Protein extractability of almond (Prunus amygdalus,batsch) seed

Studies were carried out on protein solubility of almond meal in several solvents, by varying some factors that govern the efficiency of protein extraction. Concentrations of sodium hydroxide in the range 0.025 to 0.1M extracted most of the protein in almond meal. The rate of stirring had an effect on protein extraction. Increasing the temperature to about 50°C enhanced protein solubility when extractions were carried out using 0.05M NaOH solution. The most efficient solvent: meal ratio was found to be 2000:1 (vol:wt) for a single extraction. Almond proteins displayed a markedly different pH-nitrogen solubility profile in salt solutions, showing minimal solubility at an acidic pH (pH 3), with a sharp rise in solubility to a maximum at neutrality.     

NITROGEN EXTRACTABILITY AND MOISTURE ADSORPTION CHARACTERISTICS OF SUNFLOWER SEED PRODUCTS

Diffusion-extracted (DE) sunflower meal and protein isolate were compared with untreated samples for their nitrogen extractability and moisture adsorption. Nitrogen extractability values of 90% were found at pH 7 or above in the untreated meal, whereas a maximum solubility of only 70% was achieved at pH 9.0 in the DE meal prepared at 60°C. DE meal prepared at 80°C had low solubility over a pH range of 1–11 which indicated substantial denaturation of the sunflower proteins. The untreated isolate showed a sharp minimum solubility point in contrast to the law solubility of the DE isolate over a pH range of 3–7. Moisture adsorption values for the samples held at 5, 20 and 30°C indicated little difference in moisture contents at relative humidities of 11–55%. At higher levels, however, the untreated meal adsorbed more moisture than the DE meal. A reverse trend was noticed for the isolates as the moisture content of the DE isolate was higher than the untreated sample. The rate of moisture uptake by sunflower kernels was slower than that observed with rapeseed or soybean meats and lower total moisture contents were observed after a 4 hr soaking period.     

SQUID PROTEIN ISOLATE: EFFECT OF PROCESSING CONDITIONS ON RECOVERY YIELDS

Loigo species of squid was investigated as a potential source of protein isolate. The various process parameters which influence extraction of protein (particle size, time, extraction pH, salt concentration, relative amount of solvent to squid tissue and temperature) were investigated. From this study the following parameters were chosen to optimize extraction: pH 11 (sodium hydroxide) or 4% salt concentration (sodium chloride, sodium hexametaphosphate in aqueous extractant); temperature = 22°C; time = 45 min; particle diameter = 2–3 mm; solvent-to-squid ratio = 10:1. Under these conditions, about 85% of the squid protein can be extracted. 65% of the extracted nitrogen is recovered as protein isolate by isoelectric precipitation at pH 5.     

Effect of Ice Storage on the Physicochemical and Dynamic Viscoelastic Properties of Ribbonfish (Trichiurus spp) Meat

ABSTRACT: Changes in physicochemical and dynamic viscoelastic properties of ribbonfish ( Trichiurus spp) meat during different periods of ice storage were investigated. The differential scanning calorimetry profile of fresh ribbonfish meat revealed transitions at 33.17 °C, 48.85 °C, and 60.96 °C, indicating denaturation temperature of different protein fractions. The effect of cornstarch or tapioca starch at 9% level on the viscoelastic properties of ribbonfish meat stored in ice for different periods was also evaluated. Total volatile basic nitrogen (TVBN) increased significantly ( P < 0.05) during ice storage for 24 d. However, the myosin heavy chain concentration was unaltered during the ice storage period, as revealed by sodium dodecyl sulphate-polyacrylamide gel electrophore-sis (SDS-PAGE) pattern. A significant ( P < 0.05) decrease in protein solubility (in phosphate buffer 50 m M , pH 7.5, containing 1 M NaCl), calcium-activated adenosine triphosphatase (ATPase) activity, and an increase in reduced viscosity at a protein concentration of 5 mg/mL was observed after 10 d of ice storage indicating protein denaturation and aggregation. The addition of tapioca and cornstarch enhanced storage modulus values of fresh ribbonfish meat. The gelatinization temperature of tapioca starch solution was found to be in the range of 60 °C to 65 °C and for cornstarch 67 °C to 70 °C, as revealed by the differential scanning calorimetry (DSC) profile and dynamic rheological testing. The viscoelastic properties of ribbonfish meat was altered significantly ( P < 0.05), both due to the addition of starch and ice storage period as revealed by frequency sweep of prepared gels.     

The aqueous extraction of glucosinolates from rapeseed

The losses of seed constituents from Brassica campestris var. Toria for various conditions of the leaching process developed at the Overseas Development Natural Resources Institute (ODNRI) were studied. Boiling seeds for 3 min at a seed/water ratio of 1:3 was sufficient to allow inactivation of the enzyme myrosinase; higher ratios did not increase losses in any of the constituents studied.
Heat treatment of the seeds (5 min in boiling water) reduced the nitrogen solubility at the native pH (6.5) from 28 to 8%. The pH had little effect on the extent of glucosinolate leaching from coarsely ground seeds and the minimum protein loss occurred close to the native pH. Increased water temperatures (40, 50 and 80°C) did not lead to an increased leaching efficiency over ambient temperature (20°C). Seed/water ratio was found to be the most important factor during leaching. Cross-current extraction over three stages at a seed/water ratio of 1:10 reduced the glucosinolate content by 98% while the crude protein loss was about 8.6%.     

PRODUCTION AND PROPERTIES OF PENCILLIUM ROQUEFORTI LIPASE

SUMMARY: A Penicillium roqueforti strain produced maximal amounts of lipase when grown in 0.5% casitone-1% Proflo broth, pH 5.5, at 27°C. Addition of butteroil, com oil or olive oil to the growth medium inhibited the lipase production. Under pH stasis the partially purified lipase of P. roqueforti had an optimum pH of 8.0 and an optimum temperature of 37°C. Maximum lipolytic activity occurred with 5% butteroil emulsion as the substrate. Manganese chloride and magnesium chloride stimulated the enzyme activity. Calcium, sodium and potassium sale had no appreciable effect on lipolysis; silver, mercury and zinc salts were inhibitory. The lipase was thermolabile, being inactivated completely within 10 min at 50°C. The lipase hydrolyzed tributyrin, tricaprylin, tricaprin, tripropionin and triolein in decreasing order.     

Extraction of lignans, proteins and carbohydrates from flaxseed meal with pressurized low polarity water

This study examined the application of pressurized low polarity water (PLPW) extraction of lignans, proteins and carbohydrates from defatted flaxseed meal. Key processing conditions included temperature (130, 160, 190 °C), solvent pH (4, 6.5 and 9), solvent to solid ratio (90, 150 and 210 mL/g) and introduction of co-packing material (0 and 3 g glass beads). The addition of 3 g glass beads increased the yields for all target compounds. The maximum yield of lignans (21 mg/g meal) was obtained at 170 °C with solvent to solid ratio of 100 mL/g meal at pH 9. Optimal conditions for protein extraction were pH 9, solvent to solid ratio of 210 mL/g meal and 160 °C. Total carbohydrates recovery was maximized at 215 mg/g meal (50% recovery) at pH 4 and 150 °C with solvent to solid ratio of 210 mL/g meal. The increase of temperature accelerated extraction, thus reducing solvent volume and time to reach equilibrium. For the extraction of proteins and carbohydrates, however, a temperature of 130-160 °C is recommended, as proteins and carbohydrates are vulnerable to thermal degradation.     

Optimised methodology for the extraction of protein from quinoa (Chenopodium quinoa Willd.)

Quinoa is a highly appreciated Andean pseudo‐cereal and has sparked attention worldwide due to its excellent nutritional value. The protein extraction parameters for defatted quinoa seed meal (DQSM) were optimised in this study. Initially, a Plackett–Burman design was applied to screen the factors displaying a potential effect on the quinoa protein extraction yield (Y %, g soluble protein/100 g total protein) being the main evaluated factors: pH, NaCl concentration, time, temperature, solvent type, particle size and solvent/meal ratio. Four main factors: temperature, solvent/meal ratio, pH and time selected from the screening step were optimised with a central composed design (CCD). The obtained response surface model (RSM) produced a satisfactory fitting of the results (R² = 0.9308). Optimal quinoa protein extraction conditions of 36.2 °C, solvent/meal ratio of 19.6/1 (v/w) and 90 min resulted in a protein yield of 62.1% (9.06 g of protein/100 g DQSM) which closely agree with the predicted value of 62.5%.The model was experimentally validated by extracting the quinoa protein using the optimal conditions revealed by RSM. The optimised conditions could be successfully employed in the design process of protein extraction from quinoa seed meal to obtain optimal yields.     

KINETICS OF THE THERMAL DEGRADATION OF METHYLMETHIONINE SULFONIUM IONS IN CITRATE BUFFERS AND IN SWEET CORN AND TOMATO SERUM

Thermal degradation of methylmethionine sulfonium ions was determined in sodium citrate buffers ranging in pH from 4.0–8.0. Reaction temperatures of 82 °, 88 °, 93 ° and 99 °C were studied at reaction times of 20, 40, 60 and 80 min. The same conditions were used to study the degradation of naturally occurring methylmethionine sulfonium ions in sweet corn and tomato serums. In each solvent system, the thermal degradation of these salts occurred according to first order kinetics; the reaction rates doubled for a 5–6 °C increase in temperature and activation energies of the reaction in the various media were comparable. The characteristic degradation kinetics provides a means of identifying methylmethionine sulfonium salts in fresh foods without having to resort to involved isolation procedures.     

蒸汽爆破辅助提取高温豆粕中的蛋白质

研究了蒸汽爆破对高温豆粕中蛋白质溶解性的影响和后续蛋白质提取工艺。结果表明:当蒸汽压力较低时,高温豆粕的氮溶解指数随着蒸汽压力的升高而提高,但当超过2.1 MPa时,压力对爆破处理的效果的影响不明显;豆粕的粒度对蒸汽爆破效果有一定的影响,当豆粕颗粒的平均小于100目时效果不佳,在20～80目时效果较好。当高温豆粕颗粒大小为20～80目,爆破条件为1.8 MPa,180 s时,蒸汽爆破处理使高温豆粕的氮溶解指数提高了1.1倍。对经蒸汽爆破处理的高温豆粕中蛋白质的提取条件研究表明,pH值和温度对蛋白质的提取率有较大影响。在优化条件下,经蒸汽爆破处理的高温粕的蛋白质提取率达到76.04%。     

Optimisation of extraction conditions and thermal properties of protein from the Andean pseudocereal cañihua (Chenopodium pallidicaule Aellen)

Response surface methodology (RSM) was used to optimise alkaline protein extraction from cañihua grain meal as to maximise protein extraction yield. Different factors (temperature, extraction time, solvent/meal ratio, pH and NaCl molar concentration) were screened, and their significant influence on the extracted protein yield was evaluated. The first four factors were selected and studied by RSM using a central composite design (CCD). The obtained model produced a satisfactory fitting of the results (R² = 0.801). Optimal cañihua protein extraction conditions corresponded to a temperature of 21 °C, time extraction of 5 min, solvent/meal ratio of 37/1 (v/w) at pH 10 resulting in a protein yield of 80.4 ± 1.3%, which closely agree with the predicted value of 81.4%. Moreover, protein degradation was studied via differential scanning calorimetry (DSC) obtaining a denaturation temperature of 93.4 °C and an enthalpy value of 1.22 ± 0.05 J g^?1. These results are interesting from a technological point to help in designing an optimal protein extraction process and cañihua food processing strategies.     

THE EFFECTS OF DELAYED PICKING AND HIGH-TEMPERATURE CONDITIONING ON THE TEXTURE OF HOT- AND COLD-BONED BROILER BREAST MEAT

Four trials were conducted to evaluate the effects of delayed picking for 30 min versus normal picking, high temperature conditioning at 32°C versus low temperature conditioning at 0°C, and hot boning versus cold boning on broiler breast meat tenderness, pH, sarcomere length and R-values. None of the treatments affected cold-boned shear values. Within the hot-boned group, delayed picking significantly increased shear value (14.5 kg) compared with normally picked samples (12.5 kg). Conditioning at 32°C significantly lowered shear values (12.5 kg) compared with 0°C (14.6 kg). High-temperature conditioning lowered muscle pH immediately after evisceration, but delayed picking had no effect. Following 24 h aging, treatments had no effect on muscle pH or R-value. These results indicate that 32°C conditioning temperature and early picking significantly reduced meat toughness, but not to a commercially practical degree.     

Effect of Extraction pH and Temperature on Isoflavone and Saponin Partitioning and Profile During Soy Protein Isolate Production

ABSTRACT: Soy protein isolates (SPIs) are produced industrially using methods using various protein extraction temperatures and pH values. The effects of process temperature (25°C or 60°C) and pH (8.5, 9.5, or 10.5) on isoflavone and group B saponin extraction, partitioning, and profile during bench-scale SPI production were evaluated. Protein, isoflavone, and saponin extraction increased with increasing temperature and pH. Substantial quantities of isoflavones and saponins remained in the insoluble fraction waste stream. Isoflavones were also lost to the whey waste stream, whereas saponins were not detected in the whey. Neutralization of SPI samples at the time of analytical extraction increased measured isoflavone concentrations for the pH 8.5 process extraction treatments, whereas neutralization substantially increased measured saponin concentrations in SPIs for all process extraction treatments. Malonylglucoside isoflavones were primarily converted to β-glucoside forms as temperature and pH were increased, and these conditions caused conversion of αg, βg, and βa saponins to saponin V, I, and II forms, respectively. Analytical extraction pH should receive careful consideration when analyzing soy matrices for isoflavones and saponins.     

响应面法优化碱性蛋白酶提取菜籽饼中可溶性蛋白质的研究

菜籽饼是油菜籽压榨制油的副产物,是提取蛋白质的良好资源。以菜籽饼为原料,利用碱性蛋白酶提取菜籽饼中的可溶性蛋白质。在系统考察液料比、加酶量、初始pH、提取温度及提取时间对可溶性蛋白质提取率影响的基础上,提取时间恒定在40min,利用响应面实验优化各主效因子,经回归分析获得最优的工艺条件:加酶量6500U/g、酶解温度45℃、初始pH11、液料比17∶1,在此工艺条件下可溶性蛋白质提取率为55.38%。     

Nitrogen extraction from defatted rapeseed,with particular reference to United Kingdom commercial rapeseed meal

Nitrogen extraction profiles of rapeseed (RS), post-press cake (PP) and commercial rapeseed meal (RSM), drawn from the same batch, were evaluated; the RS and PP being defatted in the laboratory prior to extraction. The RSM exhibited lower nitrogen extractability, with the profiles less sharply defined, at different conditions of pH and ionic environment than for RS or PP. This was attributed to the heat treatment received at the end of the process during the toasting-desolventisation. The nitrogen extractability of RSM was further investigated using double extraction techniques with different solvents (NaCl, CaCl₂ and water), over a wide range of pH. None of the extraction regimes studied suggested improved practical possibilities for meal protein extraction, compared with single aqueous extraction at high pH. Meal protein extracts however, were found to be comparatively high in crude protein when expressed on a solids basis, a fact which suggests the possibility for additional concentration by ultrafiltration.     

EFFECT OF TEMPERATURE DURING POST-MORTEM GLYCOLYSIS AND DEPHOSPHORYLATION OF HIGH ENERGY PHOSPHATES ON POULTRY MEAT TENDERNESS

SUMMARY– Tests made on pectoralis major muscles having post-slaughter pH values ranging between 6.1–7.0, indicated that holding poultry meat at 30 and 37°C during the onset of rigor mortis caused toughness. This toughening effect of high temperature appeared to occur when the pH level of the meat dropped from a value of about 6.3 to its ultimate low value and the adenosine triphosphate content dropped below 40% of its initial concentration. Holding temperatures at 10, 15 and 25°C during the onset of rigor mortis, or cooling to 15°C before the pH value dropped to about 6.3 produced more tender meat. After completion of post-mortem glycolysis and dephosphorylation of high energy phosphates, high temperature had no deleterious effect on tenderness. These results indicate that dephosphorylation of adenosine triphosphate at high temperature affects the mode or extent of stiffening of the muscular tissue and prevents tenderization.     

The effect of post-mortem conditions on the extractability and adenosine triphosphatase activity of myofibrillar proteins of rabbit muscle

Summary. 1. Washed myofibrils from rabbit muscle have been heated at pH values between 4.8 and 5.6 and temperatures between 35°C and 42°C. It has been found that, under these conditions, myofibrils lose their Ca²⁺ activated adenosine triphosphatase, their Mg²⁺ activated adenosine triphosphatase and also become less extractable in M KCl–30 mM sodium glycerophosphate, pH 6.2.
2. The reactions follow first-order kinetics and the rates are dependent on pH and temperature. The first order rate constants, enthalpies and entropies for the three reactions are sufficiently near each other to suggest that all three reactions are occurring simultaneously.
3. When a muscle is allowed to go into rigor at 37°C the extractability in M KCl–30 mM sodium glycerophosphate is reduced after 4 hr at 37°C when the pH of the muscle has reached 5.55. At the same time the Ca²⁺ adenosine triphosphatase activity falls but the Mg²⁺ adenosine triphosphatase does not. The latter is reduced by prolonging the period at 37°C to 6 hr.
4. It is suggested that there is present in muscle, undergoing rigor at 37°C, myosin which does not bind to actin and is readily denatured. When bound to actin, myosin in the myofibril is more resistant and denatures only after long exposure to a temperature of 37°C.     

EFFECTS OF pH ON QUALITY OF STORED TOMATO JUICE

Tomato juice was prepared by the hot-break method and filled hot into cans containing sufficient concentrated HCl to adjust pH to 4.0, 3.5, 3.0, 2.5 and 2.0. Controls were also prepared with no HCl added. Product was stored at ambient (18–22°C) and 40°C up to 3 months. As pH decreased below 4.0, consistency also showed a significant decline through pH 2.0. At the same time there was no apparent pH effect on serum viscosity. Further studies indicated that this effect was noticeable after 4 hr, at pH 3.0 to 5.0. Addition of as much as 1% NaCl to tomato juice had no effect on consistency of tomato juice. Lightness (Hunter color L ) decreased with pH after 3.5, redness (a_L) decreased after pH 4.0, and yellowness (b_L) decreased after pH 3.0. All storage effects were more profound at the higher temperature. The storage of tomato juices at pH less than 4.0 does not appear to be advantageous to the processor.     

PARTICLE SIZE, SALT CONCENTRATION and TEMPERATURE EFFECTS ON NITROGEN EXTRACTION of CHICKPEA (Cicer arietinum) BY RESPONSE SURFACE METHODOLOGY

This study was conducted to evaluate the effect of time, pH, particle size, %NaCl and temperature on total nitrogen (TN) extraction of low commercial grade chickpea ( Cicer arietinum ) grain, in order to find the optimum extraction conditions for further processing. Extraction times used were 30, 60, 90 and 120 min and the nitrogen extraction curve was carried out at a pH range of 2.0 to 11.0. Response surface methodology was used to evaluate the effect of particle size (100, 150 and 200 mesh), salt concentration (0, 0.3 and 0.6% NaCl) and temperature (25, 35 and 45C). No significant time effect was found on nitrogen extractability. However, a great pH effect on nitrogen extraction was observed. Results from the RSM analysis showed that the most adequate conditions for total nitrogen extraction were particle size, 200 mesh; 0.0% NaCl; pH 8.0; temperature, 25C; and time, 30 min. By using the above mentioned parameters a yield over 90% of nitrogen was obtained.     

Response surface methodology for protein extraction optimization of red pepper seed (Capsicum frutescens)

Response surface methodology was used to determine optimum conditions for extraction of protein from red pepper seed meal. A central composite design including independent variables such as temperature (30, 35, 40, 45 and 50 °C), pH (7.0, 7.5, 8.0, 8.5 and 9.0), extraction time (20, 30, 40, 50 and 60 min) and solvent/meal ratio (10:1, 15:1, 20:1, 25:1 and 30:1 v/w) was used. Selected response (dependent variable) which evaluates the extraction process was protein yield and the second-order model obtained for protein yield revealed coefficient of determination of 96.7%. Protein yield was primarily affected by pH and solvent/meal ratio. Maximum yield was obtained when temperature, pH, mixing time and solvent/meal ratio were 31 °C, 8.8, 20 min, 21:1 (v/w), respectively. These conditions resulted in protein yield of 12.24 g of soluble protein from extract/100 g defatted red pepper seed flour. The adequacy of the model was confirmed by extracting the protein under optimum values given by the model. These results help in designing the process of optimal protein extraction from red pepper seeds.