水热处理对糙米吸水特性及爆腰率影响的研究

首先改变浸泡温度和浸泡时间,研究糙米的吸水特性及爆腰率的变化;然后固定最佳浸泡与干燥条件,研究汽蒸温度和时间对糙米粒形变化及爆腰率的影响。结果表明:糙米常压、60℃浸泡4 h,水分达到30.8%,然后以120℃汽蒸12 m in,紧接着以110℃快速干燥15 m in,再以40℃干燥1 h,缓苏2 h,最后以40℃干燥3 h,所得糙米爆腰率最低。     

方便湿米粉的加工工艺研究

以早籼米为原料制作方便湿米粉,研究方便湿米粉的加工工艺,确定最优工艺参数,为方便湿米粉的工业化生产提供参数。结果表明,采用浸泡、两次蒸煮、一次老化、酸处理、灭菌等工艺,可以得到品质优良的方便湿米粉。适宜参数为:在40℃温度下浸泡16 h,在100℃条件下初蒸8 m in后,静置老化2 h,再在100℃下复蒸8 m in,然后在浓度为1.50%的乳酸液中酸浸5 m in,密封包装后在100℃下灭菌5 m in。     

基于多品质指标的响应面试验优化稻谷流化床干燥工艺

为优化稻谷流化床干燥工艺,采用三因素三水平Box-Behnken响应面分析法,研究干燥温度、降水幅度、缓苏时间对稻谷流化床干燥降水速率和干燥稻谷爆腰增率、垩白粒率、脂肪酸值、硬度、黏着性等品质指标的影响。结果表明：随着干燥温度和降水幅度水平的增加,稻谷降水速率、爆腰增率、垩白粒率和米饭硬度增加,脂肪酸值和米饭黏着性降低;随着缓苏时间延长,稻谷降水速率、爆腰增率、脂肪酸值和米饭硬度降低,米饭黏着性增加。而在较低的干燥温度条件下,缓苏时间延长,稻谷的爆腰增率和垩白粒率降低并不明显。Box-Behnken响应面分析法优化的流化床最优干燥参数为降水幅度2.50%（干基）、干燥温度45 ℃、缓苏时间3 h,此时隶属度综合分达最大值0.75。验证实验结果与拟合值无显著性差异（P＜0.05）,优化结果可靠有效。     

富含多酚高粱茶的工艺研究

研究高粱茶加工过程中各加工单元对高粱中多酚含量的影响。结果表明,正交实验优化的最佳工艺参数为:浸泡料液比1∶10,浸泡温度10℃,浸泡时间4 h,蒸料时间45 min,干燥温度为100℃,干燥时间为1 h,焙烤温度为185℃,焙烤时间为35 min。高粱茶产品的色泽呈土黄色,具有焙烤的焦糊香气,多酚物质保留多,表现出较强的抗氧化能力。     

速熟绿豆加工工艺的优化

为了得到最优的工艺参数,本实验研究了速熟绿豆的加工工艺。实验中通过测定吸水率、熟化率、感官、含水量等指标,优化了浸泡、蒸制、速冻和干燥工艺的技术参数。优化后的最佳工艺条件为:料液比1∶1.8(g/L),浸泡温度40℃,浸泡时间150 min;蒸制时间18 min;冷冻条件-20℃,冷冻时间60 min;干燥温度80℃,干燥时间4.5 h。按照上述工艺条件制备速熟绿豆,样品最终含水量≤6%,与原料豆相比糊化度明显提高(p0.05)。     

基于响应曲面法分析速煮绿豆加工工艺

实验对速煮绿豆加工工艺进行了优化,单因素实验表明浸泡时间、浸泡温度、蒸煮时间、蒸煮温度对复水性影响较大,且干燥方式对速煮绿豆的组织结构和形态保持上有明显影响;通过响应曲面回归分析,得到速煮绿豆优化加工工艺条件:在42℃0.5%NaHCO3浸泡液下浸泡4h,常压下100℃蒸煮40min,沥干,先恒温热风干燥30~40min,放置在密封容器24h,再微波干燥4~6min至水分含量为5%~7%,复水时间为5~12min。     

加湿速率对发芽糙米爆腰率的影响

为了降低发芽糙米爆腰率,提出采用分段加湿工艺生产发芽糙米。研究了糙米各吸水阶段不同加湿速率对发芽糙米爆腰率的影响,研究结果表明:发芽糙米爆腰率随着各阶段加湿速率的增加而增加;分段加湿工艺与浸泡工艺相比,可以使爆腰率降低25%~60%;以爆腰率最低为目标,得到的I、II、III阶段加湿速率分别为0.74%/h、1.22%/h、0.8%/h。研究结果可为进一步改进发芽糙米生产工艺提供参考。     

丹棱冻粑生产工艺的优化

以籼米为原料,对丹棱冻粑的制作工艺进行了研究。结合感官评定,通过单因素试验研究大米浸泡温度、浸泡时间、磨浆时加水量、发酵中老浆添加量以及汽蒸时间对丹棱冻粑品质的影响,并采用正交试验得到生产丹棱冻粑的最优工艺条件。结果表明:大米在35℃下浸泡4h,磨浆时泡涨大米与水比例10∶2,发酵时米浆与老米浆比例10∶3,发酵后,常压汽蒸13min得到的丹棱冻粑品质最好。     

流化床和薄层热风干燥对稻谷品质的影响

研究流化床和薄层热风干燥在干燥温度50、60、70 ℃条件下对高水分稻谷水分变化的影响,分析稻谷加 工品质（爆腰率）和稻米质构品质（硬度、黏着性、咀嚼性）的变化规律。结果表明：初始含水率相同的稻谷, 在同一干燥温度条件下流化床干燥速率大于薄层热风干燥,但是加工品质略差,对发芽率没有影响。干燥温度为 50 ℃时,流化床和薄层热风干燥稻米的品质较好。稻谷干燥温度和整精米率之间呈显著的负相关。流化床干燥后 稻米的硬度、黏着性、胶性与爆腰率呈显著性相关,薄层热风干燥后稻米黏着性、胶性与爆腰率呈显著性相关,其 他质构指标相关性均不显著。     

不同干燥方式对菊花中6种有机磷农药 残留量的影响

目的研究不同干燥方法对菊花中氧乐果、敌敌畏、甲基对硫磷、甲拌磷、内吸磷、对硫磷6种有机磷农药残留量的影响。方法将污染农药的鲜菊花分别进行蒸3 min阴干、50℃烘干、阴干和晾干处理,采用乙腈提取有机磷农药并经Carb/PSA双层固相萃取柱净化,通过气相色谱仪(配FPD检测器)测定有机磷农药残留量。结果 6种有机磷农药在0.01~0.08μg/m L浓度范围内线性良好,相关系数r0.997,回收率在78.5%~94.3%之间,相对标准偏差RSD为1.7%~5.9%,检出限为0.53~1.16μg/kg。3种干燥的菊花中均未检测到6种有机磷农药。结论蒸3 min阴干、50℃烘干和阴干3种干燥方法均显著降低菊花有机磷农药残留量。     

EFFECT OF ARTISANAL PARBOILING METHODS ON MILLING YIELD AND COOKED RICE TEXTURAL CHARACTERISTICS

ABSTRACT

One of the main objectives of artisanal rice parboiling is to reduce the levels of broken grains (brokens) on milling. Rice samples that had been parboiled using different regimes of soaking temperatures and steaming times were analyzed for their physical properties and cooked rice textures. It was established that inappropriate soaking and steaming regimes resulted in greater levels of brokens than raw‐milled paddy. Consequently, in artisanal parboiling, the initial soaking temperature should be about 90C and the steaming time should be more than 8 min, ideally, about 12 min. On cooking, more severely parboiled rice samples had firmer textures than mildly parboiled samples. The commercially parboiled sample and the more severely laboratory‐parboiled samples required a rice‐to‐water ratio of 1:3, while the raw‐milled sample and the mildly parboiled ones required a 1:2½ rice‐to‐water ratio for optimum cooking.

PRACTICAL APPLICATIONS

Artisanal rice parboiling is carried out mainly to reduce the levels of broken grains and increase the yield of milled rice in many countries. If this is carried out very well, there are economic benefits as more rice of better quality is available to be sold. This study provides information on optimum processing conditions, i.e., initial soaking temperature of about 90C and a steaming time of about 12 min. The study also provides recommendations on optimum cooking conditions, i.e., rice‐to‐water ratio, for the variably parboiled rice samples.     

速食发芽糙米的研究

以糙米为原料经过发芽处理,采用蒸煮糊化法制取速食发芽糙米。运用二次蒸煮糊化法进行糊化,将预蒸煮获得的速食发芽糙米进行浸泡和第二次蒸煮,糊化完成后进行干燥处理制成速食发芽糙米。结果表明:利用正交实验确定最佳糊化条件为:预蒸煮时间25min,浸泡温度60℃,浸泡时间35min,二次蒸煮时间30min;最佳干燥温度为80℃,时间为90min。     

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。     

Microstructure of olbyeossal,partially milled parboiled glutinous rice made by modified parboiling method

The microstructure of partially milled parboiled glutinous rice (PMPGR) before and after cooking was investigated using scanning electron microscopy to identify the changes in the microstructure due to parboiling treatments. Parboiling was performed in two different ways: conventional and modified. The conventional parboiling method involved soaking at room temperature for 24 h, followed by steaming and drying. The modified parboiling method involved tumbling to replace soaking of the rice grains, tempering, retorting, and drying. The microstructures of the PMPGR made using both methods were compared. The modified parboiling method significantly changed the microstructure of the rice, but cooking did not cause considerable changes in the microstructure of PMPGR.     

Process of Producing Parboiled Rice with Different Colors by Fluidized Bed Drying Technique Including Tempering

Steamer is utilized to gelatinize rice starch. High pressure or long steaming time is conventionally applied to obtain the dark brown color of the product. A new alternative method to produce dark brown parboiled rice was proposed in this work. High temperature fluidized bed drying technique including tempering was therefore explored to determine the operating condition to meet the requirement of light and dark brown parboiled rice along with high head rice yield. In addition, the couple of heat and mass transfer model was developed to determine the effective moisture diffusion coefficient, the temperature and moisture distributions within a grain kernel during drying. The effective diffusion coefficient was well correlated with grain temperature by Arrhenius equation. The drying temperature and moisture content after drying caused the drop of head rice yield. When the parboiled paddy at the intermediate moisture contents of 22 and 27% d.b. was tempered, the head rice quality was improved while the parboiled rice color was browner. To obtain high drying capacity, high head rice yield, and light brown color, the parboiled paddy should be dried at a maximum allowable temperature of 150 °C and tempered for 30 min. The tempering time should be extended to 60 min for the dark brown parboiled rice.     

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.     

Starch Retrogradation and Starch Damage in Parboiled Rice and Flaked Rice

The equilibrium moisture content attained on soaking in water (EMC-S) of parboiled paddy was very high immediately after steaming and fell appreciably on storage, demonstrating starch retrogradation. The extent of retrogradation was dependent on the temperature of storage as well as the moisture content. It was maximum at about 25% moisture when stored at room temperature. Roasting of soaked raw paddy raised its EMC-S due to gelatinization. When stored at room temperature there was progressive retrogradation above 18% moisture. Flaking of roasted paddy and of moist milled rice, both raw and parboiled, also raised the EMC-S. This appeared to be caused by mechanical damage of starch granules. Flaked rice, too, showed retrogradation. — These results confirmed that many properties of parboiled rice are due to starch retrogradation while those of roasted and flaked rice are due to absence of retrogradation.     

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。     

Preparation of improved quick cooking rice

Quick-cookig rice was produced by soaking milled short grain rice in water and water containing 1% and 3% of a 1:1 mixture of sodium citrate and calcium chloride with two soaking periods (15 and 30 min at room temperature). The soaked samples were cooked in an autoclave at 121 °C and 0.147 MPa pressure for 3, 5 and 8 min. Final moisture content of 12% was obtained by using two different drying methods (freeze-drying and convective air drying). After steaming the salt treated samples (1 and 3%) showed lower water absorption ratios than the untreated controls. The end product of the cooked rice, which was freeze dried, had a normal appearance. 1% salt treating (for 15 min) and freeze drying reduced the protein losses. Processing resulted in slight decrease in carbohydrate and amylose content of the product. Treatment with salt solution (1%) and freeze drying improved the rehydration ratio of this sample.     

Technological properties of microwave parboiled rice

Two rice varieties, a short grain (Giza 175) and a long grain (Giza 181), were parboiled by soaking in water at 80–85 °C for 1.5 h and then dried in the microwave oven for 3, 5, 6 and 8 min. The effect of such parboiling treatment on milling output and technological properties (cooking and eating quality) of milled rice were studied. There was a negative significant correlation between head rice and the drying time and a positive correlation between the drying time and the broken grains. The effect of such treatment on the chemical composition of milled parboiled rice, i.e. amylose, protein, fat and ash contents, showed that the amylose content of Giza 175 variety significantly decreased while not affect in Giza 181 variety. No significant differences were obtained in protein, fat and ash contents by increasing drying time. Microwave drying was more pronounced on Giza 175 variety rather than Giza 181 one. However, the optimum cooking time of the parboiled samples of the two varieties was not affected as a result of increasing the microwave drying time.