Cooked Rice Research Articles

Reducing starch digestibility of white rice by structuring with hydrocolloids

Controlling starch digestion in high glycaemic index staple foods such as white rice is of interest as it has been associated with reduced risk for conditions such as obesity and type-2 diabetes mellitus. Addition of hydrocolloids has been proposed to reduce the rate of post-prandial glucose by controlling the rate of starch hydrolysis. In this work, the potential of a range of hydrocolloids to modify starch digestibility when added (at 1 % maximum concentration) during cooking of white rice was first investigated. Low acyl gellan gum (LAG) showed the highest potential (in-vitro estimated Glycaemic Index reduced by about 20 %, from 94 in the control to 78 in the LAG rice) and was investigated further. While the grains of rice control and rice with LAG appeared similar, SEM images revealed a gel-like layer (a few micrometers in thickness) on the surface of the treated samples. Addition of LAG appeared to also have an effect on the breakdown of a simulated cm-sized bolus. During gastric digestion, bolus breakdown of the rice control was completed after 30 min, while the rice LAG bolus appeared intact after 1 h of observation. This was attributed to strengthening of the LAG gel in the acidic environment of the stomach. During intestinal digestion, rice samples containing 1 % LAG appeared to be less susceptible to breakdown when seen under a microscope and in environmental SEM, while they showed larger rice particle aggregates, compared to rice control. Overall, LAG showed potential to control starch digestion kinetics of white rice with a mechanism that may involve formation of a protective layer on the rice grains (um) that reduces bolus break down (cm) and enzymatic hydrolysis (nm). Outcomes of this work will be used to identify conditions for further relevant in-vitro and in-vivo investigations.

Impact of cooking, parboiling and fermentation on nutritional components, predicted glycemic index and pasting properties of rice

The impacts of different methods of rice grain processing like cooking, parboiling and fermentation on various bioactive components, antioxidant activity, predicted glycemic index (pGI), resistant starch (RS) along with pasting properties in three rice cultivars were investigated. Results showed that processing significantly increased the DPPH and FRAP antioxidant activity, soluble sugars (TSS), Phenolics, flavonoids and zinc (Zn) content, while protein, amylose, iron (Fe) content and ABTS antioxidant activity decreased as compared to raw unprocessed rice. Percent decrease of these components was minimum in case of parboiling as compared to raw rice. The percent increase of TSS was highest in raw fermented rice while lowest in parboiled fermented rice. Scanning electron micrograph of grain showed that cultivar CR Dhan 310 contains higher amount of protein bodies and after parboiling it increased marginally. The processing significantly decreased the pasting viscosity as compared to raw rice. The average pGI value of parboiled cooked rice(PCR) was lowest while raw fermented(FR) was highest. PCR of Naveen showed highest RS(2.7%) content whereas fermented rice of Manipuri black showed lowest value (0.31%). This finding will help rice consumers to select appropriate processed rice for getting maximum value addition in terms of nutritional quality.

Evaluation of Cooked Rice for Eating Quality and Its Components in Geng Rice.

At present, ''eating well" is increasingly desired by people instead of merely ''being full". Rice provides the majority of daily caloric needs for half of the global human population. However, eating quality is difficult to objectively evaluate in rice breeding programs. This study was carried out to objectively quantify and predict eating quality in Geng rice. First, eating quality and its components were identified by trained panels. Analysis of variance and broad-sense heritability showed that variation among varieties was significant for all traits except hardness. Among them, viscosity, taste, and appearance were significantly correlated with eating quality. We established an image acquisition and processing system to quantify cooked rice appearance and optimized the process of measuring cooked rice viscosity with a texture analyzer. The results show that yellow areas of the images were significantly correlated with appearance, and adhesiveness was significantly correlated with viscosity. Based on these results, multiple regression analysis was used to predict eating quality: eating quality = 0.37 × adhesiveness - 0.71 × yellow area + 0.89 × taste - 0.34, R2 = 0.85. The correlation coefficient between the predicted and actual values was 0.86. We anticipate that this predictive model will be useful in future breeding programs for high-eating-quality rice.

Improving rice eating and cooking quality by enhancing endogenous expression of a nitrogen-dependent floral regulator.

Improving rice eating and cooking quality (ECQ) is one of the primary tasks in rice production to meet the rising demands of consumers. However, improving grain ECQ without compromising yield faces a great challenge under varied nitrogen (N) supplies. Here, we report the approach to upgrade rice ECQ by native promoter-controlled high expression of a key N-dependent floral and circadian clock regulator Nhd1. The amplification of endogenous Nhd1 abundance alters rice heading date but does not affect the entire length of growth duration, N use efficiency and grain yield under both low and sufficient N conditions. Enhanced expression of Nhd1 reduces amylose content, pasting temperature and protein content while increasing gel consistence in grains. Metabolome and transcriptome analyses revealed that increased expression of Nhd1 mainly regulates the metabolism of carbohydrates and amino acids in the grain filling stage. Moreover, expression level of Nhd1 shows a positive relationship with grain ECQ in some local main cultivars. Thus, intensifying endogenous abundance of Nhd1 is a promising strategy to upgrade grain ECQ in rice production.

Cooking, sensory and in-vitro digestibility characteristics of rice as affected by rice-water ratio and karaya gum concentration

Cooked rice has high starch digestibility. Prolonged and excess consumption of polished rice has been associated with the incidence of diabetes amongst rice eating populations. Therefore, researchers are working on extensively to devise strategies that could retard digestion of cooked rice. Keeping this fact into consideration, four rice cultivars (SR-4, K-39, Mushq Budij and Zhag) grown in Kashmir were milled and cooked with varying concentrations (0, 2.5 and 5.0% w/w, rice basis) of karaya gum at different rice-water ratios (1:10 and 1:1.8). The prepared rice samples were evaluated for cooking and sensory properties, in-vitro digestibility and structural characteristics. Cooking of rice with karaya gum (2.5–5.0%) at large rice-water ratio (1:10) increased minimum cooking time (19.0–25.0 min) and water uptake ratio (3.23–4.69) of samples. Also, rice cooked in excess water had better sensory acceptability scores than those cooked in less water. At large rice-water ratio, Zhag rice prepared with karaya gum (2.5%) had acceptable hardness and flavour scores. With increase in gum concentration, the equilibrium starch hydrolysis percentage (C∞) and estimated glycemic index (eGI) scores of cooked rice decreased, irrespective of cultivars and rice-water ratio. Maximum reduction in C∞ was observed for Mushq Budij rice (85.20%) prepared with karaya gum (5.0%) at large rice-water ratio (1:10). Fourier transform infrared spectra of gum cooked rice samples revealed shifting of peak at 3250.0 cm−1 to higher intensities indicating hydrogen bonding interaction of starch and gum. From X-ray diffraction studies, the highest relative crystallinity (16.20%) was observed for rice prepared with 5.0% gum concentration. Therefore, cooking of rice with karaya gum at large rice–water ratio can be considered to slow down starch hydrolysis process of cooked rice.

The Effects of Genotype × Environment on Physicochemical and Sensory Properties and Differences of Volatile Organic Compounds of Three Rice Types (Oryza sativa L.).

Understanding the effects of genotype, environment and their interactions on rice quality is of great importance for rice breeding and cultivation. In this study, six rice varieties with two indica, two japonica and two indica-japonica types of rice were selected and planted at ten locations in Zhejiang Province to investigate the genotype (G) × environment (E) on physicochemical and sensory properties and the differences of volatile organic compounds (VOCs) among the three types of rice. Analysis of variances showed that apparent amylose content (AC), total protein content (PC), alkali spreading value (ASV), RVA profiles, and appearance (ACR), palatability (PCR), and sensory evaluation value (SEV) of cooked rice and texture of cooled cooked rice (TCCR) were mainly affected by genotypic variation, whereas the smell of cooked rice (SCR) was mainly affected by environment (p < 0.05). The G × E effect was significant for most parameters. The weather in the middle and late periods of filling had important effects on the formation of rice quality, especially on setback (SB) and pasting temperature (PT) (p < 0.01). They were negatively correlated with the texture of cooked rice (TCR) and SEV (p < 0.05). Peak viscosity (PV) and breakdown (BD) were positively related to the sensory evaluation parameters (p < 0.01) and could be used to predict cooked rice quality. A total of 59 VOCs were detected, and indica, japonica and indica-japonica had 9, 6 and 19 characteristic compounds, respectively. The principal component analysis showed that the physicochemical and sensory properties and VOCs of indica-japonica rice were more stable than those of indica and japonica rice at ten locations in Zhejiang Province. It is helpful for rice breeders to understand how the environment affects the physicochemical, sensory properties and VOCs of the three rice types, and it is also important for food enterprises to provide rice products with stable quality.

Characteristics of Vinegar from Black Sticky Rice Tapai with Different Cooking Methods

This study aims to (i) determine differences in the cooking method of steaming and cooking method of boiling on the characteristics of vinegar from black sticky rice tapai, (ii) to determine the antioxidant and anthocyanin activity of vinegar from black sticky rice tapai using the steaming method and cooking method of boiling, (iii), to determine the cooking technique that produces the best product based on organoleptic testing and also to find out the results of consumer acceptance tests on vinegar from the best black sticky rice tapai with commercial products. The treatment in this study was the black sticky rice cooking technique by steaming and boiling. The data obtained were analyzed using paired t-test. The results showed that the use of the steaming method and the boiling method had a significant effect (P&lt;0.05) on several characteristics of the vinegar produced from black sticky rice tapai, such as acetic acid content, alcohol content, sugar content, anthocyanin content, pH, and antioxidant activity. The total anthocyanins produced in vinegar from black sticky rice tapai using the steaming method were 20.22% and 20.14% for the boiling method, and the antioxidant activity of vinegar from black sticky rice tapai using the steaming method was 92.52% and 92.11% for the boiling method. Based on the organoleptic test, the best product obtained from the highest average preference of panelists for vinegar from black sticky rice tapai was the boiling method with parameters of color, aroma, and taste. Furthermore, in the consumer acceptance test, vinegar from black sticky rice tapai had a higher average preference value compared to commercial products with each parameter, such as color (4.04), aroma (3.92), and taste (3.88).&#x0D; &#x0D;

Decreased In Incremental Interstitial Fluid Glucose Peak After Consumption Of Rice Cooked With Low-Carbohydrate Rice Cooker Compared To Conventional Rice Cooker In Lean And Obese Adult Population

The rapid rise in glucose levels is closely related to increased free radicals and oxidative stress which are directly linked with the aging process. Carbohydrate is one of the food components which has a major impact on prandial glucose fluctuations, in addition, rice is one of the staple carbohydrates consumed in Indonesia. In recent years, low-carbohydrate rice cookers claim to be able to reduce carbohydrate content in rice. However, there are currently no in vivo study in Indonesia whether the use of these devices has an impact on reducing prandial incremental glucose peak. The aim of this study was to determine whether the consumption of rice cooked with low-carbohydrate rice cooker can provide decreased in incremental interstitial fluid glucose peak (IIFGP) compared to conventional rice cooker. This study used a quasi-experimental method to identify differences in prandial IIFGP when using a low-carbohydrate rice cooker. IIFGP was calculated from subtracting the peak with baseline interstitial fluid glucose (IFG) value during 120-minute time. There are a total of 16 participants consisting of 8 lean and 8 obese participants. The participants were paired with Freestyle Libre Continuous Glucose Monitoring for prandial glucose evaluation. Each participant will consume rice from a conventional and low-carbohydrate rice cooker on different days at the same hour and will be fasted 8-12 hours prior to the procedure. A comparison of the glucose responses from different rice cookers was carried out on the same participant. On the first procedure day, the participants were given 250 g of rice from a conventional rice cooker, afterwards the prandial glucose response was recorded for 2 hours in 5 minutes interval. On the following day, participants were given 250 g of rice from a low-carbohydrate rice cooker, then the prandial glucose response was recorded in similar manner, subsequent comparison between the two glucose responses was made. This study found differences in the IIFGP from conventional rice cooker 70.4 ± 21.0 mg/dL and low carbohydrates 60.3 ± 17.8 mg/dL, p = 0.005. Subgroup analysis of lean participants showed that there was a difference in the IIFGP between rice from a conventional rice cooker 66.6 ± 8.56 mg/dL and low-carbohydrate rice cooker 61.6 ± 9.9 mg/dL, p = 0.022. Obese participants also showed differences in IIFGP, conventional rice cooker 74.2 ± 29.0 mg/dL and low-carbohydrate rice cooker 58.9 ± 24.1 mg/dL, p = 0.029. There was also a moderate correlation between the waist to height ratio and the peak value of IFG from rice cooked with conventional rice cooker r = 0.551, p = 0.027. Low-carbohydrate rice cooker was able to improve prandial glucose response by reducing the carbohydrate component from cooked rice. Taken together, we concluded that there is a decrease in IIFGP after consumption of rice cooked with low-carbohydrate rice cooker compared to a conventional rice cooker.

Cocción de arroz: eficiencia energética, valor nutricional y metales pesados

El arroz es uno de los cereales más producidos y consumidos en el mundo, debido a su aporte calórico a la dieta de los seres humanos. El componente principal del arroz es el almidón, pero también es una fuente importante de minerales, fibras y vitaminas. El arroz puede contener también niveles importantes de metales tóxicos. Existen varios métodos utilizados para la cocción del arroz a nivel doméstico, siendo los más comunes el arroz hervido, la cocción en olla arrocera eléctrica, cocción a presión y cocción en microondas. Se evaluó la eficiencia energética de los métodos hallando que la cocción en olla arrocera eléctrica logró un ahorro del 35 – 40 % en comparación con el método por microondas y el tradicional. La cocción óhmica resultó ser la más rápida, con un tiempo de 5 – 7,5 minutos. Este cereal sufre procesos previos a su consumo, los que pueden afectar el contenido de los compuestos mencionados. El lavado del grano genera una reducción del contenido de minerales esenciales y tóxicos, así como de vitaminas B1 y B2 y de ácido fítico. El remojo no generó cambios significativos en el contenido de vitamina B2, minerales y ácido fítico. La cocción por microondas provocó una menor disminución de vitaminas y ácido fítico que la cocción a altas presiones. La cocción con remojo previo provoca no solo la disminución de metales pesados, sino también de minerales esenciales. Por último, otros autores estudiaron el efecto del tiempo y temperatura de cocción con el fin de analizar la variabilidad de las fracciones digeribles del almidón de arroz. Encontraron que, al aumentar la temperatura de 50 a 90°C, la fracción de almidón de digestión rápida se incrementa.

Use of monosodium glutamate as alternative to reduce sodium in cooking affects the physicochemical, phytochemical, and sensory attributes of pigmented and non-pigmented rice

The increased consumption of processed foods makes diets more susceptible to high levels of sodium chloride (NaCl) and foods of low nutritional value. With this, the objective was to evaluate the influence of different contents of sodium chloride (NaCl) and monosodium glutamate (MSG) during the cooking of brown, black, and red rice, in order to reduce the concentration of NaCl in the rice preparation, since it toward public health concern. Replacing NaCl with 100% MSG in the preparation of pigmented and non-pigmented cooked rice resulted in reduced cooking time (up to 25.44%), rice hardness (up to 24.32%) and improved free phenolics. In addition, black rice showed an 8.60% increase in anthocyanins, while in red rice 55% of proanthocyanidins remained after cooking with 100% MSG. On the other hand, an increase in the content of leached compounds during cooking was mainly represented by amylose, proteins and proanthocyanidins. Regarding sensory attributes, MSG improved the appearance and texture, increasing the acceptability of cooked brown, black and red rice.

Exploring influencing factors of consumers’ wasted household appliances disposal behavior considering product heterogeneity in China

E-waste has become the fastest-growing waste stream worldwide. China is the highest producer of e-waste in Asia and faces severe e-waste recycling challenges. To analyse the influencing factors of consumers regarding different e-waste disposal types, this study conducted an empirical analysis using a questionnaire survey, chi-square test, and multiple correspondence analysis. A questionnaire was designed, and 1152 valid questionnaires were collected through pre-investigation and distribution. Descriptive statistics were administered for the household appliances (rice cookers, storage-type electric water heaters, and range hoods), the processing behaviour of the respondents, and material flow. The differences in the different types of e-waste disposal behaviours were tested through a chi-square test and multiple correspondence analysis. The empirical results showed (i) significant differences in consumers’ disposal behaviours of different types of household waste appliances, (ii) a heterogeneous correlation between consumers’ disposal behaviour of household appliances and socioeconomic variables, and (iii) regional differences in the disposal behaviour of different types of household waste appliances. Storage-type electric water heaters were repaired in rural areas and in cities were recycled, and rice cookers were recycled in rural areas and discarded in cities. The results emphasise the necessity for formal recycling companies to adopt different incentive policies for different types of household waste appliances to encourage consumers to actively participate in formal recycling.

Effects of SeNPs Fertilizer on Se and Microelement Contents, Eating and Cooking Qualities, and Volatile Organic Compounds in Rice Grains

Foliar application of selenium (Se) fertilizer has been widely used in the production of Se-rich rice. However, the effect of Se-nanoparticles (SeNPs) fertilizer on rice quality remains largely unknown. Two bioSeNPs fertilizers were applied at different Se concentrations to explore the effect of the foliar application of SeNPs fertilizer on various rice grain qualities. The results showed that Se treatments resulted in 1.93–9.09 and 1.89–7.73 folds of total Se contents in brown and polished rice relative to the CK, respectively. Moreover, the Se treatments led to 1.04–2.33 folds increases in Cd contents, 14.6–26.4% decreases in As contents, a 13.9–16.7% reduction in Cr contents and no changes in Pb contents to that of the CK in rice grains. In addition, SeNPs exhibited no obvious impact on rice eating and cooking quality, and only the XY1 treatment could slightly improve the fatty acid content. Interestingly, Se treatments enhanced the contents of more than half of volatile organic compounds in brown rice. In general, SeNPs fertilizer XY at 6.4 g/ha was identified as the optimum choice for improvement in grain Se contents and grain qualities.

Effect of cooking methods on volatile compounds and texture properties in rice porridge

Rice porridge is known to be pleasant flavor and health-beneficial. This study investigated the effect of cooking time and methods on the flavor and texture of rice porridge. The volatile compounds of rice porridge were extracted using headspace-solid phase micro extraction and analyzed by gas chromatography-mass spectrometry. A total of 110 volatiles were detected in rice porridge. Except for esters, most other volatile compounds decreased with cooking time. The major volatiles, aldehydes, and esters have a relatively high content in electric rice cooker (IC). The flavor of rice porridge shifted from grass to ester with cooking time. Multiple chemometrics revealed that volatile compounds with different cooking methods were scattered separately. Texture analysis revealed that rice porridge prepared in the electric pressure cooker (EPC) had a more significant decrease trend in hardness than electromagnetic oven (EC) and IC before 40 min. In vitro starch digestibility analysis, regardless of treatments, the rice porridge was mainly composed of fast digestible starch. The amount of fast digestible starch showed an increasing trend over time. To summarize, different cooking methods had a more significant influence on the volatile compounds than cooking time, while the texture is opposite. This study can guide rice porridge production.

Optimization of Process Parameters for Quick Cooking Rice

Optimization of Process Parameters for Quick Cooking Rice

Registration of ‘PVL02’ rice

Abstract‘PVL02’ (Reg. no. CV‐158, PI 691607), a Provisia (BASF) long‐grain rice (Oryza sativa L.) cultivar, was developed by the Louisiana State University Agricultural Center at the H. Rouse Caffey Rice Research Station near Crowley, LA, and approved for release in 2019. PVL02 is the second rice cultivar released as part of the Provisia Rice System with resistance to Provisia herbicide, containing the active ingredient quizalofop‐p‐ethyl, an AACase (Group 1) herbicide. PVL02 was derived from the cross ‘Cheniere’/BASF1‐5 and advanced as an F2:3 row based on agronomic characteristics. Testing in the Provisia preliminary yield trial in 2014 and the Provisia multi‐location test in 2015 indicated good yield potential and favorable agronomic characteristics. In 2016, 2017, and 2018, PVL02 was evaluated in 26 replicated trials across seven locations in Louisiana. Four high‐yielding commercial cultivars were included as checks: ‘Jupiter’, ‘CL153’, ‘Cheniere’, and ‘PVL01’. The grain yield of PVL02 was 8.2 t ha−1 compared with 9.2 t ha−1 for Jupiter, 8.6 t ha−1 for CL153, 8.5 t ha−1 for Cheniere, and 7.6 t ha−1 for PVL01. PVL02 was taller than the checks. The milled grain length was shorter than typical long grains, with a length‐to‐width ratio of 2.81. It has a typical US long‐grain rice cooking quality with intermediate amylose and gel temperature. PVL02 is moderately susceptible to sheath blight, Cercospora spp., and leaf blast and susceptible to bacterial panicle blight.

Glycemic Index of Rice by Several Processing Methods

Background: In diabetes mellitus patients, one of the efforts to control normal blood glucose levels is to eat low glycemic index foods. Rice is an Indonesian staple food that contains carbohydrates. Several methods of processing could affect the glycemic index of rice. Objectives: To analyze the glycemic index of rice processed by several methods. Methods: The design used was quasi-experimental. A total of ten people with criteria of healthy, aged 19-29 years, having normal body mass index and blood glucose levels were used in this study. Subjects were given five treatments. Treatment: 1) was given glucose as a reference, 2) was given rice that was traditionally processed and just cooked, 3) was given rice that was traditionally processed and had been stored at room temperature (25°C) for 12 hours, 4) was given rice that was electronically processed and just cooked, and 5) was given rice that was processed in a modern way and had been stored for 12 hours in magic com at hot temperature. Among the treatments, there was a gap of 7 days. Results: Traditionally processed rice has a glycemic index of 21.6, increasing to 24.7 after being stored at room temperature for 12 hours. Meanwhile, processed electronic rice has a glycemic index of 22.9 and increases to 36,4 after being stored in a rice cooker (hot temperature) for 12 hours. Conclusions: The four rice groups processed by various methods had low glycemic index values. Rice stored for 12 hours had a higher glycemic index value than freshly cooked rice.

Influence of cooking and texture attributes of far infrared radiated Japonica rice during storage

The impact of ceramic far infrared radiation drying (IRD) pretreatment method on cooking and texture properties based on stabilization of rice protein throughout the storage (8 months) of rough japonica rice was determined. Kinetic analysis showed that IRD significantly reduced the production of carbonyl compounds and free sulfhydryl groups by oxidation of byproducts. This may because of IRD prevented the transformation of ordered secondary structures into disordered, with a 3.3% and 6.6% increase in the content of α-helix and β-fold and the exposed hydrophobic area is reduced. During 8 months of storage at 35 °C, water uptake ratio and volume expansion ratio are 13.5% and 74.3% lower than that of air drying. Therefore, IRD can slow down protein oxidation of stored rice and promote the water absorption ability, expansion of rice kernel during gelatinization, and improve rice cooking quality and texture characteristics.

Reduction effects of isoprothiolane during rice washing and cooking

Reduction effects of isoprothiolane during rice washing and cooking

Arsenic speciation as well as toxic and nutrient elements in pantavat (overnight steeped rice)

This study assessed the effect of soaking on the retention and removal of arsenic (As) along with other toxic elements and nutrients in three types of soaked rice or overnight steeped rice (pantavat), as this food dish was highlighted on the Australian MasterChef program in 2021 as a popular recipe. Results showed that brown rice contained twice as much As as basmati and kalijira rice. Cooking with As-free tap water using a rice cooker removed up to 30% of As from basmati rice. Around 21–29% removal of total As was observed in soaked basmati, brown, and kalijira rice. However, while 13% of inorganic As was removed from basmati and brown rice, no changes were noted in the kalijira rice. Regarding nutrient elements, both cooking and soaking rice caused significant enrichment of calcium (Ca) whereas potassium (K), molybdenum (Mo) and selenium (Se) were reduced substantially for the tested rice varieties. The nutrients like magnesium (Mg), iron (Fe), sulfur (S) and phosphorus (P) did not significantly change. The results indicated that soaking can minimize up to 30% As and soaked rice reduced few nutrients like K, Mo and Se. Data in this study highlights the retention and/or loss of toxic and beneficial nutrient elements in pantavat when As-free water is used to prepare this food.

A natural blue colorant from butterfly pea (Clitoria ternatea) petals for traditional rice cooking.

The online version contains supplementary material available at 10.1007/s13197-023-05752-w.