Carbohydrate Polymers 94 (2013) 594–602 Contents lists available at SciVerse ScienceDirect Carbohydrate Polymers jou rn al hom epa ge: www.elsevier.com/locate/carbpol Chemical composition and functional properties of native chestnut starch (Castanea sativa Mill) Bruno R. Cruz, Ana S. Abraão, André M. Lemos, Fernando M. Nunes ∗ CQ-VR, Chemistry Research Centre, Chemistry Department, University of Trás-os-Montes e Alto Douro, Apartado 1013, 5000-801 Vila Real, Portugal a r t i c l e i n f o Article history: Received 21 October 2012 Received in revised form 15 December 2012 Accepted 21 December 2012 Available online xxx Keywords: Chestnut Castanea sativa Mill Starch Physico-chemical composition Crystallinity Pasting a b s t r a c t Starch isolation methods can change their physico-chemical and functional characteristics hindering the establishment of a starch-food functionality relation. A simple high yield and soft isolation method was applied for chestnut (Castanea sativa Mill) starch consisting in steeping and fruit disintegration in a 25 mM sodium bisulfite solution and purification by sedimentation. Starch integrity, physico-chemical compo- sition, morphology and functional properties were determined, being observed significant differences from previous described methods for chestnut starch isolation. The X-ray pattern was of B-type, with a degree of crystallinity ranging from 51% to 9%, dependent on the starch moisture content. The onset, peak, and conclusion gelatinization temperatures were 57.1 ◦ C, 61.9 ◦ C and 67.9 ◦ C, respectively. Total amylose content was 26.6%, and there was not found any evidence for lipid complexed amylose. Swelling power at 90 ◦ C was 19 g/g starch, and the amount of leached amylose was 78% of the total amylose content. Native chestnut starch presents a type B pasting profile similar to corn starch but with a lower gelatinization (56.1 ◦ C) and peak viscosity (79.5 ◦ C) temperatures, making native chestnut starch a potential technolog- ical alternative to corn starch, especially in application where lower processing temperatures are needed. © 2013 Elsevier Ltd. All rights reserved. 1. Introduction Chestnut kernels (Castanea sativa Mill.) are a highly appreciated seasonal nut in the Mediterranean countries. They are mainly con- sumed fresh, after cooking, with roasting, boiling or frying being the most common cooking methods. Although being a highly per- ishable product, nowadays chestnuts can be found on the market all around the year due to the availability of frozen and boiled frozen chestnuts. Other important chestnut products are avail- able on the market, among them the high added value and highly appreciated “Marrons Glacés” (Comba, Gay, Piccarolo, & Aimonino, 2009), and chestnut flour obtained by grinding dried chestnuts, used for valorization of small chestnuts or chestnuts with double embryos (Sacchetti, Pinnavaia, Guidolin, & Rosa, 2004). Chest- nut flour is then used as a confectionery paste for producing desserts and jams. It is evident that a step of heat treatment of whole chestnuts or chestnut flour is always used before consump- tion. The heat treatments, like cooking, change considerably the sensorial and nutritional properties of chestnuts, many of these changes being directly or indirectly related with starch gelatiniza- tion. For example, chestnut cooking results in large changes in the ∗ Corresponding author. Tel.: +351 259350242. E-mail address: fnunes@utad.pt (F.M. Nunes). macromolecular structure of starchy material and these are cor- related with changes of digestibility (Pizzoferrato, Rotilio, & Paci, 1999). For cooked chestnuts, besides its sweetness and color, their texture like firmness and elasticity are important quality attributes (Mellano, Beccaro, Bounous, Trasino, & Barrel, 2009). Starch is one of the main components of chestnut kernels (C. sativa), accounting for approximately 50% of the chestnut kernel dry matter (Borges, Gonc ¸ alves, de Carvalho, Correia, & Silva, 2008; Vasconcelos, Bennett, Rosa, & Ferreira-Cardoso, 2009; Pereira- Lorenzo, Ramos-Cabrer, Díaz-Hernández, Ciordia-Ara, & Rios-Mesa, 2005), so it is expected that the quality attributes and behavior dur- ing industrial processing and transformation will be related to the physico-chemical and functional properties of starch from the dif- ferent chestnut cultivars available, as observed for other starchy foods. For example, the quality of cooked rice is related with its starch chemical composition and properties, with cooked rice with low amylose content being soft and sticky, while rice with high amylose content being firmer and fluffy (Juliano, 1985). Also starch gelatinization during hydrothermal treatment of cassava may play an important role in defining the final characteristics of the cooked product (Beleia, Butarelo, & Silva, 2006). Chestnut starch has been previously isolated from oven-dried chestnut flours either from C. sativa (Correia & Beirão-da-Costa, 2010; Demiate, Oetterer, & Wosiacki, 2001), Castanea crenata S. (Yoo, Lee, Kim, & Shin, 2012) and Castanea mollissima Bl. (Zhang, 0144-8617/$ – see front matter © 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.carbpol.2012.12.060