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1.
Extrusion processing is a thermal process applied to food preparation. However, its effects on food ingredients are ambiguous. The aim of this study was to elucidate the effects of extrusion processing on soluble dietary fiber (SDF) in oat bran. The yield, composition, thermal properties, rheological behavior and functionality of SDF in extruded oat bran were compared with those of SDF in untreated oat bran. The results showed that SDF in extrude oat bran had higher yields (14.2%), mean particle diameter (1718.1 nm), peak temperature (Tp = 69.0 °C), solubility, swelling capacity, solvent retention capacity, foam ability, apparent viscosity and consistency coefficient, and lower flow behavior index than those of SDF in untreated oat bran. The extrusion process improves some properties of SDF from oat bran. 相似文献
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Stir-frying, similar to roasting, is a key step for oat milling process in China. The oat flour milling yield of Bayou No.2 and Bayou No.8 and their corresponding flour quality were investigated under different processing conditions (160 °C, for 0, 10, 20, 30 and 40 min). Results showed that oat flour milling yield was increased after stir-frying, Bayou No.2 and Bayou No.8 reached the highest yield after a 10 min and 20 min of stir-frying, which were 45.40% and 52.96%, respectively. With the increasing of stir-frying time, the gelatinization degree and the particle size of oat flour gradually increased, while their angle of repose and L* values were reduced. RVA studies showed that the stir-fried oat flour exhibited lower peak, trough, breakdown and setback viscosities compared to not stir-fried oat flour, indicating that stir-fried oat flour formed a more stable network structure and stir-frying induced an inhibitory effect on the retrogradation of oat flour paste. Rheological analysis suggested that the low tanδ of stir-fried oat flour than that of not stir-fried oat flour, revealing that the stir-fried oat flour paste exhibited more elastic but less viscous behavior. 相似文献
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天然橡胶的生产主要采用传统的热风干燥,但天然橡胶是热的不良导体且自粘性强,导致热风干燥普遍具有干燥效率低、胶料发粘和夹生等问题,这对产品的性能带来不利影响。而螺杆挤压膨胀干燥工艺作为一种新干燥工艺,已被广泛应用于合成橡胶工业,具有干燥效率高、自动化水平高和工艺稳定等特点,在天然橡胶（NR）生产加工中具有良好的发展和应用前景。本研究对比了传统热风干燥（NT）和螺杆挤压膨胀干燥（NCT）2种工艺制备NR的结构,分析NCT的性能特点,以探讨螺杆挤压膨胀干燥工艺运用在天然橡胶生产加工中的可行性。结果表明：在生胶层面,螺杆挤压膨胀干燥工艺由于干燥温度低、干燥用时短,能够有效降低NR分子链在干燥过程中受到的热氧降解,因此NCT相比NT而言具有更高的塑性初值、门尼粘度和凝胶含量,且对于蛋白质、挥发分等非胶组分的影响较小;对于纯胶配方硫化胶,NCT相较NT而言表现出更快的硫化速率。通过使用Mooney-Rivlin方程对硫化胶内部网络结构进行了拟合,发现NCT硫化后的有效交联密度和化学交联网络的数量相对较低,这使得NCT的拉伸强度、撕裂强度和模量等常规力学性能低于NT,疲劳性能方面也表现出了相对较高的压缩生热和蠕变。对于炭黑配方硫化胶,NCT与NT的常规力学性能无明显差异,这可能是由于硫化促进剂N-叔丁基-2-苯并噻唑次磺酰胺的硫化速率较快所导致。但在动态力学性能方面,NCT的疲劳寿命更长,表现出更优异的动态疲劳性能,这与螺杆挤压膨胀干燥工艺能改善炭黑分散性有关。 相似文献
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Elena de la Peña Frank A. Manthey Bhavesh K. Patel Osvaldo H. Campanella 《Journal of Cereal Science》2014
A study was conducted to investigate the effect of dough formulation and hydration level on the rheological properties of pasta dough during pasta extrusion. Semolina 100%, whole wheat 100%, and the following mixtures semolina-whole wheat (49:51), semolina-flaxseed flour (90:10), whole wheat-flaxseed flour (90:10), and semolina-whole wheat-flaxseed flour (39:51:10) were the formulations used for the experiments. Dough was hydrated at 30, 32, and 34% moisture content. Pasta was extruded with a capillary and a semi-commercial pasta extruder to determine the apparent viscosity of the dough during extrusion conditions and its relationship to the behavior of the dough during pasta processing. Results showed that non-traditional pasta dough behaved like a shear thinning fluid that can be described by the Power Law model. Increased hydration levels and/or presence of flaxseed flour on the dough formulation decreased the apparent viscosity of the dough, which correlated with extrusion pressure, mechanical energy, and specific mechanical energy that were required to extrude the dough in the pasta extruder. The strong correlations found between the apparent viscosity of the dough and the pasta extrusion parameters indicates the possibility of using a capillary rheometer to determine the appropriate hydration level of ingredient formulations before extruding with a pasta press. 相似文献
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A health claim linking the consumption of barley β-glucan and the lowering of blood cholesterol has been allowed in North America and Europe which resulted in increased interest in barley products. Waxy barley flour rich in β-glucan (10% d.b.) was used to produce barley functional spaghetti and compared to semolina spaghetti. The impact of processing (extrusion, drying and cooking) on the physicochemical properties of barley blends and pasta as the molecular characterization of β-glucan were investigated. Pasta processing did not significantly affect the amount of β-glucan, but it impacted the β-glucan physicochemical properties in the end products. In all pasta, extrusion and drying were detrimental to the β-glucan properties, while cooking significantly increased the extractability and molecular weight of β-glucan, and in turn its viscosity, which determines its physiological effectiveness. In general, replacing wheat semolina with barley flour rich in β-glucan resulted in improved barley pasta containing the recommended amount of β-glucan per serving and enhanced β-glucan properties. 相似文献
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Three commercial wholegrain oat (WO) flours from Finland (WOF), Ireland (WOI) and Sweden (WOS) were evaluated for their bread making ability with the objective of finding predictive relationships between flour physicochemical properties and bread quality. Overall, significant differences were found in the bread making properties of the WO flours. Good bread quality was obtained when using WOS and WOI flour since breads showed high specific loaf volume and slice height as well as low density and hardness. Low quality breads were obtained when WOF flour was used. In addition, positive effects on oat bread quality were observed for low batter viscosity and high deformability, as obtained for WOS and WOI. Based on the physicochemical analysis of the flours, water hydration capacity was found to be the main reason for increased elasticity of WOF batters. Small flour particle size, damaged starch granules and high protein content were identified as the key factors causing increased water hydration capacity. These findings suggest that WO flours with coarse particle size, limited starch damage and low protein content result in superior oat bread quality. 相似文献
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燕麦粉不含面筋蛋白,使燕麦全粉面条煮熟后易浑汤、蒸煮损失率大,目前只能温水浸泡复水食用,是限制燕麦更广泛推广的难题之一。为了满足市场对燕麦全粉面条的需求,以利用二级挤压技术生产的燕麦全粉挤压面条为试材,对成型面条进行了调湿老化、蒸制老化及冷冻老化处理,比较了不同老化方式对燕麦全粉挤压面条蒸煮品质的影响。结果表明,调湿老化处理的面条蒸煮损失率最小(2.26%~3.34%),蒸制老化次之(4.19%~5.19%),冷冻老化最大(5.16%~7.97%)。不同老化处理的面条感官评分差异不显著,以调湿老化处理24h的面条感官评分最高(87.2分);调湿老化处理面条的淀粉相对结晶度(12.47%~16.10%)、热焓值(1.044 0~1.056 0J·g-1)及回生值(519.5~558.0cP)均最大,蒸制老化次之,冷冻老化最小。综合分析可知,对燕麦挤压面条进行淀粉老化处理,能够显著降低燕麦全粉挤压面条的蒸煮损失率,最优方式为调湿老化24h。 相似文献
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The ability of oat foods to lower serum cholesterol and post-prandial blood glucose concentrations has been linked to the physicochemical properties of the bioactive component, mixed linkage β-glucan. Oat foods frequently need to be shipped or stored prior to analysis and β-glucan characteristics may change over time. Reductions in β-glucan solubility or molecular weight lead to lower viscosity development which decreases bioactivity. Impact of freezing and freeze drying conditions on the β-glucan physicochemical characteristics in oat bran bread and porridge were studied. Two in vitro digestibility methods were used to produce physiological extracts and the results were compared. The β-glucan molecular weight, solubility and viscosity for oat bread stored at room temperature were unchanged for 3 days, followed by a gradual decline in these parameters. The extract viscosity for bread decreased significantly after freezing at −80 °C and freeze drying after freezing at −18 and −80 °C, whereas freezing in liquid nitrogen did not significantly influence viscosity. Freezing of oat bran porridge did not affect extract viscosity, but freeze drying resulted in reduction of extract viscosity compared to the fresh porridge. Freezing and freeze drying did not dramatically affect the molecular weight or solubility of β-glucan in either product. The rapid visco analyzer was more effective and reliable for sample digestion than when physiological extraction was conducted in the shaking water bath. Generally, freezing at −18 °C or by submersion in liquid nitrogen maintained the physicochemical characteristics of β-glucan in food products either for commercial products or subsequent analysis. 相似文献
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为提高花生果干燥后的品质，采用脉冲间歇式-低强度微波、高强度微波以及高&低强度微波分别与热风
进行耦合干燥，研究不同干燥工艺下花生果的干燥特性、品质特性及干燥能耗情况。结果表明：采用脉冲间歇式-
高&低强度微波热风耦合的干燥工艺最佳，其中微波强度 0.95 W/g照射时间 16.7 min，微波强度 0.48 W/g照射时间
11.7 min，干燥总耗时198.3 min，可将花生果含水率从50.0%降至15.5%，并且其总能耗比低强度微波和高强度微波
分别降低了37.1%、8.6%，干燥后花生果的品质较佳。因此，脉冲间歇式-高&低强度微波热风耦合干燥工艺的研究
对花生果的减损具有重要意义。 相似文献
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为探明饮料用原料茶的适宜干燥工艺,将不同干燥方式、干燥程度绿茶原料加工成茶饮料,研究其浸出特性及品质稳定性。结果表明:(1)低温浸提时,茶多酚浸出量以炒干最高,高温时以烘炒焙、烘炒烘处理最高。氨基酸的浸出量则均以烘干、烘焙处理最高。(2)烘干、烘焙样品在灭菌前后及贮藏期间的L值显著为高,平均值较其余处理高2.035~3.905;抗色变能力同样以烘干较强,低温贮藏时的-a/b值较炒干处理样高19.5%。(3)感官风味比较显示,大多数处理茶汤在灭菌后均呈现出绿黄或黄绿色,香气带熟,但烘干处理仍能保持绿明亮,且滋味、香气未显熟味;贮藏期间的风味稳定性也以烘干样为最佳。综合分析,饮料用原料茶的干燥工序宜采用烘干工艺,且烘干程度以5%~6%为佳。 相似文献
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Extrusion is an alternative pretreatment for oil extraction from cereal resource. The objective of this study was to assess the feasibility of extrusion pretreatment of oat bran for oil extraction. The effects of extrusion conditions including feed moisture content, screw speed and die temperature on the extraction, quality and antioxidant capacity of oat bran oil were investigated. The results showed that the extraction yield of oat bran oil varied from 3.93% to 8.43% under different extrusion conditions. A feed moisture content of 25% had an important effect on the extraction of oil from oat bran. Extrusion pretreatment could increase oil extraction efficiency by increasing expansion index and porosity of oat bran extrudates. Extrusion processing had no positive or adverse effect on the fatty acid compositions, and acid, peroxide and iodine values. Meanwhile, extrusion processing did not affect the phytochemical components and antioxidant capacity of oat bran oil. But refining process could result in decrease of phytochemical components and antioxidant capacity of oat bran oil. These results indicated that extrusion is a feasible and potential pretreatment procedure for oil extraction from oat bran. 相似文献
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本研究以槟榔为对象,采用色差、气质、液相、紫外等分析手段,研究不同干燥方法对槟榔外观形态、活性成分和抗氧化能力的影响。结果表明：槟榔的干燥速率与温度呈正相关,最快到达干燥终点的是微波干燥;干燥后槟榔外皮亮度增加,绿色度下降,黄色度提高;槟榔干制品的厚度与干燥温度呈负相关,低温的冻干可基本保持槟榔的厚度;干燥过程中槟榔的硬度出现先下降再上升的趋势,在失水率50%时硬度最低,为后续粉碎工艺提供理论支持;干燥后槟榔的总黄酮、总酚含量均显著高于新鲜青果,抗氧化能力均显著强于新鲜样品;而槟榔碱含量干燥样品均显著低于新鲜样品,因此可推断槟榔的抗氧化能力可能与其总黄酮、总酚含量相关,与槟榔碱无明显相关。不同干燥方式对槟榔的影响明显不同,在生产中应根据实际需求选择不同的干燥方式或复合使用。 相似文献
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B-glucan is one of the components that differentiate oats from other cereals and that contribute to the health-related value of oats. However, so far oats cannot easily be applied in bread-like products without loss of product quality. Here we have studied how the content and viscosity of oat β-glucan affect the technological properties of oat dough in both a gluten-free and a gluten-containing system. In both systems, increasing the β-glucan concentration resulted in an increase of dough stiffness and in a reduction of dough extensibility. β-glucan negatively impacted the elastic properties that additional wheat gluten conferred to oat dough. This effect was smaller for medium-viscosity β-glucan than for high-viscosity β-glucan. Interestingly, dough made from low β-glucan flour (<2%) had increased gas retention capacity. Overall, the impact of β-glucan on the properties of oat dough systems was governed by concentration and viscosity, with or without additional wheat gluten. Our findings indicate that β-glucan is a key component that determines the rheology of oat-based dough systems and, with that, the technological functionality of oat in dough systems. 相似文献
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Frédéric Robin Cédric Dubois Nicolas Pineau Emilie Labat Christine Théoduloz Delphine Curti 《Journal of Cereal Science》2012
Whole wheat is well known by consumers as a health-providing ingredient. Nevertheless, in extruded products it leads to textures that are less favorable to consumer preference compared to its refined flour. An understanding of the effect of extrusion on whole wheat properties is therefore necessary to improve its texture. Whole wheat flour was extruded under varying conditions of water content (18 or 22%), screw speed (400 or 800 rpm) and barrel temperature (140 or 180 °C) and its physicochemical properties were measured. Changing the extrusion conditions significantly modified the volumetric expansion index (between 9.1 and 20.6) and longitudinal expansion (between 0.93 and 2.98) of the samples. Interestingly, changing the extrusion conditions did not significantly modify the sectional expansion. Increasing barrel temperature, water content or screw speed decreased the shear viscosity of the melt. This can be explained by plasticizing effects and modification of starch properties. The change in shear viscosity at the die can mostly explain the effect of process conditions on volumetric expansion of the extruded whole wheat. The stress at rupture of the extruded samples was varied between 0.49 and 1.86 MPa depending on process conditions. It was the lowest at high water content and low screw speed. 相似文献
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Rheological properties of wheat flour processed at low levels of hydration: Influence of starch and gluten 总被引：1，自引：1，他引：1
The rheological properties of wheat flour under processing such as extrusion (with 28% moisture content, wet basis) are influenced by the molecular changes its components undergo during processing. But, there was no simple relationship between the wheat-flour characteristics and their rheological properties. In order to investigate the quantitative and qualitative effects of the individual flour components on rheological properties, model blends of wheat starch and wheat gluten with different starch/gluten ratios were studied. The effects of gluten and starch quality were also investigated by using different gluten types and by modifying the amylose content of starch, respectively. The shear viscosity of the blends, determined by capillary rheometry under controlled conditions (35% moisture content, 140 °C), was observed to be modified by both gluten and amylose content. The changes undergone by wheat gluten under these conditions were analysed by HPLC, to determine the levels of unextractable polymeric proteins, and by Lab-on-a-Chip analysis of protein composition, to follow the polymerisation of protein under processing. This study indicated that in low hydrated products in the molten state, shear viscosity is affected by the structure of the blends as determined by fluorescence microscopy and by the molecular changes occurring during processing. 相似文献
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J.S. Chen M.J. FeiC.L. Shi J.C. TianC.L. Sun H. ZhangZ. Ma H.X. Dong 《Journal of Cereal Science》2011
Wheat bran is one of the major dietary fiber sources widely used in the food industry in order to produce fiber-rich foods. The effects of particle size and addition level of wheat bran on the quality of flour and of dry white Chinese noodles (DWCN) were investigated. Results suggested that increasing wheat bran concentration and particle size decreased midline peak value (MPV). However, the MTxW and MPT increased as particle size increased. Peak viscosity, trough, final viscosity, area of viscosity, breakdown, and setback of blends decreased significantly with increasing bran levels from 5% to 20%, but there were no significant differences in the impact of particle size on pasting properties. For the 5% and 10% addition levels, there was no distinct effect in breaking strength of the noodles when bran size was 0.21 mm and 0.53 mm. Hardness, gumminess and chewiness of cooked DWCN showed a downtrend with increasing addition levels and particle size, while adhesiveness showed uptrend. The total score of DWCN showed a downtrend with increasing of addition level and particle size. For the 5% bran level, the scores of cooked DWCN were more than 83 when wheat bran particle size was 0.21 mm and 0.53 mm. By using 5–10% fine bran or using 5% medium bran in wheat flour, it is possible to satisfactorily produce fiber-rich DWCN. 相似文献