Original article An alternative strategy for corn drying (Zea mays) resulted in both energy savings and reduction of fumonisins B 1 and B 2 contamination Nes ¸ eYılmaz & Necati Barıs ¸ Tuncel* Department of Food Engineering, Engineering-Architecture Faculty, C¸ anakkale Onsekiz Mart University, 17100 C¸ anakkale, Turkey (Received 31 July 2009; Accepted in revised form 16 December 2009) Summary The objectives of this study were to investigate the effect of harvest date on fumonisins contamination and to offer an alternative drying procedure with low energy costs. Corn kernel samples above 13% moisture content were dried with hot air (HA), the technique more usually utilised by farmers and compared with infrared and infrared–hot air (IR–HA) combination techniques. The effect of harvest date on fumonisin contamination was found to be significant while drying had no influence. Due to the fact that the corn remains in the field longer than necessary for economic reasons, energy expenses of the drying techniques were calculated in terms of specific energy consumption for unit of evaporated water. It was found that the energy expenses to reduce the moisture level from 15 to 13% with HA drying were higher than the expenses to reduce the moisture level from 29 to 13% with IR–HA drying combination. Keywords Corn, drying, HPLC, infrared, maize, mycotoxin. Introduction According to Food and Agriculture Organization (FAO) statistics, corn has the third world wide culti- vated area (157 874 343 ha) after wheat (217 432 668 ha) and rice (156 952 666 ha) (FAO, 2007). However, corn has the highest worldwide pro- duction of 784 786 580 tonnes. It is utilised as both food directly and consumed in many forms as corn flour, cornflakes, corn bread, corn-germ oil, corn-sugar molas- ses, etc. Drying is an essential procedure for safe storage of corn. Drying is also one of the most energy intensive processes in food industry. Hot air (HA) drying is the most common commercial technique being used indus- trially for corn drying. However, there is a great loss of thermal energy in convective drying (Chua & Chou, 2003; Das et al., 2004; Hebbar et al., 2004; Sharma et al., 2005). Limited heat transfer due to the low thermal conductivity is the main factor responsible for slowing the HA drying process (Pathere & Sharma, 2006). On the other hand, infrared (IR) drying offers many advantages such as high heat transfer coefficients, short process time and low energy costs over HA drying. However, application of combined electromagnetic radiation and HA drying is considered to be more efficient, presumably providing a synergistic effect (Ku- mar et al., 2005). Corn reaches physiological maturity (blacklayer) in 100–120 days. Although the corn reaches physiological maturity between the limits of 29–31% moisture level (Johnson, 2000), farmers generally prefer to harvest the corn with a moisture level of 16–18% and continue with the drying until the grain moisture content of 13% using HA convective systems, in order to preserve the grain from the risk of contamination by toxins produced by moulds that probably originated during the period from maturity to harvest. But applying alternative drying techniques can reduce energy consumption during drying and give a chance to earlier harvest time and probably lower the contamination risk. Corn ears are naturally contaminated with different fungi in the field including Fusarium spp. In addition to loss of production and economic impact on the grain industry, Fusarium spp. cause a variety of toxic effects (Moss, 1998). Fumonisins are produced by several Fusarium species, mainly by Fusarium verticillioides Niremberg [syn.: Fusarium moniliforme (Sacc.) Sheldon] which is one of the most common fungi associated with corn worldwide (INCHEM, 2000). F. proliferatum, F. anthophilum, F. dlamini, F. napiforme and F. nygamai are the other sources of fumonisins (Wang et al., 2008). Since the first identification of Fumonisin B 1 (FB 1 ) , many fumonisin toxins have been characterised and the B-series found to be the most abundant ones including FB 1 accounting for *Correspondent: E-mail: baristuncel@me.com International Journal of Food Science and Technology 2010, 45, 621–628 621 doi:10.1111/j.1365-2621.2009.02175.x Ó 2010 The Authors. Journal compilation Ó 2010 Institute of Food Science and Technology