Quality Prediction of Rice Flour by Multiple Regression Model with Instrumental Texture Parameters of Single Cooked Milled Rice Grains

The purpose of this study was to develop highly accurate regression models with texture parameters of cooked milled rice grains for predicting pasting properties in terms of quality index of rice flour. Two methods were adopted as the texture measurement to acquire predictors for the models. In the calibration set, all the multiple regression models by a single‐grain method exhibited a higher R² than those by a three‐grain method. Each of the former models also showed a lower SEP and a higher RPD in the validation set. The prediction performance was best for consistency (RPD = 2.4). The single‐grain method was more advantageous for the pasting prediction. These results suggest that the models based on grain texture could predict rice flour quality.     

Prediction of Cooked Rice Texture Using an Extrusion Test in Combination with Partial Least Squares Regression and Artificial Neural Networks

Spectral stress strain analysis was used in combination with partial least squares (PLS) regression and artificial neural networks (ANN) to predict nine sensory texture attributes of cooked rice. The models calculated with ANN were significantly more accurate in predicting most of the sensory texture characteristics evaluated than the PLS models. Furthermore, ANN models were more robust and discriminative than PLS models.     

Prediction of Cooked Rice Texture Using Extrusion and Compression Tests in Conjunction with Spectral Stress Strain Analysis

Sensory texture attributes of cooked rice from two cultivars (Bengal and Cypress) harvested in 1997 (56 samples) were predicted using extrusion and compression tests along with spectral stress strain analysis. Predictive models for each of nine sensory texture attributes studied were evaluated using force values from the instrumental tests in conjunction with partial least squares regression. All sensory attributes were well predicted using both the extrusion and compression tests (relative ability of prediction > 0.70). However, the extrusion test consistently provided more accurate and discriminative predicted models (root mean square error of prediction < 0.55, S_tot/RMSEP > 2.0). Spectral stress strain analysis predictive models for adhesiveness to lips and hardness were explained.     

Physicochemical Characteristics of Chalky Kernels and Their Effects on Sensory Quality of Cooked Rice

Physicochemical characteristics of chalky rice kernels were compared with those of vitreous kernels, and the effects of chalky kernels on sensory quality of cooked rice were investigated. Chalky kernels were compared with vitreous kernels using image analysis and amylose contents. Because cooked rice is prepared through soaking and cooking, the changes in water absorption index (WAI) during soaking (15, 30, 60, and 90 min) and the structural changes during cooking (0, 3, 6, and 9 min) in chalky and vitreous kernels were investigated using image analysis and scanning electron microscopy. The effects of various proportions (0, 4, 6, 8, 10, and 15%) of chalky kernels on sensory quality of cooked rice were also studied. The chalky kernels tended to be smaller in kernel area, maximum diameter, minimum diameter, and perimeter than vitreous kernels. Amylose content in chalky kernels was slightly lower than that in vitreous kernels. WAI of chalky kernels was higher than that of vitreous kernels. The effects of chalky kernels on the sensory quality of cooked rice were not significant unless the proportion of chalky kernels was ≥15%. A sensory panel agreed that the overall sensory quality of cooked rice with 15% chalky kernels was the lowest among the samples tested.     

大气CO_2浓度升高对粳稻稻米物性及食味品质的影响

在2009和2010年利用独特的稻/麦轮作系统FACE（Free Air CO2 Enrichment,开放式空气CO2浓度增高）平台,以武运粳21、扬辐粳8号、武香粳14和武粳15为供试材料,研究了高浓度CO（2比大气背景CO2浓度高200 μmol·mol-1）对粳稻蒸煮米的硬度、粘性、香气、光泽、完整性、味道和口感等的影响。物性分析仪测定结果表明,高浓度CO2环境下粳稻熟米的硬度和粘性总体呈增加趋势,其中扬辐粳8号两指标的增幅均达显著水平。食味计测定结果显示,高浓度CO2对蒸煮稻米香气、光泽度、完整性、味道和口感等食味品质指标均没有影响。相关分析表明,CO2与品种的互作对米饭硬度和粘性有显著影响,但对食味品质参数均没有影响。CO2与年度、CO2与年度和品种间的互作对所有测定参数均无显著影响。两年数据一致表明,未来高浓度CO2环境下粳稻蒸煮米的硬度和粘性将呈增加趋势,增幅因品种而异,但米饭食味品质无显著变化。     

Characterization of Waxy Rice Cakes (Mochi) with Rapid Hardening Quality by Instrumental and Sensory Methods

The textural properties of cooked waxy rice cakes made from four waxy rice varieties including the unique varieties Kantomochi 172 (K172) and BC3 with the property of rapid hardening were analyzed by instrumental and sensory methods. For the instrumental analysis, a compression test, adhesiveness test, and tensile test were conducted. The waxy rice cakes made from K172 and BC3 showed significantly higher compressive force and resistance to break under tensile load. Significant difference in amylopectin chain‐length distribution was observed between each variety, and this difference strongly reflected the hardness of waxy rice cakes. The peak area ratio of amylopectin branch chains with 6–12 degrees of polymerization negatively correlated with the compressive force required for 50 and 80% strain. Sensory evaluation showed that the waxy rice cakes made from these varieties had a significantly harder, less stretchable, less smooth surface, whereas the scores for adhesiveness and ease to cut off (hagire) were preferable to those for other rice varieties.     

稻米蒸煮特性QTL定位及与感官食味品质的相关性分析

稻米蒸煮特性和感官食味品质是稻米品质的重要评价指标,其遗传复杂.为挖掘与利用优异的稻米品质基因,本研究利用籼稻昌恢121为受体亲本和优质粳稻越光为供体亲本构建的一套染色体片段置换系(CSSL),对稻米的吸水率(WA)、延伸率(CRE)和膨胀率(VE)3个蒸煮特性进行QTL定位.共检测到4个QTL,分布于第8和第11号染...     

Using an In‐Line Slit‐Die Viscometer to Study the Effects of Extrusion Parameters on Corn Melt Rheology

An in‐line slit‐die viscometer (SDV) was used to measure the viscosity of a melt extrudate independently of the extruder operating conditions. The melt produced by extrusion of the corn grits followed a power law rheological model. The viscosity of the melt and extrusion parameters such as specific mechanical energy (SME), torque, and die pressure decreased with increasing moisture content. The degree of starch gelatinization increased when barrel temperature increased from 90 to 130°C. At temperatures higher than 130°C, most of the starch had gelatinized. The increase in barrel temperature, however, resulted in small changes in the apparent viscosity of the melt, until a maximum of ≈130°C. At a constant feed rate, SME increased and torque decreased when screw speed increased due to the shear thinning behavior of the melt. At a constant screw speed, the torque increased and SME decreased with increasing feed rate. This was due to a decrease in apparent viscosity of the melt at higher feed rates. SME is not an independent extrusion variable and should be used with caution either when predicting the effect of thermomechanical treatment of the product or as the key and only variable for controlling the food extrusion process.     

微分光谱遥感及其在水稻农学参数测定上的应用研究

通过不同氮素营养水平的水稻田间试验,解析了水稻冠层微分光谱对消除背景(湿土、水面)信息的影响,证实微分光谱在消除背景信息的影响方面起到了很好的作用。用微分光谱确定出最优的波段宽度应小于10nm;将微分光谱应用于农学参数测定,存在红边位移现象,在孕穗期之前,红边随施氮量增加向长波方向移动“红移”;孕穗期之后“红移”现象基本消失,而发生“蓝移”。红边参数(红边、红边振幅、红边振幅与最小振幅的比值、红边峰值面积)与上层叶片的叶绿素含量、LAI有着密切的关系,而与叶片中的叶绿素b、类胡萝卜素之间相关性不明显。一些红边参数可作为水稻叶绿素含量、LAI测定的简捷方法。从而证实了利用微分光谱测定一些农学参数的可行性