挤压膨化处理对婴幼儿米粉理化和体外消化特性的影响

为探讨婴幼儿米粉基料干法制造过程中挤压膨化处理对米粉特性的影响规律,对不同品种大米经挤压膨化得到米粉的理化和消化特性差异进行比较分析,结果表明:在相同挤压膨化条件下,不同大米之间淀粉组成差异明显,导致膨化度、吸水指数和水溶性指数差异显著(P<0.05);处理后由淀粉体外消化特性得出:早籼米中抗性淀粉含量最高,接近15%;糯米快速消化淀粉含量最低,小于75%。蛋白质消化特性结果显示,糯米制品的胃蛋白酶消化率和蛋白质总消化率均低于其它3种米粉,这可能是因糯米中蛋白质的结构和组成不同所致。研究结果为挤压膨化技术在米粉生产中的应用及对不同品种大米米粉的性能影响提供理论依据。     

徽派黄酒关键香气化合物的分离、鉴定与香气特征分析

本文以气相色谱-质谱法结合气相色谱-嗅闻和定量感官评价法对徽派黄酒关键香气化合物进行了分离及鉴定,并对其香气特征进行了分析。共从徽派黄酒中分离及鉴定出65种挥发性化合物,其中酸类8种、醇类12种、酯类16种、醛/酮类8种、呋喃类5种、酚类5种、含氮化合物3种、含硫化合物3种以及其他化合物5种。与对照相比(古越龙山黄酒),两者分离及鉴定出的化合物种类高度相似(87%),但各化合物相对含量存在一定差异。通过气相色谱-嗅闻法从徽派黄酒和对照中均鉴定出19种关键香气化合物,主要赋予黄酒酸、醇、果、花、窖、焦、烟气和药香。感官评价结果显示徽派黄酒醇香和曲香和焦香突出,诸香协调;对照醇香、曲香和果香突出,诸香协调。通过上述方法鉴定出了徽派黄酒中的关键香气化合物,与对照相比徽派黄酒具有自身独特的香气特征。     

基于气味活度值对泰国香米与普通大米关键呈香化合物的差异分析

目的 研究基于气味活度值(odor activity value, OAV)下的泰国香米与普通大米中关键呈香化合物之间的差异。方法 根据挥发性物质总数、总峰面积、特征峰面积3个指标优化蒸米饭风味物质的萃取条件; 并通过固相微萃取-气相色谱-质谱法(solid phase microextraction-gas chromatography-mass spectrometry, SPME-GC-MS)对泰国香米与普通大米蒸煮后的挥发性风味化合物进行分析鉴定。结果 确定风味化合物的最佳萃取条件为: 取样量20 g、萃取温度60℃、萃取时间70 min、解析时间9 min。通过质谱鉴定和量化分析, 从泰国香米和普通大米中分别得到48种和29种风味化合物。结合OAV确定了泰国香米和普通大米中分别存在10种和8种关键呈香化合物, 如(E,E)-2,4-癸二烯醛、壬醛、1-辛烯-3-醇等物质, 其中2-乙酰基-1-吡咯啉是泰国香米区别于普通大米最关键的风味化合物。结论 本研究为分析米饭蒸煮后挥发性风味化合物提供了较为精准的检测条件, 同时为关键呈香物质的分析及泰国香米真伪的鉴别提供了基础支持。     

冰湖野米粉及其淀粉的精细结构、理化和消化特性研究

目的 探究冰湖野米粉及其淀粉的理化性质、结构特性和消化性的差异, 同时揭示不同级的冰湖野米淀粉的精细结构。方法 以3种不同级的冰湖野米和1种早籼米(对照组)为原料, 将其研磨过筛制备米粉样品, 再用焦亚硫酸钠法和甲苯法进行纯化得到对应的淀粉样品。采用体积排阻色谱分析法(Size exclusion chromatography, SEC)与荧光辅助毛细管电泳法(Fluorescence assisted capillary electrophoresis, FACE)测定冰湖野米淀粉的精细结构(直链淀粉和支链淀粉的链长分布); 利用扫描电镜、光学显微镜、X-射线衍射仪、傅里叶变换红外光谱仪和布拉班徳粘度仪等现代分析仪器对冰湖野米粉及其淀粉的理化性质和结构特性进行测定; 采用Englyst体外消化法测定冰湖野米粉及其淀粉的体外消化性。结果 研究表明, 不同级的冰湖野米粉及其淀粉的颗粒形貌特征、粘度特性、结晶结构以及直链淀粉含量无显著差异。与早籼米相比, 冰湖野米粉及其淀粉的起糊温度高, 峰值粘度低, 相对结晶度低, 热稳定性好, 慢消化淀粉和抗性淀粉含量高, 主要归因于冰湖野米的支链淀粉结构及其较高的直链淀粉含量。与冰湖野米淀粉相比, 冰湖野米粉颗粒更大, 结晶度降低, 膨胀度降低, 慢消化性增加, 主要归因于冰湖野米粉中较高的内源蛋白和纤维含量。结论 冰湖野米中的内源纤维、蛋白质、直链及支链淀粉含量对冰湖野米的粘度特性、膨胀度、结构特性以及消化性有显著的影响。     

穗型与胚乳成分对稻米黏弹性的影响

北方直立穂型水稻是超级稻的重要株型之一,但这类水稻的适口性一般并不理想。为明确该类水稻的适口性差异所在及其可能的原因,本研究选取70?份直立穗型和非直立穗型水稻材料,利用质构仪和快速黏度分析（rapid viscosity analysis,RVA）仪分别对米饭粒和米淀粉进行黏弹性检测,同时分析稻米蛋白质量分数（protein content,PC）、表观直链淀粉质量分数（apparent amylose content,AAC）以及支链淀粉精细结构（Fa、Fb1+2和Fb3）的差异。结果表明：1）根据测试性状按Ward法可以将试材分为3?类,直立穗型不能构成独立的一类,但直立穗型品种占比较大类的硬度大、黏性小、拉丝长度短、咀嚼性大,RVA的崩解值小、回冷值大,表现出不良适口性,其胚乳性状表现为AAC、PC、Fb3质量分数高,而Fa/Fb3低;2）总体上,黏弹性与AAC、Fb3质量分数、Fa/Fb3存在密切的相关关系,但类间相关关系有差异;与RVA特性相比,质构特性与胚乳性状的相关关系更紧密;3）质构测试结果的主要参数与RVA结果存在密切的相关关系。综上可见,穗型与黏弹性可能没有直接联系,部分直立穗型品种可能由于胚乳淀粉组成不佳导致米饭硬度大、黏性小的不良适口性;与RVA相比,质构测试对适口性评价更加简洁直接。     

Rice bran-soy blends as protein supplements in cookies

The effect of incorporating one of three stabilized full-fat rice brans in combination with each of four soy ingredients in a sugar-snap cookie was investigated. The four soy ingredients in a sugar-snap cookie were two soyflours (full-fat and defatted), a soy concentrate and a soy isolate. Rice bran and soy were added in place of wheat flour to increase protein content from 6% to a minimum of 9%, and the cookies were compared with each other and with a 100% wheat flour cookie. Quality characteristics evaluated included protein, spread, physical texture and colour, and sensory preference by ranking for colour, crispness and flavour. In general, the rice bran-soy cookies had less spread (even with added shortening, water and emulsifier), were less crisp and more chewy, and were somewhat darker in colour than the 100% wheat flour cookie. The soy isolate, USDA and Protex 20-S cookies were as acceptable in colour, crispness and flavour as the control.     

粳稻脂肪含量对淀粉热力学特性及米饭食味品质的影响

以江苏省种植的直链淀粉含量和蛋白质含量相近的20个粳稻品种为实验材料,采用聚类分析将稻米脂肪含量分为低脂、中脂和高脂三种类型,探究不同脂肪含量稻米回生过程中淀粉热力学特性、米饭食味品质、质构特性变化差异.结果 表明,中脂类型品种未脱脂米粉具有较高的糊化热焓值、较低的回生热焓值和回生度,米饭食味品质和质构特性显著优于低脂...     

Identification of Broken Rice Kernels Using Image Analysis Techniques Combined with Velocity Representation Method

The percentage of whole kernels remaining after milling is one of the most important physical characteristics of rice quality. A method based on flatbed scanning and image analysis was developed for the identification of broken rice kernels. Velocity representation method was developed for pattern recognition based on the contour characteristics of the rice kernels. The similarity of the boundary features of the image of rice kernel was measured by similarity coefficient, which was used to identify the broken rice kernel by comparing with threshold. High recognition rates for three rice varieties were reached by this method with 96.7% for Thailand rice, 98.73% for Pearl rice, and 97.14% for Changlixiang rice, respectively, and the recognition rate could be improved by the adjustment of the similarity coefficient threshold. Because the comprehensive boundary features were the basis for the classification, this method could be more accurate compared to other methods using the single dimension feature.     

米酒奶凝乳剂——江米酒发酵特性的研究

江米酒是我国传统乳制品米酒奶的凝乳剂,其品质直接影响着米酒奶的质量。实验中筛选出适合的酒曲,并研究江米酒的发酵特性,以期得到适宜的米酒奶凝乳剂。研究发现,酒曲C适合用于制作米酒奶的江米酒发酵。发酵条件为,酒曲添加量0.8%,30℃发酵9 d。江米酒在4℃冷藏期限为28 d。     

基于气相色谱-离子迁移谱的不同品种香稻米挥发性有机物指纹图谱分析

采用顶空气相色谱-离子迁移谱(gas chromatography-ion mobility spectrometry, GC-IMS)技术对黑龙江哈尔滨市、大庆市、佳木斯市不同品种香稻米的挥发性物质进行指纹图谱解析,深入分析不同品种香稻米的差异。结果表明：佳木斯、哈尔滨、大庆3个不同产地香稻米有明显的特征峰区域,罗勒烯、未定性物质9在哈尔滨地区香稻米品种中含量较高;正戊醇单体、正戊醇二聚体、正己醇单体在佳木斯地区香稻米品种中含量丰富,大庆地区所选3个香稻米品种特征化合物含量较低,柠檬烯单体、柠檬烯二聚体明显低于哈尔滨、佳木斯地区品种。通过相似度和主成分分析,可准确区分不同品种香稻米。     

精白保胚发芽米食用品质

以糙米、发芽糙米、精白保胚米及精白保胚发芽米为研究对象,对其食用品质的主要方面,即炊饭方法、蒸煮特性、糊化特性、质构特性及感官分析进行对比评价。结果表明：精白保胚发芽米的吸水率和膨胀率均低于其他3 种大米,而米汤固体溶出物和碘蓝值均高于糙米和发芽糙米;糊化特性分析中,精白保胚发芽米与大米食用品质相关的崩解值降低,消减值升高;质构分析表明精白保胚发芽米具有最低的硬度;感官分析结果表明,精白保胚发芽米在色泽、香气、口感、滋味方面都优于未发芽米。     

Development of an event-specific Real-time PCR detection method for the transgenic Bt rice line KMD1

The present study describes an event-specific quantitative Real-time PCR detection method for the transgenic Bt rice line Kemingdao 1 (KMD1). This rice line which is not approved in any country so far is likely to be approved in China in the near future. The developed primers amplify a DNA sequence spanning the integration site of the genetic construct in KMD1. DNA sequence information of this unknown site necessary for primer design was achieved using SiteFinding-PCR technique. The specificity of the detection method was shown by testing a number of different transgenic and conventional plant varieties (e.g. rice LL 601, LL 62, Bt 63). As alternative to genomic DNA, we developed double target hybrid amplicons as synthetic calibration standards in Real-time PCR. These amplicons contained both one copy of the KMD1 event-specific sequence and one copy of a sequence of the rice reference gene gos9. The limit of quantification (LOQ) of the method was tested to be 0.05%. R. Babekova and T. Funk contributed equally to this paper.     

不同类别大米糊化特性和直链淀粉含量的差异研究

对不同类别的市售大米样品（籼米,粳米,杂交稻米,籼糯米,粳糯米,黑米和香米）的糊化特性和直链淀粉含量进行了测定并进行了比较研究。结果表明,籼型,籼型,粳型和糯型大米的直链淀粉含量和糊化特性贡线及主要特征值（峰值粘度,最终粘度,回生值）均有明显的差异,并与其食用品质有密切相关,糊化特性曲线和相关特征值可用于鉴别市售大米的品质也可用于判别信有直链淀粉含量划分的大米类型。     

The functional effectiveness of reprocessed rice bran as an ingredient in bakery products

Rice bran, as a coproduct of the rice milling industry, is yet to be efficiently utilized for human consumption. Despite its excellent nutrition, its hypoallergenicity and recently claimed nutraceutical properties, it is mainly utilized for animal feed or simply discharged. It is of interest to incorporate this healthy ingredient back into our diet. In these studies, rice bran was processed by drum-drying and pin-milling. This processing step increased hydration capacity and removed grittiness by decreasing mean particle size from 444 to 72 microns and producing a desirable monomodal size distribution. There are no reported studies addressing differences in rice bran composition in food applications and specifically their effect on bread quality. Thus, we were interested in examining the functional properties of bread made with processed full-fat (FFRB) and defatted (DFRB) bran from three cultivars (long, medium and short grain rice) and to compare them to a control. For 10% and 20% replacements of wheat flour, respectively, loaf volume increased 2% for FFRB and decreased 6% for DFRB and decreased by 6% for FFRB and 17% for DFRB. Loaf volume was highest with medium rice bran and this was attributed to its lowest fiber content and highest starch content among three varieties. Texture profile analysis showed no significant differences as far as cohesiveness and springiness, but bread hardness, gumminess and chewiness increased with increased levels of rice bran and was higher for DFRB bread than for FFRB. Measurements of texture determined that there was no detrimental effect in adding 10% FFRB to the bread and a very slight hardening of the loaves with the 20% FFRB, when compared to the control. It was found that FFRB gave better textural characteristics than DFRB overall and differences amongst different rice bran varieties were not significant.     

Calibration model optimization for rice cooking characteristics by near infrared reflectance spectroscopy (NIRS)

The aim of this study was to evaluate the potential of near-infrared reflectance spectroscopy (NIRS) as a rapid method to estimate the cooking characteristics of rice. A total of 586 samples from rice breeding lines from 1999 to 2002, which had high variation for agronomy, location and year, were scanned by NIRS for calibration optimization by chemometric methods. Two subsets of 212 samples from one year and 400 samples from three years were employed to find suitable sample status for extending the NIRS utilities. There were three algorithms of PCA, PL1 and PL2, in which the first one was only based on the sample spectra variant and the remaining two based on the variant of both spectra and chemical characteristics to describe the relationship between any two neighboring samples. According to the results of calibration and validation by the three algorithms used, the suitable calibration samples could be chosen by the cutoff of neighborhood distance (NH) of 0.35, 0.4 and 0.45, respectively. For the cooking characteristics, the combination of SNV+D/‘1,4,4,1’ was the best pretreatment and the accuracy models were obtained with low SECV and high 1 − VRof amylose content (1.42% and 0.95%), gel consistency (9.49 and 0.76 mm) and alkali spread value (0.86 and 0.79 grade) . The models developed using brown rice and milled rice were superior to those using intact rice grains, but slightly poorer to those using their corresponding flour samples. Therefore, on-line monitoring of rice quality could be conducted in rice processing at milling stages. Due to the fewer sample mass destroyed, the brown rice (3 g) and brown rice flour (3 g or 0.5 g), by which the NIRS models were successfully developed for cooking characteristic analyses, could be introduced into quality evaluation of germplasm and intermediate lines selection in breeding projects.     

Puffing characteristics of some processed rice stored in different packaging systems

Varietal differences in the puffing characteristics of parboiled rice (PABR), parboiled milled rice (PAMR) and milled rice (MR) after storage in polyethylene bags (PLY), polyethylene impregnated jute bags and jute bags (JUB) for varying times up to 120 days were studied. Monthly observations covering changes in physicochemical properties considered to have bearings on the puffing characteristics of rice were made and the factors responsible for puffing of rice have been tentatively identified. Better puffing followed increased ageing of rice samples. PABR was a better puffer than PAMR while MR yielded charred rice and hence was unsuitable for puffed rice production. Alkali degradation and grain hardness had some regulatory effect on the quality of puffing of rice. PLY emerged as the best packaging material for storing rice for later puffing. In JUB rapid damage of rice samples occurred owing to insect infestation and it was the poorest packaging unit.     

Arsenic sequestration in iron plaque, its accumulation and speciation in mature rice plants (Oryza sativa L.)

A compartmented soil-glass bead culture system was used to investigate characteristics of iron plaque and arsenic accumulation and speciation in mature rice plants with different capacities of forming iron plaque on their roots. X-ray absorption near-edge structure spectra and extended X-ray absorption fine structure were utilized to identify the mineralogical characteristics of iron plaque and arsenic sequestration in plaque on the rice roots. Iron plaque was dominated by (oxyhydr)oxides, which were composed of ferrihydrite (81-100%), with a minor amount of goethite (19%) fitted in one of the samples. Sequential extraction and XANES data showed that arsenic in iron plaque was sequestered mainly with amorphous and crystalline iron (oxyhydr)oxides, and that arsenate was the predominant species. There was significant variation in iron plaque formation between genotypes, and the distribution of arsenic in different components of mature rice plants followed the following order: iron plaque > root > straw > husk > grain for all genotypes. Arsenic accumulation in grain differed significantly among genotypes. Inorganic arsenic and dimethylarsinic acid (DMA) were the main arsenic species in rice grain for six genotypes, and there were large genotypic differences in levels of DMA and inorganic arsenic in grain.     

蒸谷米糠和普通米糠的理化特性分析

对蒸谷米糠和普通米糠的物理特性和化学特性进行了测定.结果表明,其物理和化学特性均发生了变化.在米糠综合利用上可以分级提取米糠油和米糠蛋白,即先分级收集一、二、三机米糠作为制油原料,生成的米糠粕与抛光机米糠混合提取米糠蛋白.     

基于矿物元素分析对进口泰国、越南、柬埔寨香米产地的鉴定

目的 探讨泰国、越南、柬埔寨3国香米矿物元素含量差异,并对产地进行鉴别。方法 通过电感耦合等离子体质谱法(inductively coupled plasma mass spectrometry, ICP-MS)测定泰国、越南、柬埔寨3国75份香米中Cr、Ni、Cu、Zn、As、Se、Cd、Hg和Pb 9种矿物元素含量,对测定结果进行差异性分析、相关性分析、主成分分析和Fisher判别。结果 所有样本均未检出Pb,其中Ni、Cu、Zn、As、Se、Cd6种元素在不同国家之间有显著性差异(P<0.05),并且Cu在3个国家之间均存在极显著差异(P<0.01),6种元素相互之间存在一定的相关性。主成分分析中选取了前2个主成分,累计方差贡献率为71.334%。确定Cu、Ni和Se元素是造成不同产地香米矿质元素差异的特征因素。通过Fisher判别建立溯源模型,对越南训练集和验证集判别准确率为100%,而对柬埔寨和泰国的训练集判别准确率达到70%以上,验证集的判别准确率达到80%以上。结论 通过Fisher判别法可较为有效地鉴别泰国、越南、柬埔寨3个国家的香米。     

Cooking Quality of Brown Rice as Influenced by Gamma Irradiation, Variety and Storage

Two long grain and one medium grain brown rice varieties were gamma-irradiated at 1.0 and 2.0 kGy to ascertain if cooking time could be decreased and to determine effects of storage on chemical and physical characteristics. A tendency toward decreased cooking time was observed as dose level increased. Cooking time was not significantly (P> 0.05) affected by storage. A trend was noted in water uptake ratios, soluble starch of residual cooking water and volume expansion due to irradiation. Storage of irradiated rice produced similar changes to those of nonirradiated rice. Variety also contributed to differences in irradiated samples, such as cooking times, water uptake, starch retention and grain volume expansion.