Enrichment of Genistein in Soy Protein Concentrate with b-glucosidase

Genistein has been reported to have the most potent anticarcinogenic effect among isoflavones. Conversion of genistin in the glucoside form to genistein in the aglucone form by a b-glucosidase enzyme hydrolytic activity during soy protein concentrate (SPC) preparation was evaluated. The optimum conditions for the conversion of genistin to genistein were pH 5.0, 50 °C incubation temperature, 2 units of enzyme/g of soy flour, 1 h incubation period, and 1:10 (w/v) defatted soy flour to water ratio. Under these conditions, 1.214 mg/g genistein were obtained in SPC and is significantly (p < 0.05) higher than the genistein content in SPC prepared under similar conditions without enzyme addition (0.845 mg/g).     

EFFECT of SALT and CITRIC ACID ON ELECTRICAL CONDUCTIVITIES and OHMIC HEATING of VISCOUS LIQUIDS

Four hydrocolloid solutions (starch, 4.3%; carrageenan, 1.7%; xanthan, 2%; pectin, 2.5%) were prepared in water with varying amounts of NaCl (0.25, 0.5, 0.75 and 1%). Hydrocolloid concentrations were adjusted to result in an apparent viscosity of 0.2 Pa.s at 20C and 300 s^-1. A voltage of 150 V was applied in a static ohmic heating cell to study the effect of hydrocolloid and salt on electrical conductivity (EC) and temperature profile at their pH. the pH levels were modified by citric acid addition and the combined effect of hydrocolloid, salt and citric acid was investigated. At low salt concentration, carrageenan and xanthan had shortest heating times and highest ECs. This was followed by pectin. Starch was the least effective, having slowest heating rates and lowest ECs. At 1% concentration, the salt effect overcame that of hydrocolloid giving similar temperature profiles and ECs. the effect of citric acid addition was present but negligible.     

Determination of the fruit content of cherry fruit preparations by gravimetric quantification of hemicellulose

A method recently developed for the determination of the fruit content of strawberry fruit preparations by gravimetric quantification of hemicellulose was extended to cherry fruit preparations. Isolation of the alcohol-insoluble residue (AIR) and sequential fractionation of the cell wall compounds from cherries (Prunus cerasus L. cv. ‘Oblacinska’) was performed yielding the amount of fresh cherries per gram hemicellulose. Cherry fruit preparations with varying fruit contents (30–40%) were produced using different hydrocolloid systems (pectin, starch, guar gum, xanthan gum, carrageenan, and combinations thereof). After separation of the hydrocolloids by enzymatical digestion and successive extraction, the fruit preparations were subjected to AIR isolation. The AIR was fractionated to yield the hemicellulose fraction, which was quantified gravimetrically for the calculation of the fruit content. Compared to strawberries, modifications including additional extraction steps for the sequential fractionation were required to separate the pectin of the cherries exhaustively. Calculated and initial fruit contents were in good agreement for the single hydrocolloid components pectin and starch as well as for the combinations pectin/xanthan gum and pectin/carrageenan (26.8% vs. 30%, 38.6% vs. 40%, 42.5% vs. 40%, 37.6% vs. 40%, and 41.2% vs. 40%), whereas the preparations produced with more complex hydrocolloid systems (pectin/xanthan gum/guar gum and starch/xanthan/guar gum) showed larger deviations in their contents (46.2% vs. 40%, 49.6% vs. 40%). It is concluded that the novel method is generally suitable for the determination of the fruit content of fruit preparations, but steps of sample preparation need to be individually adapted to the different fruit matrices.     

Evaluation of Genistin and Genistein Contents in Soybean Varieties and Soy Protein Concentrate Prepared with 3 Basic Methods

The contents of genistein and its β-glucoside form, genistin, in 13 soybean varieties were determined. Soybean variety (Var-1) with high genistein and genistin contents (0.019 mg/g and 0.420 mg/g) was used to evaluate the 3 basic soy protein concentrate (SPC) production methods (acid, alcohol, and hot-water leach) for genistin and genistein retention on a total weight basis. The acid leach method gave the highest total genistin + genistein content (0.742 mg/g) compared to SPCs prepared with the hot-water leach method (0.671 mg/g), and the alcohol leach method (0.070 mg/g). The acid leach, hot-water leach and alcohol leach methods had 20.3%, 24.2%, and 91.2% losses of total genistin + genistein, respectively.     

The effect of various hydrocolloids on some physical properties of extruded corn grits

Fourteen hydrocolloids including Methocels (A4M, E4M, F4M and K4M), locust bean, guar, agar, arabic, alginate, tragacanth, carrageenan, xanthan, pectin, and gelatin gums were extruded at levels of 0, 0.1, 0.5 and 1.0% with corn grits in a Brabender Model PL-V500 extruder at barrel temperatures of 50, 75, 100, 125 and 150°C with a 1:1 screw operating at 100 rpm. Resulting products were evaluated for density, breaking strength and water absorption. Significant differences were found as influenced by hydrocolloid type/amount and extrusion temperature. In general, hydrocolloid additions significantly increased product density and either increased or decreased breaking strength and water absorption.     

Hydrocolloids in emulsions: particle size distribution and interfacial activity

The emulsification properties of 14 hydrocolloid gums (propylene glycol alginate, gellan, carrageenan, pectin, methylcellulose, microcrystalline cellulose, gum arabic, locust bean gum, guar, xanthan, mustard, flaxseed, fenugreek, oat) were investigated. Gum dispersions were prepared in water (0.5%) and emulsified with 40% oil using a Polytron homogenizer. Emulsion stability was determined by centrifugation and storage time, surface and interfacial tension by Du Nouy ring, particle size by integrated light scattering and overall morphology by light microscopy. When compared to the other gums in this study, fenugreek produced a very stable emulsion. Fenugreek was more efficient than other gums in lowering the interfacial free energy, its emulsion was composed of very small oil droplets (70%<1 μm) and under the light microscope appeared as uniform droplets with a narrow size distribution.     

Quality Characteristics and Glass Transition Temperature of Hydrocolloid Pre-Treated Frozen Pre-Cut Carrot

The effect of hydrocolloid pre-treatment, i.e., pectin, carboxy methyl cellulose, xanthan gum and sodium alginate on textural properties, drip losses and sensory quality as well as on glass transition temperature (T_g′′′) of the frozen-thawed pre-cut carrots was studied. Untreated frozen samples showed detrimental effects in texture and also excessive drip losses while the carrot tissue integrity was well retained in the hydrocolloid pre-treated samples. As the concentration of the hydrocolloid increased, hardness and fracturability were also found to increase. However, adhesiveness was observed to follow a reverse trend. Xanthan gum (0.4%) resulted in higher texture retention than other hydrocolloids used as well as than the control samples. Hydrocolloids imparted lightness and higher red and yellowness to the carrot samples due to reduced solute mobility and moisture conditioning effects. Overall acceptability of the hydrocolloid pre-treated samples was found to be more than the experimental control samples. All the hydrocolloids were found to be effective in increasing the T_g′′′ to an extent, ?2.73 to ?0.28°C compared with T_g′′′ (?5.4°C) of untreated carrot samples. T_g′′′ increased to almost 74% in CMC (0.4%) pre-treated samples. The maximum enhancement was found in carboxy methyl cellulose followed by pectin, sodium alginate, and xanthan gum. The threshold concentrations in terms of sensory attributes were determined for optimal conditioning of the product prior to freezing.     

Effect of Various Encapsulating Materials on the Stability of Probiotic Bacteria

ABSTRACT:  Ten probiotic bacteria, including Lactobacillus rhamnosus , Bifidobacterium longum , L. salivarius , L. plantarum , L. acidophilus , L. paracasei , B. lactis type Bl-04, B. lactis type Bi-07, HOWARU L. rhamnosus , and HOWARU B. bifidum , were encapsulated in various coating materials, namely alginate, guar gum, xanthan gum, locust bean gum, and carrageenan gum. The various encapsulated probiotic bacteria were studied for their acid and bile tolerance. Free probiotic organisms were used as a control. The acid tolerance of probiotic organisms was tested at pH 2 over a 2-h incubation period. Bile tolerance was tested with taurocholic acid over an 8-h incubation period. The permeability of the capsules was also examined using a water-soluble dye, 6-carboxyflourescin (6-CF). The permeability was monitored by measuring the amount of 6-CF released from the capsules during a 2-w storage period. Results indicated that probiotic bacteria encapsulated in alginate, xanthan gum, and carrageenan gum survived better ( P < 0.05) than free probiotic bacteria, under acidic conditions. When free probiotic bacteria were exposed to taurocholic acid, viability was reduced by 6.36 log CFU/mL, whereas only 3.63, 3.27, and 4.12 log CFU/mL was lost in probiotic organisms encapsulated in alginate, xanthan gum, and carrageenan gum, respectively. All encapsulating materials tested released small amounts of 6-CF; however, alginate and xanthan gum retained 22.1% and 18.6% more fluorescent dye than guar gum. In general, microcapsules made of alginate, xanthan gum, and carrageenan gum greatly improved the survival of probiotic bacteria when exposed to acidic conditions and bile salts.     

食品胶对豆浆中活性成分异黄酮苷元热稳定性的影响

研究了羧甲基纤维素钠(CMC)、海藻酸钠、黄原胶等食品添加剂对豆浆热处理过程中活性成分异黄酮苷元热稳定性的影响.高效液相色谱分析表明,CMC、黄原胶、海藻酸钠都能减少黄豆苷元、大豆黄素、染料木黄酮三种异黄酮苷元的热损失,其中CMC效果最理想,海藻酸钠次之,黄原胶最差.食品胶的复配能够减少豆浆中异黄酮苷元热损失.CMC/海藻酸钠组合明显好于CMC/黄原胶和黄原胶/海藻酸钠两种组合,当CMC/海藻酸钠=3:2时,在热处理条件为95℃,lOmin条件下,各异黄酮苷元热损失最少,黄豆苷元含量提高9.83%,大豆黄素12.67%,染料木黄酮18.63%.在三种食品胶共同复配组合中,CMC/黄原胶/海藻酸钠(4:3:3)组合的效果最好,黄豆苷元含量提高9.3%,大豆黄素10.13%,染料木黄酮18.26%.     

Effect of Hydrocolloid Pre-Treatment on Instrumental and Sensory Texture Attributes of Frozen Carrot (Daucus carota)

The effect of different hydrocolloids (pectin, carboxy methylcellulose, xanthan gum, and sodium alginate) pre-treatment used at different concentrations (0.2–0.4%) on instrumental texture parameters as well as on the sensory attributes of frozen-thawed pre-cut carrots was evaluated. Instrumental texture profile analysis of frozen-thawed carrot showed a significant (P < 0.05) increase in cohesiveness with an increase in the concentration of all the hydrocolloids. Nevertheless, the increase in springiness was not significant (P > 0.05) over the untreated control samples, whereas chewiness did not show consistent results with an increase of any of the hydrocolloids. As the concentration of hydrocolloids increased, the firmness values obtained by cutting the frozen-thawed carrot samples with a Warner Bratzler Blade were also found to increase. Higher texture retention after freezing and thawing was observed in xanthan gum (0.4%) pre-treated samples than other hydrocolloids used as well as than the control samples. It increased the firmness up to 196.2% than the control samples. However, 0.3% xanthan pre-treatment gave the best sensory results. Sensory acceptability increased on increasing the pectin and carboxy methylcellulose concentrations, while lower concentration levels of alginate pre-treatment showed higher sensory preference than the higher concentration levels. Based on the results, untreated frozen samples suffered from a detrimental texture and sensory deterioration during 15 months of frozen storage. The carrot tissue integrity was well retained during frozen storage in the hydrocolloid pre-treated samples.     

ELECTRICAL CONDUCTIVITIES OF HYDROCOLLOID SOLUTIONS

Ohmic heating was applied to solutions of 5 hydrocolloids (carrageenan, 1–3% w/w; xanthan, 1–3% w/w; pectin, 1–5% w/w; gelatin, 2–4% w/w and starch, 4–6% w/w) in a static cell to study the effect of concentration and temperature on electrical conductivities. For each experiment, the sample was poured into the cell and heated at a constant voltage gradient of 7.24 V/cm. Voltage, current, time and temperature were logged at time intervals and used to calculate electrical conductivities as a function of temperature. Of the thickening agents examined, carrageenan gave the highest value for electrical conductivity (0.2 S/m at 25C and 1% and 1.4 S/m at 100C and 3%) followed by xanthan (0.14 S/m at 25C and 1% to 1.1 S/m at 100C and 3%). Pectin and gelatin samples were found to exhibit lower, but similar electrical conductivities (0.06 S/m at 25C at the lowest concentration to 0.37 S/m at 100C at the highest concentration). Starch samples had the lowest electrical conductivity varying from 0.05 S/m at 25C and 4% to 0.21 S/m at 100C and 6%. Regression equations were established for each type of hydrocolloid solutions revealing a strong interaction between the concentration and the temperature and the electrical conductivity values. Major differences were observed between hydrocolloid types on electrical conductivities that were mainly attributed to their ash content.     

Combined Effects of Proteins and Polysaccharides on Physical Properties of Whey Protein Concentrate-based Edible Films

ABSTRACT: The water-vapor permeability (WVP) and mechanical properties of edible films formed from dry blends or co-dried preparations of protein-polysaccharide powders prepared from whey protein concentrate (WPC)-45 and alginate, pectin, carrageenan, or konjac flour (WPC-45-to-polysaccharide ratio of 95:5 w/w) were investigated. Films were prepared from 8% WPC using WPC-45 (45% protein powder), consisting of 17.76 g of WPC-45 in 82.84 g of water per 100 g solution to give 8% protein w/w. Films formed from co-dried powders had lower WVP and higher tensile strength (TS), elastic modulus (EM) ( P < 0.05), and elongation (EL) than equivalent films formed from the dry blended powders. Films containing alginate had lower WVP and higher TS, EM, and EL than films containing pectin, carrageenan, or konjac flour. There is potential to alter the physical properties of hydrophilic films by combining whey protein and polysaccharide components.     

薏苡仁饮料稳定剂配方优化

以薏苡仁为主要原料研制饮料,探讨了羧甲基纤维素、果胶、海藻酸钠、黄原胶、卡拉胶5种稳定剂对饮料稳定性的影响。通过单因素和响应面试验优化筛选出最佳的稳定剂的组合和用量。结果表明:采用0.03%羧甲基纤维素、0.04%果胶、0.10%黄原胶复合而成的稳定剂可有效地提高薏苡仁饮料的稳定性,且所得的饮料口感细腻、色泽纯正。     

食品胶对低糖蓝莓果酱的品质影响

利用质构分析和感官评定探究单一食品胶和复合食品胶对低糖蓝莓果酱的品质影响。并采用正交试验设计,以低糖果酱的感官评定为指标,确定出以低甲氧基果胶与黄原胶为复合食品胶制备低糖蓝莓果酱的最佳配方。低甲氧基果胶与黄原胶的复配比例为2∶1,添加量为1.4%,钙盐添加量为0.3 mg/g,白砂糖为18%。     

黑芝麻大豆复合饮料的研制

本研究以黑芝麻与大豆为原料研制复合饮料,探讨了黑芝麻与大豆的处理工艺、复配稳定剂以及杀菌工艺对产品稳定性的影响.结果表明,黑芝麻的最佳烘烤工艺为160℃、6min;大豆的最佳浸泡工艺为1%NaHCO3浸泡液在55℃下浸泡4h;采用0.15‰海藻酸钠、0.4‰黄原胶、0.3‰卡拉胶和0.6‰单硬脂酸甘油酯复配组合的稳定剂...     

亲水胶体对油炸外裹糊鱼块油脂含量及品质的影响

通过分析外裹糊中添加瓜尔豆胶、卡拉胶、海藻酸钠、黄原胶和羧甲基纤维素钠（carboxymethylcellulosesodium,CMC-Na）的油炸外裹糊鱼块油脂含量、水分含量、裹糊率以及色度、质构和微观结构,探讨亲水胶体对油炸外裹糊鱼块品质的影响。结果显示,与未添加亲水胶体组（外壳油脂含量22.67 g/100 g,鱼块油脂含量1.58 g/100 g）相比,添加0.3%（质量分数,下同）瓜尔豆胶、卡拉胶、海藻酸钠或0.4%黄原胶、CMC-Na时,油炸外裹糊鱼块的外壳和鱼块的油脂含量较低,外壳和鱼块的水分含量及裹糊率较高。其中添加0.4%黄原胶组的减油效果最好（外壳和鱼块的油脂含量分别为17.96、1.01 g/100 g）,且油炸外裹糊鱼块外壳金黄色、酥性值较高、硬度较低,鱼块的弹性、咀嚼性好;苏丹红染色幅度较轻,外壳微观结构紧密,鱼块无较大气孔形成。     

反向成球法制备风味“爆浆”珍珠的工艺

本研究基于果胶与海藻酸钠在钙离子体系中协同形成凝胶的原理,采用反向成球技术制得具有核壳结构的风味"爆浆"珍珠。以最大力值和咀嚼性为主要指标,通过成球性观察和质构仪测试,得到"爆浆"珍珠制作的最佳工艺;以感官评价为标准,通过正交实验得到桂花风味"爆浆"珍珠的最优配方。结果表明,制备桂花风味"爆浆"珍珠的最优工艺条件为:芯液载入量为350μL,成球反应时间10 min,固化液(壳聚糖)浓度0.5%(W/W),芯液的配方为:桂花风味糖浆用量10%(W/W)、白砂糖用量10%(W/W)及黄原胶浓度0.2%(W/W)。得到的"爆浆"珍珠为规则的圆球状,平均粒径9.5 mm、平均膜厚0.47 mm,其最大力值471 g/cm2、硬度2279 g。得到的桂花风味"爆浆"珍珠具有良好的咀嚼性和爆浆感。为奶茶行业"爆浆"珍珠的工业生产提供了参考。     

Optimization of gum combination for instant pudding based on creep and recovery parameters by mixture design approach

In the present study, gum combinations used in the pudding formulation were optimized by mixture design approach based on creep and recovery measurements. For this aim, four different gums (carrageenan, alginate, guar and xanthan gum) and their different combinations were used in the formulation. The creep-recovery properties of the pudding samples prepared with different gums or gum combinations were investigated. Burger model was satisfactorily applied for the determination of the creep-recovery characteristics of the samples. The use of the carrageenan in the pudding formulation caused a decrease in deformation of the samples. Gel strength value of the pudding samples was also calculated using the data. In order to optimize the gum combination based on the creep-recovery measurements, mixture design was carried out, and it was seen that established models satisfactorily predicted the viscoelastic parameters of the samples. During the optimization of the gum combination used in the pudding formulation, desirability function was used to optimize the ingredients simultaneously based on the requirements. The gum combination including 59.5 % carrageenan and 40.5 % guar gum or 52.7 % carrageenan, 33.8 % guar gum and 13.5 % xanthan gum was determined to be the optimum in terms of quality of the product.     

Extrusion of corn grits containing various levels of hydrocolloids

Fourteen hydrocolloids, locust bean, agar, guar, alginate, tragacanth, carrageenan, xanthan, pectin, gelatin and Methocels A4M, E4M, F4M and K4M were dry blended with corn grits at levels of 0.1, 0.5 and 1.0%. Twenty percent moisture was added and each product extruded in a Brabender Model PL-V500 laboratory extruder at temperatures of 50, 75, 100, 125 and 150°C with a 1:1 screw operating at 100 rpm. Locust bean, agar, guar, alginate, arabic and Methocels E4M, F4M and K4M significantly lowered torque at an extrusion temperature of 50°C, but did not in general produce significant reductions at higher extrusion temperatures. In contrast, tragacanth, carrageenan, xanthan, pectin, gelatin and Methocel A4M did not significantly reduce torque over the concentrations and conditions evaluated during the extrusion of corn grits. All the Methocel derivatives lowered yield at low extrusion temperatures. No gum significantly increased yield over the entire extrusion temperature range evaluated. Therefore, certain gums can significantly reduce torque without influencing yield during the extrusion of corn grits.     

Rheological properties of selected hydrocolloids as a function of concentration and temperature

In this study, rheological properties of several food hydrocolloids (carrageenan, pectin, gelatin, starch and xanthan) were evaluated using a rotational viscometer at three concentrations (1–6%, depending on the type of hydrocolloid) and four temperatures (20, 40, 60 and 80°C). Samples were subjected to a programmed shear rate increasing linearly from 0 to 300 s⁻¹ in 3 min, followed by a steady shear at 300 s⁻¹ for 10 min and finally a linearly decreasing shear rate from 300 s⁻¹ to 0 in 3 min. Experiments were performed in duplicate. In general, the power law model fitted most of the experimental results. Xanthan gum and carrageenan (at 20^oC) were exceptions, characterized by a yield stress and hence the rheograms were fitted with the Herschel-Bulkley model. Furthermore, gelatin showed a Newtonian behavior. Three models (power, exponential and polynomial) were used to evaluate the concentration effect on apparent viscosity. Arrhenius model was used to describe the temperature effect. Among the samples, carrageenan showed the most temperature dependency and xanthan gum, the least.