Quality Assurance and Safety of Crops & Foods
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Wageningen Academic Quality Assurance and Safety of Crops & Foods, 2019; 11 (4): 381-390 Publishers Effects of wheat cultivar, cooking method, and bulgur type on the yield and colour properties of bulgur A. Kaplan Evlice1* and H. Özkaya2 1Department of Food Technology, Central Research Institute for Field Crops, 06171, Yenimahalle, Ankara, Turkey; 2Department of Food Engineering, Faculty of Engineering, Ankara University, 06830, Gölbaşı, Ankara, Turkey; [email protected]; [email protected] Received: 3 September 2018 / Accepted: 1 April 2019 © 2019 Wageningen Academic Publishers RESEARCH ARTICLE Abstract Making bulgur is an ancient process and bulgur may, in fact, be man’s first processed food. Technological improvement is essential in order to achieve higher quality bulgur. The steam cooker is gaining popularity these days since it preserves the nutritional value of the food during the cooking. In the present study, coarse and fine bulgur types were produced from bread and durum wheat cultivars by using steam cooker and autoclave to determine the effects of cultivar, cooking method, and bulgur type on the yield and colour properties of bulgur. The less total bulgur yield was determined at durum wheat cultivars and autoclave cooking method because of the higher amount of bran removed. The percentage of the bulgur samples having a particle size ranging between 2.0 and 2.5 mm was the highest for both cooking methods. Durum wheat cultivars possessed harder and more breakable grain structure during the bulgur production, which caused 11.9% less coarse and 11.4% more fine bulgur yields. The kernels cooked in steam cooker also tended to break more during the debranning process which raised about 20% more fine bulgur yield. Bulgur produced from durum wheat cultivars possessed higher lightness (L) and yellowness (b), and lower redness (a) colour values. During the bulgur production, a decrease (11.6%) in ‘L’ colour value and an increase (164.6%) in ‘a’ colour value was determined from raw material to bulgur. The application of high temperature and pressure used for autoclave cooking caused darkening of bulgur colour. The coarse bulgur type had higher ‘L’ colour value and lower ‘a’ colour value. The steam cooker has been utilised for the first time in bulgur production as a cooking method, although it causes a higher amount of breakage of the kernels, the bulgur maintains the yellowish colour which is a desired trait. Keywords: bulgur quality, cultivar, cooking method, bulgur type, yield, colour 1. Introduction this production is estimated to be more than 1 million ton including the homemade production (Bayram, 2007; Bulgur, one of the first whole wheat-based foods in the Yousif et al., 2018). Bulgur production and consumption are world, has been produced in the Anatolia and the Middle increased due to its low cost, long shelf-life, taste, ease of East since the cultivation of wheat (Williams et al., 1984). It preparation, high nutritional and economic values (Yousif was called by many different names such as cerealis, dagan, et al., 2018). Turkey exported 257,298 tons bulgur to 94 arisah, burghul, ala, daliya, birghil, plegouri and parboiled countries in 2017 (TRADE MAP, 2017). wheat by different cultures throughout history (Bayram, 2007; Haley and Pence, 1960). There is no universal method or system for producing bulgur. However, Karaman and Antep systems are the two Currently, Turkey is the largest bulgur producer and exporter most popular industrial bulgur production techniques in of the world. The annual bulgur production was reported the world (Bayram and Öner, 2005; Yousif et al., 2018). as about 451,429 tons in 2016 (TÜİK, 2016). However, Further, there is a homemade bulgur production method ISSN 1757-837X online, DOI 10.3920/QAS2018.1431 381 A. Kaplan Evlice and H. Özkaya (atmospheric pressure cooking and sun-drying in open (Savaş, 2010; Yılmaz, 2012), and milling (Bayram and Öner, air) which is being used extensively in villages of Turkey. 2005) conditions. The main traditional bulgur production steps are as follows; Technological improvement for bulgur production is cleaning, cooking, drying, tempering, debranning, cracking essential to increase the bulgur quality since the production (milling), and size-classification (Özboy and Köksel, 2002; and consumption of bulgur are increasing in developing and Savas and Basman, 2016; Yousif et al., 2018). There are six developed countries (Kahyaoglu et al., 2010). Therefore, types of bulgur according to particle size defined by Bulgur each step of bulgur production should be well-considered Communiqué (2016/49) (Turkish Food Codex, 2018) and and meet with new technologies. The steam cooking is a Boiled and Pounded Wheat Standard (TS 2284) (Turkish relatively new technique and no reports have been found for Standards Institution, 2018). The first four of them are the steam cooker as a cooking method in bulgur production. coarse (pilavlık) bulgur types while the last two of them To our knowledge, the steam cooker for producing bulgur are fine (köftelik) bulgur types. was used for the first time in the present study. Therefore, the aim of the study was to determine the effects of cultivar The most critical steps are the cooking and drying stages (seven durum wheat and two bread wheat), cooking method in the bulgur production, which affects the important (steam cooker and autoclave), and bulgur type (coarse and properties of wheat (Savas and Basman, 2016; Yousif et fine) on the yield and colour properties of bulgur. al., 2018). Hence, different cooking (atmospheric, pressure, and microwave) and drying (solar, sun, sprouted bed, tray, 2. Materials and methods ventilated oven, infrared, and microwave) methods were studied to examine the effects of these stages on the quality Materials of the bulgur (Acer, 2004; Kahyaoglu et al., 2010; Koca and Anıl, 1996; Savas and Basman, 2016; Yilmaz and Koca, The material of this study consisted of seven durum wheat 2017). Pressure cooking (autoclave) and cooking under cultivars (Altın 40/98, Ankara-98, Çeşit 1252, Eminbey, atmospheric pressure (traditional method) are the most Kunduru-1149, Kızıltan-91, and Mirzabey-2000) and two frequently used cooking methods. Bright yellow colour bread wheat cultivars (Demir-2000 and Tosunbey). All in bulgur is obtained by the traditional cooking method. cultivars were grown in two locations in Turkey (İkizce/ However, with this method, the grains tend to get deformed Ankara and Altınova/Konya) and two consecutive growing which is not desired by the producers. Although, high seasons (2008-2009 and 2009-2010) under rainfed temperature and pressure used in autoclave cooking method conditions. cause darkening of the bulgur colour, this cooking method is used widely in continuous systems (Koca and Anıl, 1996; Methods Özboy, 1998). Traditionally, bulgur is sun-dried in open air, but it may cause quality degradation of the final product and Bulgur production contamination problem (Kahyaoglu et al., 2010; Savas and Basman, 2016). In modern bulgur plants, hot air drying is Bulgur samples were prepared from 36 wheat samples often used due to increased capacity and sanitation benefits (combining 9 cultivars, 2 years, and 2 locations) with two (Hayta, 2001; Kahyaoglu et al., 2012). different cooking methods (steam cooker and autoclave) and two bulgur types (coarse and fine). The samples were Beside bulgur producing technique, the wheat species or kept in a refrigerator at 4 °C until further analyses. cultivar used in bulgur production is one of the key factors affecting the quality of bulgur. Bulgur is a whole grain For all soaking, cooking, tempering, and debranning product which is commonly produced from durum wheat techniques, all treatments were determined by preliminary (Triticum durum Desf.). One of the most important quality tests. Different soaking ratios were trialled for both cooking criteria that distinguishes durum wheat from bread wheat is techniques: 1.0:1.0, 1.1:1.0, 1.2:1.0, 1.3:1.0 (w/v, wheat:water) the high yellow pigment content that is existing at different for autoclave while 0.7:1.0, 0.8:1.0, 0.9:1.0, 1.0:1.0, 1.1:1.0 levels in wheat species (Abdel-Aal et al., 2002; Hidalgo et (w/v) for steam cooker. Optimum soaking ratio was found al., 2017; Karwasra et al., 2017). The bright yellow colour 1.0:1.0 (w/v) for both cooking techniques. For cooking is the most important determinant of the bulgur quality time from 13, 15, and 17 min., 15 min. was found to be which affects the consumer’s choice in Turkey (Bayram, the optimum time for autoclave cooking technique while 2005). In order to meet the demands of the customers, 90 min. was optimum for starch gelatinisation in steam the producers are trying to achieve yellowish colour in cooker. From different tempering moistures (14 and 16%), bulgur (Balci and Bayram, 2015). Bulgur yield, which is tempering time (18 h and 30 min.), and debranning time (2, another quality parameter, is important for the producer 4, 6 and 8 min.); 16% tempering moisture content, 30 min. and varies according to the variety/species (Özboy, 1998; tempering time, and 6 min. debranning time were observed Yılmaz, 2012), cooking (Savaş, 2010; Yılmaz, 2012), drying to be the optimum for debranning process. 382 Quality Assurance and Safety of Crops & Foods 11 (4) Different factors on bulgur yield and colour Cooking less than 0.5 mm were separated as they were not classified as bulgur sample. A steam cooker (Tefal VC 7003, Rumilly, France) used in this study was utilised for the first time in bulgur production. Milling for meal and semolina One unit of cleaned wheat was cooked with 1 unit of tap water (100 °C) for 90 min until full starch gelatinisation. The wheat samples were grinded to the meal (Perten 3100, Autoclave cooking method was modified from Savas and Huddinge, Sweden) to determine moisture content as Basman (2016).