Functional properties and in vitro trypsin digestibility of red kidney bean (Phaseolus vulgaris L.) protein isolate: Effect of high-pressure treatment

The effects of high-pressure (HP) treatment at 200–600 MPa, prior to freeze-drying, on some functional properties and in vitro trypsin digestibility of vicilin-rich red kidney bean (Phaseolus vulgaris L.) protein isolate (KPI) were investigated. Surface hydrophobicity and free sulfhydryl (SH) and disulfide bond (SS) contents were also evaluated. HP treatment resulted in gradual unfolding of protein structure, as evidenced by gradual increases in fluorescence strength and SS formation from SH groups, and decrease in denaturation enthalpy change. The protein solubility of KPI was significantly improved at pressures of 400 MPa or higher, possibly due to formation of soluble aggregate from insoluble precipitate. HP treatment at 200 and 400 MPa significantly increased emulsifying activity index (EAI) and emulsion stability index (ESI); however, EAI was significantly decreased at 600 MPa (relative to untreated KPI). The thermal stability of the vicilin component was not affected by HP treatment. Additionally, in vitro trypsin digestibility of KPI was decreased only at a pressure above 200 MPa and for long incubation time (e.g., 120 min). The data suggest that some physiochemical and functional properties of vicilin-rich kidney proteins can be improved by means of high-pressure treatment.     

Effects of Acylation on the Functional Properties and In Vitro Trypsin Digestibility of Red Kidney Bean (Phaseolus vulgaris L.) Protein Isolate

ABSTRACT:  The effects of succinylation and acetylation on some functional properties and the  in vitro  trypsin digestibility of kidney bean protein isolate (KPI) were investigated. The extent of succinylation or acetylation progressively increased from 0% to 96% to 97%, as the anhydride-to-protein ratio increased from 0 to 1 g/g. Polyacrylamide gel electrophoresis (PAGE) and zeta potential analyses indicated that acylation, especially succinylation, considerably increased the net charge and hydrodynamic radius of the proteins in KPI, especially vicilin. Acylation treatment at various anhydride-to-protein ratios (0.05 to 1 g/g) remarkably improved the protein solubility (PS) and emulsifying activity index (EAI) at neutral pH, but the improvement by succinylation was much better than that by acetylation. Succinylation resulted in a marked decrease in mechanical moduli of heat-induced gels of KPI, while the mechanical moduli were, on the contrary, increased by acetylation. Additionally,  in vitro  trypsin digestibility was improved by the acylation in an anhydride-type and level-dependent manner. The results suggest that the functional properties of KPI could be modulated by the chemical acylation treatment, using succinic or acetic anhydride at appropriate anhydride-to-protein ratios.     

Wet‐fractionation of Phaseolus lunatus seeds: partial characterization of starch and protein

The optimum extraction conditions for integral use of Phaseolus lunatus seed, in alkaline medium, are 1:6 (w/v) flour:water ratio, pH 11 and a 1 h extraction time. Three main fractions were produced under these conditions: starch; protein isolate and fibrous residue by‐product. The yield is 288.4 g kg^?1 starch, 188.2 g kg^?1 protein isolate and the remaining quantity, fibrous residue. The starch has 98.4% purity, a 75 °C gelatinization temperature and high syneresis even at high concentrations. It also has high viscosity, good stability and middle retrogradation during the heating–cooling cycle. The protein isolate contains 711.3 g kg^?1 protein as well as 75.5 g lysine kg^?1 protein, 10.1 g methionine kg^?1 protein and 12.2 g tryptophan kg^?1 protein. Its in vitro digestibility is 79% with a 2.5 c‐PER. The fibrous residue contains 63 g kg^?1 of protein, 328.4 g kg^?1 of crude fiber and 567.3 g kg^?1 of NFE. Copyright © 2004 Society of Chemical Industry     

Broad bean and pea by‐products as sources of fibre‐rich ingredients: potential antioxidant activity measured in vitro

BACKGROUND By‐products generated during the processing of plant food can be considered a promising source of dietary fibre as a functional compound. The dietary fibre composition, soluble sugars and antioxidant activity of the extractable polyphenols of pea and broad bean by‐products have been analysed in this study. RESULTS: Total dietary fibre using AOAC methods plus hydrolysis (broad bean pod: 337.3 g kg^?1; pea pod: 472.6 g kg^?1) is higher (P < 0.05) in both by‐products than with the Englyst method (broad bean pod: 309.7 g kg^?1; pea pod: 434.6 g kg^?1). The main monomers are uronic acids, glucose, arabinose and galactose in broad bean pods. However, pea pods are very rich in glucose and xylose. The soluble sugars analysed by high‐performance liquid chromatography in both by‐products have glucose as the most important component, followed by sucrose and fructose. The ferric reducing antioxidant power (broad bean pod: 406.4 µmol Trolox equivalents g^?1; pea pod: 25.9 µmol Trolox equivalents g^?1) and scavenging effect on 2,2‐diphenyl‐1‐picrylhydrazyl radical (EC₅₀ of broad bean pod: 0.4 mg mL^?1; EC₅₀ of pea pod: 16.0 mg mL^?1) were also measured. CONCLUSIONS: Broad bean and pea by‐products are very rich in dietary fibre, particularly insoluble dietary fibre and their extractable polyphenols demonstrate antioxidant activity. Therefore they might be regarded as functional ingredients. Copyright © 2011 Society of Chemical Industry     

Physicochemical and functional properties of a protein isolate produced from safflower (Carthamus tinctorius L.) meal by ultrafiltration

BACKGROUND: The protein isolate obtained from safflower meal by aqueous extraction and ultrafiltration was evaluated for its physicochemical and functional properties. RESULTS: Protein, ash and moisture contents of the safflower protein isolate were 901, 51 and 45 g kg^?1 respectively. Its water and oil absorption capacities were 2.22 mL H₂O g^?1 protein and 2.77 mL oil g^?1 protein respectively. Least gelation concentration was 20 g kg^?1 at pH 2, 6, 8 and 10 but 100 g kg^?1 at pH 4. Emulsifying properties were also affected by the pH: emulsifying activity and emulsion stability at pH 6 were 82.5 and 100% respectively. The highest foaming capacity (126%) occurred at pH 2; however, it increased by 104% with the addition of 0.25 g glucose g^?1 protein to the foam system. CONCLUSION: In the light of its functional properties found in this study, safflower protein isolate produced by ultrafiltration is recommended for use as an ingredient in food products such as salad dressing, meat products, mayonnaise, cakes, ice cream and desserts. Copyright © 2010 Society of Chemical Industry     

Thermal denaturation and gelation of vicilin-rich protein isolates from three Phaseolus legumes: A comparative study

The thermal denaturation and gelation properties of vicilin-rich protein isolates from red bean, red kidney bean and mung beans (further denoted as RPI, KPI and MPI) were investigated by differential scanning calorimetry (DSC) and dynamic oscillatory measurements. The relation between the properties of these proteins to their free sulphydryl (SH)/disulfide bond (SS) contents was also evaluated. DSC analyses showed that many DSC characteristics of major endothermic peak (corresponding to vicilin component), including its denaturation temperature (T_d), enthalpy changes (ΔH) and width at half-peak height (ΔT_1/2), significantly varied with the type of protein isolates. Furthermore, the heat-induced gelation, including onset of gelation and the development of mechanical moduli, was also dependent on the type of protein isolates. The thermal denaturation of these proteins was nearly unaffected by the presence of reducing agent dithiothreitol (DTT), while the presence of DTT weakened the gel formation. The T_d of vicilin components and the mechanical moduli of corresponding formed gels were positively related to their SS contents. Additionally, the formed gels were thermo-irreversible, and heat pretreatment (carried out at temperatures higher than or close to the T_d of these vicilins) could improve the gel network formation. These results confirm that vicilin-rich protein isolates from various legumes show different patterns of thermal denaturation and gelation, and these properties are to a great extent related to their SH and/or SS contents.     

Characterisation and functional properties of watermelon (Citrullus lanatus) seed proteins

BACKGROUND: People in developing countries depend largely on non‐conventional protein sources to augment the availability of proteins in their diets. Watermelon seed meal is reported to contain an adequate amount of nutritional proteins that could be extracted for use as nutritional ingredients in food products. RESULTS: Osborne classification showed that globulin was the major protein (≥500 g kg ^?1) present in watermelon seed meal, followed by albumin and glutelin. Sodium dodecyl sulfate polyacrylamide gel electrophoresis indicated that the polypeptides had low molecular weights ranging from 35 to 47 kDa. Isoelectric focusing revealed that the isoelectric point of most proteins was in the acidic range 4–6. These proteins are rich in aspartic acid, glutamic acid and serine. An increase in pH (5–9) significantly (P < 0.05) decreased the denaturation enthalpy of these proteins. Among functional properties, albumin exhibited a much higher dispersibility index (810.3–869.6 g kg^?1) than globulin (227.8–245.4 g kg^?1), glutelin (182.1–187.7 g kg^?1) and prolamin (162.3–177.7 g kg^?1). Digestibility was in the ranges 760.6–910.0 and 765.5–888.5 g kg^?1 for Mateera and Sugar Baby watermelon protein fractions respectively, while surface hydrophobicity ranged from 126.4 to 173.2 and from 125.8 to 169.3 respectively. The foaming and emulsifying properties of albumin were better than those of the other proteins studied. CONCLUSION: The good nutritional and functional properties of watermelon seed meal proteins suggest their potential use in food formulations. Copyright © 2010 Society of Chemical Industry     

高静压处理对芸豆分离蛋白的聚集行为研究

采用排阻色谱-多角度激光光散射-折光联用技术(SEC-MALLS-RI)研究高静压处理(HP)对芸豆分离蛋白分子量分布的影响规律,揭示HP导致KPI聚集-解离行为.根据Debye plot方法,计算出芸豆球蛋白的绝对分子量为161 kDa,200 MPa HP处理解离KPI的可溶性聚集物,而400和600 MPaHP处理诱导不溶性聚集物向可溶性聚集物转化,改善KPI的溶解度(PS).     

Chemical properties and sensory quality of ice cream fortified with fish protein

BACKGROUND: Fish protein powder is a functional ingredient that can be used for enhancing the nutritional value of food products. In this study the effect of fortification with different levels of fish protein powder (FP) on chemical properties and sensory quality of Persian ice cream with 0, 30 and 50 g kg^?1 FP during storage at ? 18 °C for 4 months was investigated. RESULTS: Ice creams fortified with 50 and 30 g kg^?1 FP had significantly higher protein and solid‐non‐fat content than ice cream with 0% FP or 83, 69 and 51 g kg^?1 protein and 215, 204 and 181 g kg^?1 solid non‐fat, respectively. All products had the same levels of fat, lactose, acidity and pH. They had similar sensory quality after production except for colour, but sensory properties of fortified samples changed significantly after 2 months of storage. Colour faded, cohesiveness decreased, sandiness/coarseness increased, sweetness decreased and fish flavour and off‐odour increased. The control ice cream scored highest for additives odour and flavour. CONCLUSION: Development of ice cream fortified with fish protein powder could be an effective way to enhance nutritional and functional value of ice cream. But studies on storage stability, consumers' acceptance and attitudes are recommended if companies are planning to do so. Copyright © 2011 Society of Chemical Industry     

The relationships between physicochemical properties and conformational features of succinylated and acetylated kidney bean (Phaseolus vulgaris L.) protein isolates

The effects of succinylation and acetylation on some physicochemical properties and conformational features of kidney bean protein isolate (KPI) were investigated. The extent of N-acylation progressively increased up to 93–94% with increasing anhydride-to-protein ratio (0–1.0 g g^?1), while the O-acylation occurred only after extensive blocks of ε-amino groups. Zeta potential and size exclusion chromatography analyses indicated that the acylation and the succinylation in particular led to decreases in isoelectric point and zeta potential at neutral pH, in an extent of acylation dependent manner, while the association/dissociation state of the vicilin was slightly affected by the acylation. The surface hydrophobicity was also remarkably affected by the acylation, but the influence varied with the type and extent of acylation. Differential scanning calorimetry (DSC), intrinsic fluorescence and near-UV and/or far-UV CD spectroscopic analyses showed significant changes in tertiary and/or secondary conformations of the proteins in KPI, with extent of acylation, especially extent of succinylation. These phenomena suggest close relationships between the physicochemical properties and tertiary and/or secondary conformational features of the proteins in acylated KPI samples. It is also suggested that the physicochemical and conformational properties of KPI could be modulated by selecting the type and level of the applied anhydrides.     

Chemical composition, angiotensin-converting enzyme-inhibitory activity and antioxidant activities of few-flower wild rice (Zizania latifolia Turcz.)

BACKGROUND: The chemical compositions of the stem and leaf sheath of few‐flower wild rice were analysed. In addition, their extracts were evaluated for diphenylpicrylhydrazyl (DPPH) free radical‐scavenging activity, ferric‐reducing antioxidant power and angiotensin‐converting enzyme (ACE)‐inhibitory activity, since these are important properties of sources of nutraceuticals or functional foods. RESULTS: The stems contained more ascorbic acid (0.06 g kg^?1 fresh weight), protein (28.18 g kg^?1 dry weight (DW)), reducing sugars (308.54 g kg^?1 DW), water‐soluble pectin (20.63 g kg^?1 DW), Na₂CO₃‐soluble pectin (44.14 g kg^?1 DW), K (8 g kg^?1 dry matter (DM), S (6 g kg^?1 DM) and P (5 g kg^?1 DM) but less starch, total dietary fibre, Si, Na and Ca than the leaf sheaths. The DPPH free radical‐scavenging IC₅₀ values of the stem and leaf sheath extracts were 19.28 and 21.22 mg mL^?1 respectively. In addition, the ACE‐inhibitory IC₅₀ value of the stem extracts was 38.54 mg mL^?1. CONCLUSION: Both the stem and leaf sheath extracts exhibited good antioxidant properties, while good ACE‐inhibitory activity was detected only in the phosphate buffer solution extracts of the stem. Few‐flower wild rice could be processed into formula feeds for fish, poultry, etc. or functional foods for persons with high blood pressure. Copyright © 2011 Society of Chemical Industry     

Preparation and characterization of high‐quality rice bran proteins

Rice bran contains 120–200 g kg^?1 protein in addition to a large amount of fat, carbohydrate, and phytic acid. Rice bran protein (RBP) fractions were refined by a two‐step preparation to eliminate residual carbohydrate. The first step involved the sequential extraction of defatted rice bran into RBP fractions using their distinct solubility to give 37 g kg^?1 of albumin, 31 g kg^?1 of globulin, 27 g kg^?1 of glutelin, and 2 g kg^?1 of prolamin. In the second step, carried out by dissolving in respective solvent and isoelectric precipitation, the protein content of each fraction increased from 69% to 97% for albumin, from 71% to 90% for globulin, from 74% to 83% for glutelin, and from 18% to 20% for prolamin. The low protein content in the prolamin fraction might be due to its low solubility in the protein assay. Emulsifying stability index and surface hydrophobicity increased in the second‐step preparation of albumin and globulin, but not of glutelin. Emulsifying properties of RBPs were lower than that of a soybean protein isolate. Denaturation temperatures and enthalpy values of denaturation for albumin, globulin, glutelin, and prolamin were 50.1 °C/1.2 J g^?1, 79.0 °C/1.8 J g^?1, 74.5 °C/3.0 J g^?1, and 78.5 °C/8.1 J g^?1, respectively. No significant differences in the denaturation temperatures and enthalpy values of denaturation of RBP fractions were obtained with these two‐step preparations (P < 0.05). Copyright © 2007 Society of Chemical Industry     

The nutritional quality of two types of fish silage for broiler chickens

Fish waste was ensiled either by acidification with formic acid or by fermentation with a bacterial starter culture and molasses. The resulting liquids were mixed with wheat bran (85:15 w/w liquid: bran) and dried (70°C) to produce acid silage meal (ASM) and fermented silage meal (FSM). ASM and FSM were incorporated into wheat-based diets at 25, 50 and 100 g kg^?1 at the expense of soya bean meal. There were two control diets, one which contained soya bean meal as the predominant protein supplement and a second in which fish meal (50 g kg^?1) was added at the expense of some of the soya bean meal. Starter diets (13.25 MJ ME kg^?1, 12 g kg^?1 lysine) were fed from 1-day-old to 21-days-old and finisher diets (13.25 MJ ME kg^?1, 9.5 g kg^?1 lysine) were fed from 22 to 42-days-old to six replicates each of five birds. Birds were reared in raised-wire cages, and feed intake, liveweight and mortality were recorded. There were no significant effects of dietary inclusion of either ASM and FSM on the performance of broiler chickens relative to those fed on control diets. FSM contained less crude protein and amino acids than ASM. The recovery of amino acids relative to the total crude protein content from FSM was only 78.7%, presumably as a result of formation of Maillard reaction products during drying.     

Heat-induced modifications in the functional and structural properties of vicilin-rich protein isolate from kidney (Phaseolus vulgaris L.) bean

Heat-induced changes in the physico-chemical (and/or functional) and structural properties of protein isolate from kidney beans (KPI) were characterised. The extent of protein denaturation, free sulphydryl contents, surface hydrophobicity, as well as structural characteristics of the proteins were evaluated. Analyses of size-exclusion chromatography combined with laser scattering showed that the heating at 95 °C led to transformation of 7S-form vicilin to its 11S-form, and even higher molar mass (MW) oligomers or polymers. Moderate heating (for 15–30 min) significantly improved protein solubility, emulsifying and foaming activities (at neutral pH), whilst extensive heating (for 60–120 min) on the contrary decreased these properties. Spectral analyses of fluorescence and/or Raman spectroscopy showed that tertiary and secondary conformations of protein in KPI were remarkably affected to a varying extent by the heating. The results suggested a close relationship between functional properties of the vicilin from kidney bean and its conformational characteristics.     

Functional and structural properties and in vitro digestibility of acylated hemp (Cannabis sativa L.) protein isolates

The effects of succinylation and acetylation on some functional, structural properties and in vitro trypsin digestibility of hemp protein isolate (HPI) were investigated. The extent of acylation gradually increased from 0 to 60–70%, with the anhydride‐to‐protein ratio increasing from 0 to 1.0 g g^?1. Size exclusion chromatography showed that succinylation led to formation of more soluble protein aggregate than acetylation, especially at anhydride levels higher than 0.1 g g^?1. Succinylation led to gradual increase in protein solubility (PS) from 30 to 85–90%, while in the acetylation case, the PS was improved only at low anhydride levels, increasing from 30 to about 50% with anhydride‐to‐protein ratio increasing from 0 to 0.2 g g^?1. At neutral pH, the emulsifying activity indexes (EAI) of HPI was 22.1 m² g^?1, and the EAI linearly and significantly increased with the extent of acylation. The EAIs of succinylated and acetylated HPI (1.0 g g^?1) were 119.0 and 54.4 m² g^?1, respectively. Differential scanning calorimetry (DSC) and intrinsic fluorescence spectrum analyses indicated gradual structural unfolding of proteins, or exposure of hydrophobic clusters to the solvent, especially at higher anhydride levels. Additionally, the in vitro trypsin digestibility was significantly improved by the succinylation. The results indicated that the chemical acylation treatment (especially succinylation) could be applied to modify some selected functional properties of hemp proteins, especially PS and emulsifying ability.     

Characterisation of the leaf meals,protein concentrates and residues from some tropical leguminous plants

Leaf meals (LMs) from freshly harvested leaves of butterfly pea (Centrosema pubescens), devil bean (Mucuna pruriens), flamboyant flower (Delonix regia), Bauhinia tomentosa, coast wattle (Acacia auriculiformis), quick stick (Glyricidia sepium) and ipil‐ipil (Leucaena leucocephala) were analysed for their nutrient and anti‐nutritional content. Then, leaf protein concentrates (LPCs) were produced from the leaves by fractionation and characterised along with the fibrous residues. On average, the LM contained 181 g kg^?1 dry matter (DM) CP (range: 100–280 g kg^?1 DM), 139 g kg^?1 DM crude fibre (range: 77–230 g kg^?1 DM) and 133 g kg^?1 DM ether extract (range: 86–165 g kg^?1 DM) while the gross energy averaged 17.0 MJ kg^?1. On average, leaf protein fractionation enhanced the CP, ether extract and the gross energy in the LPC by 39.5%, 33.5% and 22.0%, respectively, while the crude fibre of the LMs was reduced by 41%, on average, in the LPCs. Fractionation reduced the mineral content of the leaves generally. The mean phytin content varied from 0.36 g kg^?1 in LPCs to 0.86 g kg^?1 in leaf meal, while the mean phytin‐P content varied from 0.10 g kg^?1 in LPCs to 0.24 g kg^?1 in leaf meal. The total phenol levels in the LMs were reduced by 33.7% in the LPCs, on average. These results suggest that, while the LPCs from these plants could be used as protein supplements in non‐ruminant feeds in regions where there is an acute shortage of plant protein, the LMs or LPC fibrous residues could be fed to ruminant animals. Copyright © 2006 Society of Chemical Industry     

Characterisation and functional properties of proteins of some Indian chickpea (Cicer arietinum) cultivars

BACKGROUND: Chickpea (Cicer arietinum L.) proteins have received attention during recent years owing to their higher biological values and better functional ingredients than oilseed proteins. In this study the composition, fractionation, electrophoretic behaviour and functional properties of five chickpea protein concentrates were determined. RESULTS: The chickpea proteins contained 15.9–54.8 g kg^?1 albumin, 48.9–154.1 g kg^?1 globulin, 39.2–76.5 g kg^?1 glutelin and traces of prolamin. Electrophoresis of the various fractions revealed that albumin and globulin were made up of sub‐units of different molecular weights ranging from 7 to 96 kDa. Water and oil absorption of the protein concentrates varied from 1.15 to 2.75 g g^?1 and from 2.60 to 5.65 g g^?1 respectively. Foaming capacity and foam stability of the protein concentrates were good and improved with the addition of salt (10 g L^?1 NaCl) or sugar (100 g L^?1 sucrose) at both isoelectric and neutral pH. Emulsifying capacity and emulsion stability of the protein concentrates were good and excellent respectively. CONCLUSION: Protein concentrates prepared from chickpeas have potential use in food formulations owing to their good emulsifying/foaming and water/oil‐binding capacities. Copyright © 2008 Society of Chemical Industry     

Chemical composition,protein fractionation,essential amino acid potential and antimetabolic constituents of an unconventional legume,Gila bean (Entada phaseoloides Merrill) seed kernel

Physical characteristics of pods and seeds, proximate composition, different protein fractionation, SDS‐PAGE analysis of proteins, amino acid composition, starch content, fatty acid profiles and various antimetabolic substances of Gila bean (Entada phaseoloides Merrill) were studied. The pod length and the number of seeds per pod ranged from 55 to 90 cm and from 5 to 11 respectively. The kernel comprised 66.1% of the seed weight (18.41 ± 1.14 g). The seed kernels contained 256.7 g kg^?1 crude protein, 108.1 g kg^?1 lipid, 27.3 g kg^?1 ash and a high content of carbohydrate (585.7 g kg^?1). The levels of potassium, phosphorus, zinc and iron were similar to those in conventional pulses. Among the different protein fractions of seed kernels, albumins constituted the major storage proteins (69.7%). The kernel proteins were rich in essential amino acids, particularly sulphur‐containing amino acids, and their values appeared to be higher than the FAO/WHO (1990) reference protein for a 2–5‐year‐old growing child and soybean, and comparable to hen egg. Seed kernel lipids contained high levels of unsaturated fatty acids, oleic and linoleic acids, which accounted for 83% of the total fatty acid recovered. The kernel exhibited high trypsin and chymotrypsin inhibitor activities (96.65 mg TI g^?1 and 30.02 CIU mg^?1 sample respectively) in addition to containing phenolics, phytic acid, lectins and oligosaccharides. Another major toxic constituent was identified as a group of triterpenoid saponins (3.21%), which had high haemolytic activity (HeU) against cattle erythrocytes and caused high mortality in fish. The in vitro digestibility of the kernel protein was low (67%). © 2001 Society of Chemical Industry     

Physical properties of yogurt fortified with various commercial whey protein concentrates

The effects of whey protein concentrates on physical and rheological properties of yogurt were studied. Five commercial whey protein concentrates (340 g kg^?1 protein nominal) were used to fortify milk to 45 g protein kg^?1. Fermentation was performed with two different starters (ropy and non‐ropy). Resulting yogurts were compared with a control yogurt enriched with skim milk powder. The water‐holding capacity of the yogurt fortified with skim milk powder was 500 g kg^?1 and ranged from 600 to 638 g kg^?1 when fortified with whey protein concentrates. Significant rheological differences have been noticed between the yogurts fortified with different whey protein concentrates, independent of the starter used. Three whey protein concentrates generated yogurts with a behavior similar to the control. The two others produced yogurt with lower firmness (15 g compared with 17 g), lower Brookfield viscosity (6 Pa s compared with 9 Pa s), lower yield stress (2 Pa compared with 4 Pa), lower complex viscosity (13 Pa s compared with 26 Pa s), and lower apparent viscosity (0.4 Pa s compared with 1 Pa s) than the control, respectively. The yogurts with the lowest firmness and viscosity were produced with concentrates which contained the highest amount of non‐protein nitrogen fraction (160 g kg^?1 versus 126 g kg^?1 of the total nitrogen), and the highest amount of denaturation of the whey protein (262 versus 200 g kg^?1 of the total nitrogen). Copyright © 2004 Society of Chemical Industry     

Soybean cultivars impact quality and function of soymilk and tofu

The functional properties of soymilk and tofu prepared from Benning and Danbaekkong soy cultivars were identified. The protein content in soymilk was significantly higher for Danbaekkong, at 46.4 g kg^?1, than for Benning at 42.0 g kg^?1. The 11S/7S globulin ratios of Danbaekkong and Benning were estimated at 0.93 and 0.38, respectively. Soymilk from Danbaekkong was more non‐Newtonian (n = 0.69) than soymilk from Benning (n = 0.84). Tofu prepared from Danbaekkong was significantly harder, chewier and gummier than tofu from Benning. Differences in protein content, protein ratio, viscosity, textural properties and color of soymilk can be applied as indicators of quality and functionality in soy foods such as tofu. Copyright © 2005 Society of Chemical Industry