Evaluating Strategies to Control Enzymatic Browning of Minimally Processed Yacon (Smallanthus sonchifolius)

Abstract

To control enzymatic browning in minimally processed yacon (Smallanthus sonchifolius), strategies combining anti-browning agents and modified atmosphere were investigated. Yacon slices were immersed in anti-browning agent solutions-sodium metabisulfite (0.5 %), L-cysteine (0.5 %), or the acids lactic (1 %), malic (1 %), succinic (1 %), ethylenediaminetetraacetic (EDTA; 1 %), ascorbic (3 %), citric (3 %) or tartaric (3 %), or a control (0.5 % de sugar)-for 5 min, then packaged with air or modified atmosphere (N 2 ) and stored at 5°C. Sensory and physical-chemical (soluble solids, phenolic content, peroxidase activity, pH, color, instrumental texture, and mass variation) analyses were performed. For a given anti-browning agent, any significant difference was not found between yacon slices stored under air or N 2 . However, when comparing the different antibrowning agents, only ascorbic, citric, and tartaric acids were effective enzymatic browning inhibitors without significantly changing typical sensory attributes of yacon. Among them, tartaric acid is not often reported in literature for controlling enzymatic browning in vegetal products, contrarily to the two others.

Evaluation of different bleaching methods applied to yacon

“…The speed of the enzymatic browning reaction is due to the oxidation of diphenols catalyzed by PPO. In comparison to the other reactions that occur in enzymatic browning, this one is significantly faster, resulting in the production of quinones, which in turn suffer chemical condensation reactions, possibly involving amines and proteins, generating dark compounds (melanins) in a short period of time (Damodaran & Parkin, ; Vasconcelos et al, ).…”

“…Citric acid, besides acting as an acidulant, also functions as the chelator of copper. Vasconcelos et al () observed that tartaric, citric, and ascorbic acids, all at a 3% concentration (m/m), that is, 30,000 ppm, were efficient in inhibiting the enzymatic browning of yacon slices and, in addition, maintained their sensory quality. Rodrigues, Asquieri, and Orsi () performed the bleaching yacon by immersing the slices in solutions with 15‐mM ascorbic acid (~2,641.8 ppm) and 7.5‐mM citric acid (~1,440.93 ppm) for 20 min.…”

“…The acceptable daily intake of sulfite, established by the Joint (Favero, Ribeiro, & de Aquino, 2011;Lien et al, 2016). Vasconcelos et al (2015) studied the use of 0.5% sodium metabisulfite for the bleaching of yacon slices. However, this agent did not satisfactorily minimize the browning of this tuberous root.…”

“…These carbohydrates are considered prebiotics, with immunostimulatory properties. Thus, these properties induce antioxidant, anti‐inflammatory, anti‐microbial activity, and anti‐cancer effects, increase the absorption of some minerals and stimulate the production of B vitamins (Bisinella, de Oliveira, Zappani, Schnitzler, & Masson, ; das Graças Vaz‐Tostes et al, ; Delgado, Thomé, Gabriel, Tamashiro, & Pastore, ; Rolim et al, ; Santana & Cardoso, ; Scheid, Genaro, Moreno, & Pastore, ; Vasconcelos et al, ).…”

“…The speed of the enzymatic browning reaction is due to the oxidation of diphenols catalyzed by PPO. In comparison to the other reactions that occur in enzymatic browning, this one is significantly faster, resulting in the production of quinones, which in turn suffer chemical condensation reactions, possibly involving amines and proteins, generating dark compounds (melanins) in a short period of time(Damodaran & Parkin, 2017;Vasconcelos et al, 2015).Ascorbic acid and citric acid, both at 400 ppm, were of low efficiency in the minimization of ΔE values over time (Figure 2), since the sample curves of bleached samples were very similar to the curves of their respective control samples. This fact can be observed due to the proximity between the horizontal asymptotes of the bleached and mathematical model of the control samples, the difference between these values and those of the control samples having been 2.08 and 4.22 for ascorbic acid and citric acid, respectively(Figure 3).…”