Quick-boiling noodle production by using infrared drying Arzu Basman ⇑ , Seda Yalcin Hacettepe University, Faculty of Engineering, Food Engineering Department, 06800 Beytepe, Ankara, Turkey article info Article history: Received 17 March 2011 Received in revised form 14 May 2011 Accepted 17 May 2011 Available online 24 May 2011 Keywords: Infrared Noodle Quick-boiling Drying Quality abstract In this study, infrared treatment at different powers was used at drying stage of noodle production. Dry- ing time was reduced to 3 min 30 s and 50% reduction in cooking time was obtained at the highest power. Lower cooking loss and total organic matter values, higher maximum force values were obtained for noo- dles dried by using infrared, indicating improved quality. Infrared treatment generally caused an increase in Rapid ViscoAnalyzer viscosity values of the noodles. Starch granules of the noodles dried by using infrared retained their birefringence to a large extent and increase in intensity of some peaks and forma- tion of a new peak at 2h = 20° (V-type diffraction pattern) were observed in X-ray diffraction patterns. Relative intensities of some protein bands in SDS–PAGE patterns decreased, total dietary fiber and enzyme resistant starch contents increased slightly. Starch digestibility (in vitro) values increased grad- ually as the infrared power applied increased. Ó 2011 Elsevier Ltd. All rights reserved. 1. Introduction Wheat flour noodles are staple foods in many Asian Countries. Noodle type product popular in Anatolia is called ‘‘eriste’’ and plays an important role in Turkish diet. Processing includes various stages such as mixing of wheat flour with water and salt, sheeting, cutting into strips and drying. In some regions, egg, milk, whey powder and some other additives are also included in the formula. Traditionally, ‘‘eriste’’ is generally dried under the sun, in an oven or in a roasting pan (Ozkaya et al., 2001). Various combinations of these drying methods might also be used. Most of the important quality factors are related to characteristics of raw material and drying stage, which is the most critical step in noodle production in terms of final product quality and economical aspects. Generally as noodle drying technologies, air drying, deep frying or vacuum drying are used. Air drying process is used in many noodle types (e.g. Chinese raw noodles, Japanese udon noodles, instant noodles). Drying time of 5–8 h is needed for air drying of long and straight regular noodles while it takes 30–40 min for steamed and air dried instant noodles. Drying by frying takes only a few minutes. Vac- uum drying of frozen noodles gives premium quality products (Hou and Kruk, 1998). Characteristics preferred in dried noodles are minimal disintegration during cooking and smooth surface without stickiness (Oh et al., 1985). Ideally, drying processes could be designed to shorten drying time and to minimize energy and capital costs while maintaining high product quality. Several researchers investigated effects of various drying techniques or different drying temperatures on quality characteristics of pasta. Berteli and Marsaioli (2005) evaluated efficiency of air drying with assistance of microwave energy in short cut pasta production. A drying time reduction, a higher quality pasta, an increased produc- tion and reduced cost was obtained as compared to the one obtained in traditional process. Baiano et al. (2006) studied effects of different drying temperatures (60 °C for 7.5 h, 75 °C for 5.5 h, 90 °C for 5 h) on spaghetti quality and better cooking and sensory properties were obtained at the highest temperature. Pilli et al. (2009) reported that microwave caused reduction in cooking time and total organic matter (TOM) values of pasta samples as com- pared to conventional drying. In a study by Guler et al. (2002), it was found that pasta sample dried at high temperatures (60– 67 °C) had lower quality scores based on TOM, cooking loss values and sensory evaluation as compared to the ones dried at very high temperature (80–94 °C). Recently, with changes in our lifestyles, reduction of cooking time is expected because it takes a relatively long time for water outside the noodle to migrate into dried and ungelatinized center of noodle. Quick-boiling noodles are increasingly popular due to ease of preparation. Quick-boiling noodles on the market are pre-cooked and sometimes dried, fully pre-gelatinised in center or surface part of noodle (Thammathongchat et al., 2005). How- ever, controlling degree of gelatinization during heating and drying stages are complex and difficult. Xue et al. (2008) produced a par- tially gelatinized noodle strain by making pre-heated dough using a 150 W microwave oven. For the partially gelatinized noodle, rate of water uptake at 100 °C was faster as compared to ungelatinized noodle. In a study by Thammathongchat et al. (2005), new type of processed Japanese noodle that is pre-gelatinized only in center was produced to overcome textural problems occurred during noo- dle production by surface gelatinization. Because of the precooked 0260-8774/$ - see front matter Ó 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.jfoodeng.2011.05.019 ⇑ Corresponding author. Tel.: +90 312 297 71 15; fax: +90 312 299 21 23. E-mail address: basman@hacettepe.edu.tr (A. Basman). Journal of Food Engineering 106 (2011) 245–252 Contents lists available at ScienceDirect Journal of Food Engineering journal homepage: www.elsevier.com/locate/jfoodeng