Bulgur Production Research Articles

Chemical and nutritional changes in bitter and sweet lupin seeds (Lupinus albus L.) during bulgur production.

In this research, bitter and sweet Lupin (Lupinus albus L.) seeds were used in bulgur production. The proximate chemical compositions and the contents of phytic acid, mineral, amino acid and fatty acid of raw material and processed lupin seeds as bulgur were determined. The sensory properties of bulgur samples were also researched. Bulgur process decreased ash, fat and phytic acid content of lupin seeds while significant increase (p < 0.05) was observed in protein content of bulgur compared with lupin seeds. Phytic acid losses in bitter and sweet lupin bulgurs were found as 18.8% and 21.3%, respectively. Generally sweet lupin seeds/bulgurs showed rich essential amino acids composition than that of bitter seeds/bulgurs. Linoleic and linolenic acid content of the lupin was negatively affected by bulgur process. Bitter lupin bulgur received lower scores in terms of taste, odor and overall acceptability than sweet lupin bulgur in sensory evaluation. Sweet lupin bulgur can be used as new legume-based product with high nutritional and sensorial properties.

MILLING QUALITY OF HULLED WHEAT BULGUR WITH STONE MILL

ABSTRACT In recent years, hulled wheat species have increased in importance because of their advantageous features as underutilized crops which have provided additional income to farmers and also contributed to agricultural diversification. Einkorn and emmer as two hulled wheat species have been used in this study. The milling quality of these hulled wheats was determined on fixed top stone and fixed bottom stone (FBS) mills at 1.75‐ and 2.5‐mm stone gap levels. The effects of parameters such as stone mill type, stone gap and milling quality of hulled wheat species have been studied. The obtained products have been classified as coarse (over 2 mm), medium (under 2 mm–over 1 mm), fine (under 1 mm) and husky. It reveals that FBS mill has ground in little particles and more unsteadily. This study also indicates that the grinding of emmer has brought along smaller particles due to its spindly structure and 1.75‐mm stone gap has been thought more acceptable because of the less husky product. PRACTICAL APPLICATIONHulled wheat species are very important due to their high nutrition potential. As compared with common wheat, hulled wheats are generally more resistant to diseases and have the ability to withstand drought so they can grow in harsh environments and poor soil. Hulled wheat is especially used for bulgur production because of its delicious taste. The milling operation is one of the most important steps in bulgur production. It needs abrasive mills because of its husky structure. In this study, milling quality of two hulled wheat (emmer and einkorn) bulgurs was determined on stone mills. We believe that the results of this research provide insights into the production of marketable bulgur and the choosing of suitable bulgur mill.

Determination of applicability and effects of colour sorting system in bulgur production line

In this study, a modified colour sorting system was used in the bulgur production line to prevent economical losses in undeveloped and developing countries due to unavailable homogeneous hard wheat i.e. free of foreign and reddish seeds. It is impossible to separate undesired different coloured materials using available wheat pre-cleaning systems. The bulgur production steps were firstly investigated to determine suitable stages for the effective application of the colour sorting system. The modified colour sorting system was applied on the pre-cleaned raw material (wheat), cooked and dried wheat, dehulled-intact-bulgur, milled-unclassified-bulgur and fine bulgur to determine the efficiencies by measuring the colour values, i.e. L, a, b and YI values, and percent purity (% # of acceptable particles/total # of particles) at the sorter inlet–outlet and resort inlet–outlet. It was found that the colour sorting system was not suitable for applying on wheat (raw material), and cooked and dried wheat due to their surface properties and not present dominant colour differences. The L and b values of the dehulled-intact-bulgur and milled-unclassified-bulgur increased after the sorting system in contrast to decrease in the a and YI values due to the removing reddish or brown bulgur and foreign materials. Each colour value illustrated that the colour sorting system increased the colour quality of bulgur. The increase in the particle size of bulgur increased the efficiency of the colour sorting system to 99.10%. The protein content of the dehulled-intact-bulgur was increased from 12.55% to 12.69% due to removing undesired materials by the colour sorter and the product quality increased. By using the colour sorting system in the bulgur processing line, bulgur quality, product acceptability and production flexibility can be increased.

Determination of the cooking degree for bulgur production using amylose/iodine, centre cutting and light scattering methods

In the present study, the amylose/iodine and light scattering methods were used to determine the cooking degree based on starch gelatinization for the production of bulgur as alternative to traditionally used centre cutting method. Cooking operation was carried out at boiling temperature (97 °C) using Triticum durum wheat for 130 min. The cooking degree was controlled using the three methods and the deformation degree of the intact wheat kernels. It was found that the gelatinization values obtained from the amylose/iodine method were higher than the others up to reaching 100% cooking degree. The results for the cutting method were same with the light scattering method. The optimum cooking time was determined as 40 min. Excess cooking caused significant deformation on the intact wheat kernel during the cooking operation. Both alternative methods i.e. amylose/iodine and light scattering can be used to the control of cooking system. In addition, the light scattering method can be preferred in the automation having bulgur production systems.

Thermodynamics of the Dimensional Changes in the Wheat Kernel during Cooking for Bulgur Production

Thermodynamics and physical properties of the dimensional changes in the wheat kernel during cooking was carried out for bulgur production at 87, 92 and 97°C for 140min. There were determined changes of the length ( x-dimension), two widths ( y- and z-dimensions), weight, volume and density of the wheat kernel. The length of the wheat kernel during cooking decreased, although crease-side width ( y-dimension) and secondary width ( z-dimension) significantly increased ( p 0.05) at each cooking temperature between 6.95-68.05% and 9.95-69.00%, respectively. The volume of the kernel during cooking also significantly ( p 0.05) increased (27.35-185.20%), and had a greater percentage change value than the weight (19.25-160.70%) due to swelling of the wheat kernel. Therefore, density decreased negatively. Activation energy, enthalpy, entropy and Gibbs free energy were used to describe the changes of physical attributes of the wheat kernel during cooking. Rate constant values for the length and density of the wheat kernel were negative in contrast to positive rate constant values of the widths, weight and volume of the wheat kernel. The influence of cooking temperature on the physical properties of the wheat kernel revealed that the rate of change in the secondary width ( z-dimension), weight and density of the wheat kernel were more sensitive to temperature due to their greater activation energies, 5.95 107, 5.26 107 and 6.11 107 J, respectively. In contrast, the y-dimension of width of the wheat kernel required a lower amount of energy due to crease side. All of the changes in physical properties agreed with the positive values of Gibbs free energy.

Physicochemical and Sensory Properties of Soymilk‐incorporated Bulgur

ABSTRACT Bulgur cooked in soymilk of 6% and 9% solid content had significantly (P &lt; 0.05) higher bulk density compared with bulgur cooked in soymilk of 3% solid content and control bulgur cooked in water. As the soymilk solid content increased, pilav bulgur yield increased whereas fine bulgur yield decreased. The SDS‐extractability of bulgur proteins increases with the increase in soymilk solid content. Water absorption capacity of fine bulgur samples was affected by soymilk incorporation, and variations in oil absorption capacity were not significant (P &gt; 0.05). Soymilk incorporation improved color and sensory properties of pilav and fine bulgur. The results of this study suggest that soymilk can be successfully applied to bulgur production.

Effect of cooking time and temperature on the dimensions and crease of the wheat kernel during bulgur production

In this study, the effect of the cooking time and temperature on the dimensions and crease of the wheat kernel was studied during bulgur production. Wheat was cooked at 87, 92 and 97 °C for 140 min. The change of the length, two widths, weight, volume and density for the wheat kernel were determined during the cooking operation. In addition, in order to determine the effect of cooking time and temperature, rates, activation energy, Q 10 and z-values were determined. Negative percent change values and the rate constant for the length and density of the wheat kernel were obtained at different cooking temperature ( P>0.05). A positive rate constant was determined for other properties. The crease side width increased gradually at each cooking temperature between 6.95–68.05%. Cooking time also significantly affected the change of the crease side ( P<0.05). The secondary width was affected significantly ( P<0.05) by the cooking temperature and time, and its value changed between 9.95–69.00%. The big change for the secondary width was obtained at 97 °C. The crease has important guarding property for the length and secondary width and it also guards the kernel for the secondary width against the internal force up to 97 °C. The volume of the kernel also increased (27.35–185.20%) during the cooking operation significantly ( P>0.05), and has greater percent change value than the weight (19.25–160.70%) due to high amount of swelling of the wheat kernel. Therefore, density changed negatively. E a, Q 10 and z-values were determined for all physical properties of the wheat kernel and found that cooking temperature significantly affected the change of the c, W and ρ values.

Influence of soaking on the dimensions and colour of soybean for bulgur production

Soaking of soybean was studied to produce the soy-bulgur as a new type food product by measuring the changes in the properties of soybean kernel. Soybeans were soaked in deionized water at different temperatures (30, 50, 70 °C) for 120 min. Dimensions (three-dimensional changes; x, y, z), weight, volume, density, moisture content and colour ( L, a, b and YI-values) for soybean were determined during the soaking operation. All responses were affected by time and temperature ( P<0.05) significantly during the soaking operation. Percent change in the length ( x) increased to 63.3–75.6 ( P<0.05) significantly at different temperatures. Widths ( y and z) of the soybean also increased significantly ( P<0.05). The y-value increased sharply at 100, 40 and 20 min for 30, 50 and 70 °C soaking, respectively. After the sharp rising, the change in the y-value decreased steadily. Percent change in the volume (129.6–146.3) was higher than the percent change in the weight (113.7–120.9%) at the end of the soaking operation due to high amount of swelling of the soybean kernel. A negative percent change in the density was obtained with respect to time at each temperature. The critical moisture content for ideal bulgur production for soybean (40%, w.b.) was reached at each temperature. L (lightness) and b (yellowness) values of soybean colour increased during the soaking in contrast to a (redness) and YI (yellowness index) values ( P<0.05).