Raw Milled Rice Research Articles

Exploring Rice Consumption Habits and Determinants of Choice, Aiming for the Development and Promotion of Rice Products with a Low Glycaemic Index.

Current consumption drivers, particularly those related to health and wellbeing, have been influencing trends for the lower consumption of cereals, particularly rice, due to their typical high glycaemic index (GIs) and consequent impacts on obesity. To satisfy this consumer concern, more food innovations that promote healthy eating habits are required. Such innovations must be consumer-oriented to succeed, understanding the dynamics of consumer habits and responding to consumer expectations. This study explored these habits, from acquisition to consumption practices, and the expectations of the European market from the perspective of the major European consumer, Portugal, to obtain insights that support the development of low glycaemic index (GI) rice products. A mixed-methods approach was applied. For the first quantitative questionnaire, 256 Portuguese rice consumers aged 18-73 years were recruited. Twenty-four individuals were selected according to their gender and rice consumption profiles for in-depth interviews. The results confirmed that rice was the main side dish for the participants and was mainly consumed at home, cooked from raw milled rice. The drivers of consumption differ according to the provisioning process stage. In the acquisition stage, participants reported benefits from the rice's dynamic market by comparing products on price, brand, and rice types. In the preparation stage, participants reported the adequacy of the recipe and occasion, while in the consumption stage, participants enhanced their sensory preferences, depending on the rice dish. Although the GI concept was unknown to half of the participants, it was perceived as interesting and positive for healthy eating. Consumers showed concern about the taste and naturalness of the product, preferring it to be as close to a homemade dish as possible. The negative perceptions we verified were interpreted to be due to a lack of knowledge about the GI concept. Therefore, awareness actions and informative campaigns are recommended to promote low-GI rice products.

Physicochemical properties and molecular mechanisms of different resistant starch subtypes in rice.

Resistant starch (RS) can help prevent diabetes and decrease calorie intake and that from plants are the main source of mankind consumption. Rice is many people's staple food and that with higher RS will help health management. A significantly positive correlation exists between apparent amylose content (AAC) of rice and its RS content. In this study, 72 accessions with moderate or high AAC were selected to explore the regulatory mechanisms and physicochemical properties on different proceeding types of rice RS. RS in raw milled rice (RSm), hot cooked rice (RSc), and retrogradation rice (RSr) showed a wide variation and distinct controlling mechanisms. They were co-regulated by Waxy (Wx), soluble starch synthase (SS) IIb and SSI. Besides that, RSm was also regulated by SSIIa and SSIVb, RSc by granule-bound starch synthase (GBSS) II and RSr by GBSSII and Pullulanase (PUL). Moreover, Wx had significant interactions with SSIIa, SSI, SSIIb and SSIVb on RSm, but only the dominant interactions with SSIIb and SSI on RSc and RSr. Wx was the key factor for the formation of RS, especially the RSc and RSr. The genes had the highest expression at 17 days after flowering and were beneficial for RS formation. The longer the chain length of starch, the higher the RS3 content. RSc and RSr were likely to be contained in medium-size starch granules. The findings favor understanding the biosynthesis of different subtypes of RS.

Evaluation of Nutritional and Nutraceutical Content of Polished and Unpolished Barnyard Millet - An Analytical Study

Barnyard millet (Echinochloa frumentacaea) is an indigenous under utilized millet variety of south India with bounty of health benefits due to the abundance of dietary fiber antioxidant and minerals like iron. This gluten free wonder millet can be a healthy alternate dietary source for diabetic, obesity and CVD patients. Scientific evidence based studies on nutritional quality of this millet both in polished and unpolished form is less. The current study aims at “Evaluation of nutritional and nutraceutical content of polished and unpolished barnyard millet”. Both polished and unpolished barnyard millets were procured from local market, cleaned to remove dirt, dust and stone. The cleaned millets were dried powdered and sieved using 60 mesh sieves (250 Micron). The powdered millet flour was stored in airtight container. Nutritional content of Barnyard millet was analysed for macro, micro nutrients and nutraceutical properties of both polished and unpolished form using standard AOAC method - 20th edition (2016). The analysed nutrient content were compared statistically at 99% and 95 % confidence interval (t-test).The result shows that, the quantum of carbohydrate present in polished barnyard millet was 11.37 % lesser than the milled parboiled rice and 9 % lesser than the brown rice and 12.45 % lesser than the raw milled rice. The total dietary fibre content of unpolished barnyard millet was 14.2 gm and polished barnyard millet was 8.5 gm. Crude fibre content of unpolished barnyard millet was noted as 11.2 gm and the same in polished barnyard millet was 4.5gm. The protein content of unpolished barnyard millet (10.4gm) was found to be superior to polished barnyard millet (6.8gm).The presence of nutraceutical components were more nutritionally superior in unpolished barnyard millet compared to polished one.

Nutrients and nutraceutical content of polished and unpolished kodo millet – a quantitative analysis

Kodo millet (Paspalum scrobiculatum) is an ethnic underutilized millet variety of south India with bounty of health benefits due to the abundance of dietary fiber antioxidant and minerals like iron. This gluten free wonder millet can be a healthy alternate dietary source for diabetic, obesity and CVD patients. Scientific evidence based studies on nutritional quality of this millet both in polished and unpolished form is less. The current study aims at “Analyzing the quantum of nutrients and nutraceutical present in polished and unpolished Kodo Millet”. Both polished and unpolished Kodo millets were procured from local market, cleaned to remove dirt, dust and stone. The cleaned millets were dried powdered and sieved using 60 mesh sieves (250 Micron) . The powdered millet flour was stored in airtight container. Nutritional content of Kodo millet was analysed for macro, micro nutrients and nutraceutical content of both polished and unpolished form using standard AOAC method - 20th edition (2016). The analysed nutrient content were compared statistically at 99% and 95 % confidence interval (t-test). The result shows that, the quantum of carbohydrate present in polished kodo millet was 10.53 % lesser than the milled parboiled rice and 8.1 % lesser than the brown rice and 11.61 % lesser than the raw milled rice. The total dietary fibre content of unpolished kodo millet was 12.98 gm, this value was almost double the amount of total dietary fibre present in samai (7.72 gm). Crude fibre content of unpolished kodo millet was noted as 7.66 gm – which is more than seven times the crude fibre content of raw and parboiled rice (0.2 gm) and more than six times the crude fibre content of whole wheat (1.2gm) respectively as per Nutritive value of Indian food.

Variation of resistant starch content in different processing types and their starch granules properties in rice

Ninety-nine lines from recombinant inbred lines were selected to investigate the effects of starch synthesis-related genes on resistant starch (RS) content in different proceeding types. RS in raw milled rice (RSm), hot cooked rice (RSc), and retrogradation rice (RSr) showed a wide variation among the lines, especially RSm arrived at 10.61%. Divergent variability of RSm, RSc and RSr indicated that there were different regulation mechanisms for them. Waxy wildtype allele (Wxa) could elevate RSm, RSc and RSr, but Soluble starch synthase IIa (SSIIa) only played a vital role in regulating RSm. Wxa-indica SSIIa could increase RSm, and Wxa-japonica SSIIa (SSIIaj) could elevate RSc and RSr. The mean diameter of Wxa-SSIIaj was significantly bigger than others. The bigger starch granules, the higher RSc and RSr. Starch granules morphology with high-RSm would have a higher percentage in polyhedral and angular shape. The results provide new information for rice breeding with high-RS content.

Product development with the enrichment of fenugreek seeds for celiac disease (CD)

Celiac disease (CD) is an autoimmune disorder in which the inability to digest cereals protein gluten. Patients may suffer from malabsorption diarrhea, abdominal pain, anemia, osteoporosis, and failure to thrive. Either CD is a genetic disorder but diet could play an important role to control from pathogenic symptoms. The susceptible person's slow growth rate, it also affects the productive life and also produces low immunity. The present study aimed to develop a gluten-free diet for celiac disease and analyses the acceptability by hedonic rating scale at 9 point scale, like extremely to dislike extremely. The study has done with the enrichment of fenugreek seeds to the preparation of fermented food Idli for celiac patients. Idli batter is prepared by soaking raw milled rice and decorticated black gram for 4 hour at 30 ± 1 °C in water. The soaked mass was ground using a mixer grinder with adequate amount of water. Fenugreek seeds contain protein, with the mixing of other pulses the quality of proteins enhances. Fenugreek seeds also contain mucilaginous fiber which is good for health promotion growth, improves immunity.

Evaluation of sensory, physicochemical properties and Consumer preference of black rice and their products.

This study was aimed to evaluate the physicochemical, textural, sensory and antioxidative attributes of various rice products such as boiled rice, beaten rice, popped rice, puffed rice and raw milled rice, prepared from the Indian black rice cultivars Chakha (CH), Kalobhat (KB), Mamihunger (MA) and Manipuri Black (MN). A popular white rice variety Swarna Sub-1 (SW) was considered as control. Significant differences in most of the physicochemical and cooking parameters of raw rice were observed across different cultivars. The head rice recovery, amylose content, elongation ratio (ER) and kernel length after cooking of MA were most satisfactory among the black rice cultivars and are found to be 50.67%, 17.6%, 1.87 and 10.10mm respectively, while popped rice of MA recorded highest length (10.83mm) and elongation ratio (ER; 2.01). MA showed the highest adhesiveness (11.18mJ) in boiled rice but hardness (183.53N) was medium in raw rice. Other textural quality varied differentially according to the various products and cultivars. The highest a* value was obtained from puffed rice of MA (6.61) but L value was highest in raw rice of MN. Popped and boiled rice of MA displayed higher DPPH-antioxidant activity (88.74% and 84.74% respectively) as compared to all other products. The raw rice of KB registered higher anthocyanin (57.23mg/100g) content while boiled rice of SW recorded the least (0.21mg/100g). A survey on the consumer preference of these products indicated that boiled rice was usually preferred in lunch and dinner by most of the consumers whiles other products in breakfast. With respect to most of the traits, MA showed the good potential for rice Industry as well as for breeding material.

Status in physical properties of coloured rice varieties before and after inducing retro-gradation.

Three varieties of paddy in brown, red (non-waxy) and black (waxy) forms were de-husked and milled before and after inducing retro-gradation and their physical properties were studied. Normalized grain weight, porosity of parboiled paddy (PP) and its de-husked rice (DR), were high compared to their respective native. True and bulk density were lowest for black variety, its DR, its raw and parboiled forms compared to other varieties of paddy. Angle of repose increased from raw paddy to PP whereas it decreased from raw DR to parboiled DR. Under similar conditions of milling of DR, raw and parboiled milled rice of black variety was the darkest. Raw husk showed higher EMC compared to husk of parboiled. Hardness followed the pattern: Raw: Paddy (~230-280N) > DR (~120-260N) > Milled rice (~110N); for parboiled: DR (~270-480N) > PP (~260-425N) > Parboiled milled rice (~250-340N). Cooking time was high for DR of parboiled ones and least for waxy raw milled rice. Results of this study will be helpful in understanding the quality of pigmented rice cultivars, design and fabrication of some of the equipments in rice processing industry.

Determination of quality characteristics of indigenous organic Asian Indian rice variety -Neelam Samba

Organic farming is a production system that avoids or largely excludes the use of synthetically produced agricultural inputs like fertilizers, pesticides, growth regulators, live stock feed additives etc. Besides, the economic value of rice is largely determined by the milling quality of the rice varieties. Increasingly, consumers are also interested to get rice which possesses good cooking and eating qualities. In view of the health benefits of organic crops and the quality demands of the consumers, the present study was under. The results of this study highlighted that Neelam samba had acceptable physical, nutritional, cooking, and milling qualities. It was also observed that parboiled milling procedure yields better quality rice than raw milled rice.

찰벼 품종을 이용한 파보일드미의 물리·호화특성

This study analyzed the physical and pasting properties of parboiled rice using glutinous rice cultivars. The Sinseonchal cultivar of japonica and the Tongil–type Hangangchal showed the highest and the lowest hardness, respectively, after parboiling treatment and increased in hardness 1.6 to 3.8 times over that of raw milled rice. The solid contents in the parboiled rice of all cultivars were lower than those of raw milled rice. Hwaseonchal showed the highest water binding capacity and increased after parboiling by 1.9 to 5.3 times. The Colormetric L value decreased after parboiling and it tended to darken compared to raw milled rice. The solubility and swelling power of raw milled rice were higher when treated at 75C than when treated at the normal temperature of 25C. Parboiling increased swelling power but decreased solubility. As for amylogram characteristics, the pasting temperature was in a range of 62.1 to 69.4C and there was no significant difference among all the cultivars except Tongil–type Hanganchal. For the paste viscosity properties of parboiled rice, the peak viscosity increased and setback decreased when compared to that of raw milled rice in all cultivars except Hangangchal. Especially, setback viscosity showed a negative value which seems to be the result of the slow retrogradation of cooked parboiled rice. In the case of X-ray diffraction, raw milled and parboiled rice showed the same pattern A and the relative crystallinity of flour particles showed a decrease by 9-30%, which verified the result that a part of the crystalline regions’ structure was disintegrated.

Effects of Simultaneous Parboiling and Drying by Infrared Radiation Heating on Parboiled Rice Quality

An infrared (IR) radiation heating and vibrating apparatus was used to study a simultaneous parboiling and drying process. Physicochemical properties such as milling yield, color, and pasting properties of parboiled paddy were evaluated. Radiation intensity levels of 46.7 kW/m2, variable exposure time, and rice samples at fixed initial moisture contents (IMC) of 30 and 32% wet basis (wb) were used. It was discovered that the radiation intensity of 46.7 kW/m2 and 32% wb moisture content yielded a quality level similar to that of conventional steam-parboiled rice. The head rice yield (HRY) of IR paddy slightly decreased with increased exposure time. The HRY of IR heating was more than 60% compared to HRY values of 67.68 to 69.34% for conventional steam-parboiled rice. The b-values of 23 to 25 for IR samples showed lighter yellowness than the 29.7 b-value of conventional steam-parboiled rice. The pasting properties of all IR samples showed lower viscosity compared to the raw-milled rice samples but higher than conventional steam-parboiled rice. Initial moisture content of paddy affected the degree of starch gelatinization (SG) by differential scanning calorimetry (DSC). Under IR heating for 18 min of exposure time, the 32% wb IMC sample showed SG at 80.15% compared to SG at 59.02% with the 30% wb IMC sample. Hence, while employing simultaneous parboiling and drying with IR heating for an exposure time of 18 min, the sample retained more parboiled flavor as a result of a higher degree of starch gelatinization. The sample showed lower HRY, but yellowness was within the acceptable range. Energy requirement for producing 1 ton of parboiled paddy by the IR heating process is lower than the conventional steam-parboiled process but statistically nonsignificant (P > 0.05). However, the process time was reduced to one third of the conventional process, leading to improved quality. In addition, initial investment cost was minimal because a steam generator was not required.

Preparation, digestibility, and glucose response in mice of rice coated with resistant starch type 4 using locust bean gum and agar

SummaryThis study investigated the technical feasibility of coating type 4 resistant starch (RS4) onto rice with the edible polymers locust bean gum (LBG) and agar. The coating solutions were prepared using LBG, agar, and a mixture of LBG and agar at three concentrations (0.01%, 0.1% and 1%). The raw milled rice was soaked in the prepared coating solutions, rolled in RS4 powder and dried. Microscopic observation revealed that the RS4 coating on the rice surface with 0.1% and 1% LBG–agar mixture had a resistance to washing and cooking and covered the whole surface of the rice with good adherence. The thickness of the RS4 coating on the rice surface with 0.1% and 1% LBG–agar mixture was approximately 74 and 233 μm, respectively. Compared with uncoated rice and rice mixed with RS4, the RS4‐coated rice showed lower starch digestibility, a decreased glucose response and a slower rate of blood glucose decrease.

Effect of processing paddy on digestibility of rice starch by in vitro studies.

Paddy (Oryza sativa L) (variety 'IR - 64'), was parboiled, puffed by sand roasting and flaked by edge runner and roller flaker and variations in physical and physicochemical properties were studied. Moisture contents were lower (5.8-10.8%) in processed rice products compared to raw materials (11.8%). Ratio of rice to sand in the case of puffed rice preparation was optimized. The equilibrium moisture content was 27.4% in raw rice while it was much higher (38.9-81.0%) in processed rice. Sedimentation volume was lowest (6.2 ml) in raw rice and highest (18.8 ml) in popped rice. Starch content was 84.8 and 76.5-83% in raw and processed rice, respectively. In vitro starch digestibility was highest in roller flaker flakes and lowest in raw milled rice. Among the ready to eat products, popped rice showed least starch digestibility (∼30%).

Effect of amylose content and rice type on dynamic viscoelasticity of a composite rice starch gel

Amylose content is an important indicator to determine the utility of raw milled rice. Indica type rice with high amylose content is usually used for manufacturing rice noodles, while Japonica rice may be mixed partially to adjust the noodle texture. The effect of amylose and rice type on dynamic viscoelasticity of rice starch gel was investigated using a model starch composite in this study. The information will be helpful to control and obtain the required noodle texture by combination of different rice types. The results show that nonwaxy Indica and waxy Japonica rice starches in a composite mixture were incompatible and demonstrated their individual gelatinization behavior during heating. High amylose starch showed higher moduli and lower loss tangent values, as well as higher retrogradation rate. The starch gel made from Japonica rice starch showed a slow retrogradation rate even containing a similar amount of amylose to Indica starch. The storage modulus of the gel made from higher amylose rice was shown to be more independent of frequency. Not only amylose content but also chain length distribution in amylopectin affected the dynamic viscoelasticity of rice gel. Japonica rice starch, with fewer super-long chains in amylopectin, retrograded slower after gelatinization than Indica rice, thus the paste is too sticky for production of rice noodles.

Effect of fermentation metabolites on rheological and sensory properties of fermented rice noodles

AbstractBACKGROUND: Considering the effect of natural fermentation on the textural improvement of fermented rice noodles in China and South Asia, and given the lack of reports concerning the roles of fermentation metabolites (enzymes, organic acids, glucose and maltose), this study aims to determine fermentation metabolites produced during fermentation of raw milled rice grains, and investigate their effects on rheological and sensory properties of rice noodles.RESULTS: α‐Amylase activity was correlated with reducing sugar content significantly in the supernatant during fermentation process (r = 0.76, P < 0.05). Lactic acid was the dominant organic acid produced by fermentation. Protein and lipid content decreased significantly by fermentation. Treating the rice grains with trypsin, lipase or lactic acid could modify the rheological characteristics and improve the sensory properties of rice noodles. Removal of protein and lipid by physical extraction confirmed the results. The residue of glucose and maltose in rice flour weakened the noodle texture.CONCLUSIONS: Fermentation of raw milled rice decreased protein and lipid content, increased the purity of rice starch, and thus improved the texture of fermented rice noodles. The low molecule weight sugars produced during fermentation should be removed for their negative effect on texture. Copyright © 2008 Society of Chemical Industry

Validação e aplicação de metodologia analítica na determinação de nutrientes inorgânicos em arroz polido

Um método de digestão parcial de arroz polido cru (Oryza sativa), para a determinação de nutrientes inorgânicos (Ca, Cu, Fe, K, Mg, Mn, Na, P e Zn) por espectrometria de emissão óptica com plasma de argônio indutivamente acoplado, foi validado. Baseado na hidrólise com HCl, o método é simples e relativamente rápido, e apresentou características satisfatórias de desempenho. Através deste método, prepararam-se 40 amostras de arroz polido cru comercializadas no Estado de São Paulo (Brasil). Depois de determinação por espectrometria de emissão, os teores médios (em mg.100 g-1 de arroz) e desvios-padrão obtidos para Ca, Cu, Fe, K, Mg, Mn, Na, P e Zn foram, respectivamente, 4,31 ± 0,44; 0,22 ± 0,10; 0,32 ± 0,08; 58,0 ± 15,0; 26,1 ± 5,7; 1,06 ± 0,26; 1,78 ± 0,55; 92,1 ± 15,2; 1,24 ± 0,18. Comparando-se estes teores com informações de 7 tabelas de composição de alimentos, observaram-se discrepâncias principalmente para Ca, Fe, Na e K. Os resultados foram ainda usados para estimar a contribuição do consumo de arroz na Ingestão Diária Recomendada (IDR) de Ca, Cu, Fe, Mg, Mn, P e Zn. Verificou-se que o arroz pode contribuir significativamente, principalmente nas recomendações das IDRs do Mn, do Cu e do Zn, especialmente se for considerado o consumo médio diário per capita de arroz no Brasil.

Starch Properties of Mutant Rice High in Resistant Starch

As the staple food of over half the world's population, hot cooked rice high in resistant starch (RS) is of particular interest, which will have greater impact in the dietary prevention of diabetes and hyperlipidemia. A mutant rice high in RS in hot cooked rice, described as RS111, was comparatively studied with the wild type and common rice. Despite obviously low RS content in the raw milled rice, the RS content in the hot cooked rice of mutant RS111 was significantly higher than that of the wild type and common rice and, correspondingly, in vitro starch hydrolysis by porcine pancreatic alpha-amylase tends to be incomplete with low hydrolysis extent for the cooked mutant rice high in RS. Obvious differences in physicochemical properties, starch granule morphology, pasting properties, thermal properties, and X-ray diffraction pattern were observed among the mutant RS111, wild type, and common indica rice. The high-RS mutant was characterized by significantly higher apparent amylose content and crude lipid content, higher percentage of oval-shaped granules and bigger oval size, reduced paste viscosity, and low onset temperature, peak temperature, final temperature, enthalpy of gelatinization, and crystallinity.

Edible coating materials—their properties and use in the fortification of rice with folic acid

This study investigated the technical feasibility of adding folic acid on to rice and coating with edible polymers. The coating solutions were cast into film and their properties were investigated. A concentrated premix of rice was prepared in a rotating coating pan by spraying first with folic acid solution, and then with polymer solutions and drying. The fortified rice premixes were evaluated for washing and cooking losses. The loss of folic acid in washing was lowest in rice premixes coated with ethyl cellulose followed by pectin, composite mixtures of locust bean and other coating materials with highest loss in gum arabic coated rice. No edible polymer could satisfactorily retain folic acid during boiling in excess water. Edible polymers failed to mask the yellow color of folic acid and additional masking agent was needed. The premixes had a higher water uptake ratio than raw milled rice had. Triangle tests did not show any significant difference ( α=0.05) between the sensory qualities of cooked fortified rice and raw milled rice.

Effect of Aging on the Quality of Glutinous Rice Crackers

ABSTRACTThe experiment was conducted to study the effects of aging on the physicochemical properties of two Thai cultivars of milled glutinous rice (RD6 and RD8). The amylose and protein content of rice samples did not change when stored from 0 to 4 months. Amylograph curves from samples of milled rice stored from 0 to 8 months were analyzed. Both cultivars gave constant gelatinization temperature during aging. The values for peak viscosity, final viscosity on cooking at 94°C, viscosity on cooling to 50°C and breakdown decreased significantly for RD6 cultivar, whereas the setback value and consistency were not changed significantly. For RD8 cultivar, no significant difference was observed for viscosity on cooling to 50°C and consistency during aging up to 8 months. Peak viscosity and breakdown value were reduced during storage, whereas the final viscosity on cooking at 94°C and setback value increased with time. Raw milled rice of both RD6 and RD8 cultivars have similar water uptake rates. Stored rice tended to have a lower water uptake rate which increased proportionately with soaking time. Samples from both rice cultivars were used to make rice crackers to study the effects of aging on quality. Volume expansion of rice crackers made from RD6 and RD8 cultivars tended to decrease during storage which resulted in an increase in the hardness of the crackers.

Occurrence of aflatoxins in parboiled rice in Sri Lanka

In Sri Lanka, rice is the main staple which is mostly processed into parboiled rice. The levels of aflatoxin B1 (AFB1) and aflatoxin G1 (AFG1) in parboiled and raw milled rice collected from major rice producing areas and rice consuming townships were estimated. In almost all the samples of parboiled rice examined, the AFB1 and AFG1 contents were significantly higher than in raw milled rice. The highest AFB1 content was 185 micrograms/kg and AFG1 content 963 micrograms/kg. These samples were collected from a major rice producing/milling district where the mean relative humidity is 78% and mean annual temperature 27 degrees C which is the highest amongst the rice growing areas in Sri Lanka. Raw rice was either free of aflatoxins or when toxins were detected, they occurred in less than 10% of the samples. The frequency of occurrence of surface fungal flora (Aspergillus/Penicillium) and aflatoxin content in market samples was closely related. Brownish or greenish moldly rice samples with fermented odour contained over 1000 micrograms/kg of AFB1.