667 Proximate Content and Starch Granule Structure in Raw and Boiled Chestnuts with Different Aptitude to Candying C. Mert Uludag University Faculty of Agriculture Department of Horticulture Gorukle Campus 16059, Bursa Turkey Keywords: Castanea sativa, boiling effect, starch morphology Abstract In this research the effect of protein, starch and total sugars content and granule structure of starch on the suitability to produce candied chestnut were studied. Additionally starch granule structures of the cultivars were observed under Scanning Electron Microscope (SEM). Large, medium and small size of starch granules were observed in studied cultivars. After boiling during candied chestnut production significant morphological variation was observed in starch granule structure among the chestnut cultivars. Also, there were significant changes between the raw and boiled materials in their total protein, total sugars and starch quantities. There is a probable relationship between starch granule size ratio of the cultivar and the suitability to produce quality candied chestnut. The cultivar which has much more small starch granules may be much more suitable to produce candied chestnut. INTRODUCTION The chestnut (Castanea sativa Mill.) is a traditional nut from European countries and one of the most popular across the world. From a nutritional point of view, chestnut is considered as having interesting characteristics. Chestnuts are among the main sources of starch (up to 75% dry weight basis) but contain low amounts of protein and fat. They present several minerals and vitamins and appreciable levels of fibre (Soylu, 2004; Ertürk et al., 2006). This characteristic increases its use in diets. Starch is the main bioavailable carbohydrate in the human diet and a major polysaccharide reserve in chestnut. Starch consists of two main components: mainly linear amylose and highly branched amylopectin. The minor starch components include bound and free lipids, proteins and minerals (Ölçer and Akın, 2008). Starch granules vary in shape, size and composition depending on their botanical origin (French, 1984). Starch granule structure, amylose and amylopectin molecular structure, amylose and amylopectin ratio, and also lipid, protein and phosphate content are the main determinants that affect the functional properties of starch and, in turn, its industrial application. The following functional properties can be mentioned about starch molecules: specific viscosity, gel structure, stability in relation to its freezing and thawing, clearness, crystallization, colour, swelling and resistance to swelling (Ölçer and Akın, 2008). Chestnut is widely used as a food by cooking as well as in the cake and candy industry (Soylu, 2004). Starch granules can be physically altered during the boiling process. Consequently the morphological granular characteristics and the sensory properties of the chestnuts are modified. Starch and modified starch, which are commonly present in cereals, wheat and barley, have been extensively studied by many researchers concerning their structural properties (Patel and Seetharaman, 2006; Li et al., 2004), but a few studies reported about the starch modification of chestnuts (Pizzoferrato et al., 1999; Attanasio et al., 2004). Additionally there was no information about morphological and chemical modifications with respect to boiled nuts. So we have started serial investigations on a research on suitability of some chestnut cultivars for candied chestnut, and relationships between content and granule structure of starch and protein. In this study some morphological modifications in starch granules were followed (using SEM and LM) and chemical changes in raw and processed materials of six chestnut cultivars Proc. 1 st European Congress on Chestnut - Castanea 2009 Eds.: G. Bounous and G.L. Beccaro Acta Hort. 866, ISHS 2010