蒸汽酶解调质-挤压膨化工艺改善速食米粉冲调分散性和预消化性

为建立具有良好冲调分散性和消化特性的速食米粉加工技术,本研究以大米为原料,分析了蒸汽酶解调质-挤压膨化工艺对速食米粉冲调分散性、淀粉糊化度、体外消化特性、以及可溶性蛋白和还原糖含量等的影响。结果表明,与直接挤压膨化相比,蒸汽酶解调质-挤压膨化制得的速食米粉的水溶性指数提高了96.60%,吸水性指数、结块率及分散时间分别降低了72.68%、51.39%及38.27%,米糊的粘度也显著降低,且该速食米粉在低剪切速率下具有较低粘度,其粘度曲线趋于平直;其休止角及滑角均显著降低,说明蒸汽酶解调质-挤压膨化工艺显著改善了速食米粉的冲调分散性及其粉体流动性。此外,蒸汽酶解调质-挤压膨化制得的速食米粉的亮度和总色度显著低于直接挤压膨化,产生了肉眼可见的色差。蒸汽酶解调质-挤压膨化处理还显著增加了速食米粉的可溶性蛋白和还原糖含量,其快消化淀粉比例也较直接挤压膨化明显提高。总之,蒸汽酶解调质-挤压膨化较直接挤压膨化进一步改善了速食米粉的冲调特性及其预消化性。     

预糊化-复合酶解法制备婴幼儿留胚米粉及其理化性质研究

以留胚米为原料,制备高品质的婴幼儿米粉,研究预糊化-复合酶解法在婴幼儿米粉加工过程中的应用及其对理化性质的影响。经焙炒-挤压膨化预糊化后酶解,通过单因素和正交试验,得到最佳的复合酶解技术的工艺条件,同时研究了酶解工艺对婴幼儿留胚米粉表层形态、水溶性指数和吸水性指数、冲调分散性、溶解度和糊化特性的影响。结果表明:复合酶总添加量1250 U/g,酶解时间150 min,酶解温度58 ℃,在此条件下DE值（还原糖当量）33.08%±0.33%,WSI 0.823%±0.07%,综合评分1.012;与未经处理的留胚米粉、预糊化的留胚米粉比较,经预糊化-酶解制得的留胚米粉的吸水性指数、分散时间和黏度显著降低（P<0.05）,水溶性指数、溶解度显著提高（P<0.05）。综上,预糊化-复合酶解法得到的婴幼儿留胚米粉具有黏度低、冲调性和消化性好的优点。     

预酶解-挤压膨化对全谷物糙米粉品质特性的影响

以3 种糙米（普通糙米、红色糙米、黑色糙米）为原料,预酶解-挤压膨化制备实验组糙米粉,未经预酶解处理直接挤压膨化制备对照组糙米粉,分别测定其水溶性指数、吸水性指数、结块率、分散时间、米糊黏度、色度、糊化度、感官评分以及淀粉、还原糖、蛋白质含量等指标,并对淀粉和蛋白质进行体外模拟消化,比较并分析预酶解-挤压膨化对糙米粉品质特性的影响。结果表明：与直接挤压膨化相比,预酶解-挤压膨化处理使普通糙米、红色糙米、黑色糙米3 种糙米粉的水溶性指数分别提高了2.04、1.35 倍和1.71 倍;吸水性指数分别降低了67.87%、60.96%和62.17%;结块率分别提高了5.44、6.27 倍和3.07 倍;分散时间分别缩短了66.61%、61.79%和64.30%;米糊黏度降低,黏度曲线趋于平直,剪切稀释效应减弱;淀粉含量分别降低了29.22%、28.71%和26.70%,糊化度分别降低了19.53%、8.94%和13.13%;可溶性蛋白含量分别提高了1.50、2.87 倍和2.27 倍;差异均达显著水平（P＜0.05）。同时,亮度值略有升高,色差值分别为3.01、4.66、3.28;快消化淀粉比例降低,慢消化淀粉和抗性淀粉比例升高;蛋白质体外消化速率加快,消化率升高;综合感官评分显著升高（P＜0.05）。实验结果表明预酶解-挤压膨化处理提高了糙米粉的冲调分散性、降低了米糊黏度,提高了感官评分和蛋白质体外消化性能,对糙米粉品质具有提升作用。为拓宽糙米的加工利用途径、促进预酶解-挤压膨化技术在谷物加工领域中的应用提供了理论指导。     

小米粉在水和牛奶中稳定性参数及糊化特性的探究

本文用炒、烤、微波三种方法对小米进行熟化处理,并进行不同粒径的粉碎处理,研究熟化处理对小米粉糊化特性的影响,粒径对小米粉在水和牛奶中冲调时稳定性的影响。结果表明:熟化处理方法和粒径对小米粉在水中和牛奶中的稳定性有影响,且对小米粉的糊化特性也有一定影响。三种处理方法对小米粉糊化特性有不同影响。相比于未处理的对照样品,微波处理对小米粉的糊化特性影响较弱。烤小米粉糊化淀粉在温度和剪切力的作用下的耐受能力最强;炒小米粉回生能力最强。粒径对小米粉的糊化特性、热稳定性有着很大的影响,冲调稳定性随着粒径的减小而增大,冲调结块率和水溶性指数随着粒径的减小而减小。水中和牛奶中的小米粉的稳定性显示出相同的趋势,但是在牛奶中小米粉的变化规律更加明显。     

热处理对谷物粉物化性质及淀粉体外消化性的影响

为了研究热处理对谷物粉物化性质和淀粉体外消化性的影响,测定燕麦、小米和玉米3种谷物粉经蒸汽和烘烤热处理前、后糊化特性、膨胀势、吸水性和不同淀粉组成含量的变化。结果表明:热处理使燕麦粉的糊化温度显著降低、小米粉和玉米粉显著升高(P<0.05),燕麦粉和小米粉的回生值显著升高、玉米粉显著降低(P<0.05),玉米粉峰值黏度和崩解值显著降低(P<0.05)、燕麦粉和小米粉的变化不同;蒸汽和烘烤处理使燕麦粉膨胀势分别降低32%和12%,吸水性指数升高20%以上,但是小米粉和玉米粉变化较小;热处理使3种谷物粉水溶性指数降低28%~55%;热处理使3种谷物粉中快消化淀粉含量降低10%~20%,慢消化淀粉含量升高3%~30%,抗性淀粉含量升高20%,尤其热处理对燕麦淀粉组成含量影响最大。扫描电镜观察燕麦、小米和玉米淀粉颗粒直径分别为5,10,15 μm,经热处理后淀粉发生团聚和黏结现象,尤其燕麦淀粉团聚和黏结程度最大。结论:适当的预热处理可以改变谷物粉的物化特性,进而改善其加工性能。热处理改变了谷物淀粉的构成,减缓了淀粉的消化性,提高了其功能特性。     

预糊化对燕麦全粉理化性质的影响

燕麦营养均衡,具有调脂降糖等生理功效,受到消费者青睐,然而,由于燕麦的加工适应性差,限制了其在食品中的应用。本研究以生制燕麦全粉(ROF)为原料,通过蒸制、挤压膨化和滚筒干燥进行预糊化处理,得到蒸制燕麦全粉(SOF)、挤压膨化燕麦全粉(EOF)和滚筒干燥燕麦全粉(DOF),对比分析不同预糊化方式对其理化性质的影响。结果表明,预糊化处理可钝化燕麦中过氧化物酶和脂肪酶活性,3种方式的糊化度呈上升趋势、且差异显著(P0.05);预糊化燕麦全粉的吸水性指数、水溶性指数和膨胀势增大;室温黏度增大,糊化特性发生显著变化。由此可见,预糊化处理有效提高了燕麦全粉的加工适应性与贮藏稳定性。     

熟化处理对赤豆粉理化特性及冲调风味的影响

以赤豆为原料，研究挤压、炒制、微波熟化和热风熟化4种热处理方式对赤豆粉色度、水和特性、糊化、凝胶、冲调特性及冲调风味的影响。结果表明：与赤豆生粉相比，熟化处理粉的亮度降低，色泽偏向红黄色；吸水性指数、水溶性指数和膨胀势均显著增加（P＜0.05），尤以挤压熟化粉最高，其吸水性指数、水溶性指数和膨胀势分别为生粉的1.26、1.92倍和1.44倍；熟化处理粉的糊化黏度、崩解值和回生值均显著降低（P＜0.05），而糊化温度略升高，且起始糊化温度、峰值温度和终止糊化温度值高于赤豆生粉，各处理粉的焓变值显著降低（P＜0.05）；熟化粉凝胶的硬度、内聚性、胶着性、回复性显著降低（P＜0.05）。冲调试验表明微波熟化粉的分散时间、湿润时间最短，分别为19.45、26.61 s，其结块率最低；各熟化处理粉经冲调后酸味减弱，甜味、苦味明显增强，且挤压熟化粉与赤豆生粉滋味、气味相近，而炒制、微波、热风熟化粉冲调液的气味较接近。     

不同糊化度留胚米粉理化性质和体外消化性研究

以留胚米为原料在螺杆转速为100 r/min,水分含量为30 %,挤压温度分别为70~150 ℃的条件下制备不同糊化度的留胚米粉,研究不同糊化度对留胚米粉的理化性质和体外消化特性的影响。结果表明：随着糊化度的增大,留胚米粉的蛋白质、脂肪、可溶性膳食纤维、总淀粉和直链淀粉含量显著下降(P<0.05);色度、粒径、吸水性指数、水溶性指数及膨胀度呈上升趋势,且差异显著(P<0.05);高糊化度留胚米粉与原留胚米粉相比峰值黏度、谷值黏度、最终黏度及回生值均显著降低(P<0. 05),消化性显著提高(P<0.05)。不同糊化度留胚米粉的理化性质和体外消化特性具有明显差异。     

双酶协同滚筒干燥加工冲调糙米粉的工艺研究

为制备高品质冲调糙米粉,本研究探讨了纤维素酶和中温α淀粉酶协同滚筒干燥处理对冲调糙米粉品质的影响,并对其加工工艺进行了优化,对产品质量进行了分析。结果表明,酶制剂添加量、滚筒温度及转速等对产品吸水性有不同程度的影响,当纤维素酶添加量为0.4%,中温α淀粉酶添加量为0.25 U/g,米浆质量浓度为27%,滚筒温度为160℃,滚筒转速为5.20 r/min时,所得冲调糙米粉的水溶性指数最高,为70.5%。表明纤维素酶和中温α淀粉酶协同滚筒干燥处理可显著改善冲调糙米粉的冲调性,其物化及微生物性质均符合国家标准,且有较好的稳定性。     

高温α-淀粉酶-挤压膨化耦合处理对全谷物糙米粉品质的影响

以普通糙米、红米和黑米为原料,分析了高温α-淀粉酶-挤压膨化耦合处理对全谷物糙米粉径向膨化率、水溶性指数、吸水性指数、分散时间、结块率、黏度、糊化度以及还原糖、总蛋白质含量和可溶性蛋白质含量的影响。结果表明:3种全谷物糙米经过高温α-淀粉酶-挤压膨化耦合处理后其径向膨化率和糊化度均显著降低(P<0.05);水溶性指数显著升高(P<0.05)了2.51倍、1.89倍和2.73倍,吸水性指数显著降低(P<0.05)了77.29%、33.41%和67.44%;分散时间和结块率均显著降低(P<0.05),分散时间分别减少了64.60%、60.66%和65.40%,结块率分别降低了75.57%、84.64%和75.24%;冲调黏度均显著下降(P<0.05),加酶处理的糙米粉在低剪切速率下具有较低黏度,其黏度曲线趋于平直;还原糖和可溶性蛋白质含量显著提高(P<0.05),总蛋白质含量提高不显著(P>0.05)。     

Crystallinity and Rheological Properties of Pregelatinized Rice Starches Differing in Amylose Content

Three rice starches with different amylose contents (Glutinous: 1.4%, Jasmine: 15.0% and Chiang: 20.2%) were pregelatinized in a double drum dryer at 110, 117 and 123°C. Starch crystallinity was determined by X‐ray diffractometry and Fourier transform infrared (FTIR) spectrometry. Rheological properties were assessed by a Rapid Visco Analyser (RVA) and rheometer. Pregelatinized starches obtained from Glutinous (PGS) and Jasmine rice (PJS) gave an RVA pasting profile with cold peak viscosity. At drum temperature 110°C, PGS and PJS showed X‐ray patterns that were indicative of amorphous structures. However, pregelatinized Chiang rice starch (PCS) exhibited RVA hot peak viscosity and the presence of an amylose‐lipid complex with remaining granule structure. The PCS had a lower water absorption index (WAI) and water solubility index (WSI) than PJS and PGS. After pregelatinization at increased drum temperature (117, 123°C), the PGS had a lower WAI, whereas PCS showed an opposite trend indicating lower degree of granule disruption. In addition, the cold peak viscosity of PGS and PJS decreased with increasing drum temperature. For all drum temperatures, the apparent viscosity at 25°C for PGS and PJS decreased with increasing shear rate, indicating shear‐thinning behavior.     

工程重组方便米复配机理的研究

长期以来,方便米的复水特性和复水后的食用品质是制约传统工艺发展的主要症结之一,人们为此进行了不懈的努力。本文以大米粉作为主原料,复配食品添加剂,采用挤压技术生产“工程重组米”的新思路,完全克服传统工艺对大米进行表面处理的局限性,试图为制备具有良好品质的方便米另辟蹊径。本文研究了单甘酯(GMS)、大豆卵磷脂(LC)、硬脂酰乳酸钠(SSL)对米粉挤压过程中理化特性的变化以及对制备的方便米复水特性的影响,研究表明随着乳化剂添加量的增加,工程重组米的糊化度(DG)、水溶性碳水化合物(WSC)有所降低。随着GMS的增加,挤出物的膨胀度、水溶性蛋白质(WSP)、吸水指数(WAI)、方便米的复水率下降,硬度增加,而粘度在低于添加量0.8%时上升,高于0.8%时下降。而添加SSL,膨胀度变化较小,WSP、WAI有所增加;添加LC,膨胀度和WAI都有所增加,WSP变化较小。与对照组相比,大豆磷脂和SSL添加量小于0.8%时,复水率有所提高,硬度与粘度下降。     

Development of a Protein-rich Composite Sorghum-Cowpea Instant Porridge by Extrusion Cooking Process

To develop an instant high protein porridge, various ratios of sorghum and cowpeas were extruded at 130 and 165 °C and a water content of 200 g/kg using a twin-screw extruder. An increased proportion of cowpeas resulted in an increase in protein content, nitrogen solubility index (NSI), yellow colour, water absorption (WAI) and solubility (WSI) indexes and in a decrease in total starch (TS), enzyme-susceptible starch (ESS), expansion ratio (ER), and porridge firmness. The higher extrusion temperature gave lower NSI, TS and WAI. ESS, ER and WSI increased with severity of heat treatment. The composite of 50% sorghum and 50% cowpeas extruded at 130 °C was the most similar to a commercial instant maize-soya composite porridge in terms of composition and functional properties. A serving of 100 g would contribute 28% of the recommended dietary allowance (RDA) for protein. This represents a 110% increase in the protein RDA compared to sorghum only.     

Effect of heating condition and starch concentration on the structure and properties of freeze-dried rice starch paste

The structure and characteristics of freeze dried rice starch paste were investigated at low starch concentrations (1%, 3% and 5%). The microstructure of samples made at 1% of starch concentration showed a loose filamentous network compared to other concentrations (3% and 5%). Especially the samples prepared at processing conditions above 110 °C and 3% were appeared a coarse honeycomb-like structure. Crystallinity of samples calculated by intensities of X-ray diffraction peaks was very low values (3.3–9.8%). The mechanical properties (hardness, cohesiveness and springiness) of the samples were highly influenced by starch concentration and heating temperature. The relative increment of water absorption index (WAI) according to increasing of heating temperature showed the highest value at 1% of starch concentration, and the heating temperature was analyzed to the important factor affecting WAI and WSI (water solubility index). The digestibility of samples showed an increasing trend with heating temperature regardless of starch concentration. Overall, the important factors influencing the properties of freeze dried rice starch paste were starch concentration and heating temperature.     

不同加工方式对米糠粉食品配料理化特性的影响

为了改善米糠的理化特性,开发新型米糠食品配料,本文研究了挤压膨化、微波蒸煮和高温焙炒三种整体加工方式对脱脂米糠理化特性的影响。结果表明,脱脂米糠经过三种整体加工方式处理后,理化特性均得到改善,其中挤压膨化米糠具有最高的水溶性指数、吸水性指数、糊化度及分散稳定性。与未处理组相比,挤压膨化米糠水溶性指数、吸水性指数和糊化度分别提高了4.82%、18.92%和96.04%。同时,三种整体加工方式显著减少了米糠中还原糖和植酸的含量,而分析米糠的酚类物质和抗氧化活性时,发现高温焙炒显著增加了脱脂米糠中总酚含量及抗氧化能力,但挤压膨化降低了脱脂米糠中总酚含量和抗氧化能力。本研究可以为脱脂米糠作为糊粉类营养代餐食品配料的加工提供指导。     

Extrusion cooking properties of white and coloured rice varieties with different amylose content

Five white and coloured rice varieties with different AM contents (long grain rice: 34%, Thai Jasmine rice: 15%, glutinous rice: 7%, red rice: 18% and black rice: 5%) were pregelatinised using a twin‐screw extruder at a barrel temperature of 150°C and two levels of feed moisture (12 and 16%). The correlation of AM content to water absorption index (WAI), water solubility index (WSI), starting viscosity, hot viscosity and final viscosity of the five rice extrudates were determined. Total anthocyanin content (TAC), total phenolic content (TPC) and antioxidant activity of extrudates were analysed by spectrophotometric methods. AM content was positively correlated to WAI and final viscosity. High AM content of the rice varieties resulted in high WAI and high final viscosity of extrudates. In addition, higher feed moisture content (16%) increased WAI and pasting properties of rice extrudates, but decreased WSI. Extrusion cooking reduced TAC, TPC and antioxidant properties, but the remaining values were high enough to suggest a further use for (functional) food production.     

Unlocking the potential of pasting properties to predict extrudate characteristics of corn grits blends with high amylose corn starch,potato starch,or rice flour

The development of new production lines of extruded ready-to-eat (RTE) snacks often results in high losses of edible food due to the trial-and-error approach in industry. Being able to predict extrudate characteristics of new formulations before having to run trials on industrial scale would be beneficial for reducing waste and having a more efficient development process. With this study, the correlation between pasting properties of seven blends of flours/starches and extrudate characteristics was investigated (100% corn grits, 25% and 50% replacement of corn grits with high amylose starch, potato starch, and rice flour). The predictive power of pasting characteristics on extrudate's moisture content, water absorption and solubility index, sectional expansion index (SEI) and hardness was studied. Results indicated the potential of predicting SEI, water solubility index (WSI), and water absorption index (WAI) of RTE-snacks. WSI and WAI were, respectively, negatively correlated with peak temperature (R² = 0.897), and positively with peak temperature and positively with trough viscosity (R² = 0.855). One can conclude that the rheometer can be a useful tool to gain insight into the characteristics of the extrudate, although further research with enlargement of the dataset is necessary to make the rheometer effectively deployable for potentially other extrudate characteristics.     

Effect of processing conditions on some functional characteristics of extrusion‐cooked cassava starch/wheat gluten blends

Extrusion‐cooked blends of cassava starch (CS) and wheat gluten (WG) were studied. The data were analysed using response surface methodology. The results showed the formation of new structures characterised by lower radial expansion (RE) and specific volume (SV) when gluten was added to CS. WG content was the most important variable affecting RE, water absorption index (WAI), water solubility index (WSI), SV and difference in colour (ΔE) of the extruded products, but feed moisture content and barrel temperature also influenced RE. WAI was affected by a significant interaction between WG content and barrel temperature. The extruded products had lower WAI values and higher WSI values than WG‐free products. Heat, high shear rate and high pressure during extrusion cooking caused mechanical destruction or denaturation of the WG and gelatinisation and dextrinisation of the starch components. The extruded blends could have diverse applications. © 2002 Society of Chemical Industry     

Effects of partial substitution of potato flour on cooking characteristics,texture properties and in vitro starch digestibility of fresh extruded rice-shaped kernels

Effects of partial substitution of potato flour (0%, 10%, 20%, 30% and 40%) for rice flour on cooking characteristics, textural properties and in vitro starch digestibility of fresh extruded rice-shaped kernels (FER). With the increase in potato flour content, the water absorption index (WAI) increased gradually, the water solubility index (WSI) decreases gradually. Hardness, elasticity, adhesion and chewiness first increased and then decreased. When the potato flour content was 30%, the peak viscosity, trough viscosity, breakdown viscosity, final viscosity and setback viscosity of the pasting test were 325, 168, 157, 312 and 144 cp, respectively. The WAI of the cooking test was 7.50 g g⁻¹, and the WSI was 4.71%. The texture test had a hardness of 1211.82 g, flexibility of 0.85 mm, cohesiveness of 0.73 gs, adhesion of 715.38 g and chewiness of 519.28 g. The highest overall acceptability score was 4.51 in sensory evaluation. Finally, the predicted glycaemic index indicated that potato flour is a suitable raw material for low GI products.     

Effects of Extrusion Process Variables on Quality Properties of Wheat-Ginseng Extrudates

The present study investigated the effects of extrusion process variables (feed moisture, screw speed, and barrel temperature) on the physical [expansion ratio, water absorption index (WAI), and water solubility index (WSI)], pasting, and thermal properties of wheat-ginseng extrudates (WGE). A wheat flour-ginseng powder (GP) blend (10% GP, w/w) was extruded in a twin-screw extruder (L/D ratio of 25:1) with full factorial combinations of feed moisture (25, 30, and 35%), screw speed (200 and 300 rpm), and zone 5 barrel temperature (110, 120, 130, and 140°C). The expansion ratios of WGE were significantly increased with decreasing feed moisture, decreasing screw speed, and increasing barrel temperature. Increasing feed moisture significantly increased WAI values of WGE and significantly decreased WSI values of WGE. However, an increase in either screw speed or barrel temperature caused a significant decrease in WAI values of WGE and a significant increase in WSI values of WGE. Rapid visco analyzer peak viscosity values of WGE were significantly affected by changes in extrusion process variables studied, indicating that the degree of starch degradation and/or gelatinization in WGE is a very important factor associated with their peak viscosity. WAI values of WGE were positively correlated (r = 0.88, p ≤ 0.001) with peak viscosity values of WGE samples, whereas WSI values of WGE samples were negatively correlated (r = 0.82, p ≤ 0.001). Increasing feed moisture resulted in an increase in values of transition peak temperature (T_p) of WGE, whereas increasing screw speed and barrel temperature each led to a decrease in T_p values of WGE, determined by differential scanning calorimetry.