxylic acids

We report the development of a new method of alkali-catalyzed low temperature wet crosslinking of plant proteins to improve their breaking tenacity without using high temperatures or phosphorus-containing catalysts used in conventional poly(carboxylic acid) crosslinking of cellulose and proteins. Carboxylic acids are preferred over aldehyde-containing crosslinkers for crosslinking proteins and cellulose because of their low toxicity and cost and ability to improve the desired properties of the materials. However, current knowledge in carboxylic acid crosslinking of proteins and cellulose requires the use of carboxylic acids with at least three carboxylic groups, toxic phosphorous-containing catalysts and curing at high temperatures (150-185 degrees C). The use of high temperatures and low pH in conventional carboxylic acid crosslinking has been reported to cause substantial strength loss and/or undesired changes in the properties of the crosslinked materials. In this research, gliadin, soy protein, and zein fibers have been crosslinked with malic acid, citric acid, and butanetetracarboxylic acid to improve the tenacity of the fibers without using high temperatures and phosphorus-containing catalysts. The new method of wet crosslinking using carboxylic acids containing two or more carboxylic groups will be useful to crosslink proteins for various industrial applications.

Preventive effects of a soy-based diet supplemented with stevioside on the development of the metabolic syndrome and type 2 diabetes in Zucker diabetic fatty rats

The world witnesses an explosive increase in diabetes, demanding intensified prevention and treatment not least for the low-income population. The plant, Stevia rebaudiana Bertoni, has been used for the treatment of diabetes in traditional medicine. We have previously demonstrated that stevioside, a diterpene glycoside isolated from the plant Stevia rebaudiana Bertoni, possesses insulinotropic, glucagonostatic, antihyperglycemic, and blood pressure–lowering effects in animal studies. We have also found that a dietary supplement, Abalon, of soy protein, isoflavones, and cotyledon fiber has beneficial effects on cardiovascular risk markers in type 2 diabetes. The aim of this study was to investigate if the combination of stevioside and a dietary supplement of soy protein possesses beneficial qualities in the treatment of type 2 diabetes and the metabolic syndrome. We randomized male Zucker diabetic fatty rats into 4 groups and fed them the different test diets for 10 weeks: (A) standard carbohydrate-rich laboratory diet (chow), (B) chow + stevioside (0.03 g/kg body weight [BW] per day), (C) 50% soy (Abalon) + 50% chow (adjusted for vitamins and minerals), and (D) 50% soy (Abalon) + 50% chow + stevioside 0.03 g/kg BW per day. We measured plasma glucose, blood pressure, weight, and food intake once weekly. The animals were equipped with an intra-arterial catheter, and at week 10, the conscious rats underwent an intra-arterial glucose tolerance test (2.0 g/kg BW). Stevioside exerts beneficial effects in type 2 diabetic Zucker diabetic fatty rats, that is, lowers blood glucose (area under the glucose curve [AUC 30min]: group A vs B, a 19% reduction; and group C vs D, a 12% reduction; P < .001). We did not detect any effect on insulin or glucagon responses. After 2 weeks of treatment, a decrease in the systolic blood pressure was observed in the stevioside-treated groups ( P < .01). Abalon had beneficial effects on cardiovascular risk markers, that is, (1) lowers total cholesterol ( P < .01), (2) reduces triglycerides ( P = .01), and (3) reduces free fatty acids ( P < .001). The combination of stevioside and soy supplementation appears to possess the potential as effective treatment of a number of the characteristic features of the metabolic syndrome, that is, hyperglycemia, hypertension, and dyslipidemia. A long-term human study of the concept in type 2 diabetic subjects is needed to verify these promising results in animal diabetes.

The effect of collection and cooling conditions on water transport characteristics of equine spermatozoa

Recently, two-way oil/water separation materials bearing both “water-removing” and “oil-removing” functions are of great interest for treating environmental water pollution. Despite having switchable surface wettability, these materials are generally designed to possess superhydrophilicity in air, which, standing on the viewpoint of thermodynamics, is unstable and easy to lose the superwetting property. Concerning the full exploitation of sustainable biomass resources, herein, we use soy protein and ramie fiber to fabricate a cross-linked biocomposite whose amphiphilicity can be tuned by introducing a low surface-energy agent, octadecylamine. The resultant composite can be used as a coating for stainless steel meshes, preparing stably hydrophobic surface in air as well as achieving dual superlyophobicity under liquid that is required for efficiently separating light and heavy oils from water. Furthermore, a high separation efficiency is acquired for both light oil/water and heavy oil/water mixtures during cyclic usage. Notably, the fully bio-based coating displays high resistance against mechanical abrasion and harsh chemical corrosions (acid, alkaline, and salt) without losing high separation efficiency, indicating the potential application of such material in oily wastewater treatment.

Beneficial Effects of a Soy-Based Dietary Supplement on Lipid Levels and Cardiovascular Risk Markers in Type 2 Diabetic Subjects

Consumption of soy protein has recently been shown to improve the blood lipid levels in nondiabetic subjects. The purpose of this study was to evaluate if a dietary supplement of soy protein, isoflavones, and cotyledon fiber (Abalon) affects cardiovascular risk markers, blood glucose, and insulin levels in type 2 diabetic subjects. Twenty type 2 diabetic subjects participated in a crossover trial. They were randomized to double-blind supplementation for 6 weeks with Abalon (soy protein [50 g/day] with high levels of isoflavones [minimum 165 mg/day] and cotyledon fiber [20 g/day]) or placebo (casein [50 g/day] and cellulose [20 g/day]), separated by a 3-week wash-out period. The results are expressed as means +/- SD. The percentage mean treatment difference between Abalon and placebo demonstrated significantly lower mean values after Abalon for LDL cholesterol (10 +/- 15%, P < 0.05), LDL/UHDL ratio (12 +/- 18%, P < 0.05), apolipoprotein (apo) B100 (30 +/- 38%, P < 0.01), triglycerides (22 +/- 10%, P < 0.05), and homocysteine (14 +/- 21%, P < 0.01), whereas the total cholesterol value tended to be less significant but still lower (8 +/- 15%, P < 0.08). No change occurred in HDL cholesterol, apo B100/apo A1 ratio, plasminogen activator inhibitor 1, factor VIIc, von Willebrand factor, fibrinogen, lipoprotein(a), glucose, HbA1c, or 24-h blood pressure. These results indicate beneficial effects of dietary supplementation with Abalon on cardiovascular risk markers in type 2 diabetic subjects. This improvement is seen even in individuals with near-normal lipid values.

Production of Textile Fibers from Zein and a Soy Protein‐Zein Blend

ABSTRACTZein fibers were successfully prepared by a wet‐spinning technique from a zein suspension formulated with 15% zein, 60% water, 22% 0.4N sodium hydroxide, and 3% urea by weight. Tenacities were measured with an Instron machine, and flexibility was determined by noting the smallest diameter rod around which a fiber could be looped without breaking. After spinning, the tenacity of the zein fibers was improved by modification with several agents: acetic anhydride for acetylation, glutaraldehyde, and dialcohols for cross‐linking and physical stretching. The tenacity and flexibility of the fibers were measured at 11, 65, and 100% rh. Untreated fibers had tenacities of 3.41, 2.65, and 0.17 g/tex at 11, 65, and 100% rh, respectively. A combination of chemical treatments (20% glutaraldehyde and 95% acetic anhydride) and 115% stretching increased tenacities to 6.89. 6.56, and 1.17 g/tex at 11, 65, and 100% rh, respectively. Control zein fibers had flexibilities of 5 and 2.5 mm at 11 and 65% rh, respectively, whereas the treated fibers had flexibilities of 1.5 mm at both humidities. Extrusion of zein fibers was not successful. Zein‐soy protein mixture could be extruded, but properties of wet‐spun fibers of zein‐soy blends were not much improved over those of soy protein alone. The tenacity of blended soy protein‐zein fibers was greater than that of soy protein fibers at 11% rh.

Endocrinological response to soy protein and fiber in mildly hypercholesterolemic men

Soy protein and soy fiber may affect hormones involved in cholesterol metabolism. Therefore, plasma insulin, total thyroxine (T4), free thyroxine index (FTI), triiodothyronine (T3), and thyroid stimulating hormone (TSH) were measured in 17 hypercholesterolemic men consuming baked products containing 50 g/d of protein and 20 g/d of fiber from either soy flour (SF), soy protein isolate (ISP)/soy fiber (ISP/SCF), ISP/cellulose (ISP/Cell), or nonfat dry milk/cellulose (NFDM/Cell). A latin square design was used and included all four dietary treatments, each lasting four weeks. Hormones were analyzed at the end of each experimental period and after an initial baseline period of 10 days. Although the mean values of T4 showed an increase in all treatments relative to baseline, significant differences ( p<0.05) occurred only between the ISP groups and baseline. A similar pattern was observed with FTI ( p<0.01). Mean insulin concentrations significantly increased ( p<0.05) when subjects were fed SF compared to the ISP/SCF treatment. No effects were seen with either T3 or TSH. Results are consistent with the findings of animal studies, as well as human studies investigating T3/T4 influences on lipid metabolism, and suggest that the mechanism for the hypocholesterolemic effect of soy protein is via a T4-mediation.

Nutritional benefits of soy protein and soy fiber

Soy protein and soy fiber are common ingredients in many foodstuffs. Various kinds of soy protein, including soy flour, soy-protein concentrate, and isolated soy protein, are currently used in human foods. Soy proteins are used in infant formulas and enteral nutrition products, as ingredients in meat products, and as protein supplements. Although it is a plant protein, the protein quality of soy protein is excellent. Soy fiber is used in enteral nutrition products and some bakery goods. Research shows that soy fiber provides the important health benefits usually associated with dietary fiber, including improved laxation and cholesterol-lowering ability. This review provides background information on soy protein and soy fiber and their use in human foods.

Soy products and the human diet

This review focuses upon the nutritional significance of soy products in the human diet. The impact of the consumption of soy foods on a range of diet and health issues are discussed, including protein quality and growth promoting effects of soy protein, allergies in children, hypocholesterolemic effects of soy protein and soy fiber, effects of soy products upon glucose tolerance, and the bioavailability of zinc and iron from soy foods. Recent research reports involving humans and relevant animal studies are reviewed.

Morphology and Texture of Turkey Summer Sausages

Several turkey summer sausage formulations with different proportions of mechanically deboned turkey meat (MDTM), hand deboned turkey meat (HDTM), texturized MDTM (heat denatured strands), beef fat, and structured soy protein fiber were made. The morphology was studied microscopically and related to the firmness of the product. Higher shear force values in sausages containing hand deboned meats coincided with a higher proportion of intact structural components mainly contributed by muscle fibers. The use of 100% MDTM in summer sausages resulted in a very soft and almost unacceptable product. By incorporating 65% HDTM and other ingredients with 35% MDTM, the texture was improved and judged acceptable by a taste panel.

Optimum Utilization of Turkey in Summer Sausages

Summer sausages were formulated with different proportions of hand deboned turkey meat (HDTM), mechanically deboned turkey meat (MDTM), texturized MDTM (heat denatured strands), and turkey hearts. Various nonturkey ingredients such as structured soy protein fiber (SPF), beef fat, and a natural red beet color were also included in some of the formulations. Objective and subjective techniques were used to analyze the summer sausages.The results indicated that a sausage formulation with approximately one-third MDTM combined with two-thirds HDTM (equal portions of dark turkey bits and turkey hearts) provided a very acceptable product texture. The addition of a small amount of beef fat or red beet color further improved the appearance of the sausages. Close adherence to proper grinding and mixing temperatures resulted in good particle definition. The optimum combination of ingredients provided a turkey product as acceptable as the traditional beef summer sausage, which was used as a comparison treatment for the chemical, physical, and sensory evaluations. Meat ingredient costs for the turkey summer sausages manufactured in these experiments were substantially lower than the costs for a similar product made with beef.

Descriptors for Texture Profile Analysis of Frankfurter‐Type Products from Minced Fish

ABSTRACTThe texture profile of frankfurter‐type products prepared from minced Spanish mackerel (Scomberomorus maculatus) was evaluated. Twelve character notes were identified: springiness, hardness, cohesiveness, moisture release, crumbliness, coarseness, graininess, juiciness, adhesiveness, lumpiness, chewiness, and mouthfeel‐oiliness. Overall texture acceptability was also evaluated. Differences in juiciness and mouthfeel‐oiliness were not detected. Springiness, hardness, cohesiveness, and lumpiness had the highest correlation with the overall texture acceptability. Products with 10% soy protein fiber (SPF) were better accepted than those having 20% or no SPF. Egg white (to 20%) improved the texture; however, its flavor was detectable when 10% or more was added. The most acceptable texture was exhibited by products containing 5–10% ground drumdried fish.

PROCESSING AND INGREDIENT INFLUENCES ON TEXTURE OF COOKED COMMINUTED FISH MUSCLE

ABSTRACTThe study was conducted to determine process requirements and formulations necessary to prepare a coarse textured smoked fish sausage. Sausages prepared from Spanish mackerel, using two different comminution processes and different levels of shortening, soy protein fiber (SPF) and added ice, were evaluated for texture using both instrumental methods and taste panels. Previous work has shown that fish muscle chopped with NaCl and polyphosphate in a silent cutter had a texture similar to a hard gelatin gel when steam cooked and a mushy texture when cooked in a smokehouse. The cooked fish sausages had a sponge‐like texture after freezing and thawing. These unacceptable textural characteristics were overcome by the incorporation of at least 12g shortening/100g fish muscle, and SPF at 15:85 SPF/fish muscle using a two‐stage comminution process. Shear and compressive strength were markedly diminished when ice was added in excess of 15%. The addition of shortening at the level of 12 g/100g fish muscle and SPF significantly improved taste panel ratings on texture relating to the structure of material and increased juiciness. The mechanical properties of the sausages were significantly modified by addition of SPF in a ratio 30g SPF/70g of fish muscle. A comminution process for the formulation containing 25g shortening/100g fish muscle resulted in significantly reduced strength and water‐holding capacity and increased brittle‐ness of the cooked product. There were no significant differences in texture and general acceptability between products prepared from the mechanically deboned as compared to the filleted fish if the moisture content and bone residue in the raw material were carefully controlled.

Palatability of Ground Beef Patties Containing Peanut Meal, Structured Soy Protein, and Mechanically Processed Beef

Abstract Ground beef patties containing, varying levels of peanut meal, structured soy protein fiber, and mechanically processed beef were formulated. A trained sensory panel evaluated patties for differences in tenderness, juiciness, and cohesiveness. Tenderness was also evaluated with the Universal Instron Testing Machine. Addition to MPB of PM alone increased the tenderness and cohesiveness of ground beef patties but did not affect juiciness. Addition of SPF decreased tenderness and juiciness but did not affect the cohesiveness of ground beef patties. Formulations containing SPF had less cooking loss than formulations without SPF.

SENSORY AND PHYSICAL MEASUREMENTS OF DRY FERMENTED SALAMI PREPARED WITH MECHANICALLY PROCESSED BEEF PRODUCT AND STRUCTURED SOY PROTEIN FIBER

ABSTRACTDry fermented salami was prepared from formulations in which 0, 15 and 30% levels of both mechanically processed beef product (MPBP) and structured soy protein fiber (SSPF) were incorporated. A 10‐member trained sensory panel for flavor found that the frequency of undesirable flavors was highest for salami with 15% SSPF‐pH 6.2‐0% MPBP and lowest for 0% SSPF‐15% MPBP and 0% SSPF‐30% MPBP. A second l0‐member trained panel found that the salami with 30% SSPF‐0% MPBP was lightest in color, while a 116‐member untrained panel found this formulation was undesirable in flavor, tenderness, and overall desirability. Instron and Hunter Color Difference measurements reflected a toughening and lightening of color, respectively, for the 30% SSPF‐0% MPBP salami in contrast to those treatments made with MPBP. Data from objective measurements (Instron and Hunter Color Difference Meter) were combined for all treatments and showed that salami increased in firmness and darkened with drying time. Both the trained and untrained sensory panels rated salami manufactured with 15 or 30% MPBP as generally comparable to the control salami.

Lactic Acid, pH and Bacterial Values of Dry Fermented Salami Containing Mechanically Deboned Beef and Structured Soy Protein Fiber

Various combinations of mechanically deboned beef (MOB) and structured soy protein fiber (SSPF) were used at 15 and 30% levels in formulation of dry fermented salami. Lactic acid, pH and bacterial assessments were conducted at 24-h intervals during the pan-curing stage and at 15-day intervals during the 60-day drying period. The substitution of MDB or SSPF in the 11 separate salami treatments had no effect upon pH, lactic acid content or growth of various bacteria. Bacterial evaluation included determination of total aerobic plate counts, Lactobacillus, Staphylococcus and psychrotrophic bacteria. Lactic acid content and pH values were within ranges typical for dry fermented salami. Lactic acid content increased as a function of increased Lactobacillus numbers resulting in lowered pH values. Total aerobic plate and psychrotrophic numbers paralleled to some degree the Lactobacillus counts over the entire study. A low incidence of non-mannitol fermenting-coagulase positive Staphylococcus was observed. It would appear that MOB and SSPF can be successfully substituted at elevated levels in dry fermented salami from a microbiological standpoint, while not interfering in lactic acid production needed for flavor and preservation.

Quality of Patties Containing Mechanically Deboned Broiler Meat, Hand Deboned Fowl Meat and Two Levels of Structured Protein Fiber

Structured soy protein fibers (SPF) at 8 and 16% levels were incorporated into two poultry patty formulations containing mechanically deboned broiler meat (MDBM) and hand deboned fowl meat (HDFM). A third formula composed of MDBM and HDFM with no SPF served as a control. The soy product was a flesh-like fiber structured from soy isolate. Ingredients were mixed, ground and stuffed into casings. Products were tempered to —3°C, sliced and stored at —40° C. for up to eight weeks. Quality characteristics measured were color (Hunter Color and Color Difference Meter), texture (Instron), and cook loss. A 12-member trained panel characterized the products by Quantitative Descriptive Analysis (QDA).Frozen and heated patties exhibited a darker (lower l value) and redder (higher aL value) appearance as level of SPF decreased. Texture, as measured by force to shear a 2.5 cm. slice, increased from 2.10 to 2.57 kg. as level of SPF increased from 0 to 16%. Cook losses, evaporative and drip, were greatest in patties with 0% SPF (36.11%) and least in patties with 16% SPF (30.32%). Panelists characterized the patties with 0% SPF as more chewy and elastic, coarser in particle size and shape, and more moist than the other products. Patties with 0 and 8% SPF ranked highest for overall impression, scoring 37.6 and 37.0 respectively on a 0—60 QDA scale.

Texture — Structure Relationships in Texturized Soy Protein 1. Textural Properties and Ultrastructure of Rehydrated Spun Soy Fibers

Texture is a major problem of soy based texturized food products (meat analogs). The texture and structure of rehydrated spun soy protein fibers was investigated and compared with meat. Physical properties were measured using an Instron tester. An average breaking strength of 2.12×103g/g was obtained, higher than for most cooked red meats, but the addition of amorphous components to soy fibrils during manufacture may lower the breaking strength of resulting meat analogs. Break elongation of spun soy was 304%, much higher than that of cooked meat and this parameter appears an important determinant of soy texture. To evaluate the effect of repeated applications of stress such as might result during mastication, soy and cooked meat samples were cycled at half their break elongation and the force required for this elongation compared. Soy experienced a faster decrease in force needed for constant elongation than did meat. Elasticity and stress relaxation measurements made at half break elongation showed that soy fibers were less able to return to their original form upon the removal of stress and lost more applied stress than cooked meat. Scanning electron microscopy of spun soy fibers revealed them to be uniform and homogeneous, lacking the repeating structure of muscle.