Analytical Methods Nondestructive estimation of fatty acid composition in soybean [Glycine max (L.) Merrill] seeds using Near-Infrared Transmittance Spectroscopy A.G. Patil * , M.D. Oak, S.P. Taware, S.A. Tamhankar, V.S. Rao Genetics Group, Division of Plant Sciences, Agharkar Research Institute, Agarkar Road, Pune 411 004, Maharashtra, India article info Article history: Received 6 January 2009 Received in revised form 26 October 2009 Accepted 28 November 2009 Keywords: Soybean Fatty acid composition Near-Infrared Transmittance (NIT) Spectroscopy Modified Partial Least Squares (MPLS) Chemometric models Spectral Analysis abstract The potential of Near-Infrared Transmittance (NIT) Spectroscopy for estimation of fatty acid composition in soybean seed samples was studied. Total 612 whole seed samples with wide range of variability for major fatty acids were used to develop calibration equations by applying SNV de-trend and first deriva- tive mathematical treatment in the range of 850–1048 nm. Useful chemometric models for most impor- tant fatty acids present in soybean seed oil were developed using Modified Partial Least Squares (MPLS) regression method. In external validation oleic (r 2 = 0.89, SEP = 1.61), linoleic (r 2 = 0.86, SEP = 1.50) and palmitic (r 2 = 0.89, SEP = 0.17) acids were predicted with good accuracy, while the predictions for linole- nic acid (r 2 = 0.78, SEP = 0.36) and stearic acid (r 2 = 0.63, SEP = 0.11) had relatively poor accuracy. The whole-seed NIT spectroscopy equations for fatty acid estimation would be useful for improving efficiency of breeding programs aimed at altering fatty acid composition in soybean. Ó 2009 Elsevier Ltd. All rights reserved. 1. Introduction Soybean is one of the major oilseed crops of the world. The soy- bean oil contains approximately 110 g kg À1 palmitic, 40 g kg À1 stearic, 240 g kg À1 oleic, 540 g kg À1 linoleic, and 70 g kg À1 linolenic acid (Schnebly & Fehr, 1993). Improvement of nutritional and func- tional properties of soybean oil by modification of fatty acid com- position has been a major objective of plant breeders. Reduction in polyunsaturated (linoleic and linolenic acids) and increase in monounsaturated (oleic acid) fatty acids content improves nutri- tional quality and shelf life of soybean oil (Lui & White, 1992; Rakow & McGregor, 1973). This avoids need of hydrogenation which results in increased content of unhealthy trans-fats (Willet & Ascherio, 1994). In contrast, soybean cultivars with high content of saturated fatty acids (palmitic and stearic acids) can be impor- tant for production of margarine and solid fats (Fehr, Welke, Ham- mond, Duvik, & Cianzio, 1991; List, Mounts, Orthoefer, & Neff, 1996). Soybean lines with altered fatty acid composition have been developed through mutation breeding (Fehr & Hammond, 1998; Patil, Taware, Oak, Tamhankar, & Rao, 2007; Rahman, Takagi, Kubota, Miyamoto, & Kawakita, 1994). Identification and tracking of a target trait is an important component of a breeding exercise. In conventional crop improvement, a large number of seed samples in small quantity and even single seeds need to be evaluated to study desired traits in early generations. Consequently, nonde- structive and rapid analysis of seed samples is necessary. Conven- tional method of fatty acid estimation is labor-intensive and time consuming (Sato, Uezono, Morishita, & Tetsuka, 1998). Therefore, there is a need for developing cost-effective and rapid method to determine fatty acid composition in oil seeds. Near-infrared (NIR) Spectroscopy is one of the most useful, rapid, nondestructive, cost-effective and reliable multi-trait technique in agricultural and food analysis (Cen & He, 2007; Wang & Paliwal, 2007). It can analyze, large number of samples in small quantity in the form of whole grains, minimizing sampling error, especially for plant breeding applications. Near-Infrared Spectroscopy was used for the first time to measure moisture concentration in soybean (Ben-Gera & Norris, 1968) and since then has been used to measure moisture, protein, oil and starch concentration in forage, legume and cereal crops, as well as other food commodities. It has also been applied for fatty acid profiling in oilseeds like rapeseed (Velasco, Moellers, & Becker, 1999), peanut (Tillman, Gorbet, & Person, 2006), sunflower (Sato et al., 1995), sesame (Sato, Maw, & Katsuta, 2003), and soybean (Kovalenko, Rippke, & Hurburgh, 2006; Pazdernik, Killam, & Orf, 1997; Sato, Takahashi, & Matsunaga, 2002). The correlation between standardized NIR absorbance at 1708 nm and linoleic, oleic acid (À0.85 and 0.88 respectively) in soy flour was examined by Sato et al. (2002). The palmitic (r 2 = 0.93), stearic (r 2 = 0.89), oleic (r 2 = 0.95) and linoleic acid (r 2 = 0.93) of soybean cotyledons has also been estimated using NIR spectroscopy (Roberts, Ren, Beuselinck, Benedict, & 0308-8146/$ - see front matter Ó 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.foodchem.2009.11.066 * Corresponding author. Tel.: +91 20 25653680; fax: +91 20 25651542. E-mail address: archie_2180@yahoo.co.in (A.G. Patil). Food Chemistry 120 (2010) 1210–1217 Contents lists available at ScienceDirect Food Chemistry journal homepage: www.elsevier.com/locate/foodchem