The fate of bioactive compounds during traditional preparation of einkorn wheat (Triticum monococcum L. subsp. monococcum) bulgur

Einkorn wheat bulgur is a traditional food deeply rooted in some areas of Turkey, since ages. The objective of this study was to evaluate the impact of simulated traditional bulgur preparation on einkorn wheat bioactive compound content.A local einkorn wheat grain sample from Turkey was boiled for 2, 3 and 4 h, then dried in a thermo-ventilated oven. Tocols, carotenoids, phytosterols and phenolics, determined as free (FPC) and bound (BPC) phenolic compounds, were analysed in hulled (spikelets) and dehulled (kernels) bulgur samples, to highlight also glumes’ contribute to their content and evolution.Kernel carotenoid and tocol content significantly decreased following bulgur preparation, to an extent of 42–58% and 15–30%, respectively. Phytosterols slightly decreased in cooked (12–19%), with respect to raw kernels. Phenolics showed different patterns, highlighting glumes’ contribute: kernel FPC increased (+87%) after 4 h of boiling, whereas no significant variations were observed for BPC. A drastic decrease of total and BPC (20.5–28.0%), was observed in spikelets following bulgur preparation. Ferulic and p-coumaric acid resulted the most abundant phenolic acids, respectively, in kernels and spikelets.Decreases in tocol, carotenoids and phytosterol contents were observed whereas an increase of kernel FPC content was calculated after cooking.     

Effects of wheat cultivar,cooking method,and bulgur type on nutritional quality characteristics of bulgur

The aim of this study was to investigate the effects of different wheat cultivars, cooking methods, and bulgur types on nutritional quality of bulgur. Cultivars, cooking methods, and bulgur types had significant effects on phytic acid, total phosphorus, soluble, insoluble, and total dietary fibre contents of bulgur. Besides, cultivars and cooking methods were found to have significant effects on yellow pigment, thiamine, and riboflavin contents of bulgur. The results indicated that the variation among genotypes was wide on all parameters investigated. Bulgur cooked using the steam cooker cooking method had better nutritional properties. Regardless of the cooking method, fine bulgur type had higher nutritional values. However, it was observed that there were losses in nutritional values (ranging from 17.5% to 55.7%) during bulgur production from wheat. The losses resulted particularly from cooking and debranning steps during bulgur production. It can be concluded that the steam cooker cooking method showed promising results in terms of the nutritional quality of the bulgur.     

Usage of undersize bulgur flour in production of short-cut pasta-like couscous

Couscous is a traditional cereal product produced by rubbing durum semolina particles with water by hand, but can be produced by using pasta pressing technique. This study aimed to produce a short-cut pasta type couscous by substitution of semolina with undersize bulgur at 25, 50, 75 and 100%, by determining optimum parameters. Bulk density, cooking loss, volume and weight increases, protein and ash contents, color, sensory, texture and functional properties were determined. Couscous samples were prepared and dried using packed bed (60 and 80 °C) and microwave dryers (180 and 360 W) to determine optimum parameters. It was found that the quantity of bulgur flour was significantly (p ≤ 0.05) effective on the sensory attributes, bulk density, cooking loss, volume and weight increases, protein and ash contents in contrast to functional properties. Weight and volume increase values decreased with increasing quantity of bulgur flour. Couscous samples containing bulgur flour have higher protein than the control due to higher protein content of bulgur. According to texture profile, hardness of couscous containing bulgur flour was lower than the semolina control for each drying technique. Results revealed the fact that the production of pasta type couscous is possible using totally undersize bulgur instead of semolina.     

Wheat products as acceptable substitutes for rice

The objective of the study was to compare the acceptability to semi-trained US American and Asian palatability panelist, of four wheat products processed to be possible replacers of rice in human diets. Products evaluated using rice as the control standard of excellence were steamed whole wheat, couscous (steamed, extracted wheat flour semolina), rosamarina (rice shaped, extracted wheat flour pasta), and bulgur (steamed, pre-cooked partly debranned, cracked wheat). Using a ten point hedonic rating scale, both groups of panelists gave rosamarina closely followed by couscous, most favorable ratings although these ratings were somewhat lower than that of the positive control, steamed polished rice. Bulgur wheat was given the lowest evaluation and was, in general, found to be an unacceptable replacement for rice by both American and Asian judges because of its dark, greasy color and distinctive flavor. In their personal dietaries, judges included rice from 0.25 to 18 times per week with the Asian judges consuming rice significantly more times per week than did the American judges (10.8±4.71 vs 1.75±1.65,p<0.01). However, rice consumption patterns, nationality, race, or sex of the judges was not demonstrated to affect scoring of the wheat products as rice replacers.Published as University of Nebraska Agricultural Research Division Journal Series No. 9826. Supported by University of Nebraska Agricultural Research Division Project 91-031.     

Modification of mechanical polishing operation using preheating systems to improve the bulgur color

Bulgur is an increasingly popular foodstuff that has existed since antiquity, and one that displays high consumption worldwide. Polishing is a key operation to improve the yellow color of bulgur which, by extension, also improves the competitiveness in business and markets. In this study, the traditional electrical heater-aided mechanical polishing system (EHA-MP) was modified with preheating systems so as to decrease the energy consumption and to improve the bulgur color. Additionally, it was investigated that the effects of the tempering methods (spray and steam) before polishing, the preheating (microwave and infrared, at 40, 60 and 80 °C) by determining changes in the bulgur color (CIE L*, CIE b*, CIE a*, CIE YI), total carotenoid content (TCC), chemical composition (moisture, ash and protein contents, %, d.b.) and the energy consumption of the process. Both tempering methods increased significantly (P ≤ 0.05) the CIE L* and CIE b* values of bulgur. The temperature of polishing increased the TCC of bulgur significantly (P ≤ 0.01). Infrared preheating was the most economical method according to energy consumption. Taken together, these new findings offer new insights and improvements in the bulgur production and its attendant business competitiveness and responds to demands by consumers.     

Stone, disc and hammer milling of bulgur

The effects on the milling quality of bulgur were compared using stone, disc and hammer mills. For each milling system bulgur particles were examined for appearance, surface structure, dimensions (max., min., mean, standard deviations and coefficient of variance), particle size distribution, bulk density and 1000 particle weight. Smooth and regular shaped bulgur particles were obtained using the abrasive stone and disc mills. Stone milled bulgur particles, were not split or glassy, but were opaque. Hammer milling significantly affected the appearance and surface characteristics of the bulgur particles and gave the lowest minimum dimensions and the highest deviation and variance in dimensions. The milling yields for hammer (98.3%) and stone (97.4%) mills were higher than for the disc mill (96.5%). Each mill gave a different distribution between coarse, medium and fine fractions. The highest yield of the coarse fraction (83.1%) was obtained using the stone mill. The results indicate that due to loss of quality, hammer milling is not suitable for bulgur preparation.