JIA-2019-11

Journal of Integrative Agriculture 2019, 18(11): 2644–2651 RESEARCH ARTICLE Available online at www.sciencedirect.com ScienceDirect Changes of moisture distribution and migration in fresh ear corn during storage WANG Hao 1 , LIU Jing-sheng 2 , MIN Wei-hong 2 , ZHENG Ming-zhu 2 , LI Hao 2 1 College of Food Science and Engineering/The National Engineering Laboratory on Wheat and Corn Further Processing, Jilin Agricultural University, Changchun 130118, P.R.China 2 The National Engineering Laboratory on Wheat and Corn Further Processing, Jilin Agricultural University, Changchun 130118, P.R.China Abstract Understanding of moisture changes in fresh ear corn ( Zea mays L.) during storage is imperative for maintaining fresh corn quality. The changes of moisture distribution and migration in fresh ear corn during storage were investigated using low-field nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI). Water loss was greater than water migration in fresh ear corn within the first hour of storage; thereafter, water loss was weaker than water migration. With the extension of storage time, the signal intensity of MRI in different parts of sliced fresh corn with cob showed a downward trend, and the rate of signal intensity reduction was higher in the peripheral area than at the central part of sliced fresh corn with cob. The relative proportion of bound water increased with a concomitant drop in that of free water, when the total water content reduced in fresh ear corn under storage. In conclusion, NMR and MRI are useful and non-destructive tools for real-time monitoring of moisture distribution, migration, and loss in fresh ear corn during storage to assess its quality. These results can be used for future design of the preserving and processing conditions for fresh ear corn. Keywords: fresh ear corn, NMR, MRI, moisture distribution, moisture migration needs to be harvested at an appropriate grain moisture level to ensure its edible quality. The moisture content of fresh corn suitable for harvesting usually falls in 50 and 60%. The nutritive value of fresh corn originates from its contents of amylopectin, sugar, protein, amino acids, vitamins, cellulose, calcium, iron, and phosphorus (Queiro et al . 2013). Fresh corn becomes increasingly popular among domestic and overseas consumers for its delicate flavor and sweet fragrance under cooking. Aseries of physical, physiological, and biochemical changes occur quickly in fresh corn during storage due to its high level of metabolism, which include changes in the content, distribution, and migration of moisture (Christopher et al . 2003). These quick changes are liable to affect the quality of fresh corn and shorten the time span for its processing. Therefore, if appropriate measures Received 14 January, 2019 Accepted 16 April, 2019 WANG Hao, Mobile: +86-13504469072 , Email: wanghao9072@ jlau.edu.cn; Correspondence ZHENG Ming-zhu, Mobile: +86- 13843183809, Email: zhengmingzhu@jlau.edu.cn © 2019 CAAS. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/) . doi: 10.1016/S2095-3119(19)62715-2 1. Introduction Fresh corn ( Zea mays L.) refers to corn picked at the milk stage for processing or direct consumption. Fresh corn