Enzymatic browning in avocado (Persea americana) revisited: History, advances, and future perspectives

Abstract

Considering nearly 80 years of research regarding one of the enzymes responsible for catalyzing the formation of pigments in higher animals, plants, fungi and bacteria, this review will focus on collecting and categorizing the existing information about polyphenol oxidase (PPO) in fruits, with particular emphasis on the information in relation to avocado, which is one of the hardiest species in terms of inactivation, has documented dual activity (EC 1.14.18.1/EC 1.10.3.1), and represents one of the oldest challenges for food science research and fruit processors. It is expected that this review will contribute to the further development of the field by highlighting the questions that have arisen during the characterization of PPO, the progress that has been made and the questions that remain today, in addition to new methodologies that are being applied to study this system. Holistic methodologies offer unexplored potential for advancing our understanding of the complex phenomena that govern PPO activity in fruits, because these methodologies will enable the characterization of this family of enzymes in all of its complexity. Subsequently, it will be possible to develop better techniques for controlling enzymatic browning in this valuable fruit.

ACTIVIDAD ENZIMÁTICA DE PALTA FUERTE (persea americana) DURANTE EL ALMACENAMIENTO EN REFRIGERACIÓN

“…La palta (Persea americana Mill.) es una fruta climatérica altamente susceptible al pardeamiento enzimático y ha sido objeto de varios estudios donde se evaluaron diferentes compuestos antioxidantes sintéticos, temperaturas de almacenamiento y la aplicación de atmósferas modificadas para evitar el pardeamiento (Oms-Oliu et al, 2010;Soliva, Elez, Sebastián, & Martín, 2001); sin embargo, la PPO de la palta tiene una alta actividad catalítica y una resistencia considerable a los tratamientos de inhibición comunes en comparación con las PPO de otras frutas (Toledo & Aguirre, 2016;Weemaes et al, 1999), por esta razón su inhibición es un tema de investigación debido a la dificultad de preservar la calidad fresca de la palta durante períodos prolongados (Gendel, 2012). Los compuestos fenólicos también son relevantes en términos del flavor de los alimentos, ya que pueden desempeñar un papel en el sabor amargo, dulce, picante o astringente de algunos productos y también pueden contribuir al aroma.…”

Effects of cold plasma on avocado pulp (PerseaamericanaMill.): Chemical characteristics and bioactive compounds

“…However, agroindustrialization of the fruit is a challenge due to its intrinsic characteristics, such as the high concentration of enzymes responsible for enzymatic browning, mainly polyphenol oxidase (PPO), which catalyzes the oxidation reaction of o‐diphenols in the presence of molecular oxygen, transforming them into o‐quinones, which produce dark pigments (Dantas et al., 2018). The PPO present in avocados has high catalytic activity and significant resistance to common inhibition treatments, including whitening, modified atmosphere and others, compared to that in other fruits (Toledo & Aguirre, 2017).…”