Effect of Chitin as Coagulating Aid on Protein Yield, Composition and Functionality of Tomato Seed Protein Concentrates

The effectiveness of chitin as coagulating aid, protein coagulants and coagulation temperatures in recovering tomato seed proteins, and their effect on composition and emulsion properties of tomato seed protein concentrates (TSPC) were investigated. Citric acid, hydrochloric acid, or a mixture of citric acid and hydrochloric acid were used and chitin addition ranged from 0 to 1.0% (protein basis). Coagulation temperatures employed were 25°C, 60°C or 95°C. Samples with no chitin added resulted in significantly (P < 0.05) lower protein yields than samples with chitin addition. Ash content of the TSPC was significantly (P < 0.05) affected by chitin addition and coagulation temperature. Lowest crude fat content was obtained with citric acid at 25°C. Lowry protein and total nitrogen was highest without chitin addition. Samples coagulated at 25°C showed highest emulsion ability and emulsion stability. The least stable emulsions were produced with hydrochloric acid. Chitin addition did not affect emulsion properties.     

Effects of Selected Inorganic Phosphates, Phosphate Levels and Reduced Sodium Chloride Levels on Protein Solubility, Stability and pH of Meat Emulsions

The effects were determined of four selected inorganic phosphates at two levels combined with two reduced levels of sodium chloride on the stability, pH, solubilized protein and water-holding capacity of raw meat emulsions. Tetrasodium and tetrapotassium pyrophosphates resulted in higher raw pH, greater protein solubility and improved emulsion stability and water-holding capacity than sodium or potassium tripolyphosphate. Increasing the sodium chloride level from 0.75% to 1.50% decreased the relative effects of phosphate type and level on emulsion stability. The effect of doubling phosphate level on emulsion stability was much less than the effect of doubling the sodium chloride level; however, doubling phosphate level was more effective in increasing pH and soluble protein level of raw emulsions.     

Emulsification of Commercial Dairy Proteins with Exhaustively Washed Muscle

The addition of dairy proteins to exhaustively washed chicken breast muscle improved the emulsion stability in heated cream layers (emulsions) containing whey protein concentrate (WPC) or whey protein isolate (WPI). The initial weight of the heated cream layers made with WPC or WPI was heavier than those for sodium caseinate (CNate) or milk protein isolate (MPI). The addition of CNate or MPI resulted in decreased emulsion stability and increased inhibition of myosin heavy chain and actin participation in the emulsion formation compared to WPC or WPI.     

酸角乳酸菌饮料的研制

以全脂乳粉、酸角为主要原料,探讨了酸角乳酸菌饮料的制备工艺条件。通过正交试验研究了酸角乳酸菌饮料产品配方及乳化稳定剂的复配方案。结果表明,酸角乳酸菌饮料最适配料为白砂糖10.0%、酸角汁4.0%、蜂蜜1.0%、酸角香精0.075%。酸角乳酸菌饮料最佳稳定剂为羧甲基纤维素钠0.30%、果胶0.15%、三聚磷酸钠0.06%。     

Effects of Collagen and Alkaline Phosphate on Time of Chopping, Emulsion Stability and Protein Solubility of Fine-Cut Meat Systems

Four meat emulsions were prepared with two levels of collagen and alkaline phosphate. Samples were taken at five different chopping temperatures and evaluated for total chopping time, emulsion stability and protein solubility. Adding additional collagen to meat emulsions shortened total chopping time, and decreased emulsion stability but had no effect on protein solubility. The addition of 0.25% sodium tripolyphosphate (STPP) improved emulsion stability but resulted in no significant (p>0.05) change in chopping time or protein solubility. The high-collagen-phosphate (HCP) treatment resulted in less fat, gelliquid, solid and total cookout when compared with high-collagen no-phosphate (HC) and low-collagen no- phosphate (LC) treatments. Maximum emulsion stability was obtained at 13°C.     

pH and Sodium Chloride Effects on Emulsifying Properties of Egg Yolk Phosvitin

The emulsifying properties of phosvitin dissolved in water and 0.1, 0.5 and 1.0 M NaCl were determined from pH 3 to 10. The change in its emulsifying activity (EA) with pH was slight but significant (p<0.05) and emulsion stability (ES) was relatively high (68-73%), except at pH 5 (17%) and 10 (48%). The EA of phosvitin was higher than that of bovine serum albumin (BSA) at pH 3 or 8 and ES was higher than BSA at all pH levels except at pH 5 and 10. Added NaCl decreased in the EA of phosvitin at pH 3 and 10 and decreased the ES between pH 3 and 9. Increased instability of emulsions resulted mainly in coalescence of oil droplets at NaCl ≥ 0.5M. Salt increased the viscosity of phosvitin emulsion only at pH 3 but not at pH > 5. The viscosities of BSA emulsions were higher than those of phosvitin at pH 3, 5 or 8.     

Some Physical Parameters Involved in the Addition of Inorganic Phosphates to Reduced-Sodium Meat Emulsions

The effects of preblending, order of addition and the physical state of alkaline phosphates on the stability of reduced sodium chloride (0.75%) meat emulsions were determined. Preblending meat batches with reduced sodium chloride for 16 hr resulted in no significant effect upon the stability of meat emulsions, with or without the presence of alkaline phosphates. However, the addition of sodium tripolyphosphate (STPP) and tetrasodium pyrophosphate (TSPP) significantly improved emulsion stability. Neither the order of TSPP addition in relation to that of sodium chloride nor the physical state of its addition (dry or in solution) affected emulsion stability or the soluble protein level.     

Effects of Reduced Sodium Chloride and Added Phosphates on Physical and Sensory Properties of Turkey Frankfurters

Turkey frankfurters containing 20 and 40% salt (NaCl) reductions were manufactured and evaluated in comparison to a standard formulation containing 2.5% sodium chloride. Additionally, either 0.4% sodium tripolyphosphate (TPP), sodium hexametaphosphate (HMP), or sodium acid pyrophosphate (SAPP) were incorporated into frankfurters containing similar salt reductions. Phosphates improved emulsion stability and yields, especially in formulas with 40% salt reductions. TPP increased frankfurter firmness compared to that provided by SAPP or HMP regardless of salt level, but TPP had a deleterious effect on freshness at the 2.0% salt level. SAPP was more effective than HMP in improving plumpness and enhancing salt flavor intensity. Overall, SAPP appeared to provide greater benefits than either HMP or TPP as a single polyphosphate for reduced salt turkey frankfurters.     

Phosphate and Modified Beef Connective Tissue Effects on Reduced Fat, High Water-added Frankfurters

The effects of acidic, neutral and alkaline phosphates and amounts of modified beef connective tissue (0, 10 or 20%) were determined on the characteristics of 20% fat/20% water-added frankfurters or 10% fat/30% water-added frankfurters. Processing yields were lowest in both formulations with acidic phosphate. Cured meat color intensity was higher with the acidic phosphate than with alkaline or neutral phosphates. Alkaline or neutral phosphate samples partially recovered losses in emulsion stability that had occurred due to connective tissue level. The addition of 20% connective tissue improved processing yields and decreased cohe-siveness of 10% fat/30% water added frankfurters. Connective tissue addition had no effect on microbial stability. Acidic phosphates might be more effective in direct treatment of high collagen materials in a preblend rather than in direct addition into a frankfurter formulation.     

Effects of Inorganic Phosphates and Sodium Hydroxide on the Cooked Cured Color, pH and Emulsion Stability of Reduced-Sodium and Conventional Meat Emulsions

Phosphates that increased meat emulsion stability the most also caused the highest decrease in cured color development. The addition of 0.125% sodium hydroxide also reduced cured color development. Holding uncooked emulsions, containing either sodium tripolyphosphate or tetrasodium pyrophosphate, up to 60 min after emulsion preparation plus adding tetrasodium pyrophosphate later in the emulsification procedure improved cured color development upon cooking. In both cases, cooked pH increased as cured color improved, and emulsion stability declined. This suggested that phosphate effects other than, or in addition to, pH were involved in cured color development and emulsion stability.     

Recovery of proteins from beef bone and the functionality of these proteins in sausage batters

Four solutions [4% sodium chloride (control), 4% sodium chloride with 0.3% sodium tripolyphosphate (STP), 0.3% tetrasodium pyrophosphate (TTP) or 0.05 M sodium hydroxide (NaOH)] were used to extract proteins from beef bones. Three bone solution ratios (1:1, 1:4 or 1:10), three bone types [vertebra (lumbar), rib (4-7) and leg (femur)] and two methods of protein recovery from the extraction slurries [dialysis against 0.03 M potassium phosphate buffer (pH 5.3) and acid precipitation] were evaluated. Solutions containing phosphates or NaOH were more effective in extracting protein than sodium chloride alone. Total protein recovery was highest from vertebra bones while extraction of proteins from leg bones resulted in the lowest recovery. A solution to bone ratio of 1 to 10 recovered more total protein from vertebra or rib bones than leg bones. Dialysis recovered more total protein from extraction solutions when the protein concentration was low. Acid precipitation, however, worked best if the protein concentration in the extraction solution was high. Extraction procedures resulted in some myosin degradation. Proteins extracted from beef bone materials and recovered by dialysis, performed equally as well as other commercially available proteins when added to a finely comminuted sausage product.     

Oil-in-Water Emulsions Stabilized by Sodium Caseinate or Whey Protein Isolate as influenced by Glycerol Monostearate

Competitive adsorption between glycerol monostearate (GMS) and whey protein isolate (WPI) or sodium caseinate was studied in oil-in-water emulsions (20 wt % soya oil, deionized water, pH 7). Addition of GMS resulted in partial displacement of WPI or sodium caseinate from the emulsion interface. SDS-PAGE showed that GMS altered the adsorbed layer composition in sodium caseinate stabilized emulsions containing < 1.0 wt % protein. Predominance of β-casein at the interface in the absence of surfactant was reduced in the presence of GMS. The distribution of α-lactalbumin and β-lactoglobulin between the aqueous bulk phase and the fat surface in emulsions stabilized with WPI was independent of the concentration of added protein or surfactant.     

超高压及三聚磷酸钠质量分数对肌球蛋白凝胶保水性及热胶凝过程的影响

为探究超高压处理及三聚磷酸钠质量分数对肌球蛋白凝胶保水性及热胶凝过程的影响,在不同压力条件（100、200、300 MPa）下对添加不同质量分数（0%、0.15%、0.30%、0.45%）三聚磷酸钠的兔骨骼肌肌球蛋白进行25 ℃、9 min超高压处理后再经程序升温（1 ℃/min）制备凝胶,以未经超高压处理的含质量分数0.30%三聚磷酸钠的肌球蛋白为对照组,测定凝胶的保水性,并筛选出对其有显著影响的参数组合。在该条件下对蛋白的溶解度、ATP酶活力和升温过程中的蛋白二级结构含量、表面疏水性、活性巯基含量、静态流变性以及凝胶微观结构等指标进行测定。结果显示：含质量分数0.15%三聚磷酸钠的肌球蛋白经不高于200 MPa的超高压处理后,其溶解度显著下降,ATP酶活力显著上升（P＜0.05）;质量分数0.15%三聚磷酸钠对超高压处理诱导的肌球蛋白功能特性变化存在拮抗作用,且蛋白在升温过程中的变性、聚集受抑制,随着三聚磷酸钠质量分数升高到0.30%,拮抗作用消失,蛋白在热胶凝过程中结构充分展开,疏水基团与所包埋的巯基快速暴露,形成的凝胶结构富有弹性且致密有序,保水性显著提高（P＜0.05）;而300 MPa超高压处理使蛋白的ATP酶活力丧失,溶解度及热变性程度降低,分子间交联弱化,最终使凝胶保水性显著下降（P＜0.05）。三聚磷酸钠通过影响蛋白的结构与理化特性,改变其热凝胶形成过程中的变性速率与交联方式,导致最终凝胶保水性发生变化。     

Pretreatment of Coastal Bermudagrass with Sodium Hydroxide and Cellulase Before Ensiling

When a cellulase produced by Trichoderma viride was added to Coastal bermudagrass before ensiling to increase digestibility, the content of the residual water-soluble carbohydrate was increased significantly above controls or NaOH-treated silage. Significant increases of acetic and lactic acids were obtained by pretreatment with NaOH followed by neutralization before ensiling and also by NaOH plus cellulase treatment (both neutralized and not neutralized) before ensiling. Treatment of Coastal bermudagrass with NaOH, which was not neutralized before ensiling, produced poor silage with high pH and butyric acid content. Digestibility was significantly increased by either NaOH treatment with or without cellulase. In addition, acetic acid produced during in vitro digestibility studies was significantly higher after 48-h incubation for all treatments compared with controls. Coastal bermudagrass silage made with all treatments except NaOH that was not neutralized showed significantly higher propionic acid content at the end of 48-h fermentation than controls. Laboratory studies suggest that treatment with NaOH and cellulase improves silage.     

Characteristics of Sodium Caseinate- and Soy Protein Isolate-Stabilized Emulsion-Gels Formed by Microbial Transglutaminase

ABSTRACT:  Protein-stabilized emulsion gels were prepared via microbial transglutaminase (mTGase) catalysis, and their physicochemical characteristics were examined. Emulsion oil droplet size and interfacial protein load were measured. The sodium caseinate and soy protein isolate emulsion gels exhibited different microstructures and physical properties. The emulsion gels improved the storage stability of aroma compounds. Rheological measurements of the emulsion gels revealed interesting strength, gelation kinetics, and thermal sensitivity properties. The mTGase-induced emulsion gels comprised a fine network which led to less release of aroma compounds upon storage than did emulsions. These results suggest that emulsion gels may be used to improve the texture of food emulsions and to control release of food aromas.     

Influence of xanthan gum on the formation and stability of sodium caseinate oil-in-water emulsions

Studies have been made of the changes in droplet sizes, surface coverage and creaming stability of emulsions formed with 30% (w/w) soya oil, and aqueous solution containing 1 or 3% (w/w) sodium caseinate and varying concentrations of xanthan gum. Addition of xanthan prior to homogenization had no significant effect on average emulsion droplet size and surface protein concentration in all emulsions studied. However, addition of low levels of xanthan (≤0.2 wt%) caused flocculation of droplets that resulted in a large decrease in creaming stability and visual phase separation. At higher xanthan concentrations, the creaming stability improved, apparently due to the formation of network of flocculated droplets. It was found that emulsions formed with 3% sodium caseinate in the absence of xanthan showed extensive flocculation that resulted in very low creaming stability. The presence of xanthan in these emulsions increased the creaming stability, although the emulsion droplets were still flocculated. It appears that creaming stability of emulsions made with mixtures of sodium caseinate and xanthan was more closely related to the structure and rheology of the emulsion itself rather than to the rheology of the aqueous phase.     

Sodium hydroxide and sodium tripolyphosphate effects on bind strength and sensory characteristics of restructured beef rolls

Restructured beef rolls formulated with 1% NaCl (controls) or with 1% NaCl plus 0.07% NaOH or 0.375% sodium tripolyphosphate (STPP) had different (p < 0.05) relative bind strength and cooked yield, as follows: STPP > NaOH > controls. Percent cooked yield was inversely affected (p < 0.05) by added water level (5 > 10 > 20%). Bind values were lower (p < 0.05) in rolls with 20% added water. NaOH and STPP rolls had higher pH (p < 0.05) than controls (6.28, 6.22, and 6.07, respectively). Panel cohesiveness, juiciness, and acceptability scores were also generally higher (p < 0.05) for NaOH and STPP rolls, compared to controls. There was a high correlation (0.93) between panel cohesiveness scores and instrumental bind values. At 20% added water, STPP rolls were preferred, but at 10% added water, STPP and NaOH rolls were similar in overall acceptability. Thus, if added water level is not too high, NaOH alone or perhaps with other binding agents may be an alternative to phosphates in cooked beef rolls.     

Functional Properties and Bitterness of Sodium Caseinate Hydrolysates Prepared with a Bacillus Proteinase

The functional and physicochemical characteristics, and bitterness were evaluated on sodium caseinate hydrolysates generated with a commercial Bacillus proteinase complex. At low degrees of hydrolysis (0.5 and 1.0% DH) the hydrolysates compared to the unhydrolyzed substrate had increased emulsion activity at pH 2 and 4. However, higher DH resulted in lower emulsion activities. At pH 8 and 10, the low DH hydrolysates displayed increased foam expansion and decreased foam drainage compared to the starting substrate. The Bacillus proteinase hydrolysates at higher DH had similar bitterness values to tryptic hydrolysates at equivalent DH. However, the Bacillus hydrolysate at 0.5% DH was less bitter (p<0.05) than the tryptic hydrolysate at the same DH.     

The effect of addition of flaxseed gum on the emulsion properties of soybean protein isolate (SPI)

The effect of addition of flaxseed gum on the emulsion properties of soybean protein isolate (SPI) were investigated in this study. Flaxseed gum with 0.05-0.5% (w/v) concentration was used together with 1% (w/v) SPI to emulsify 10% (v/v) soybean oil. The emulsion was analyzed for emulsion activity (turbidity), stability, particle size, surface charge, and rheological properties. The turbidity and absolute zeta-potential values decreased initially by the addition of flaxseed gum and subsequently increased with further increase in the gum concentration to reach their peak around 0.35% (w/v) gum. The particle size of the emulsion decreased and reached a minimum value at 0.1% (w/v) gum concentration. Any increase in gum concentration beyond this value resulted into increase in the particle size. This study would help to widen the application of SPI and flaxseed gum mixture, and also contribute to the understanding of protein-gum interaction in emulsion.     

紫菜酶解物的制备及其特性

坛紫菜用纤维素酶和木瓜蛋白酶分别或联合处理,考察了提取物的得率、DPPH自由基清除率、氨基酸组成、蛋白溶解性和乳化性等性质。结果发现,利用木瓜蛋白酶对紫菜进行酶解时,固形物提取率稍微高于纤维素酶,利用这两种酶进行复合酶解时虽然可以提高紫菜的固形物得率,但不会改变蛋白提取率。紫菜酶解物的DPPH自由基清除率与蛋白含量之间存在显著的正相关关系,可能与提取物中具有抗氧化活性的氨基酸含量增加有关。另一方面,紫菜经复合酶酶解4h以上,提取物的蛋白溶解性在任一pH下都接近100%。而且,紫菜酶解物的乳化性在pH9最好,但乳化稳定性在pH7最低。