Research Article Preservation of Bioactive Compounds and Quality Parameters of Watermelon Juice Enriched with L-Citrulline through Short Thermal Treatment Martha P. Tarazona-Díaz, 1 Ascensión Martínez-Sánchez, 2,3 and Encarna Aguayo 2,3 1 Department of Food Engineering, Universidad Jorge Tadeo Lozano, Carrera 4, No. 22-61, Bogot´ a, Colombia 2 Postharvest and Refrigeration Group, Department of Food Engineering, Universidad Polit´ ecnica de Cartagena, Paseo Alfonso XIII 48, Cartagena, 30203 Murcia, Spain 3 Institute of Plant Biotechnology, Universidad Polit´ ecnica de Cartagena, Plaza del Hospital s/n, Campus Muralla del Mar, Cartagena, 30202 Murcia, Spain Correspondence should be addressed to Encarna Aguayo; encarna.aguayo@upct.es Received 11 May 2017; Revised 13 August 2017; Accepted 12 September 2017; Published 29 October 2017 Academic Editor: Jorge Moreno Copyright © 2017 Martha P. Tarazona-D´ ıaz et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. L-citrulline is a nonessential amino acid with demonstrated health benefts for humans, and watermelon is a fruit rich in this amino acid. Te juice industry is developing functional beverages through the enrichment with external bioactive compounds; this kind of industry uses conventional pasteurization because of its efciency and simplicity. In this experiment, the efects of pasteurization (80 ∘ C for 40 s or 90 s) and storage (4 ∘ C for 30 days) on diferent parameters were evaluated in a watermelon juice (3.68 g kg −1 of natural L-citrulline) enriched with external L-citrulline (12 g kg −1 ). Enzymatic activity (peroxidase, pectin methyl esterase, and polygalacturonase) was inactivated (74 to 89%, 89 to 90%, and 11 to 15%, resp.) with the pasteurization treatment, obtaining the highest degradation with the longest heating time. According to the rheology study, the juice’s elasticity was mainly afected by type of heat treatment while its viscosity was more stable and afected by storage time. A reduction in bioactive compounds content, around 10–16% for lycopene and 19–20% for L-citrulline, was observed afer the pasteurization treatments, with a higher decrease with increased treatment time. Storage time also induced a reduction in lycopene and L-citrulline. Te shelf life was limited by sensorial parameters. 1. Introduction At present, there is growing consumer interest on the benefts of foods with functional properties, as these foods have improved nutritional value, promoting better health and disease risk reduction. At this time, the food industry is promoting functional juices rich in vitamins, minerals, and antioxidants to help maintain good health. As a result, the market acceptance of watermelon juice is increasing world- wide due to its sensorial and health properties. Watermelon is very rich in bioactive compounds such as lycopene and L-citrulline, which makes it an extremely attractive product for consumers, with excellent growth prospects in the juice market [1, 2]. Lycopene is a carotenoid of great interest due to its antioxidant capacity and its role in the reduction of coronary heart disease and some types of cancers such as prostate and kidney cancer [3]. L-citrulline is a nonessential amino acid that can be metabolized to L-arginine, an essential amino acid for humans, which produces nitric oxide (NO) [4], improving athletic performance and relieving muscle soreness [5]; it also has cardioprotective efects [6] among other properties. Tus, L-citrulline is commercially available in the form of pharmaceutical compounds or more recently as dietary supplement beverages such as juices. Watermelon juice enriched with L-citrulline can be defned as a func- tional food according to Goldberg [7]. A functional food is any food or food ingredient that has a positive impact on an individual’s health, physical performance, or state of mind in addition to having nutritive value. Mandel et al. [1] described an increase in plasma citrulline and arginine Hindawi Journal of Food Quality Volume 2017, Article ID 3283054, 10 pages https://doi.org/10.1155/2017/3283054