Germinated grains – Sources of bioactive compounds O.N. Donkor a,⇑ , L. Stojanovska a , P. Ginn b , J. Ashton b , T. Vasiljevic a a School of Biomedical and Health Sciences, Victoria University, Werribee Campus, P.O. Box 14428, Melbourne, Vic 8001, Australia b Sanitarium Development and Innovation, P.O. Box 40, Cooranbong, NSW 2265, Australia article info Article history: Received 22 March 2012 Received in revised form 18 April 2012 Accepted 14 May 2012 Available online 23 May 2012 Keywords: Germination Phenolic compound Antioxidant a-Glucosidase a-Amylase abstract Germination of seven selected commercially important grains was studied to establish its effects on the nutritional and chemical composition. The changes in the concentration of the nutrients, bioactive com- pounds and the inhibitory effect of extracts on a-glucosidase and a-amylase activities were investigated. These were measured through proximate analysis, inhibition assays and HPLC. Germinated sorghum and rye extracts inhibited (p < 0.05) a-glucosidase activity, whereas barley and sorghum extracts exhibited higher inhibitory activities against a-amylase. Germinated grains contained substantial amounts of total phenolics with rye having significantly higher content compared with the non-germinated grains. Radical scavenging activities of the phenolic extracts were between 13% and 73% for non-germinated and 14% and 53% for germinated. Inositol phosphate (InsP) 4, 5 and 6 were noted in all the grains, but InsP 6 was significantly lower in concentration. This study indicates the potential of germinated barley, sor- ghum and rye for the development of effective physiologically bioactive compounds for the reduction of the risk of diabetic agents and colon cancer. Crown Copyright Ó 2012 Published by Elsevier Ltd. All rights reserved. 1. Introduction A number of epidemiological studies have shown that regular consumption of whole grains reduces risks of various types of chronic diseases, such as cardiovascular disease (Anderson, Hanna, Peng, & Kryscio, 2000), type 2 diabetes (Liu et al., 2000; Meyer et al., 2000), some cancers (Kasum, Jacobs, Nicodemus, & Folsom, 2002; Nicodemus, Jacobs, & Folsom, 2001) and reduced mortality (Jacobs, Meyer, & Solvoll, 2001). Whole grains are rich sources of fibre, vitamins, minerals, and phytochemicals, including phenolics, carotenoids, vitamin E, lignans, b-glucan, inulin, resistant starch, sterols, and phytates. Bioactive phytochemicals, found in signifi- cant amounts in fruits, vegetables and whole grains, may provide desirable health benefits beyond basic nutrition to reduce the risk of chronic diseases (Liu, 2004; Slavin, 2000). Recent evidence sug- gests that the complex mixture of bioactives in whole grain foods may be more healthful than individual isolated components (Liu, 2004). Wheat, rice, and corn are the major important grains in the hu- man diet. The minor grains include oats, barley, rye, triticale, sor- ghum, millet, and buckwheat. Notably buckwheat is referred to as a pseudocereal related to sorrels, knotweeds, and rhubarb (Chlopicka, Pasko, Gorinstein, Jedryas, & Zagrodzki, 2011). Whole grains contain unique phytochemical complex that complement those in fruits and vegetables when consumed together. The vari- ous classes of phenolic compounds in grains include phenolic acids, anthocyanidins, quinones, flavonols, chalcones, flavones, flavanones, and amino phenolic compounds (Lloyd, Siebenmorgen, & Beers, 2000). However, germinated cereals/pseudocereal or sprouts are believed to have a greater nutritive and physiological value than cereal and pseudocereal grains and their products (Price, 1988; Prodanov, Sierra, & Vidal-Valverde, 1997; Rozan, Kuo, & Lambein, 1999, 2000). Numerous studies have shown that the nutritional and chemi- cal profile is altered following germination of cereal grains such as wheat, rice, barley, oats and rye (Price, 1988). The most signifi- cant change occurs in starch, which is broken to simpler sugars by amylases. The degree of the changes seen in starch depends on var- ious germination conditions, such as temperature, humidity, cul- turing media, steeping (soaking) and the length of germination (Koehler, Hartmann, Wieser, & Rychlik, 2007). This means direct comparison is difficult, and optimum conditions will need to be de- fined for individual cereals. At the same time with synthesis of no- vel compounds, the concentrations of some nutrient inhibitors may decrease. For example, phytic acid is hydrolysed by increased phytase activity, decreasing phytate concentration subsequently leads to releasing phosphate, inositol and minerals (Bohn, Meyer, & Rasmussen, 2008). In germinated flour, protein, fibre, fat and en- ergy increased significantly as did anti-nutrients (tannins, phytates and trypsin) and total amino acid content increased, while mineral 0308-8146/$ - see front matter Crown Copyright Ó 2012 Published by Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.foodchem.2012.05.058 ⇑ Corresponding author. Tel.: +61 3 9919 8059; fax: +61 3 9919 8284. E-mail address: Osaana.Donkor@vu.edu.au (O.N. Donkor). Food Chemistry 135 (2012) 950–959 Contents lists available at SciVerse ScienceDirect Food Chemistry journal homepage: www.elsevier.com/locate/foodchem