不同品种稻米的米饭风味分析

采用固相微萃取结合气相色谱-嗅闻-质谱技术对7种籼米、4种粳米共11种米饭样品的风味化合物进行分析。结果表明,粳米中风味化合物种类略高于籼米。米饭中关键风味化合物在粳米、籼米样品中存在显著差异,2-乙酰基-1-吡咯啉在籼米样品中未被检出;4-乙烯基苯酚只在粳米中被检测出;香草醛在粳米中的相对含量显著高于籼米;而籼米中1-辛烯-3-醇、戊醛、己醛的相对含量显著高于粳米。利用米饭风味物质的主成分分析方法,可以区分出粳米与籼米的品种差异。     

超声-微波处理对米饭品质的影响

研究了超声-微波协同加热、微波加热和传统加热对粳米米饭和糯米米饭品质特性的影响。结果表明,与传统加热的样品相比,超声-微波协同加热和微波加热的粳米米饭感官综合品质较好,米饭硬度较小且非烃类风味物质含量较高,体外淀粉消化速度较慢且酶解终点葡萄糖含量较少。与粳米米饭相比,糯米米饭变化差异较小。原因在于微波加热和超声-微波协同加热方式下米饭中淀粉颗粒破裂不充分,且物理辐射下不同品种的米饭性质变化的敏感程度与其直链淀粉含量相关。      

不同烹煮方式对米饭食味品质的影响

以4种市售大米为研究对象,利用质构仪、气相色谱-质谱(gas chromatography-mass spectrometry,GC-MS)及感官评价等检测和评价手段,对不同烹煮方式的米饭进行基本蒸煮品质、质构特性以及风味物质等食味品质的评价,并探究其与感官评价的相关性。旨在探究不同大米品种(粳米和籼米),以及不同蒸煮工艺(高压烹煮、电饭锅烹煮、微波烹煮和电蒸锅烹煮)对米饭食味品质的影响,寻找一种能够综合评价米饭食味品质的方法,为米饭的制作及米饭食味品质的改善提供理论参考。结果表明:经高压烹煮后的米饭吸水率、膨胀率、碘蓝值均高于其他方式,且米饭硬度小,弹性和黏性较大,感官品质评价最优,而微波烹煮米饭食味品质最差。米饭膨胀率与感官评价中米饭的滋味和形态呈显著正相关(P0.05,P0.01),硬度与口感呈极显著负相关(P0.01),弹性与米饭形态呈极显著正相关(P0.01)。此外,米饭风味物质分析表明经高压烹煮和电饭锅烹煮的米饭,醛、醇、酮等主要的米饭风味物质含量和种类均高于其他烹煮方式,且因品种不同大米的香气有所差异。     

基于气相色谱-离子迁移谱和电子鼻技术研究籼米口腔加工过程中的风味释放

为研究籼米米饭在口腔加工过程的风味释放规律,通过志愿者对籼米米饭进行咀嚼制备不同咀嚼阶段食团,采用气相色谱-离子迁移谱（gas chromatography-ion mobility spectrometry,GC-IMS）法和电子鼻技术对比分析籼米在不同口腔加工阶段挥发性成分的差异及标志性差异物。电子鼻结果分析表明,咀嚼前、后籼米米饭风味与咀嚼过程中有显著差异。GC-IMS分析共分离鉴定出33种风味物质。与咀嚼前相比,咀嚼过程中食团的醛类相对含量分别降低了62.01%、47.60%、69.19%和71.78%,醇类相对含量分别增加了59.89%、42.59%、29.94%和17.73%,酮类相对含量分别降低了31.92%、17.87%、34.92%和38.45%。通过偏最小二乘判别分析,共筛选出11种米饭特征性化合物,包括己醛（单体）、己醛（二聚体）、辛醛、庚醛、1-丙醇（单体）、1-丁醇、2,3-戊二酮、2-庚酮、2-戊基呋喃、D-柠檬烯（单体）和D-柠檬烯（二聚体）等。     

三种稻米在贮藏过程中蒸煮特性变化的比较

分别以新收获籼米、粳米和糯米为原料,采用温度37℃、相对湿度85%条件进行人工加速陈化试验,比较贮藏过程中3种稻米的蒸煮特性和耐贮性。研究结果发现:随着贮藏时间的延长,3种大米RVA特征谱中峰值黏度先上升后下降,回生值和糊化温度逐渐上升;籼米浸渍吸水率增加,粳米和糯米浸渍吸水率先上升后下降;3种大米的加热吸水率、延伸率、膨胀率和米饭浸出液透光率增加,米饭浸出液碘蓝值和pH值减小。表明贮藏过程中籼米、粳米和糯米食用品质下降。通过对比表征大米蒸煮食用品质指标的变化幅度比较3种大米的耐贮性,结果发现糯米的耐贮性最差,籼米耐贮性最好,粳米居中。     

酿酒用生、熟大米挥发性风味物质差异分析

目的：明确大米、米饭和在酸性条件下蒸煮的米饭，它们之间挥发性香气物质的差异，为分析浓香型白酒蒸馏过程中挥发性风味差异提供数据支持。方法：采用顶空固相微萃取-全二维气相色谱-飞行时间质谱（HS-SPME-GC-TOFMS）对大米生料（米粉）和熟料（米饭、加酸米饭）中的挥发性香气化合物进行鉴定，依据正交偏最小二乘判别分析（OPLS-DA）和香气活力值（OAV）分析样品间的挥发性风味物质差异。结果：米粉、米饭和加酸米饭中共鉴定出98种挥发性风味物质，分别为65,55种和68种挥发性物质，其中共有物质31种，物质种类数量和含量均以醇类、醛类、酯类和酮类为主。基于3种样品中挥发性风味化合物含量进行OPLS-DA分析，结果表明，3种样品中的VIP>1的差异物质54种，其中，米粉中有2-庚酮、2,3-辛二酮、丙位壬内酯等24种物质，米饭中3-噻吩甲醛、2,3-戊二酮、茶香酮等6种，加酸米饭中糠醇、糠醛、异戊酸等24种。OAV计算分析表明，己酸乙酯在3种样品中OAV值较高，米粉和米饭中2-乙酰基-1-吡咯啉的OAV>10；加酸米饭中OAV值最高的是己酸乙酯，2-乙酰基-1-吡咯啉在加酸米饭...     

电磁烹制米饭的营养特性研究

以两种大米为原料,采用电磁加热蒸煮米饭,研究电磁加热模式对米饭营养成分、质构特性、淀粉和蛋白质消化性的影响,为电磁烹制提供理论依据。结果表明,热源种类、电磁烹制模式和大米品种对米饭的感官品质和营养特性具有较大影响。电磁烹制模式综合感官品质较电热模式优良,具有口感黏柔、滋味淡雅,黏弹性好,淀粉、蛋白质消化性好等特点。低强度的米饭IH烹制模式有利于米饭淀粉、蛋白质的降解,使米饭的香气、口感较优,水溶性蛋白、淀粉含量较高,淀粉和蛋白质的消化率较好。三江大米制作的米饭硬度和黏附性较星2号米大,星2号米的IH烹制模式间的品质差异较大。     

基于GC-MS和电子鼻技术的大米挥发性风味成分分析

以8种市售大米为研究对象,利用顶空固相微萃取气相色谱质谱联用技术(solid-phase microextraction,SPME/gas chromatography-mass spectrometer,GC-MS)和电子鼻分析了大米中的挥发性物质,旨在鉴定粳米和籼米的特有香气,并比较两者差异。实验结果表明:运用电子鼻技术和主成分分析(principal component analysis,PCA)能有效区分不同品种大米,粳稻和籼稻在挥发性成分上差异明显。在此基础上,通过GC-MS定性定量检测大米中的挥发性成分,籼米的挥发性成分(149种)多于粳米(94种),籼稻中挥发性物质最多的是茉莉香米,粳稻中挥发性物质最多的是稻花香米。壬醇、癸醇和2-乙基-1-己醇等醇类物质只存在于籼米中,而2-环己酮和2-癸酮等酮类物质只在粳米中检测到,可能是这些物质导致了两个大米种类香气的差异。粳米和籼米中的重要风味物质主要是醛类、酮类和醇类,如己醛、辛醛、壬醛、苯甲醛、2-戊基呋喃等物质在粳米和籼米中都存在,这些挥发性成分阈值小,对大米特征香气的形成起重要作用。研究结果可为大米的产地及品种鉴别提供一定的参考价值。     

基于GC-IMS分析碾减率对籼米米饭挥发性物质的影响

目的：研究碾减率对籼米米饭挥发性物质组成的影响。方法：以籼稻“隆科早1号”为原料制备理想碾减率为0%~14%的籼米,同时采用气相色谱—离子迁移色谱（GC-IMS）测定米饭的挥发性物质,并根据指纹图谱结合多元统计分析籼米米饭中挥发性物质差异。结果：当碾减率为8%时,籼米米饭的感官评分最高。米饭中挥发性物质主要是醛类、酮类、醇类及少量的呋喃类等。大部分挥发性物质在碾减率为0%~6%的籼米米饭中含量较高;当碾减率为10%~14%时,米饭中的挥发性物质组成无明显差异。采用正交偏最小二乘法判别分析（OPLS-DA）筛选出 18 种特征标志物（VIP>1）,其中,2-甲基-1-丁醇、乙酸异戊酯、异戊醇、2-戊烯醛、3-甲基丁酸、2-乙基呋喃等可以作为“隆科早1号”不同碾减率大米米饭的差异性挥发性物质。结论：碾磨可以降低糙米米饭中挥发性物质含量,当碾减率为8%时,米饭具有良好的气味和感官品质。     

大米凝胶特性测定中凝胶制备工艺参数研究

以籼米和粳米为原料,通过单因素及正交试验探索并优化确定制备大米凝胶的工艺条件。结果表明：米浆浓度、加热温度、蒸制时间、静置温度与时间等因素对形成的凝胶的硬度、弹性、粘性、内聚性、咀嚼性等均有一定影响。凝胶制备条件为：粳米米浆浓度为25%,籼米米浆浓度为20%,80℃水浴糊化成悬浮液,而后转入蒸锅中蒸制15min,取出冷却至室温后,于4℃恒温箱中分别静置24h、36h。静置时间对粳米凝胶的感官综合评价有较为显著影响,而米浆浓度和蒸制时间影响不显著;米浆浓度对籼米凝胶的感官综合评价影响较为显著,而静置时间与蒸制时间影响不显著。     

不同储藏年限稻谷的品质及蒸谷米加工适应性分析

为了解不同储藏年限的稻谷加工蒸谷米的品质变化,为蒸谷米加工原料的选择提供依据.以不同储藏年限的籼稻、粳稻各40份样品为研究对象,将其加工成蒸谷米,并对蒸谷米的蒸煮特性、外观及其制备米饭的食用品质与质构特性等指标进行测定,采用描述统计分析、方差分析、主成分分析等方法对蒸谷米的品质指标进行分析,采用聚类分析探讨稻谷的蒸谷米...     

不同类型大米吸着等温线差异性研究

对11个大米样品（5个粳米、2个籼米、4个糯米）,采用静态称重法测定了水分吸附和解吸等温线数据,温度分别为10、20、25、30、35℃,相对湿度范围11.3%⁹6%,并分别采用修正Chung-Pfost方程（MCPE）拟合等温线。在10³5℃范围内,拟合的粳米、籼米及糯米每个温度水分吸着等温线依次降低。粳米与糯米之间吸附等温线差异显著大于粳米与籼米之间吸附等温线差异,籼米与糯米之间吸湿性相似,粳米与籼米解吸等温线之间差异不显著,但是粳米与糯米解吸等温线之间在10³0℃范围、低相对湿度下存在差异。Mixolab分析仪适量加水实验显示,粳米米粉的吸水率大于籼米和糯米。粳米、籼米、糯米米粉团的蛋白质网络强度（C2）依次减少,但是米粉团淀粉糊化（C3）、糊化淀粉粒的物理溃败（C4）和淀粉回生（C5）减少次序是籼米、粳米和糯米。与籼米比较,糯米米粉团具有弱的蛋白网络、低的淀粉糊化粘度值、低的糊化淀粉粒物理溃败和淀粉回生值,这些物理化学特性不降低其米粉吸水率。      

Effect of heating oils and fats in containers of different materials on their trans fatty acid content

BACKGROUND: The nature of the container material and temperature employed for deep‐frying can have an influence on the development of trans fatty acids (TFAs) in the fat used. The present study was undertaken to determine the effect of heating vegetable oils and partially hydrogenated vegetable fats with different initial TFA content in stainless steel, Hindalium (an aluminium alloy), cast iron and glass containers. Ground nut oil (oil 1), refined, bleached and deodorised (RBD) palmolein (oil 2) and two partially hydrogenated vegetable oils with low (fat 1) and high (fat 2) TFA content were uniformly heated at 175–185 °C over a period of 12 h. RESULTS: An increase in TFA content to 20 g kg^?1 was observed in oil 2 in the cast iron container, while a decrease in TFA content of 20–30 g kg^?1 was observed in fat 2 in all containers. The heating process of fats and oils also led to an increase in Butyro refractometer reading and colour values. CONCLUSION: This study showed that the TFA 18:1t content of oil 1, oil 2 and fat 1 increased with repeated or prolonged heating. The cast iron container showed the highest increase in TFA 18:1t for RBD palmolein (oil 2). The amount of linoleic acid trans isomers formed in the heating process was negligible. Fat 2 with high initial TFA content showed a decrease in TFA 18:1 and 18:2 on heating in all containers. Oils heated in glass and stainless steel containers showed less TFA 18:1t formation. Copyright © 2012 Society of Chemical Industry     

基于电子鼻技术对米饭食用品质中气味评价

通过电子鼻测定15种籼型和15种粳型米饭样品有关气味的10个感应器指标信息,利用主成分分析分别构建了籼型和粳型米饭的气味品质预测评价模型,建立了基于电子鼻技术的米饭气味评价方法。结果表明：籼型和粳型米饭气味前两个主成分的特征值均大于1,且两个主成分的贡献率分别达到了94.087%和96.408%,可以代表米饭样品的绝大部分气味信息;构建的米饭气味评价模型分别为Z=0.782Z1 0.126Z2(籼米)和Z=0.838Z1 0.159Z2(粳米),用此模型获得米饭气味的综合得分,其中除了籼米中4个样品和粳米中3个样品与感官评价的排序有差异外,其余各样品排序结果均与感官评价相一致。说明两种方法具有很好的一致性,使用电子鼻技术对米饭食味品质中气味进行评价是可行的,并为米饭气味品质的客观评价探索了一条新途径。     

A comparative study of the nutritional values,volatiles compounds,and sensory qualities of pea pastes cooked in iron pot and clay pot

In the current study, the nutritional values, volatiles compounds, and sensory qualities of pea pastes cooked in iron pot and clay pot were compared. Results showed that the iron pot‐cooked pea pastes contained profoundly more iron, total sugar, and starch than the clay pot‐cooked ones, and the effects were found related to iron ion by comparing the results between clay pot‐cooked pastes with and without iron ion addition. Samples prepared with the two utensils demonstrated similar contents of protein, polyphenol, and tannin, but differed in the composition of some volatile alcohols, alkanes, aldehydes, ketones, esters, and organic acids. The clay pot‐cooked samples had higher score of “color,” “mouthfeel,” “taste,” and “overall quality” than the iron pot‐cooked pastes. In conclusion, iron pot can allow the production of iron‐enriched pea pastes whose sensory qualities are remarkably lower than those of the clay pot‐cooked samples but are still in the acceptable range.

Practical applications

Iron utensil plays an important role in modern food industry due to its durability and convenience to handle. Cooking with iron pot is a simple and useful method of dietary iron fortification for the prevention of iron‐deficiency anemia in developing countries. Pea paste is a popular legume food with high nutritional value and good palatability. Traditional pea paste producers believe cooking with clay pots can give rise to product with more desirable features than using iron pots. However, there were no scientific evidences regarding the effects of cooking utensils on pea paste qualities. It has been proved in the current study that iron pot can allow the production of iron‐enriched pea pastes whose sensory qualities are remarkably lower than those of the clay pot‐cooked samples but are still in acceptable range.     

High Temperature Storage Effect on Longevity of Rice Seeds

Storage of Indica (Oryza sativa L. cv. Katakutara) and Japonica (Oryza sativa L. cv. Kusabue) rice seeds at 30° and 40°C for 2 months in the dark did not result in the loss of viability in both cultivars. Storage at 60°C, however, resulted in a complete loss of germination after 45 days in the case of Kusabue while the Katakutara rice seeds retained the germination potential well above 95%. Corresponding increases in the linoleic acid content of the free fatty acid fraction and TBA values of the extracted lipid fraction were also observed in Kusabue rice seeds. The investigation indicated that the Indica rice seeds were better protected than the Japonica rice seeds by the enclosing rice hull during the storage period.     

不同烹制模式对鸡汤中鸡肉营养及风味特征的影响

研究电磁加热、电热盘加热和瓦罐烹制模式对鸡肉营养成分、质构和风味特性、蛋白质和脂肪消化性的影响。结果表明：烹制模式对鸡肉的感官品质和营养特性具有较大影响。电磁加热模式烹制鸡肉的综合感官品质优良,具有质地柔嫩、香气浓郁、滋味鲜美、风味成分较丰富等特点,同时鸡肉的维生素、脂肪、必需氨基酸含量较高,蛋白质的消化率较好;瓦罐模式烹制鸡肉中蛋白质和矿物质含量较高,脂肪消化率高;电热模式烹制鸡肉的各项指标介于上述2 种烹制模式之间,其中,电磁加热模式烹制鸡肉中的VB3含量达10.34 mg/100 g,粗脂肪含量为5.58%,蛋白质消化率为33.31%;另外,鸡肉中的醛、酮、酯类物质含量亦较高,挥发性物质种类可达37 种。总体来讲,电磁加热是一种较好的鸡肉烹制模式。     

Quantitative NMR imaging study of the cooking of Japonica and Indica rice

NMR imaging was used to follow changes in the water content and distribution during the cooking of Nipponbare (Japonica), Khao Dawk Mali (Indica) and High Amylose (Indica) rice. Samples were cooked in closed glass vials for various times, quenched to stop cooking and then investigated using two-dimensional multi-echo ¹H imaging experiments at 20 °C. Images calculated from the first-echo revealed changes in the water content of the rice grains. T₂ images calculated using the first 16 echoes were converted into quantitatively reliable contour maps of the water concentration using an empirical T₂ vs. water content calibration determined from a series of water/rice starch mixtures. Considerable differences in the rate of water uptake and diffusion, the average water contents and the proportions of under-, optimally- and over-cooked rice were observed for the three rice types studied.     

低温等离子体处理对糙米原料及糙米饭风味特性的影响

为研究低温等离子体处理对糙米原料及糙米饭风味特性的影响,采用气相色谱-离子迁移色谱（gas chromatography-ion mobility spectroscopy,GC-IMS）对低温等离子体技术处理前后糙米原料及糙米饭样品特征风味进行测定与分析,以数据可视化形式表征样品中挥发性风味物质指纹图谱差异性及变化,进一步利用LAV软件中Matching matrix插件对样品进行相似度分析。结果表明,低温等离子体处理后糙米与糙米挥发性风味物质的相似度为83.25%;低温等离子体处理后糙米原料的2,3-丁二酮、丙酮、桉树脑单体、桉树脑二聚体、正己醇单体、正己醇二聚体、二烯丙基二硫醚、蒎烯和柠檬烯等醇、酮、萜类物质相对含量增加,呈现出更多的花香、松木等清香气味。而糙米饭与低温等离子体处理后的糙米饭的相似度为89.5%,低温等离子体处理后糙米饭样品的醛类物质和萜类物质的相对含量增加,对糙米的整体风味起到一定的烘托作用,丰富了糙米风味物质,且无不良风味物质产生,实验为低温等离子体技术对糙米风味的研究提供了一定的理论依据和数据支持。