Assessing variation in physicochemical, structural, and functional properties of root starches from novel Tanzanian cassava (Manihot esculentaCrantz.) landraces

Abstract

Starch/Starke 2016, 68, 1–14 DOI 10.1002/star.201500179 R ESEARCH A RTICLE Assessing variation in physicochemical, structural, and functional properties of root starches from novel Tanzanian cassava (Manihot esculenta Crantz.) landraces Mariam K. Mtunguja 1,2 , Maysaya Thitisaksakul 2 , Yasinta C. Muzanila 3 , Rungtiva Wansuksri 4 , Kuakoon Piyachomkwan 4 , Henry S. Laswai 1 , Guihua Chen 2,5 , Charles F. Shoemaker 6 , Neelima Sinha 7 and Diane M. Beckles 2 Department of Food Science and Technology, Faculty of Agriculture, Sokoine University of Agriculture, Morogoro, Tanzania Department of Plant Sciences, MS3, University of California, Davis, CA, USA Department of Biological Sciences, Faculty of Science, Sokoine University of Agriculture, Morogoro, Tanzania Cassava and Starch Technology Research Laboratory, National Center for Genetic Engineering and Biotechnology, Patumthani, Thailand Agricultural college of Inner Mongolia Agricultural University, Hohhot, Inner Mongolia, P. R. China Department of Food Sciences, University of California, Davis, CA, USA Department of Plant Biology, University of California, Davis, CA, USA Cassava is an ideal “climate change” crop valued for its efficient production of root starch. Here, Received: June 28, 2015 the physicochemical properties and functionality of starches isolated from six cassava landraces Revised: November 26, 2015 were explored to determine how they varied from each other and from those previously Accepted: November 26, 2015 described, and how they may be potentially used as value-added foods and biomaterials. Among genotypes, the parameters assayed showed a narrower range of values compared to published data, perhaps indicating a local preference for a certain cassava-type. Dry matter (30–39%), amylose (11–19%), starch (74–80%), and reducing sugar contents (1–3%) differed most among samples (p 0.05). Only one of the six genotypes differed in starch crystallinity (41.4%; while the data ranged from 36.0 to 37.9%), and mean starch granule particle size, (12.5 mm instead of 13.09–13.80 mm), while amylopectin glucan chain distribution and granule morphology were the same. In contrast, the starch functionality features measured: swelling power, solubility, syneresis, and digestibility differed among genotypes (p 0.05). This was supported by partial least square discriminant analysis, which highlighted the divergence among the cassavas based on starch functionality. Using these data, suggestions for the targeted uses of these starches in diverse industries were proposed. Keywords: Cassava starch / Manihot esculenta / Starch digestibility / Starch functionality / Starch structure Additional supporting information may be found in the online version of this article at the publisher’s web-site. Correspondence: Dr. Diane M. Beckles, Department of Plant Sciences, MS3, 3 University of California, Davis, CA 95616, USA. E-mail: dmbeckles@ucdavis.edu Fax: þ1-530 752 9659 Abbreviations: CLD, chain length distribution; DigRaw, digestibility of raw starch after 24 h incubation; DM, dry matter; HPAEC, high- performance anion-exchange chromatography; PKT, peak temperature; PLS-DA, partial least squares discriminant analysis; PST, pasting temperature; PV, pasting viscosity; RC, relative crystallinity; RS, reducing sugars; RVA, rapid viscosity analysis; SOL70 /90, solubility at 70°C/90°C; SV, setback viscosity; SWPW 70/90, swelling power at 70°C/90°C; SY, starch yield; SynRf, Syneresis at 20°C; Syn re, Syneresis at 4°C s 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Introduction Cassava (Manihot esculenta Crantz) has been classified as an ideal 21st century “climate change” crop because it grows resiliently under adverse conditions, and has diverse uses as food, fuel, and polymer [1, 2]. This has led to a 60% increase in global production between 2000 and 2012 with further increases projected [2]. Cassava is valued primarily for its starch, which is an important source of calories for over 800 million people in Sub-Saharan Africa, Asia, and South www.starch-journal.com