高纯度大米蛋白和淀粉的分离提取

高纯度的大米蛋白和大米淀粉可以作为大米综合利用的两个主产品，本研究采用碱法将大米蛋白和淀粉分离，研究表明最适提取条件是：NaOH求度0．05N，提取2h此条件下分离体系不受破坏，且大米蛋白的蛋白含量可达94.03％(干基)，蛋白得率63．37％；大米淀粉中蛋白含量0．39％(干基)，淀粉得率47．87%。     

Processing of commercial rice bran for the production of fat and nutraceutical rich rice brokens,rice germ and pure bran

Successive sieving of commercial rice bran on the basis of particle size was performed and different fractions were obtained of which the rice brokens and rice germ fractions contained fat 33 g/kg and 207 g/kg, oryzanol 400 mg/kg and 874 mg/kg, total tocols (tocopherols and tocotrienols) 16.5 mg/kg and 87.8 mg/kg, and total phytosterols 128.7 mg/kg and 769.6 mg/kg respectively, thus indicating that these fractions are a good source of fat and nutraceuticals. The residual fat (6 g/kg) from commercial defatted rice bran contained high oryzanol content of 4.8 g/100 g, indicating that commercial defatted rice bran as a source of oryzanol. The fat from pure rice bran fraction of commercial rice bran decreased in the color value (48.5%) indicating that sieving could also improve the quality of crude rice bran oils.     

Hydrothermal treatments of rice starch for improvement of rice noodle quality

Two types of hydrothermal treated rice starches were prepared by annealing and heat-moisture treatment (HMT). Annealing of starch slurry was conducted at 55 °C for 24 h and HMT was applied in starch with 20 g/100 g moisture at 110 °C for 1.5 h, based on the optimization of the treatment conditions. The apparent changes on gelatinization, swelling, RVA paste viscosities and gel hardness of starch were observed. The study on 50% substitution of rice flour with untreated (UR), annealed (AR) or heat-moisture treated (HR) rice starches proved that the cooking and texture quality of rice noodle was substantially affected by the treatments. The composite noodles of flour and hydrothermal treated rice starches exhibited quality parameters which were closer to those of commercial noodles. The results revealed the possibility of utilizing these starches with low quality rice flour so as to produce noodles of acceptable quality. The study also inferred that characterization of RVA paste viscosities and gel texture of flour could become a practical method for predicting the quality of the derived noodle.     

发酵型营养米乳的研制

以大米为原料,经过糊化等预处理后接入一定的乳酸菌进行发酵,最终获得了感官、组织状态良好的发酵型米乳。本研究对大米的加水量、菌种的种类及比例、发酵条件等进行了选择和优化,确定了最佳工艺条件。     

The application of monascal rice in rice beverage preparation

To investigate the effect of antioxidant activity of monascal rice, we used monascal rice only, a mixture of monascal rice and rice, and rice only in the rice beverage production. Reducing sugar and carbohydrate (glucose, maltose, and maltotriose) contents increased with reaction time. When using rice only, there was a higher reducing sugar content than with the use of monascal rice. After 6 h, the reducing sugar content of the rice beverage produced using only rice was 69.8 mg/mL. After 6 h, the maltose contents produced using monascal rice only, a mixture of monascal rice and rice, and rice only were 64.5, 92.9, and 113.9 mg/mL, respectively. After 6 h, the total phenolic contents of the beverages produced with monascal rice only, a mixture of monascal rice and rice, and rice only were 113.9, 92.9, and 69.7 μg/mL, respectively. 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activities increased linearly up to 4 h of hydrolysis, and then increased slightly beyond that. After 6 h, the IC₅₀ and ascorbic acid equivalent antioxidant activity (AEAC) values of the beverages produced from monascal rice only, a mixture of monascal rice and rice, and rice only were 60.9, 100.6, and 164.4 μg, and 31.5 , 31.2, and 25.7 mg/100 g, respectively. In conclusion, the rice beverage prepared from monascal rice might be somewhat beneficial to the antioxidant protection system of the human body and help protect against oxidative damage.     

An update on the processing of high‐protein rice products

The component of protein in rice, at 7–9% by weight, is relatively low, but the total amount of rice protein potentially available is significant because the production of rice worldwide, at 380 million tons annually, is huge. Rice proteins are recognized as nutritional, hypoallergenic, and healthy for human consumption, and rice protein products have been in demand in recent years. However, because of difficulties in the processing, rice protein products, particularly high‐protein content ones, have not been readily available. Two of the main sources of rice protein, rice bran and, to a lesser extent, broken rice kernels, have been under‐used and under‐priced. This report provides an update on the processing of these sources for rice proteins. Methods of protein processing are highlighted including the traditional alkaline extraction, enzyme‐assisted extraction, and the novel uses of physical treatment prior to water extraction. Also discussed are effects of processing on the functional and nutritional properties of rice protein.     

A thermal lethal model of rice weevils subjected to microwave irradiation

An industrial continuous microwave oven was employed to investigate pest control in rice to develop a new, innocuous and safe method to replace chemical fumigation. Microwave irradiation conditions affecting rice temperature and pest mortality were studied. Adults and eggs of rice weevils (Sitophilus oryzae L.) suffered 100% mortality when final rice temperature was above 55 °C, while the corresponding energy consumption of the microwave was above 0.017 kW h/kg. Lower power with a longer treatment time is more effective at killing insect pests using the same total energy consumption. A mortality model for rice weevils based on final rice temperature was formulated. Eggs were more susceptible to temperature than adults.     

3种乳酸菌发酵米浆对发糕品质的影响比较研究

目的 以清酒乳杆菌清酒亚种、类干酪乳酪杆菌类干酪亚种、发酵黏液乳杆菌为发酵菌种,研究3株不同乳酸菌发酵米浆对米发糕品质的影响。方法 米发糕由发酵的大米磨成米浆,再经酵母发酵,加热汽蒸而成。以米浆的密度、黏度、持水率、流变特性为测定指标,测定乳酸菌发酵米对米浆性质的影响;以米发糕的质构、感官、比容为测定指标,测定乳酸菌发酵对米发糕品质的影响。结果 乳酸菌发酵原料大米相比其自然发酵和未发酵大米制作的米浆,米浆的密度与酸度最低、米浆的持水性与黏度最高,具有良好的流变学特性;不同乳酸菌菌种由于产酸与酶量不同,对米浆性质影响也不同,3株乳酸菌中发酵黏液乳杆菌发酵黏液乳杆菌制作的米浆密度小、黏度大、pH低、发酵能力强、流变特性中稠度系数大;米浆性质对米发糕的品质有直接影响,乳酸菌发酵相比于其他方法对米浆性质影响大,制得的米发糕品质最好,如比容较大、弹性较大、内部气孔均匀致密;不同乳酸菌发酵米浆性质不同导致米发糕品质也不同, 3株乳酸菌中发酵黏液乳杆菌制作的米发糕的比容最大、硬度最大(1409.43gf)、咀嚼性最大(718.81gf)、黏聚性与回复性最优。结论 发酵黏液乳杆菌发酵米发糕感官评分最高...     

Oxidative stability of fried dough from rice flour containing rice bran powder during storage

The aim of this study was to evaluate the efficiency of rice bran powder on lipid peroxidation inhibition of fried dough from rice flour during storage. Rice flour dough containing rice bran powder at 5, 10 and 15 g rice bran powder/100 g mixed rice flour were fried in soybean oil at 160 °C for 1 min and stored in dark at 60 °C for 10 days. Lipid peroxidation of fried dough was determined by change of fatty acid compositions, oxygen absorption in vial headspace, lipid hydroperoxides, TBA values including decreasing tocopherol and gamma-oryzanol contents during storage. Polyunsaturated fatty acid decreased rapidly in fried dough without rice bran powder, while an increase of oxygen absorption in vial headspace, lipid hydroperoxide and TBA values were significantly lower (p?0.05) in fried dough containing rice bran powder. In addition, tocopherol degradation was significantly lower in fried dough containing rice bran powder during storage (p?0.05). However, there was no significant difference in gamma-oryzanol contents among fried dough during storage (p>0.05). These results demonstrated that rice bran powder shows the antioxidative effects on fried dough during storage.     

Effect of microwaves on rice quality

The effect of microwave radiation on rice quality was investigated using an industrial continuous microwave oven. Effects of microwave treatment, packaging method and storage time on rice quality during storage were assessed. Water content, free fatty acid content and protein content were reduced but the blue value (BV) of rice and the sensory quality of cooked rice increased as microwave-energy consumption increased. Qualities of both microwave-treated and untreated rice changed during storage, but the changes were less in the treated rice sample. Differences in the protein content, fat content and total sugar content between the microwave-treated and untreated rice were significant at the beginning of storage but not after storage for more than 120 days. Variance analysis showed that rice storage qualities were significantly affected by treatment methods and storage time while packaging methods had no significant effect on any of the qualities.     

Screening of rice cultivars for brewing high quality turbid rice wine

To screen proper rice cultivars for brewing high quality turbid rice wine, 5 high-yield rice cultivars, 9 high-eating-quality rice cultivars and 5 glutinous rice cultivars were collected. At the end of fermentation, significant differences (p < 0.05) were observed in the fermentation properties, sensory properties and suspension stability of the original fermented mash (OFM) among individual rice cultivars. The assayed fermentation properties of OFM included pH value, total acidity, amino acidity, reducing sugar, alcohol yield, fusel alcohols and ethyl acetate. Seven rice cultivars were screened out for producing high quality wine by the comparative analysis. This research provided the basic scientific data for producing potential high quality turbid rice wine.     

蛋白组分对米蛋白功能性质影响的研究

以不同配比米蛋白组分的样品为试材,比较各样品的功能性质变化,明确各蛋白组分对蛋白产品品质影响的差异,为今后进行分子设计和重组生产米蛋白产品提供理论支撑。通过各蛋白样品的溶解性,乳化特性,起泡特性,持水性/持油性等功能性质研究,结果表明,米糠浓缩蛋白的溶解性比大米浓缩蛋白高200%左右;米糠蛋白各功能性质显著优于大米蛋白,但大米蛋白的起泡稳定性比米糠蛋白提高近20%。米蛋白中的清蛋白提高产品的溶解性、持水性/持油性,降低起泡稳定性;醇溶蛋白提高产品的乳化特性;谷蛋白提高产品的起泡稳定性。蛋白产品的功能性质与蛋白组分的组成密切相关。     

蚕丝宣纸工艺研究

探讨了蚕丝与宣纸结合制成蚕丝宣纸的工艺,用制好的纸浆与练白蚕丝、染色蚕丝按不同比例复配。试验结果表明:浆液中剪断后的蚕丝两端自然成帚化状态,并借助宣纸的氢键缔结,宣纸纸浆、蚕丝按比例配伍搅拌后,静止后的悬浮状态完全一样,分散均匀捞纸时无需再搅拌。通过湿压、烘干、收边、中温熨烫等工艺制成的蚕丝宣纸,除保留传统宣纸的特性外,还增加了成品肌理的视觉美感,吸墨、发色、透气、透色性俱佳。     

大米变性淀粉的制备研究

对比研究了挤压法和湿法制备乙酰化大米淀粉与交联大米淀粉的工艺与理化特性。结果表明要得到相同取代度的变性淀粉,湿法的原料消耗量远远大于挤压法。挤压法制备的乙酰化大米淀粉和交联大米淀粉的溶解度大幅增加、糊化温度消失,说明挤压法制备的两种变性淀粉还有预糊化淀粉的特性。超微结构表明挤压法制备的大米变性淀粉的淀粉结构已经消失。     

大米中挥发性风味物质的研究进展

大米是全球的最重要的主食之一, 大米香气是大米中挥发性风味物质所呈现的整体香气和人类感官感知的综合结果, 也是大米品质的重要组成部分、影响消费者对大米的可接受程度的主要因素。对近15年稻米风味方面的相关研究进行了综述, 介绍了大米挥发性风味成分种类、大米风味的影响因素、对大米挥发性风味的研究方向进行了展望, 为大米挥发性风味研究技术的提升和大米行业的高品质发展提供新的思路和理论参考。     

Studies on the relationship between antioxidative activity of rice hull and germination ability of rice seeds

An investigation of the germination potentials of seeds of Indica and Japonica rice varieties revealed that while the long-life rice seeds retained the germination ability even on storage for a year at 30°C, the germination ability of the short-life rice seeds tended to decrease when stored beyond 6 months. The role of rice hull constituents in the preservation of the germination property during ageing of rice seeds was investigated with special emphasis on rice antioxidants. Antioxidative assay with chloroform-methanol and methanol-water extracts of hull, bran-germ and grain fractions of two Indica and five Japonica rice varieties indicated that all of the seed varieties belonging to Indica and Japonica possessed a strong antioxidative activity in the hull fraction. Hull extracts of long-life rice seeds showed relatively higher activities than those of short-life rice seeds. In contrast, hull extracts of long-life rice seeds had higher inhibitory effects on lipoxygenase activity than did those of short-life varieties. Quantification of the natural antioxidants indicated that ^α-tocopherol in rice oil to be present in the range of 318.3–450.1 μg g^?1 oil while the amount of oryzanol in the hull, bran-germ and grain fractions of rice was found to be 1.0–5.8, 95.4–279.8 and 3.0–9.4 μg g^?1 sample respectively. The results, however, did not show any positive correlation between the amount of natural antioxidants in rice hull and germination potentials of rice seeds. The amount of total phenolic constituents in rice hull was found to range from 190–390 μg g^?1 sample, the levels being far higher in long-life rice seeds in comparison with the short-life rice seeds. These values seemed to agree well with the germination data of the corresponding rice variety. The investigation revealed a strong influence of the level of phenolic constituents in rice hull on the storability of rice seeds.     

The economic effects of Rhyzopertha dominica on rice quality: Objective and subjective measures

Infestations of internal feeders such as Rhyzopertha dominica cause damage to stored grains, including rice. Few studies, though, have measured the economic effects of that damage. In this study, samples of rough long grain rice were infested with R. dominica at several rates (0, 20, and 200 adults/kg). The effects of these infestations on rice quality and quantity were measured objectively using color and milling yield. They were also measured subjectively with a blind taste/sensory consumer taste test and a non-hypothetical auction measuring consumer willingness to pay for the different qualities of rice.The objective quantity and value loss ranged from 2% for lightly-infested rice to 3.5% for heavily-infested rice. For subjective effects, results of the auction suggested that participants on average were willing to pay only a small premium for less infested rice. This test confirmed results of the sensory taste panel, which showed that participants on average detected very little difference among rice samples with alternative levels of infestation. However, when they were given extra information verifying that rice with lower infestation levels was higher quality or that the rice was stored using IPM methods, the potential price increase from reducing R. dominica infestation could range from $0.44/kg. to $0.79/kg., plus a $0.13/kg. premium for using IPM storage methods. However, results suggest that in order to capture that value rice sellers must be able to convey information about quality and storage attributes to consumers in a way that is relevant and trustworthy.     

大米蛋白质中砷分布规律研究

米蛋白在婴幼儿产品和高端产品领域应用具有广阔前景,然而重金属易于在稻米蛋白质中富集增加了米蛋白制品的安全风险。以砷污染大米为研究对象,通过Osborne法连续提取大米中清蛋白、醇溶蛋白、谷蛋白和球蛋白,用SDS-PAGE、MALDI-TOF-MS等方法对蛋白进行表征,并运用红外光谱法,紫外扫描分析研究了各蛋白的光谱吸收特征。利用ICP-MS法测定重金属含量得到不同蛋白结合砷的能力差异,得出砷与清蛋白是优势的结合形态。通过氨基酸组成分析并比对正常大米的氨基酸组成,推测砷可能与蛋白中的脯氨酸结合紧密。     

HACCP在米粉生产中的应用

为研究米粉生产过程中的质量控制，提高米粉的安全性。进行了米粉生产过程中的危害分析和关键控制点（HACCP）管理体系分析，对米粉生产而言，主要危害包括：生物性危害、化学性危害、物理性危害、品质危害。关键控制点包括：原料质量控制、大米浸泡、复蒸、烘干、分装。将HACCP应用于米粉的生产过程，是确保米粉安全性的有效措施。     

水稻中镉积累状况及控制的研究进展

镉(Cd)是一种释放到农业环境中的有毒金属,会导致植物生长和生理发生许多变化。水稻中Cd的积累及其随后向食物链的转移是世界范围内的主要环境问题,严重威胁着人类的粮食安全。剖析Cd在水稻中积累的原因,有助于减少Cd在水稻中的积累,提高大米的品质。在本研究中,首先回顾了我国水稻中Cd积累的原因,包括灌溉水、施肥、土壤酸化、土壤氧化还原电位变化。接下来讨论了减少水稻Cd积累的方法,包括水稻新品种的选育、土壤修复、田间管理、改变耕作模式等。这些结果将有助于解决Cd在水稻中的积累问题,确保我国的食品安全,减少Cd对国民的健康风险。