Studies on preparation,popping and functional properties of bulgur wheat

Wheat was steeped to 36% moisture and agitated for 2 min in sand heated to 170 °C. This dry heat bulgur was comparable to bulgur prepared by steam treatment. The dry heat bulgur of 14% moisture content was popped in hot (230 °C) sand medium. The expansion ratio of popped bulgur was 2.1. Some of the functional properties of popped bulgur flour were compared with native, 48 h malted and roller dried wheat flours. Water absorption index was highest for roller dried followed by popped and malted wheat, whereas water solubility index was highest for malted followed by roller dried and popped wheat. Roller dried wheat exhibited higher cold paste viscosity (360 BU) than popped (30 BU) wheat. Popped wheat had a peak viscosity of 300 BU. The viscogram of malted wheat was typical of cereal flours when the enzyme activity of malt was inhibited. The gel permeation chromatograms of popped and roller dried wheat indicated thermal degradation of starch during popping and roller drying. The in vitro carbohydrate digestibility of popped wheat was higher than roller dried and malted samples. The scanning electron microscopic examination of native and popped bulgur revealed that the endosperm of bulgur wheat was a homogenous mass containing gelatinized starch whereas that of popped bulgur was made up of thin layers of popped starch with irregular air spaces.     

Development and nutritional quality evaluation of weaning foods based on malted, popped and roller dried wheat and chickpea

Optimal conditions for malting wheat and chickpea for preparation of weaning foods were standardized and malted flours from 48 h germinated wheat and 24 h germinated chickpea were blended to prepare malted weaning food. Wheat was dry-heat-parboiled (bulgurized), popped in hot sand and blended with popped chickpea flour to prepare popped weaning food. Mildly toasted and debranned wheat and dehusked chickpea flours were mixed and the blend was roller-dried for preparation of roller dried weaning food. the formulations had 60% wheat, 30% chickpea, 5% skim milk powder and 5% sucrose and contained about 16% protein. the cooked paste viscosity (dietary bulk) of malted food, popped food with malt, and roller dried food with malt was significantly lower than popped and roller dried foods at all comparable slurry concentrations. the energy density of malted and malt-added food slurries at spoon feeding consistency was 4.2 KJg⁻¹. PER (2.91), biological value (88.3) and true digestibility (87.5) values of malted food were higher than that of the other formulations.     

Changes in carbohydrates, proteins and lipids of finger millet after hydrothermal processing

Finger millet was soaked, steamed and dried to prepare hydrothermally processed millet, followed by decortication to prepare decorticated millet. The physicochemical properties and carbohydrate, protein and lipid profiles of control and processed millet were determined. The carbohydrates were fractionated to amlypectin and amylose equivalent fractions using gel permeation chromatography. The non-starch polysaccharides were isolated and their alditol acetyl derivatives were characterized by gas chromatography (GC). The proteins were extracted using different solvents and the total proteins were fractionated using SDS-PAGE. The ether extractable lipids were esterified and fractionated through GC. Hydrothermal processing decreased the amylopectin fraction and increased the amylose equivalent portion of the starch. Decortication further lowered the first fraction and increased the second fraction. A decrease in cold, hot water soluble and hemicellulose-B fractions and an increase in pectic polysaccharides, hemicellulose-A and cellulosic fractions were observed as a result of hydrothermal processing. Decortication significantly reduced the total non-starch polysaccharides specifically the cellulose fraction. Hydrothermal processing decreased the overall extractability of proteins by 50% but decortication increased it to 80%. It was observed that hydrothermal treatment did not change the gross nutrients composition of finger millet but for their profile. Decortication of hydrothermally processed millet caused significant changes in the nutrient contents and also in their profiles.     

Effects of processing methods on amaranth starch digestibility and predicted glycemic index

Amaranth has attracted a great deal of interest in recent decades due to its valuable nutritional, functional, and agricultural characteristics. Amaranth seeds can be cooked, popped, roasted, flaked, or extruded for consumption. This study compared the in vitro starch digestibility of processed amaranth seeds to that of white bread. Raw seeds yielded rapidly digestible starch content (RDS) of 30.7% db and predicted glycemic index (pGI) of 87.2, the lowest among the studied products. Cooked, extruded, and popped amaranth seeds had starch digestibility similar to that of white bread (92.4, 91.2, and 101.3, respectively), while flaked and roasted seeds generated a slightly increased glycemic response (106.0 and 105.8, respectively). Cooking and extrusion did not alter the RDS contents of the seeds. No significant differences were observed among popped, flaked, and roasted RDS contents (38.0%, 46.3%, and 42.9%, respectively), which were all lower than RDS content of bread (51.1%). Amaranth seed is a high glycemic food most likely because of its small starch granule size, low resistant starch content (< 1%), and tendency to completely lose its crystalline and granular starch structure during those heat treatments.     

Changes in physico‐chemical and rheological properties of rice during flaking

Hydration, solubility, pasting and rheological properties of roasted‐parboiled rice and flakes were examined in comparison to raw rice. There was an increase in the hydration capacity, swelling power and solubility during roasting‐parboiling of rice as a result of gelatinization of its starch. Flaking caused further increase due to damage of starch by application of mechanical force. The changes were higher in flakes from roller‐flaker as compared to those from edge‐runner. Pasting characteristics of flour slurries in Rapid Visco Analyzer showed a typical profile for pregelatinized products viz. a higher initial viscosity but a lower peak viscosity for roasted‐parboiled rice and flaked rice than for raw rice. The viscosity curves and flow curves of the products over a wide range of shear rate indicated a non‐Newtonian, pseudoplastic behaviour for all the samples. All samples showed typical hysteresis loop in their viscosity curves indicating their thixotropic nature. Flakes from roller‐flaker exhibited lower viscosity but more thixotrophy indicating higher starch breakdown in them than in edge‐runner flakes, which seemed to have more of heat damaged starch.     

Optimization of Process Parameters for Decortication of Finger Millet Through Response Surface Methodology

Decorticated finger millet is prepared by hardening the endosperm by hydrothermal processing and polishing the processed grains. The yield of the decorticated grains is of paramount importance in the millet industry. Milling yield depends on the grain moisture content and incipient moisture conditioning during milling. It was found that steaming conditions such as steaming time and steam pressure significantly influenced the milling yield. Hence, studies were undertaken to determine the influence of moisture and steaming conditions on the yield of decorticated millet. Steaming conditions were optimized through response surface methodology. The responses studied were hardness, milling yield, porosity and water uptake of hydrothermally processed millet. The studies indicated that hydrothermally processed millet with 16±1% moisture content, tempered with 5% added water at I stage and 4% water in the II stage milling, resulted in a yield of 64.6%. The relationship of milling yield, hardness and porosity of the millet was quadratic with the severity of steaming conditions, while water uptake of the steamed millet exhibited a linear relationship. Based on the regression analysis, optimum conditions estimated for steaming time and pressure were 17.5 min and 313.8 kPa, respectively. At this condition, the milling yield, water uptake, porosity and hardness values were also predicted and the values were 68.33 g/100 g, 63.43 g/100 g, 52.23% and 204.01 N, respectively. The studies indicate that steaming the millet at elevated pressure and temperature increases the milling yield and steaming beyond the threshold level has a detrimental effect on the yield of head grains.     

Effects of Germination of Wheat,Oats, and Pearl Millet on Alpha-Amylase Activity and Starch Degradation

Hard red winter wheat, oats, and pearl millet were germinated at 15°C for periods up to 14 days. Endosperm areas in kernels fractured with a razor blade and starches isolated from the malted flours were examined with a scanning electron microscope to determine the morphology of starch granules and the nature of α-amylolytic attack on granules. Free sugars content, damaged starch content, and α-amylase activity of the flours were determined to establish relationships between physical changes in the cereal grains and formation of α-amylase during germination. Starch granules in the three cereals were degraded during germination by α-amylase accompanied by production of free sugars and increases in the damaged starch of flours milled from the germinated grains. The cementing material embedding starch granules in endosperms of wheat and oats decreased and disappeared during germination; these changes were not obvious in germinated millet endosperm. Amorphous-appearing material seemed to cover starch granules in the endosperm of wheat and oats during later stages of germination, but were not observed in the isolated starch granules. Although wheat starch granules had the highest α-amylase activity, this enzymic degradation was less than expected. Enzymic attack was evidenced as channels or pits on the surfaces of wheat and millet starch granules. Compound oat starch granules were relatively resistant to enzymic attack and no evidence of erosion of the granule surface was observed; small granula were released from the compound granules during germination. The most extensive degradation was obtained with millet starch, appearing as discrete holes leading to the interior of the granule. Concentric shells were visible in the interior of wheat and millet starch granules, but were not observed in oat starch granules.     

Effect of Popping on the Properties of Some Millet Starches

Starches were isolated from popped bajra (Pearl millet), ragi (Finger millet) and Navane (Foxtail millet). Popping resulted in complete loss of birefringence characteristics of starch granules, increased solubility in DMSO, low cold paste and setback viscosity and lower relative viscosity in KOH. Popped starches in comparison to native starches exhibited higher susceptibility to in vitro enzymatic digestibility.     

Physical evaluation of popped cereal snacks with spent hen meat

Various blends of spent hen meat and grains (potato starch, corn starch, and rice flour) were popped using a popping machine. Lowest bulk density was observed in the snack with 1:2 ratio of meat and potato starch. Except for the popped snack with meat and rice flour, as the starch content increased, bulk density decreased gradually. Popped snacks with grains only were higher in L* value than those with meat and grains. The a* and b* values increased with increasing meat content. All popped snacks were significantly different (P<0.001) in bulk density, color, and breaking force. As the grain content of snacks increased, the size of the air cells also increased. Results of scanning electron microscopic and optical microscopic observations revealed the popping degree of snack with starch and spent hen meat was affected by the presence of meat. The optimum ratios of meat to grain for high expansion ratio were determined to be 1:2 and 1:3 of meat to corn starch and potato starch.     

RHEOLOGICAL AND HYDRATION PROPERTIES OF POPPED RICE

The cold-slurry viscosity, sediment volume and hydration power of popped rice, along with those of dry-heat parboiled rice and expanded rice for comparison, were determined. Values of all these properties increased with increasing severity of processing treatment but decreased with starch reassociation. The cold slurries of these products showed time-dependent thinning, indicating thixotropic nature. A yield value appeared beyond a certain minimum concentration. The viscosities of the products, their hydration power and sediment volume were all interrelated. The popped rice was well gelatinized with little or no starch reassociation.     

Popping of amaranth grain (Amaranthus caudatus) and its effect on the functional,nutritional and sensory properties

The popping of amarunth grain (Amaranthus caudatus var INIAP‐Alegría) by hot air processing was studied. A household corn popper adapted to control heating and airflow was used. The effects of temperature, load, airflow and moisture on the popping capacity and on the functional properties, nutritional quality, crude protein content, lysine content and sensory texture of the poppei grain were investigate. The yield, expansion volume and density of popped grain showed that the optimal conditions for the popping process were 240 °C, 22 g load, 0.013 m³ s^?1 airflow and 12% grain moisture. The proportion of popped grain with butterfly shape was highest (p < 0.05) at 220 °C, 22 g load, 0.014 m³ s^?1 airflow and 14% grain moisture. The functional and physic‐chemical properties of popped grain obtained by various treatments showed completely gelatinised starch. The total, available and resistant starch contents were similar among the different treatments. The enzymatic degradation of starch was 65% within 5–15 min of incubation with α‐amylase. The crude protein content was almost 15% for all the treatments, while the total lysine content was 45.2–48.0 mg g^?1 protein. The in vitro availability of protein of popped grain obtained at 0.013 m³ s^?1 airflow and 14% grain moisture was above 84%. The highest available lysine value was found for popped grain obtained at 0.014 m³ s^?1 airflow, 18–22 g load and 12–14% grain moisture. However, six of the eight treatments had available lysine contents that varied between 41.2 and 47.4 mg g^?1 protein. Sensory analyses showed that the treatments with the highest popping capacity produced grains with high crunch and expansion capacities. © 2002 Society of Chemical Industry     

山西谷子全粉淀粉指标间相关性及消化特性研究

本文主要研究了77个山西谷子全粉样品中淀粉组分的相关性以及淀粉消化特性。分别测定了谷子金粉中淀粉、直链淀粉和抗性淀粉(RS)含量。制备谷子淀粉并分析了淀粉中快速消化淀粉(RDS)、慢速消化淀粉(SDS)、RS的含量以及淀粉消化指数(SDI)和持续消化淀粉(LS)。结果表明:各品种间RS含量差异性较大;全谷物以及制备得到的淀粉所测定的备指标间相关性较强。其中。谷子中RS与直链淀粉相关性最强(r=0.885),对谷子中RS聚类分析后发现。RS与直链淀粉近似呈线性相关(r=0.954)。对谷子淀粉体外消化研究表明:黄谷(2010)等品种中SDS舍量较高,晋谷21号(2010)等品种中RS含量较高,而陇谷10号(2012)等品种中LS含量相对较高,这些品种适用于糖尿病等人群食用或有助于开发相关降糖产品。     

Influence of depigmentation of pearl millet (Pennisetum gluacum L.) on sensory attributes, nutrient composition and in vitro digestibility of biscuits

Presence of high concentration of pigments in the pericarp and endosperm regions of pearl millet imparts undesirable gray color to its products. This study attempts to improve the acceptability of pearl millet products through processing technique and to study its effect on nutritional composition of pearl millet product. Pearl millet grains were depigmented by soaking in 0.2 N HCl for 18 h followed by washing, blanching at 98°C for 30 s and sun drying. Three different types of biscuits were prepared from refined flour (Reference), native or unprocessed pearl millet (T-I) and depigmented pearl millet (T-II). Results indicated that depigmentation improved the sensory attributes especially the color of pearl millet biscuits (T-II). The protein, fat, ash and total dietary fiber of pearl millet based biscuits (T-I as well as T-II) were significantly (P?0.05) higher than the reference biscuits. Depigmentation significantly improved the in vitro starch digestibility, in vitro protein digestibility and the soluble dietary fiber content of pearl millet biscuits (T-II) by 14.50, 6.56 and 6.18%, respectively. On the other hand, a significant decrease of 6.73, 2.43 and 17.03 g/100 g in protein, starch and insoluble dietary fiber was detected in pearl millet biscuits (T-II) due to depigmentation.     

Sweetener Effects on Flaked Millet Breakfast Cereals

White proso and foxtail millets were used in the formulation of a flaked whole grain ready-to-eat (RTE) breakfast cereal where the effects of dried honey or molasses as secondary sweeteners were evaluated. Some sensory attributes were affected by type of millet and by secondary sweetener. Crispness was affected by sweetener type after 4 min hydration. Sweetness scores and color were inversely related, whether evaluated by sensory or instrumental means. The use of 100% millet in RTE breakfast cereals is feasible and the type of sweetener used affects the cereal color, flavor and crispness in milk.     

THE ULTRASTRUCTURE OF GERMINATING SORGHUM AND MILLET GRAINS

The parenchyma tissues of ungerminated and germinated sorghum and millet grains contain abundant fat and protein deposits, which undergo various metabolic changes during germination and seedling growth. The presence of these and other organelles which are characteristic of the mature plant cell was confirmed by a combination of light and electron microscopy. During the early period of the germination process in the millet scutellum, evidence of starch synthesis was apparent, suggesting that fat to starch conversion possibly occurred in the cells of this tissue. In the endosperm of 72 h germinated sorghum and millet grains, starch degradation occurred although such degradation was more extensive in sorghum than in millet.     

Rheological Properties of Certain Processed Rice Products

Two popular rice products, namely expanded rice and flaked rice, are prepared from parboiled rice. As about 90% dry weight of milled rice is starch, the behaviour of rice and its products reflects largely the behaviour of its starch. The above precooked rice products which undergo a high degree of thermal and/or mechanical treatment during processing have a high degree of gelatinization and display therefore properties like those of pregelatinized starch. Both expanded rice and flaked rice have high water binding capacity and cold-swelling properties. Under suitable moisture conditions they undergo retrogradation and show reduced hydration and viscosity. Normal steam-parboild rice shows much lower viscosity because of a comparatively low degree of starch gelatinization during processing and its subsequent retrogradation. Rheologically the cold slurry of these products indicates a thixotropic system demonstrating time dependent thinning. Further, a dependence on slurry concentration and degree of processing and a yield value behind a certain concentration were also apparent. The cold swelling properties of flaked rice and expanded rice show potential use of their flour as a possible subsitute for pregelatinized starch in food and other industries.     

Influence of varying protein and starch degradabilities on performance of lactating cows

A milk production and digestibility trial with 32 cows (2 X 2 factorial with 8 cows per treatment) was conducted to test animal response to varying rumen degradation of dietary starch and protein. Four rations (barley-cottonseed, barley-brewers dried grains, milo-cottonseed, and milobrewers dried grains) were compared in early lactation cows fed 65% concentrate and 35% forage for 60 d. Digestibilities of starch were higher for barley than milo diets; whereas, those for organic matter were higher for cottonseed meal than brewers dried grains. Milk production was highest on barley-cottonseed with mean adjusted values of (kg/d): 37.4, 34.9, 34.2, and 34.6 for respective treatments. Dry matter intakes were not different among rations. Milk fat was higher on milo than barley with respective diets averaging (%): 3.1, 2.9, 3.4, and 3.6, and resulting in lowest FCM for the barley-brewers dried grains diet. Milk protein was not altered by treatment. These data suggest that responses to varying protein degradability can be altered by rate of starch breakdown in the rumen.     

高乳化稳定性小米淀粉Pickering乳液的制备

淀粉基Pickering乳液在食品、医药、化妆品等领域的研究日益广泛。为获得高乳化稳定性淀粉基Pickering乳液,作者采用超声辅助辛烯基琥珀酸化、球磨处理改性小米淀粉,通过测定取代度、水解度、特征官能团、结晶结构、微观形貌、粒径及乳化指数等指标,研究了小米淀粉乳化能力及影响其稳定性的因素。结果表明,超声处理提高了小米淀粉酯化反应效率和取代度,OSA基团主要接枝在小米淀粉无定形区,少量进入了结晶区;球磨破坏了OSA小米淀粉的颗粒形态和晶体结构;随着球磨时间和OSA小米淀粉添加量的增加,OSA小米淀粉形成Pickering乳液的能力和乳化稳定性显著增加。超声辅助辛烯基琥珀酸化结合球磨处理是一种制备高乳化稳定性淀粉基Pickering乳液的有效方法,有助于拓展淀粉资源在Pickering乳液领域的开发利用。     

Physical,chemical and nutritional characteristics of puffed quinoa

Puffed quinoa can be used as ready-to-eat breakfast food or as an ingredient in snack formulations. In this study, puffed quinoa products with and without starch–chitosan coating were developed by gun, extrusion and microwave puffing at different process conditions (pressure, power, moisture content and energy consumption). Size, bulk density, colour, expansion index, water absorption and solubility, microstructure, mechanical and thermal properties, chemical composition and in vitro digestibility of organic matter and proteins of popped quinoa were assessed. Optimal process conditions for gun puffing were maximum 1.31 MPa after 780 s, 500 r.p.m. and 180 s for extrusion puffing and 1200 W for 60 s applying microwave puffing at 18–20% moisture contents. Gun and extrusion puffing yielded high-quality popped quinoa with a biological availability of organic matter between 84–88% and 79–90% for proteins. Extrusion and gun puffing are the most promising processes to prepare quinoa snacks.     

Response of lactating dairy cows to steam-flaked sorghum, steam-flaked corn, or steam-rolled corn and protein sources of differing degradability

Protein sources with different degradabilities were fed to 48 lactating Holstein cows receiving 37 or 39% of dietary dry matter as steam-flaked sorghum (360 g/L), steam-flaked corn (360 g/L), or steam-rolled corn (490 g/L) in a 3 x 2 factorial arrangement of treatments. Cows were fed an alfalfa-based diet with 7% soybean meal or 5% of an animal-marine protein blend and 37 or 39% grain. Although not significant, cows fed flaked grain yielded a mean of 1.5 kg/d more milk than did those fed rolled grain. Gross feed efficiency was not affected by grain processing or protein source, but diets with the animal-marine protein blend had 9% higher estimated net energy for lactation than did diets with soybean meal. The greater gains in body weight and increased digestibility of the diets with the animal-marine protein blend verify the higher energy concentration of those diets. Yield of milk protein was increased by flaked grain or the animal-marine protein blend, and flaked grain increased percentages of lactose and solids nonfat. Increasing the ratio of rumen-degradable starch to rumen-degradable protein increased milk protein content and yield linearly and increased contents of lactose and solids nonfat. A linear response of dry matter, organic matter, crude protein, and starch digestibilities was observed as the ratio of rumen-degradable starch to rumen-degradable protein increased. These data show improved performance of dairy cows fed a high rumen-undegradable protein source with diets high in rumen-degradable starch from steam-processed grains.