scholarly journals Extrusion Conditions and Amylose Content Affect Physicochemical Properties of Extrudates Obtained from Brown Rice Grains

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Rolando José González ◽  
Elena Pastor Cavada ◽  
Javier Vioque Peña ◽  
Roberto Luis Torres ◽  
Dardo Mario De Greef ◽  
...  

The utilization of whole grains in food formulations is nowadays recommended. Extrusion cooking allows obtaining precooked cereal products and a wide range of ready-to-eat foods. Two rice varieties having different amylose content (Fortuna 16% and Paso 144, 27%) were extruded using a Brabender single screw extruder. Factorial experimental design was used to study the effects of extrusion temperature (160, 175, and 190°C) and grits moisture content (14%, 16.5%, and 19%) on extrudate properties. Specific mechanical energy consumption (SMEC), radial expansion (E), specific volume (SV), water absorption (WA), and solubility (S) were determined on each extrudate sample. In general, Fortuna variety showed higher values of SMEC andS(703–409 versus 637–407 J/g; 33.0–21.0 versus 20.1–11.0%, resp.) than those of Paso 144; on the contrary SV (8.64–3.47 versus 8.27–4.53 mL/g) and WA tended to be lower (7.7–5.1 versus 8.4–6.6 mL/g). Both varieties showed similar values of expansion rate (3.60–2.18). Physical characteristics depended on extrusion conditions and rice variety used. The degree of cooking reached by Paso rice samples was lower than that obtained for Fortuna. It is suggested that the presence of germ and bran interfered with the cooking process, decreasing friction level and broadening residence time distribution.

Proceedings ◽  
2020 ◽  
Vol 70 (1) ◽  
pp. 101
Author(s):  
Cristiana Pereira ◽  
Regina Menezes ◽  
Vanda Lourenço ◽  
Teresa Serra ◽  
Carla Brites

Rice consumed as white cooked polished grain has been considered a high glycemic index (GI) food, particularly compared with other starchy foods. However, the GI levels of rice based food can vary among different rice types and food processing technologies. Rice GI variation can be affected by several factors, such as rice variety, the genetic background of rice as well as due to crop edaphoclimatic conditions. The main difference in rice starch composition that influences GI is the amylose content. Besides the chemical composition of rice, the gelatinization characteristics and food processing can also contribute to starch retrogradation, thus increasing the level of resistant starch with a great influence on GI. To understand the glycemic response of rice types differing in amylose and viscosity profiles, four rice samples were analyzed and compared with standard and resistant HI-MAIZE corn starches. An in vitro enzymatic starch hydrolysis procedure was applied to estimate GI. The results indicate substantial differences in the starch hydrolysis of the two corn starches. Starch hydrolysis tended to be more rapid and efficient for ‘Waxy’ and ‘Ceres’ (intermediate-amylose) rice types than for ‘Maçarico’ (high-amylose rice). In addition, the data show that the Maçarico variety has the lowest estimated GI and the highest retrogradation rate compared with ‘Waxy’, ‘Ceres’ and ‘Basmati’ type. The results obtained reinforce the importance of knowing amylose content and viscosity profiles for the prediction of rice glycemic responses.


2017 ◽  
Vol 2 (3) ◽  
pp. 24
Author(s):  
Nazeer El-Bialee ◽  
AbdelGawad Mohammed Saad ◽  
Mohamed Ibrahim El-Didamony ◽  
Gamal Zahran

Gluten free products remain the cornerstone for celiac patients. Insufficiency, poverty and little offered about gluten free products (quality and quantity) represented a high obstacle for Egyptian celiac patients. Therefore, the purpose of this research is to modify a single screw extruder to produce gluten–free pasta (GFP) (tagliatelle type). The GFP was made from corn flour under screw rotation speed (N) of 10, 25 and 50 rpm at 40, 65, 90 and 115 ºC of barrel temperature (BT). Extruder performance was evaluated as specific mechanical energy (SME) and expansion ratio (Er). The cooking quality of GFP as optimum cooking time (OCT), cooked yield (CY), swelling (Sw), cooking losses (CL) and sensory characteristics (appearance, colour, taste, mouth feel and overall acceptability) were evaluated. The better results of the GFP sensory evaluation were obtained at BT= 80 ºC, N =25 rpm and Er ≈ 1.38 with OCT ≈ 3.3 min, CY= 196%, Sw = 210% and CL= 16.3%. All parameters were given a direct proportion with processing variables N and BT, except CL. Furthermore, it can be predicted cooking properties values for GFP by SME value using the following equation; SME » 1.8675 (Er) + 0.8037 » 0.0608 (OCT)1.5984  » 8×10-17 (CY)6.7878 » 2×10-9 (Sw)3.494  » -0.0306 (CL) + 0.7877.


2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Thuy Linh Nguyen ◽  
Khanh Son Trinh

Five Vietnamese rice varieties, which differ in their basic chemical composition (starch content, amylose content, fiber content) including polished rices and whole grain rices, were chosen for this study. High-fat diet-induced obesity, using these rice, was subjected to in vivo experiments to evaluate the effects of body weight gain, caloric intake, postprandial blood glucose level (PBGL), and glycemic index (GI) in tested mice groups. PBGL peaks appeared at 30th minute after eating, and GI of each experimental group was ranked in order as GN > TL > HR > GM > L Đ and GN > LT > HR > L Đ >   GM , respectively, in which, brown rice (LĐ) and germinated brown rice (GM) had low GI. Furthermore, these rice varieties caused the lowest LDL cholesterol and the ratio of LDL/HDL cholesterols in mice. In this study, the higher the amylose and fiber contents were, the lower glycemic index, triglycerides, LDL, and LDL/HDL values were. The golden flower glutinous rice (GN), with low amylose and fiber content, gave worse blood lipid parameters than that of GM and LĐ. Histopathological studies of white adipose and liver tissues showed that LĐ and GM significantly reduced the symptoms of obesity and fatty liver compared with the others, especially compared to GN. The results obtained from this study help patients with overweight, obesity, and type 2 diabetes choose the right rice variety for their daily diet to be able to control their diseases.


2016 ◽  
Vol 6 (8) ◽  
pp. 506 ◽  
Author(s):  
Madan Kumar Chapagai ◽  
Nordiana Abu Bakar ◽  
Rohana Abdul Jalil ◽  
Wan Abdul Manan Wan Muda ◽  
Taewee Karrila ◽  
...  

Background: The prevalence of diabetes has increased dramatically in recent decades in the regions where people excessively consume white rice. In spite of the higher nutritional values and bioactive components, only the low to medium glycaemic index (GI) brown rice could be of interests as an alternative to white rice in these regions.  Methods: Five varieties, Chiang (CH), Sungyod (SY), Lepnok (LP) from Thailand and Long grain specialty 1 (LS1) and Long grain specialty 2 (LS2)  from Malaysia were tested for GI. Ten test foods were prepared from 5 varieties by 2 cooking techniques (pressure cooker, PC and rice cooker, RC). Overnight fasted healthy subjects were fed with 25 g glucose as a reference food (RF) on 3 occasions and amount equivalent to 25 g available carbohydrate portion of test food (TF) on 1 occasion in separate days. Fasting and post-prandial capillary blood glucose was measured via finger-prick methods at 0, 15, 30, 45, 60, 90 and 120 min, and the incremental area under curve (iAUC) was determined. The GI of each TF was calculated as percentage of incremental area under curve (iAUC) of TF over RF.Results: The mean GI values of SY (72 – 81, high), CH and LP (59 – 65, medium) and LS1 and LS2 (64 – 73, medium to high) were found due to cooking by PC and RC methods. The GI did not vary significantly (p>0.05) among varieties as well as between cooking methods. GI showed a significant negative correlation with the amylose content (r = –0.70, p<0.05) and significant positive correlation with cold peak viscosity (r = 0.80, p<0.01).Conclusions: All five varieties by either cooking methods are classified as medium to high GI. Medium GI varieties could have potential of being used in diabetic diet. Cooking methods did not significantly alter the glycaemic characteristics of the studied varieties. Amylose content and pasting properties can be used for predicting GI of brown rice. It is urgent to explore low GI brown rice varieties in these regions.    


2017 ◽  
Vol 33 (4) ◽  
pp. 479-489 ◽  
Author(s):  
Shadrack K. Amponsah ◽  
Ahmad Addo ◽  
Komla A. Dzisi ◽  
Jean Moreira ◽  
Sali A. Ndindeng

Abstract. Performance of a Sifang mini rice combine, originally developed in China, was evaluated under local farmer field conditions in Benin. Results from field evaluation show that the combine worked satisfactorily on less dense rice fields with minimal weeds at grain moisture contents between 19.1% and 20.1% w.b. on soils with moisture content from 23% to 33% d.b. while causing no significant changes to soil physical properties. With harvesting speed ranging from 0.8 to 4.5 km/h, the harvester had a field capacity of 0.10 to 0.39 ha/h and consumed fuel of up to 11 L/ha while having track slip of 6% to 9%. Harvesting using 2- and 1-L gear offered the best efficiency for IR841 and Nerica L20 rice varieties, respectively. As harvesting speed increased, harvesting efficiency decreased and crop throughput increased irrespective of rice variety. The combine produced low mechanical grain damage with total grain loss ranging from 1.43% to 4.43% and 1.85% to 5.6% for the IR841 and Nerica L20 rice varieties, respectively. At an investment cost of US$5000 and hiring at US$10 per h, owning the mini combine harvester becomes profitable after 342 h of machine use; equivalent to approximately 133 ha of paddy field harvested at a harvesting capacity of 0.39 ha/h. Further testing of the combine under a wide range of crop and soil conditions across different agro-ecological zones and economic comparison with manual harvesting is recommended. This would offer smallholder farmers diverse options of rice harvesting mechanization to facilitate future adoption of improved technologies. Keywords: Crop throughput, Field capacity, Field efficiency, Grain loss, Mini rice combine, Sifang.


2016 ◽  
Vol 20 (2) ◽  
pp. 125-131 ◽  
Author(s):  
Magdalena Kręcisz

AbstractThe objective of the paper was to determine the impact of the rotational screw speed and the level of moisture of raw material on the efficiency and energy consumption of the extrusion-cooking process. Measurement of the extrusion-cooking process efficiency (Q) was carried out through determination of the extrudates mass and energy consumption was determined with the use of a specific mechanical energy (SME). Based on the research results it was found out that the factor which significantly decides on the measured values was a rotational screw speed. Along with the increase of this parameter the energy consumption and extrusion-cooking process efficiency increased during processing of corn grits. Extrusion-cooking process efficiency depended also on the level of moisture of raw material. At lower moisture of raw material the efficiency decreased along with the increase of the screw speed and above 18% of the moisture level it increased. Reverse relation was reported during testing the energy consumption of the extrusion-cooking process.


2020 ◽  
Vol 45 (3) ◽  
pp. 53-69
Author(s):  
Temidayo Omoniyi ◽  
Dare Adesanya

This study was carried out to design, fabricate, assemble and evaluate the performance of a laboratory scale wood-plastic composite (WPC) single screw extruder that can be used for recycling wood and plastic waste materials using locally sourced materials based on availability, strength and cost effectiveness. The extruder is separated into four units; the feeding, conveying, heating and forming unit. The designed parts were; the hopper capacity, the shaft diameter, the screw dimensions (pitch, helix angle and diameter), and the capacity on the conveyor (feed throats, compression and metering units) units. The developed machine was evaluated by using it in extruding low density plastic wastes and gmelina (Gmelina arborea) sawdust. The results showed a hopper capacity of 38.3m3, shaft diameter of 60mm, screw dimensions (diameter=20mm, pitch=50mm, and helix angle = 17.650 ). The performance evaluation of the machine indicated an efficiency of 85% for the machine at an operating speed of 268rpm (4.5rps) with a throughput of 17.55kg/hr during a maximum period of 5 minutes. The mean water absorption (0.45-13.68%) and thickness swelling (0.14 - 0.94%) observed for the composites produced compared favorably with those reported in literature for WPCs recommended for non-structural indoor application purposes. The wood contents and soaking period had effects on the sorption properties and not the effectiveness or ineffectiveness of the machine. The machine conserves cost and energy due to low specific mechanical energy consumption of 191.21kJ/kg.


2021 ◽  
pp. 1-8
Author(s):  
Md. Abdul Kader ◽  
A. K. M. Shalahuddin ◽  
Tapas Kumer Hore ◽  
Ratna Rani Majumder ◽  
Md. Ehsanul Haq ◽  
...  

Recently released zinc enriched, high yielding, medium slender grain containing rice variety BRRI dhan100, appropriate for irrigated ecosystem of Bangladesh is an improvement over existing zinc enriched rice varieties for Bangladesh. The variety has satisfactorily passed the Proposed Variety Trial (PVT) conducted in the farmers’ field in Boro 2019-20 season. As a result National Seed Board (NSB) approved this variety for commercial cultivation in the Boro season (dry season) in 2021. It has modern plant type with 101 cm plant height and matures by 148 days. The proposed variety showed 1.20 t/ha higher yield than check variety BRRI dhan84. Identifying characters of this variety are green leaf, intermediate plant height, erect flag leaf, medium slender grain, intermediate leaf senescence grain. It can produce 7.7 - 8.8 t/ha grain yield. Thousand grain weight of the variety is 16.7 gm and head rice yield is 64%. The rice has zinc content 25.7 mg/kg, 26.8% amylose content with 7.8% protein content. The zinc enriched BRRI dhan100 is a superb variety for cultivating in the Boro season (dry) and farmers can be economically benefited and the country will be nutritionally benefited by the cultivation of BRRI dhan100.


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