蒸谷米浸泡工艺参数初探

通过研究浸泡温度、浸泡时间、浸泡压力对蒸谷米含水量的影响,采用正交试验优化蒸谷米浸泡工艺参数,经过中试试验修正的工艺参数为:浸泡温度55℃、浸泡压力400kPa、浸泡4 h.     

蒸谷米快速浸泡工艺研究

研究不同浸泡工艺包括温度-时间、微波、酸碱溶液、低浓度乙醇、酶对稻谷吸水率的影响,结合蒸谷米外观品质及米饭质构分析,筛选有效的快速浸泡工艺。结果表明,在稻谷∶水为1∶1(g/mL)、温度60~70℃、浸泡4~5 h时,便达到浸泡工艺要求,吸水率达到30%;能显著提高稻谷吸水率的方法是质量比5%的纤维素酶浸泡4 h,吸水率达30.07%;能显著缩短浸泡时间方法是5 min、700 W微波浸泡,吸水率为31.69%。且2种浸泡工艺对蒸谷米的外观品质和米饭质构无不良影响,有望作为蒸谷米快速浸泡工艺进行应用。     

蒸谷米浸泡工艺研究

以籼稻为原料,研究浸泡工艺条件对蒸谷米品质的影响,以确定蒸谷米生产的最佳浸泡工艺条件。结果表明,蒸谷米生产工艺中最佳的浸泡工艺参数为:浸泡温度55℃、浸泡压力150kPa、浸泡时间5h。浸泡之后的稻谷吸水量较优,浸泡液中蛋白质损失量和可溶性糖损失量在吸水量达到最优的前提下保持较低水平。     

不同工艺条件对蒸谷米品质的影响

以早籼稻为原料,设定浸泡温度65、70、75℃,浸泡时间3、3.5、4h,蒸煮温度90、95、100℃,蒸煮时间25、30、35 min,进行L9(34)正交试验,分别测定各参数组合处理所得产品的色度、营养品质和蒸煮品质。综合各品质指标选出生产蒸谷米的最佳工艺条件为:浸泡条件为65℃~70℃、3.5 h~4 h,蒸煮条件为100℃、30 min。     

浸泡对早籼稻水分含量及蒸谷米品质的影响

以早籼稻为对象,通过改变浸泡时间和温度,测定分析浸泡条件对早籼稻的水分含量、蒸谷米VB1的含量以及蒸谷米品质的影响。结果显示,浸泡条件对蒸谷米品质影响明显,当浸泡温度为75℃、时间为3.5 h时,蒸谷米的品质最好,VB1含量最高。     

超声波辅助浸泡对稻谷含水量和蒸谷米品质的影响

以早籼稻为材料,研究超声波功率、超声波处理时间及料液比对稻谷含水量、蒸谷米的整精米率以及糊化特性的影响,并采用正交试验对超声波辅助浸泡工艺进行优化。结果表明:在超声波功率为600W,超声波处理时间为25min,料液比为1∶3(g/mL)时的工艺组合条件最优,整精米率达68.82%,蒸谷米的品质最好。     

浸泡与发芽对蒸谷米镉含量的影响

目的:探讨稻谷发芽与糙米发芽两种发芽方式对蒸谷米镉含量的影响,并对工艺条件进行优化,为降低蒸谷米的镉含量提供技术参考。方法:以湘早籼24号稻谷为试验材料,设置浸泡不发芽、浸泡发芽、浸泡发芽+二次浸泡3种处理方式,分析比较浸泡、发芽与二次浸泡对稻谷发芽和糙米发芽的蒸谷米镉含量的影响,并对柠檬酸浓度、浸泡时间、浸泡温度进行单因素及正交试验优化,选出最佳蒸谷米降镉工艺条件。结果:糙米发芽的蒸谷米镉含量降低效果优于稻谷发芽,糙米发芽的二次浸泡工艺优化后,得到最佳工艺组合为柠檬酸浓度0.15 mol/L,浸泡时间24 h,浸泡温度35 ℃。结论:发芽可以降低镉与蛋白的结合能力,二次浸泡后镉含量显著下降,与稻谷发芽处理相比,糙米发芽工艺的蒸谷米镉含量更低,经过二次浸泡条件优化,在最佳工艺组合条件下镉降低率为56.34%。     

浸泡和超高压预处理对大米品质的影响

对浸泡和高压处理条件对大米品质的影响做了初步研究。实验表明,用0.8%的柠檬酸溶液浸泡大米有助于提高其糊化度,随着压强的升高,大米淀粉的糊化度逐渐增强,400 MPa压强下糊化度的边缘效应,能够显著降低大米的老化度,提高米饭的品质。     

蒸谷米的湿热处理与工艺优化

对浸泡,蒸煮,干燥等湿热自理对蒸谷米品质的影响进行了研究,结果表明,采用酸醇分步浸泡,高压蒸煮和高温高湿干燥相结合的新工艺生产的蒸谷米维生素Ｂ２的含量较高,且产品色泽好,饭香浓,出米率高,蒸饭时间短。     

蒸谷米的湿热处理与工艺优化

本文对浸泡、蒸煮、干燥等湿热处理对蒸谷米品质的影响进行了研究。结果表明,采用酸醇分步浸泡、高压蒸煮和高温高湿干燥相结合的新工艺生产的蒸谷米维生素B_2的含量较高,且产品色泽好、饭香浓,出米率高,蒸饭时间短。适宜的工艺参数为:先用1.2％的柠檬酸溶液浸泡2小时,再用1.5％乙醇溶液浸泡1.5小时,经121℃高压蒸煮30min,再用55％相对湿度,90℃热风干燥30min,缓慢冷却2.5小时后,立即用常规方法砻谷和碾米。出米率和整米率分别为67.28％和87.0％,成品色泽浅、米饭香味浓而无异味,维生素B_2的含量为2.473mg/100g。     

蒸谷米生产工艺简析

介绍了中粮(江西)米业有限公司的蒸谷米生产工艺。     

Limited multilayer desorption of brown, parboiled rice

Two mathematical models, the BET-equation and the Caurie-equation, are used to analyse experimental desorption isotherms of two long-grain varieties of brown, parboiled rice at different temperatures. Monolayer moisture contents and maximum number of sorbed water layers, estimated by the Caurie-model, decrease with increasing temperature. From the temperature dependence of the desorption isotherms, isosteric heats of desorption are calculated. For both varieties, the differential heats of desorption are already very small (1.4 kJ/mol) at a moisture content of 20%. Thus, additional moisture behaves almost like pure water.     

A study on the acceptability and consumer attitude towards parboiled rice

Despite nutritional claims and other advantages that parboiled rice possesses, its consumption is still low in Brazil mainly because of the local preference for milled rice. In the first part of this study, the acceptability of five commercial brands of parboiled and milled rice was assessed by 100 consumers and similar acceptance levels were observed, evidencing that consumers might not reject parboiled rice for its sensory properties. In the second part, 286 consumers were surveyed about their eating habits and attitude towards rice, focusing especially the nutritional value, sensory and convenience aspects of parboiled rice. In the survey 35% of the respondents were unaware of parboiled rice. Cluster analysis performed on data grouped consumers in one segment with positive attitude and in two other segments with negative attitude towards parboiled rice. Segmentation was mainly because of negative beliefs about the sensory characteristics of the product, although its nutritional claims were unknown to most respondents, revealing the need of marketing efforts focused on informing consumers the health benefits and convenience of eating parboiled rice.     

Iron fortification and parboiled rice quality: appearance,cooking quality and sensory attributes

BACKGROUND: Iron (Fe) fortification of parboiled rice increases both Fe concentration and bioavailability in milled grains (i.e. white rice). The aim of the present study was to evaluate parboiled rice fortified with 250 and 450 mg Fe kg^?1 paddy rice for its pre‐cooking appearance, cooking quality, basic sensory attributes and overall acceptance in comparison with unfortified parboiled rice in Thailand and local parboiled rice in Bangladesh. RESULTS: Fe fortification at 250 mg Fe kg^?1 paddy rice significantly elevated Fe concentration in white rice to as high as 19.1 mg Fe kg^?1 white rice, compared with 6.2 mg Fe kg^?1 white rice for unfortified parboiled rice, without any adverse impact on consumer acceptance based on the current preliminary assessment. The added Fe was well retained in the cooked rice, with significant residual value for human intake. Panellists in Thailand and Bangladesh did not detect significant differences in the acceptability of parboiled rice fortified at 250 mg Fe kg^?1 paddy rice compared with unfortified and local parboiled rice respectively. However, Fe fortification of parboiled rice at the higher level of 450 mg Fe kg^?1 paddy rice significantly intensified the yellow colour of the grain and changed the off‐flavour, chewiness and flakiness of the cooked Fe‐fortified parboiled rice. This resulted in a low acceptability ranking of parboiled rice fortified at 450 mg Fe kg^?1 paddy rice by panellists in both Thailand and Bangladesh. CONCLUSION: Fe fortification of parboiled rice at an appropriate level (e.g. 250 mg Fe kg^?1 paddy rice) is dosage‐effective and acceptable to rice consumers. Consumer acceptability of Fe‐fortified parboiled rice is closely related to pre‐cooking appearance, cooking quality and sensory attributes. Copyright © 2009 Society of Chemical Industry     

超高压对食品中微生物的影响及应用

近年来超高压技术在食品工业中的应用日臻成熟。本文评述了超高压技术在食品工业中的杀菌作用,其中着重介绍了超高压处理对微生物细胞形态、遗传机制、生化反应、细胞膜及芽孢壳的影响。     

A comparative study on the physicochemical,cooking and textural properties of fortified rice kernels prepared from raw and parboiled rice

Fortified rice kernels (FRK) are extruded rice-shaped kernels manufactured by blending broken rice flour and vitamin–mineral premix. In this study, four parboiled and three raw rice with intermediate amylose content (20–24%) were processed to manufacture FRK. The system parameters (torque and die pressure), physicochemical properties (length, lightness, water absorption index and water solubility index), cooking properties (cooking time, solid loss, elongation) and textural properties of FRK were analysed and correlated using the Pearson correlation coefficient. The torque and die pressure were 16.76–22.76 Nm and 92.56–136.41 bar, respectively. Compared to raw rice, the parboiled rice showed the highest torque, die pressure and axial expansion in uncooked FRK while longer cooking times, higher elongation ratio and hardness; lesser water absorption ratio and solid loss in cooked FRK. The raw rice FRK showed higher lightness. There was a significant difference between all FRK for water absorption index (1.74–2.52) and water solubility index (2.06–3.53%).     

超高压处理对大菱鲆品质的影响

通过对超高压处理后的大菱鲆质构、色差、pH和挥发性气味变化的测定,研究不同压力处理对大菱鲆不同部位品质的影响。结果表明,高压处理对大菱鲆背腹部的品质影响是比较一致的。随着压力升高,大菱鲆质构特性表现为凝聚性呈上升趋势,胶黏性持续上升,黏附性不断下降,硬度先下降后上升;色差L*值上升,a*值下降;pH随压力增大不断增大;超高压处理后挥发性气味与未处理组有明显差异,100和200MPa、300和400MPa处理后大菱鲆挥发性气味具有相似性结论。