Effect of carboxymethylcellulose and locust bean gums on some of physicochemical,mechanical, and textural properties of extruded rice

Extrusion is a composite process consisting of many different unit operations such as mixing, cooking, pasting, and molding. In this process, the raw material is forced through a tiny opening to be transformed into a product with a desired and unique shape, texture, color, and taste. In combination with different amounts and types of additives, this technique can result in functional food products for a broad range of people suffering from micronutrient deficiency. The hydrocolloid compounds are now employed to improve the texture and performance properties of many food products. Therefore, this study scrutinized the effects of carboxymethylcellulose and locust bean gums at different levels (0.5, 0.75, and 1%) alone or in combination with each other on chemical, physical, mechanical, and textural properties of extruded rice in comparison with the qualitative properties of the control rice. A completely random design was used along with three replications to analyze the test results. Then the means were compared through Duncan's multiple range test at (α = 5%). According to the results, addition of gums increased moisture, ash, total color difference, water absorption capacity, solubility, failure force, rupture energy, elasticity module, and toughness when reduced lateral expansion was compared to the control. Moreover, the addition of gums after the cooking process increased cooking loss, texture hardness, chewability, and elasticity of the specimens in comparison with the control. According to the results of pre‐ and post‐cooking tests, the specimens containing locust (0.75%) and carboxymethylcellulose (0.75%) gums were the best treatments.     

Effect of guar gum content on some physical and nutritional properties of extruded products

The effect of guar gum (0-10%) added to flour (maize, potato, rice, and wheat) prior to extrusion on the microstructure, physical properties (texture, expansion, density, pasting) and nutritional properties (starch digestibility) was investigated. The inclusion of guar gum did not decrease starch digestibility; rather, at 10% guar gum rapidly digestible starch increased by 24%, 15%, 25% and 43%, in maize, potato, rice and wheat flour-based products, respectively. In general, increases in starch digestibility appear to be related to the weaker microstructure (i.e., lower textural hardness), larger matrix surface area, and lower viscosity (pasting properties) of extrudates containing guar gum. These results suggest that microstructural changes affect the starch digestibility of extrudates; nevertheless, probably other factors such as particle size during digestion may also play an important role.     

The effects of xanthan and guar gums on staling of gluten-free rice cakes baked in different ovens

The objective of this study was to determine the effects of different concentrations of xanthan and guar gums and their blends on staling of gluten-free rice cakes baked in microwave-infrared combination oven (MW–IR) and to compare the cakes with conventionally baked ones. Gums were added at concentrations of 0.3% and 1.0%. For preparation of gum blend, 0.5% xanthan gum was mixed with 0.5% guar gum. In order to understand the staling behaviour of cakes, cakes were stored at 22 ± 2 °C for 120 h. Xanthan-guar gum blend decreased hardness, weight loss, retrogradation enthalpy and the change in setback viscosity values of cakes during storage for both types of ovens as compared to control formulation. It was found that oven type was a significant factor in affecting staling parameters of gluten-free cakes.     

挤压膨化制备婴儿膨化营养米粉的工艺优化及其性质研究

以大米、绿豆为原料通过挤压膨化技术制备婴儿膨化营养米粉,以物料湿度、螺杆转速及五区机桶温度为响应因子,以体积密度(BD)、水溶性指数(WSI)、糊化度(DG)为响应值,采用可旋转中心组合实验设计(CCRD),对制备工艺进行优化。结果表明:物料湿度14%,螺杆转速545 r/min,机桶五区温度175℃经过实验验证在此条件处理下,大米-绿豆婴儿膨化营养米粉的体积密度(BD)为0.064 7、水溶性指数(WSI)为31.225 0、糊化度(DG)为91.363 2,与预测值相接近。通过扫描电镜及体外消化实验对产品进行分析可知;挤压后淀粉颗粒表面碎片增加,表面粗糙度提高,致密度降低;婴儿膨化营养米粉淀粉消化速率高于市售婴儿营养米粉,婴儿膨化营养米粉与市售婴儿营养米粉消化率分别为91.37%和88.14%(P0.05)。     

Digestible energy value of gums in the rat--data on gum arabic

Male Wistar rats were fed a defined formula diet free from non-starch polysaccharides and either containing no additive or supplemented with gum arabic or cellulose or starch. Food and faeces were analysed by bomb calorimetry both to assess the effect of these substances on the apparent digestibility of dietary gross energy and to ascribe digestible energy values to the supplements. The former was not affected by starch and was decreased more by cellulose than by gum arabic. The energy values obtained were 17.4 +/- 0.4 kJ/g starch, 1.7 +/- 0.6 kJ/g cellulose and 14.7 +/- 0.5 kJ/g gum arabic. The latter is consistent with the high apparent digestibility of gum arabic in vivo and casts doubt on the validity of growth assay procedures that suggest a near-zero energy value for gum arabic.     

挤压大米蛋白-葡萄糖接枝复合物制备及其性质研究

对挤压大米蛋白与葡萄糖接枝复合物的制备及其性质的测定进行研究。以挤压温度、大米蛋白水分含量、螺杆转速为考察因素,分析了不同挤压条件对糖接枝反应接枝度的影响,并利用Design–Expert 8.0软件对大米蛋白挤压工艺进行优化,制备最佳挤压工艺下获得的大米蛋白与葡萄糖接枝复合物,并对其溶解性、乳化活性、乳化稳定性进行测定,通过红外光谱测定及扫描电镜对其进行分析与观察。结果表明:在挤压温度90℃、大米蛋白水分含量36%、螺杆转速182 r/min的挤压条件下制备挤压大米蛋白与葡萄糖接枝复合物,接枝度达到最大值31.0%±0.3%,与天然大米蛋白相比,得到的挤压大米蛋白与葡萄糖接枝复合物的溶解性提高了76.6%,乳化性和乳化稳定性分别增加了67.0%和52.6%,傅里叶红外光谱和扫描电镜表明挤压糖接枝反应显著改变了蛋白结构,能够提高大米蛋白应用价值。     

膨化糙米粉添加量对面条特性的影响

将两种不同挤压条件制得的膨化糙米粉分别以0、10%、20%、30%、40%和50%的比例添加到小麦粉中,研究糙米粉添加量对面条蒸煮品质和质构性质的影响。结果表明,随着挤压膨化糙米粉(EBR)添加量的增加,面条干物质吸水率显著降低(P0.05),干物质损失率增加,干面条的折断强度先升高后降低,熟面条硬度、耐咀性、弹性等质构参数降低。添加由物料水分30%、挤压温度80℃、螺杆转速220 r/min条件下挤压制备的膨化糙米粉的面条干物质吸水率高而损失率相对较小,同时面条的硬度、咀嚼性以及弹性要高于添加由物料水分25%、挤压温度120℃、螺杆转速220 r/min条件下挤压制备的膨化糙米粉的面条。     

Effect of xanthan and guar gums on the formation and stability of soy soluble polysaccharide oil-in-water emulsions

The incorporation of relevant amounts of non-adsorbing hydrocolloids to oil-in-water (O/W) emulsions is a suitable alternative to reduce creaming. The effect of incorporating xanthan gum (XG) or guar gum (GG) in soy soluble polysaccharide (SSPS) stabilized oil-in-water (O/W) emulsions was studied. The emulsions contained 6 wt.% of SSPS, 20 wt.% Perilla seed oil (PSO), an omega-3 vegetable oil, and variable amounts of XG or GG ranging from 0.03 to 0.3 wt.%. The presence of minute amounts of XG or GG in fresh emulsions significantly decreased the emulsion droplet size (EDS) although such low concentrations did not provide enough continuous phase viscosity to arrest creaming. Emulsion microstructure indicated the presence of flocculation even at high concentrations of XG or GG caused by a depletion mechanism. All emulsions with XG or GG exhibited pseudoplastic behavior while the control emulsions showed an almost Newtonian behavior. Emulsion droplet polydispersion generally decreased with increase in the continuous phase viscosity indicating the importance of continuous phase viscosity in the dissipation of shear energy throughout the emulsion during homogenization. The characteristics of the emulsions were closely related to the rheological changes of the continuous phase.     

Rheological properties of rice pasta dough supplemented with proteins and gums

Rheological properties of rice pasta dough were studied by creep-recovery tests for various formulations containing guar gum (0.5%), casein (1%), and egg white (1%) mixtures. Non-gelatinized rice semolina (RS) was also mixed with gelatinized RS in different ratios (0, 25, 50, 75 and 100%) for each formulation. The effects of gelatinization, gum and proteins on pasta dough rheology were determined by a control stress rheometer (Haake Rheostress 1). From the creep-recovery data it was obvious that as the amount of gelatinized fraction increased there was an increase in the elasticity of the samples. However, the samples that were produced with 75 and 100% gelatinized RS in the formulation were not smooth in texture, but lumpy. From the creep-recovery and dynamic oscillation measurements it was found that guar gum and protein mixture can be used as a stabilizer together with 50% pre-gelatinized rice semolina. This will result in an improvement in dough properties during gluten free pasta processing from rice.     

挤压杂粮重组米糊化特性研究

以陈化早籼米粉为主要原料,荞麦、青稞、藜麦、鹰嘴豆、燕麦麸皮等杂粮为辅料制备挤压重组米,以RVA快速黏度分析仪为研究手段,探究不同杂粮添加物以及不同的添加量(0%,5%,10%,15%,20%,25%)对重组米糊化特性的影响。结果表明:当燕麦麸皮添加量>15%时,其和藜麦、青稞均能显著增加重组米的峰值黏度(P<0.05),小添加量的燕麦麸皮和荞麦、鹰嘴豆均会显著降低重组米峰值黏度(P<0.05);添加藜麦、荞麦和青稞均会使重组米的谷值黏度显著增加(P<0.05),添加燕麦麸皮和鹰嘴豆会显著降低重组米的谷值黏度(P<0.05);荞麦、青稞、藜麦及添加量>20%燕麦麸皮均能显著增加重组米的最终黏度(P<0.05),小添加量的燕麦麸皮和鹰嘴豆均能显著降低重组米的最终黏度(P<0.05);燕麦麸皮、添加量>20%青稞、添加量>15%藜麦均能显著增加重组米的衰减值(P<0.05),鹰嘴豆、荞麦与小添加量的青稞和藜麦均能显著降低重组米的衰减值(P<0.05)。5种杂粮均使重组米的回生值显著增加(P<0.05)。     

Immunogenicity, immunological cross reactivity and non-specific irritant properties of the exudate gums, arabic, karaya and tragacanth

An animal model has been used to investigate the immunogenicity and non-specific irritant properties of exudate gums. The materials studied were four preparations of gum arabic (Acacia spp.), two of gum karaya (Sterculia spp.), two of gum tragacanth (Astralagus spp.) and a residue obtained after ethanol extraction of gum arabic. Groups of animals were intradermally immunized with the gum in complete Freund's adjuvant. Serum antibody levels were measured by an ELISA technique and delayed hypersensitivity responses by a footpad swelling test. Antigenic cross-reactivity within each gum species was tested in a crossover fashion. All gum preparations elicited systemic immune responses after immunization. Further processing reduced immunogenicity, although there was no evidence that systemic immunity to these complex polysaccharide antigens responses could be completely abolished by processing or purification. The ethanolic extract, and some of the gum preparations, particularly tragacanth and karaya, caused considerable footpad swelling when injected intradermally. It is concluded that processing and awareness of subspecies differences can reduce the inherent immunogenicity and potential irritant effects of exudate gums.     

Effect of granularity on the characteristics of extruded rice snack

Rice flours of different granularity over 542 pm (30 mesh), 542–286.5 pm (30–50 mesh), 286.5-175 pm (50–80 mesh) and throughs of 175 pm (80 mesh) were processed using a Wenger X-5 extruder with a 1/8 inch die and at an exit temperature of 95°C. With increased fineness of the flour, the expansion ratio, water absorption index and water solubility index of the product increased from 1.4,4.91 and 0.016 to 2.6,7.16 and 0.027, respectively. The extent of gelatinization of the starch component increased from 36.1% to 55.1% as the flour particle size became finer. This was also supported by amylograph paste viscosity data. The organoleptic evaluation of samples at the equilibrated moisture content showed that 43% ERH corresponding to 6.56% moisture and 11.3 kg breaking strength of the product was critical for acceptable textural properties of the product.     

膨化米糊流变学特性及其感官指标的相关性研究

通过对籼稻、粳稻和糯稻三种不同类型稻米的膨化米糊的流变学特性与感官指标进行研究,确定膨化米糊的流体类型,分析其流变学特性与感官指标之间的联系。结果表明：膨化米糊为假塑性流体,其感官指标（色泽、香气、总分）与流变指数呈显著负相关,其黏度系数对感官指标有影响。     

添加膳食纤维对挤压工程米品质的影响

以大麦苗粉为膳食纤维来源,以不同比例添加到大米粉中,混匀后,利用挤压质构重组法制备膳食纤维营养强化米。对强化米产品进行蒸煮实验,确定最佳料水比为1:0.8。用质构仪对强化米进行分析,观察添加膳食纤维对挤压工程米质构特性的影响。结果表明,在膳食纤维添加量为5%~20%范围内,挤压工程米的胶着性、咀嚼性、硬度随着膳食纤维的添加呈现先上升后下降的趋势,在添加量为10%时达到最大值;弹性呈现先上升后下降的趋势,上升的幅度不是很大;粘性呈现先上升后下降的趋势,在15%时达到最大值;内聚性随添加量的增加呈现缓慢下降的趋势。     

Effect of operating conditions on physical characteristics of extruded rice starch

The effect of screw speed, flow rate, barrel temperature and added moisture on physical characteristics of high moisture extruded rice starch was studied. the product physical characterization was made by measuring density, final moisture content and the maximum load force in a puncture test. Rice flour containing approximately 1.5% protein and 6% moisture was mixed with 55–65% (w/w) water and extruded in a co-rotating twin screw extruder with a slit die. A two level factorial design was used to analyse each parameter. It was found that added moisture was the most important variable affecting the force-deformation curve maxima, with the interaction between added moisture and barrel temperature exhibiting a less significant effect. Added moisture and flow rate each affected density, with the interaction between added moisture and screw speed showing a less significant effect. Temperature and flow rate affected final moisture interactively with added moisture, which was evidently the most important variable.     

Rheological behaviour of aqueous systems of tragacanth and guar gums with storage time

Rheological properties of aqueous systems of tragacanth and guar gums at nominal concentration of 10 g/L were evaluated as a function of storage time (up to 47 days) under steady (at shear rates ranging from 0.01 to 1000 s⁻¹) and dynamic (at strain of 5% and angular frequency from 0.1 to 100 rad s⁻¹) shear testing conditions, using a controlled stress rheometer, at 25 °C.     

不同离子胶对玉米磷酸酯双淀粉性质的影响

研究了离子胶(羧甲基纤维素钠、海藻酸钠、卡拉胶、壳聚糖)不同添加量(0∶1、1∶9、3∶7)对玉米磷酸酯双淀粉糊化特性、凝胶质构特性、溶胀度和吸油率等性质的影响。结果表明,阴离子胶(羧甲基纤维素钠、海藻酸钠、卡拉胶)降低了玉米磷酸酯双淀粉的峰值黏度、衰减值;而阳离子胶(壳聚糖)使玉米磷酸酯双淀粉的峰值黏度、衰减值显著增加。阴离子胶使玉米磷酸酯双淀粉凝胶硬度下降,而壳聚糖则使其凝胶硬度上升。阴离子胶能促进玉米磷酸酯双淀粉的溶胀,但壳聚糖抑制其溶胀。壳聚糖使玉米磷酸酯双淀粉吸油率增加。离子胶对玉米磷酸酯双淀粉性质的影响,不仅与离子胶自身性质有关,而且可能与二者之间的静电作用密切相关。     

谷氨酰胺转氨酶对挤压糙米粉面团蛋白特性和面条品质的影响

将挤压糙米粉(EBR)与小麦粉以1∶1(m/m)的比例混合制成面条,研究了谷氨酰胺转氨酶(TG)添加量(0.5%、1.0%和1.5%)对面条性质的影响。结果表明,TG添加后,面条中游离巯基含量减少,SDS-PAGE条带显示面条中形成了大分子质量的聚集体。随着TG的添加,面条最佳蒸煮时间增加,干物质损失率降低,吸水率升高。添加量为1.0%时,面条最佳蒸煮时间和吸水率达到最大值,蒸煮损失率达到最小值。TG添加量为0.5%时,面条的硬度、耐咀性、回复性和剪切力最大。扫描电镜结果显示,TG的添加明显增强了面条内部结构的连接与聚合,面条内部变得更加紧实,连续性增强。TG添加量为0.5%~1.0%时,挤压糙米粉面条质构品质和蒸煮品质较好。     

pH和阿拉伯胶对大豆分离蛋白/大豆蛋白酶解产物乳化性质的影响

研究了pH和阿拉伯胶对大豆分离蛋白(soy protein isolate,SPI)或低限度酶解改性产物的乳化性质的影响。结果表明:SPI酶解改性处理后制备的乳液颗粒粒径和液滴间絮凝程度明显降低;添加阿拉伯胶促进了SPI或大豆蛋白酶解产物(soy protein hydrolysate,SPH)在油水界面的吸附,SPH-阿拉伯胶复合物制备的乳液在pH4的条件下室温放置14 d具有较好稳定性;添加阿拉伯胶前后,SPH制备的乳液黏度均低于SPI。