The Effect of an Edible Coating with Tomato Oily Extract on the Physicochemical and Antioxidant Properties of Garambullo (<i>Myrtillocactus geometrizans</i>) Fruits

• Main Authors: César Uriel López-Palestina, César Leobardo Aguirre-Mancilla, Juan Carlos Raya-Pérez, Juan Gabriel Ramírez-Pimentel, Jorge Gutiérrez-Tlahque, Alma Delia Hernández-Fuentes
• Format: Article
• Language: English
• Published: MDPI AG 2018-11-01
• Series: Agronomy
• Subjects: <i>Myrtillocactus geometrizans</i>; edible coating; shelf life; bioactive; compounds; antioxidants
• Online Access: https://www.mdpi.com/2073-4395/8/11/248

The <i>Myrtillocactus geometrizans</i> (Mart. ex. Pfeiff.) fruit, locally called garambullo, is an important source of bioactive compounds, mainly betalains, polyphenols, and ascorbic acid. However, information on the application of post-harvest technologies that prolong the shelf life of the fruits is still insufficient. The objective of the present research was to evaluate the effect of a gelatin coating incorporating 0%, 1%, or 3% tomato oily extract (TOE), compared to a control (without coating), on the physicochemical and antioxidant properties of garambullo fruits stored for 15 days at 5 &#176;C. The gelatin coatings with TOE significantly (<i>p</i> &#8804; 0.05) delayed changes in weight loss, brix degrees, titratable acidity and pH, compared to the control during storage. Fruits coated with TOE-gelatin had a higher content of betalains, ascorbic acid, total phenols, and flavonoids. The results showed that a higher concentration of phytochemicals increased antioxidant activity <i>in vitro</i>; the maximum values found for Trolox equivalents per kg of fresh weight were 10.46 and 17.65 mM for the 2,2&#8242;-diphenyl-1-picrylhydrazyl (DPPH) and Trolox Equivalent Antioxidant Capacity Method (TEAC) tests, respectively. The gelatin coating with TOE-3% (COTE-3%) reduced water loss by 1.66 times, compared to the control. In addition, the fruits covered with COTE-3% showed the highest concentration of bioactive compounds during storage.