Milled Rice Kernels Research Articles

Varietal Differences in the Physical and Engineering Attributes of Underutilized Pigmented and Non-pigmented Paddy and Rice Landraces

Traditional rice landraces cannot be processed using standard machinery or unit operations. Traditional rice, on the other hand, is becoming more popular as its purported health benefits spread. Cracked rice grains, broken rice, and subpar milled rice kernels result from using non-standard equipment on landraces. So, studying the physical characteristics of rice and paddy is crucial for modifying milling equipment to lessen post-harvest losses. To preserve and familiarize the underutilized landraces, a comparative study of three pigmented and three non-pigmented landraces were assessed for their physical, gravimetric, and engineering traits using standard analytical protocols. The analysis demonstrated substantial variation among the evaluated properties. The majority of the traditional landraces were classified as long-bold and long-slender grains. The landraces exhibited variations in the equivalent diameter ranging from 0.29 to 0.46 mm and 2.54 to 3.38 mm for rice and paddy samples respectively. The major differences in other attributes like sphericity, aspect ratio, and surface area were also observed. Gravimetric properties of paddy and rice samples of Madumuzhungi (MMP) showed significantly lower values in contrast to other landraces. The highest porosity (51.43%), moisture content (14.97%) and water activity (0.88) was exhibited by the Madumuzhungi paddy sample. The non-pigmented rice samples displayed lower values for thousand kernal weight (TKW), grain volume and surface area. Almost all the variants except White mappillai samba paddy were under 30 g for TKW, indicating the differences between pigmented and non-pigmented landraces. Moisture content significantly affected the gravimetric and engineering properties of the landraces. The correlations between the dimensions and engineering qualities were investigated using principal component analysis (PCA). Five principal components, which account for 100% of the total variance, were used via PCA to reduce the dimensionality of the data.

Analysis of chalk in rice by two-dimensional correlation spectroscopy

To extract the characteristic information of chalk in rice, the chalky milled rice were analyzed systematically by mid-infrared (IR), near-infrared (NIR) spectra analysis and two-dimensional (2D) correlation spectroscopy. 24 non-chalky and 24 chalky rice samples for four types milled rice were prepared in laboratory. NIR diffusing reflection and IR attenuated total reflection (ATR) spectra of all samples were collected at room temperature. The synchronous 2D NIR-NIR correlation spectra was calculated to show the differences between chalky and non-chalky rice more remarkably. The 2D IR-NIR correlation spectra was used to confirm the near-infrared characteristic peak. According to the IR spectra, a lot of starch was found in rice samples. Besides, in the NIR spectra, peaks at around 4332 and 4732 cm−1 could be considered as the key factors to discriminate chalky rice kernels. And the higher peak intensity ratio of 5168/5624 cm−1 was found compared to the non-chalky sample. In addition, significant differences emerged in the 2D NIR-NIR correlation by the intensity and number of the auto-peaks and cross-peaks in synchronous spectra. There was three auto-peaks near 4484 cm−1, 4752 cm−1and 4958 cm−1 in chalky rice sample. While only one auto-peak near 4958 cm−1 in non-chalky rice sample. Besides, chalky rice sample has one cross-peak between 4484 and 4958 cm−1, while it was absent in non-chalky rice. The technique for chalky rice kernels detection of milled rice kernels was rapid and non-destructive, which could be used to provide technical support for rice quality improvement breeding.

Single nucleotide polymorphisms in GBBSI and SSIIa genes in relation to starch physicochemical properties in selected rice (Oryza sativa L.) varieties

Single nucleotide polymorphisms in GBBSI and SSIIa genes in relation to starch physicochemical properties in selected rice (Oryza sativa L.) varieties

Fissuring Kinetics of Rough Rice during the Drying Process

HighlightsDrying rough rice using harsh air conditions causes fissures to appear instantaneously during active drying.For mild drying air conditions, a time interval is required after the cessation of active drying before fissures appear.The majority of fissures due to active drying in rough rice kernels appear after drying has ceased.Abstract. Fissuring of rough rice kernels leads to breakage during milling, which results in head rice yield reductions. While other studies have addressed the fissuring kinetics of milled rice kernels, rice is normally dried and stored as rough rice. Thus, the objective of this research was to study the fissuring kinetics of rough rice kernels during the drying process and to characterize the configuration of the fissures. Rough rice kernels of cultivar CL XL745 with a bulk moisture content of 17% were dried using air at 40°C, 50°C, and 60°C each at relative humidity (RH) levels of 20%, 40%, and 60%. During the drying process (drying, tempering, and subsequent storage), X-ray images of rice kernels were recorded to enumerate fissures. As the drying air temperature was increased, the percentage of fissured kernels increased for all RHs evaluated. Conversely, as RH was increased, the percentage of fissured kernels decreased. Approximately 90% of fissures appeared after drying had ceased, increasing rapidly in the initial 6 h after drying. Kernels dried at high-temperature, low-RH drying air combinations had fissuring occur and appear instantaneously during active drying. In low-temperature drying conditions, fissures did not appear during active drying. Fissuring under such conditions required a time delay after active drying. This study shows the stages of the drying process when fissures appear in rough rice and the durations after active drying when fissures are expected to appear. Keywords: Glass transition, Post-drying, Relative humidity, Rice drying, Temperature, Tempering, X-ray imaging.

Functional properties of endosperm protein from size‐fractionated broken rice kernels generated after milling of parboiled and nonparboiled rice

AbstractBackground and objectivesThe quantity and functionality of proteins in different sizes of broken rice (brokens) may inform the different pasting properties observed in rice flour derived from brokens. This study was conducted to determine properties of protein from size‐fractionated parboiled and nonparboiled milled broken rice kernels. In addition, the research sought to determine the extent to which properties of proteins influence functionality of rice flour derived from the studied brokens.FindingsWhole kernels and medium brokens of nonparboiled rice recorded the highest quantity and yield of protein isolate, while the lowest was recorded in large brokens. A strong negative correlation existed between sample protein content and the size of parboiled brokens. Parboiled samples had decreased protein extractability than nonparboiled samples. Emulsifying activity (EA) of parboiled rice had a significantly strong negative linear association with size of brokens. Emulsifying stability (ES) on the other hand had a significantly strong positive linear association with size of brokens, and about 82% of the variation in ES was explained by size. The trend was opposite in the nonparboiled stream with ES having a strong negative linear association with size. A very strong positive linear association existed between foaming capacity (FC), foaming stability (FS), and size of nonparboiled samples. Surface hydrophobicity (SH) was significantly different among parboiled and nonparboiled rice, with weak positive correlations existing between SH and size of parboiled and nonparboiled samples. Solubility curves in nonparboiled stream were more uniform than the parboiled stream. Strong significant positive correlations existed between peak, trough, breakdown, final, setback viscosities, and ES. A strong positive linear association was observed between peak, trough, final viscosities, and FS. Differences in protein contents of whole kernels and size‐fractionated brokens may be attributed to either the variations in the distribution of inherent components of the kernel or variations in milling efficiency. Results in this research are specific for long‐grain hybrid rice and may vary depending on cultivar and environmental factors.ConclusionsProteins influence the pasting properties of brokens. Understanding the functional properties of size‐fractionated broken rice kernels from parboiled and nonparboiled streams is essential in directing the right kind of brokens to the right end‐use.Significance and noveltyThis study provides useful information to better utilization and value addition of brokens.

Moisture Adsorption Rate and Effective Diffusivity in Chinese Milled Rice

Four varieties of Chinese milled rice samples with 11.90–15.56% initial moisture content (IMC, wet basis) were used to determine the rate of moisture adsorption using the gravimetric method at 10, 20, 25, 30, and 35°C under 65%, 86%, and 100% relative humidity (RH), respectively. A moisture diffusion equation was modified to fit the relationship between the moisture ratio (MR) of samples and exposure time. In the range of 65% to 100% RH, the lower IMC of milled rice samples corresponded to higher moisture adsorption rate at temperatures of 10 to 35°C. The moisture adsorption rate of samples increased with an increasing temperature. The moisture sorption rate of samples with the same IMC increased with increasing RH at certain temperatures. A single milled rice kernel was geometrically considered a finite homogeneous cylinder shape, and the analytical solution of the partial differential equation of moisture diffusion was given. The effective moisture diffusivity was calculated using a slope method by plotting the experimental data in terms of ln (MR) versus rewetting time. In the range of 10–35°C, the effective moisture adsorption diffusivity of milled rice kernels with normal moisture was 4.321×10-9–1.117×10-7 m2h-1. For the same IMC, the effective moisture diffusivity of milled kernels tended to increase with increases in surrounding temperature at certain relative humidity levels, but decreased with an increase in RH at certain temperatures. It was concluded that the milled rice samples from different types had similar effective moisture diffusivity when similar IMC was given.

Impact of environmental factors on rice starch structure: A review

Among cereal grains, rice is the world's leading source of caloric energy in the human diet. About 90% of a milled rice kernel is starch (dry weight basis), thus justifying the need to understand the impacts of factors affecting starch composition and behavior when processed. This review presents past and current perspectives regarding the effects of growing environment on the macro, micro, and nano level structures of rice starch. The environmental elements considered in this work are: air temperature, atmospheric carbon dioxide, light, water, and soil nutrients. All these elements are essential for plant development and reproduction. The effect of air temperature is the most widely explored aspect of the environment in relation to rice production and grain quality. This could be attributed in part to the recently purported and highly publicized global warming phenomenon. Amylose content has remained a major predictor of rice starch quality but emerging instrumental techniques have facilitated more thorough research addressing the fine structure of amylopectin, which constitutes ∼70% of the starch present in a milled rice kernel. Kernel chalkiness appears to be the most common visual manifestation of environment‐related stress. Typically, there are genotype by environment interactions; this may result in inconsistent temporal and spatial findings. However, such interactions may prove useful in identifying particular genotypes that are adaptable and stable across growing locations.

A Brown Planthopper Resistant and High Grain Quality Rice Variety ‘Anmi’ Developed by Molecular Breeding Method

‘Anmi’ is a new BPH (Brown planthopper) resistant japonica rice cultivar possessing the Bph18 gene derived from wild rice, Oryza australiensis and high yield potential with good grain quality. ‘Anmi’ was derived from a cross ‘Junam’ and ‘IR65482-7-216-1-2’ by a molecular marker assisted backcross breeding. The introgression line ‘IR65482-7-216-1-2’, the source of the Bph18 gene, was used as the donor parent for BPH resistance and ‘Junam’, a BPH-susceptible elite japonica cultivar with good grain quality, was used as the recurrent parent. ‘Anmi’ was developed by three times backcross the F1 plants with ‘Junam’. The heading date of ‘Anmi’ is August 15 in central plain area, which is 5 days later than that of ‘Hwaseong’. It has 77 cm in culm length, 21 cm in panicle length. The number of spikelets per panicle is more than that of ‘Hwaseong’ and 1,000 grain-weight of brown rice is 22.1 g which is less than 22.7 g of ‘Hwaseong’. Milled rice kernel of ‘Anmi’ is clear in appearance, low in amylase content and excellent in palatability of cooked rice. ‘Anmi’ shows resistance to BPH, leaf blast disease, bacterial blight, rice stripe disease but susceptible to other virus disease and insect pest. The milled rice yield performance of ‘Anmi’ is about 5.76 MT/ha in local adaptability test for three years. This cultivar is adaptable to central plain area of Korea.

Starch and flour from defective rice kernels and their physicochemical properties

The objective of this study was to evaluate the extraction yield and the physicochemical, crystallinity and thermal properties of starch from rice kernels with different types of defects. The defects present in milled rice kernels were separated and classified into five groups: Yellow, Damaged 1, Damaged 2, Red-Streaked and Chalky & Immature. Starch was isolated from the defective kernels, kernels without defects (Non-defective), and original samples (from the industrial electronics selector). The Yellow, Damaged 1 and Chalky & Immature kernels presented higher extraction yield of starch (approximately 66%) as compared to Non-defective kernels (60.1%). The starch from kernels with and without defects differed in pasting properties, indicating that the defects affect the quality of the starch; however, major differences were also observed in the flour. Starches isolated from defective kernels had higher pasting temperatures, peak viscosity and final viscosity than the starches of Non-defective kernels, with the exception of the starch of Red-Streaked kernels, which had a lower peak viscosity and final viscosity and higher breakdown characteristics.

Use of Microscopy To Assess Bran Removal Patterns in Milled Rice

During rice milling, the bran and germ are successively removed from the caryopsis (kernel). Because bran and germ contain large quantities of lipid, the amount of lipid remaining on the kernel surface may be used as a method for the assessment of milling quality. Bulk samples of rice pureline varieties and an experimental hybrid were milled for 0, 10, 20, 30, and 40 s. Scanning electron microscopy (SEM) revealed that brown rice kernels had large contours of linear protuberances and depressions running lengthwise along the kernel surface. The protuberances were abraded successively during milling, but varying amounts of material remained in the depressions. Light microscopy combined with the lipid-specific probes Nile Blue A or Sudan Black B demonstrated that the material in the depressions observed with SEM was lipid. Sections of whole, milled rice kernels, prepared using a modified sectioning technique and stained with Nile Blue A, showed that portions of the embryo remain after milling and that lipid is located on or near the surface of the kernel. Differences in quantity and distribution of residual lipid as milling duration increased were documented photographically to indicate the extent to which the bran and embryo components were removed during milling. This paper provides proof of concept that residual lipid is a robust measure of the degree of milling.

Vitamin fortified rice grain using spraying and soaking methods

The objective of this work was to fortify three types of rice grains (brown, white milled and parboiled) with B complex vitamins (B 1, B 2, B 3, B 5, B 6, B 12), using two different physical treatment methods, (1) soaking of whole dehusked or milled rice kernels in vitamin solutions at 90 °C for 15 min and (2) full spraying of whole kernels with vitamin solution at 35 °C, both followed by oven drying. Various nutrient concentrations were added and the vitamin retention of dried fortified as well as of cooked rice were determined. Fortified rice was evaluated based on vitamin retention, estimated as the percentage of vitamin in rice after fortification treatment versus the total amount of added plus its initially vitamin quantity. It was found that the average retention of all vitamins in dried rice was high and varied from 54.3% to 85.3% for the spraying and from 53.5% to 76.2% for the soaking method respectively. After rice cooking, the retention was maintained in sufficient level (>70%) for all vitamins except for B 12. When excess of water was used for cooking, the water-soluble vitamins were leached; however a significant amount of vitamins still remained, varying from 13.5% (B 12) to 51.2% (B 1). The good retention of vitamins, even after cooking, achieved applying these relatively simple techniques, may be attributed to the absorption and diffusion of vitamins in the interior of rice kernels in high concentrations. Dried fortified rice samples properties were evaluated.

Milled Rice Fissure Formation Kinetics

Milled rice samples at various moisture contents (MCs) were exposed to air inside a chamber that was equipped with a video camera and monitoring system that enabled observation of fissure formation over 24-h exposure durations. The effects of milled rice kernel MC (11%, 12%, 13%, or 14%), cultivar (Bengal, Wells, and CL161), air relative humidity (RH; 10%, 20%, 30%, 45%, 60%, 75%, or 90%), and air temperature (5C, 10C, 15C, 20C, or 30C) on the rate and amount of kernel fissuring were quantified. Rice cultivar and MC played minor roles in determining the rate and amount of fissuring relative to air temperature and RH. Fissuring rates were greatest at low (10%) and high (90%) RH levels; fissuring occurred almost immediately after kernels were exposed to these RH levels. Greater air temperatures considerably increased the rate and total amount of fissured kernels. Little fissuring was observed in an RH range of 30% to 75%, at any air temperature tested, providing a safe window for milled rice exposure to environmental conditions.

MODELING VARIETAL EFFECT ON THE WATER UPTAKE BEHAVIOR OF MILLED RICE (ORYZA SATIVA L.) DURING SOAKING

ABSTRACT Milled rice is soaked until saturation before cooking and other processing. The soaking behavior of the milled rice is affected by varietal factor as well as initial moisture content (M0) of the samples. In the present study, tests were performed for milled whole kernels of 10 rice varieties ranging from low to high amylose content (16–29% d.b.) with three initial moisture levels (approximately 8, 12 and 16% d.b.) for monitoring water uptake in rice kernels during soaking at room temperature (25 ± 1C), in relation to the varietal differences manifested by the physicochemical properties. The water uptake by milled rice kernels took place at a faster rate in the beginning and was followed by a diminishing rate finally leading to a saturated value during soaking. The water uptake of the kernels during soaking could be best expressed by a modified exponential relationship with R2 values ranging from 0.971 to 0.998 for all varieties. The slope of the fitted straight line between actual and estimated moisture contents of milled rice during soaking using a modified exponential relationship was about unity (0.998) with a high R2 value of 0.989 and a root mean square error of 1.2% d.b. The parameters of the fitted model were the function of the M0 and the physicochemical properties of the milled rice. Using developed relationship, the water uptake of the milled rice during soaking could be estimated from its M0 and the physicochemical properties within±10% of the actual values.PRACTICAL APPLICATIONSThis information would be useful for the scientific world working on the soaking characteristics of various varieties of rice, mainly for the modeling of the soaking process. It could also be used as a tool in selecting the rice varieties to meet their desired water uptake properties in relation to their psychochemical properties by rice breeder scientists.

Dimensional changes in milled rice ( Oryza sativa L.) kernel during cooking in relation to its physicochemical properties by image analysis

The present study was aimed to develop model for describing the changes in dimensions of milled whole kernels during cooking in excess water. Samples of ten Thai rice varieties ranging from low to high amylose content (16–29% d.b.) with three initial moisture levels (approximately, 8%, 12% and 16% d.b.) were used to investigate the influence of initial moisture content and variety manifested by the physicochemical properties such as amylose content (AC), alkali spreading value (AS), gel consistency (GC) and protein content (PC) on the kernel dimensional changes. It was found that the kernel initial moisture content did not affect the dimensional changes during cooking. The changes in kernel dimensions during cooking could be best expressed by either an exponential relationship with the R 2 for fitting ranging, respectively, from 0.969 to 0.997, 0.921 to 0.973, 0.936 to 0.997 and 0.968 to 0.995 or by a Peleg model with the R 2 for fitting ranging, respectively, from 0.969 to 0.997, 0.921 to 0.977, 0.937 to 0.997 and 0.968 to 0.995 for kernel length, width, perimeter and projected area for all rice varieties. The regression coefficients of the fitted relationship for describing changes in kernel dimensions during cooking were found to be the function of physicochemical properties, namely, AC, AS and PC of rice varieties and could be estimated within ±5% of actual values. It was observed that the regression coefficients of the power model describing kernel expansions in terms of water absorbed during cooking were the function of the physicochemical properties of the milled rice. It was concluded that the kernel expansions due to water uptake could be estimated from the physicochemical properties, namely, AC and AS during cooking.

Net Isosteric Heats of Adsorption and Desorption for Different Forms of Hybrid Rice

Hygroscopy of hybrid rice affects storage, handling, and processing. The thermodynamic relationship upon which the estimate of isosteric heat is based is the Clausius-Clayperon equation. The net isosteric heat of sorption was determined from the slope of the ln(rh) versus 1/T lines at a constant moisture content. Net isosteric heat of desorption was found higher than that for the adsorption within a moisture content range of 12–20% for all of the rice kernels. The net isosteric heats of desorption and adsorption were higher for hybrid rough rice kernels followed by brown rice and milled rice kernels, respectively. An empirical equation was fitted to describe the net isosteric heats of hybrid rice kernels as a function of moisture content and was found adequate to predict the net isosteric heats. The intercept K was also found to be a function of moisture content and the model predicted the K value well (r2 = 0.85 for adsorption and r2 = 0.92 for desorption). This set of two equations would be useful in the simulation of hybrid rice during storage.

A New Approach to Predicting the Complex Permittivity of Rice

The initial attempts in relation to the present study, i.e., to develop a moisture calibration from the intrinsic dielectric properties of rice and wheat kernels, were unsuccessful. It was observed that the behavior of the loss factor with the variation of moisture content of the samples was less than predictable. The foregoing statement corroborates earlier results. Earlier researchers introduced the term moisture density (product of decimal moisture content and bulk density) and showed that variation in dielectric constant attributable to bulk density variation can be reduced when data are presented in terms of moisture density. The data, however, for the loss factor were not presented. In an attempt to find the moisture dependence of the relative permittivity and loss factor of different cultivars and kinds of rice at 2.45 GHz to produce quadratic and cubic models for the variation of the relative permittivity and loss factor with moisture content and density, a new term, moisture-specific volume (ratio of decimal moisture content to the bulk density), is introduced in the present work. Data are presented in light of this new term and in light of seven equations for the dielectric properties of random media. Further, two equations out of the seven are found to be equivalent. The data for the moisture-specific volume and hence for the moisture content of different samples and the relationships provide the estimates for the relative permittivity and loss factor of rice kernels over almost the entire range of moisture content, without the aid of reference data points. A comparative study of the two proposed models with those of previous researchers is also reported. Results for the two dielectric properties for rough, brown, and white or milled rice kernels of 'Lebonnet' and 'Pecos' cultivars, in terms of moisture-specific volume presented in the form of quadratic and cubic models, are found satisfactory.

Modeling changes in milled rice ( Oryza sativa L.) kernel dimensions during soaking by image analysis

Tests were performed for milled whole kernels of ten Thai rice varieties ranging from low to high amylose content (16–29%) with three initial moisture levels (approximately, 8, 12 and 16% d.b.) for monitoring the dimensional changes in rice kernels during soaking in relation to the varietal differences manifested by the physicochemical properties. It was observed that the two-dimensional shape factor of the milled rice kernel remains constant during whole soaking duration. The change in kernel dimension during soaking could be best expressed by a modified exponential relationship with the R 2 for fitting ranging, respectively, from 0.983–0.999, 0.985–0.999, 0.984–0.999 and 0.985–1.000 for kernel length, width, perimeter and projected area for all rice varieties. The parameters of the fitted relationship for describing changes in kernel dimensions during soaking were found to be the function of initial moisture content and physicochemical properties of rice varieties under study. The dimensional features, namely, length, width, perimeter and projected area of milled rice kernel during soaking could be estimated from its initial moisture content and physicochemical properties such as amylose content, alkali spreading value, and protein content within ±5% of the experimental value.

Small‐Scale Induction of Postharvest Yellowing of Rice Endosperm

ABSTRACTRice endosperm often develop a yellow discoloration during commercial storage in conditions of high temperature and moisture, thereby reducing the value of the grain. This postharvest yellowing (PHY) appears to be coincidental with fungal presence. To study the yellowing process in a controlled manner, we developed a technique to induce PHY on a small, laboratory scale. Milled rice kernels were rinsed with water and incubated in clear test tubes or microfuge tubes at 65–80°C. This allowed direct observation of the color change and measurement using a colorimeter. Every rice cultivar tested (long and medium grain japonicas and indicas) showed some level of PHY, which increased with temperature yielding a maximum color change at 79°C. Most color change occurred within one day. The moisture parameters required for yellowing to occur were measured. Using sterilization and culture techniques, we found no indications of direct fungal involvement in the yellowing process.

EVALUATION OF LABORATORY MILLS FOR MILLING SMALL SAMPLES OF RICE

The International Rice Research Institute (IRRI) Test Tube Mill and the Kett ”Pearlest” Polisher were evaluated in terms of milling performance in comparison with a McGill No. 2 Mill. Degree of milling (DOM), evaluated in terms of percent bran removal (the percentage of weight lost during milling) from brown rice, and whole kernel yield (WKY) were compared using sample lots of medium– and long–grain rice at 12 and 15% m.c. (wet basis). The milling effect of each mill on the shape and size of kernels was compared and analyzed using a Satake image analysis system and a video microscope. Degree of milling and WKY versus milling duration curves were determined for the three mills. The removal of bran as the milling duration increased resulted in a linear reduction of WKY for each mill, although the relationship varied for each mill. The type of mill, moisture content of the samples, and milling duration affected WKY. The type of mill and milling duration affected the shape and dimensions of the milled rice kernels. Overall, the IRRI Test Tube Mill performed better than the Kett Polisher and was comparable to the McGill No. 2 Mill.

Monitoring milling quality of rice by image analysis

Rough rice is milled to produce polished edible grain by first subjecting to dehusking or removal of hulls and then to the removal of brownish outer bran layer known as whitening. The control of whiteness (degree of milling) and percentage of broken kernels in milled rice is required to minimize the economic loss to the millers. Digital image analysis was used to determine the head rice yield (HRY), representing the proportion by weight of milled kernels with three quarters or more of their original length, and the whiteness of milled rice. Ten varieties of Thai rice were subjected to varying degrees of milling by adjusting the test duration from 0.5 to 2.5 min. Three-dimensional features (namely, length, perimeter and projected area) were extracted from the images of individual kernels in a milled sample and used to compute a characteristic dimension ratio (CDR) defined as the ratio of the sum of a particular dimensional feature of all head rice kernels to that of all kernels comprising head and broken rice in the sample. HRY and CDR were found to be related by power functions based on the above-mentioned dimensional features, with R 2 more than 0.99 in all cases. The CDR based on the projected area of kernels in their natural rest position provided the best estimate of the HRY with the lowest root mean square error of 1.1% among all dimensional features studied. In case of the whiteness of milled samples, the values provided by a commercial whiteness meter and the mean of gray level distribution determined by image analysis correlated with an R 2 value of 0.99. The results of this study showed that two-dimensional imaging of milled rice kernels could be used for making quantitative assessment of HRY and degree of milling for on-line monitoring and better control of the rice milling operation.