Short communication Exit of seed weevil and its parasitoid changed testa color but not phenolic and tannin contents in faba beans J.Τ. Tsialtas a, * , M. Irakli b , A. Lazaridou c a Aristotle University of Thessaloniki, Faculty of Agriculture, Laboratory of Agronomy, 541 24, Thessaloniki, Greece b Hellenic Agricultural Organization-"Demeter”, Institute of Plant Breeding and Genetic Resources, 570 01, Thermi, Greece c Aristotle University of Thessaloniki, Faculty of Agriculture, Laboratory of Food Chemistry and Biochemistry, 541 24, Thessaloniki, Greece article info Article history: Received 10 December 2018 Received in revised form 6 February 2019 Accepted 17 March 2019 Keywords: Broad beans Bruchus rufimanus Grain legumes Seed coat Triaspis thoracicus abstract Seeds of eight faba bean accessions, grown under field conditions, were subjected to L*a*b*(L*, lightness; a* redness; b* blueness) scale examination and phenolic and tannin determination after classification as intacts, bruchid- and parasitoid-damaged. Accessions differed in testa color and phenolic and tannin contents. L* and b* were negatively correlated with phenolics and tannins while a* was positively correlated with phenolics. Bruchid- and parasitoid-damaged seeds had increased a* indicating a shift of testa color tο red but phenolics and tannins did not differ between seed classes. Thus, testa discoloration in insect-damaged seeds was not the result of oxidation of phenolics but possibly due to Maillard re- action indicating accelerating aging of seeds. © 2019 Elsevier Ltd. All rights reserved. 1. Introduction Faba bean (Vicia faba L.) seeds are rich source of protein (25e37%) and starch for both human and animal consumption. As a feed, faba beans can be a partial replacement of soybean meal for monogastrics (Cr epon et al., 2010). Nutritional value of faba beans is compromised by the presence of antinutritional factors found in seed coat (testa) and cotyledons. Phenols and tannins mainly reside in testa and reduce digestibility and digestible energy and increase the endogenous excretion of proteins (Cr epon et al., 2010). These adverse effects can be miti- gated by dehulling the seeds and thermal cooking, a processing not feasible, practically and economically, when faba beans are used for feed. However, the existence of tannins in faba bean seeds has physiological and phytoprotective benefits; tannin containing cul- tivars are less susceptible to frost (Henriquez et al., 2018) and seed weevil (Bruchus rufimanus Boheman) damages (Mohamed and Abd-El Hameed, 2014). Faba bean varieties differ significantly in their resistance to seed weevil and parasitization of bruchid larvae by a braconid wasp [Triaspis thoracicus (Curtis, 1860)] contributes to this (Seidenglanz and Hu nady, 2016). Low-tannin seeds retain their harvest testa color for longer compared to tannin-containing seeds (Cr epon et al., 2010). Dark- ening of testa under improper storage conditions was accompanied by a fall of phenolic content (Nasar-Abbas et al., 2009). A change of testa color from green to brown has also been observed in bruchid- infested peas (Pisum sativum L. subsp. sativum L.) without any report of changes in seed phenolics (Teshome et al., 2015). Briefly, testa discoloration has been reported as the result of both improper storage conditions and bruchid infection with the former to cause a concomitant change of seed chemical composi- tion. However, there is no report on whether testa discoloration by bruchids is accompanied by changes in seed chemical composition. In addition, we are unaware of any report about the effects of the natural enemy of bruchid, Triaspis thoracicus, on testa color or seed chemical composition. Thus, the aim of the present work was to study in eight faba bean accessions whether seeds damaged by seed weevil adults or the braconid wasp show changes in testa color and phenolic and tannin contents. 2. Materials and methods 2.1. Plant material and experimental set up Seven large-seeded (V. faba var. major) accessions (hereafter * Corresponding author. E-mail address: tsialtas01@windowslive.com (J.Τ. Tsialtas). Contents lists available at ScienceDirect Journal of Stored Products Research journal homepage: www.elsevier.com/locate/jspr https://doi.org/10.1016/j.jspr.2019.03.004 0022-474X/© 2019 Elsevier Ltd. All rights reserved. Journal of Stored Products Research 82 (2019) 27e30