Biochemical characterization of enzymatic browning in selected apple genotypes

Abstract

S. 2007. Biochemical characterization of enzymatic browning in selected apple genotypes. Can. J. Plant Sci. 87: 1067-1074. Enzymatic browning in apples (Malus × domestica Borkh.) caused by polyphenol oxidases (PPO) is the major factor responsible for the deterioration of quality in processed apple products such as juice, fresh-cut slices, and chips. Selected apple genotypes with a range of low post-cut enzymatic browning were investigated to understand the biochemical mechanisms leading to enzymatic browning. Post-cut enzymatic browning, polyphenolic profiles using LC-MS/MS, PPO activity, vitamin C, total antioxidant capacity using the Ferric Reducing Antioxidant Power (FRAP) and the Oxygen Radical Absorbance Capacity (ORAC), and elemental composition were determined in two recently released cultivars [Eden TM (also known as SJCA38R6A74) and SuperMac], and one new advanced line (SJCA16) and compared with two commercial cultivars (Empire and Cortland). Eden TM exhibited the least post-cut enzymatic browning as estimated by Whiteness Index. SJCA16 possessed a characteristic yellowish flesh color. Whiteness Index (WI) values were inversely related to chlorogenic acid, catechin and epicatechin contents present in apple slices. Vitamin C content showed a strong positive correlation with WI. Among the mineral elements, the content of copper had a strong positive correlation with PPO activity.

Nutritional characterization of apple as a function of genotype

“…The maximum ascorbic acid content was recorded in red cultivars, 'Starkrimson' (32.08 mg 100 g -1 ) and 'Oregon Spur II' (31.76 mg 100 g -1 ) whereas the least ascorbic acid was recorded in 'Well Spur' (19.38 mg 100 g -1 ) ( Table 2). Our data on this attribute are lower than those reported by Jan et al (2012) and have wider range than those reported by Joshi et al (2007) who reported ascorbic acid in the range of 14.3-45.9 mg 100 g -1 and 10.27-12.49 mg 100 g -1 , respectively in apples. This deviation in the values of ascorbic acid may be due to fact that we analyzed different varieties than those studied by them.…”

“…In a similar study, Wang et al (2015) reported that the antioxidant activity was significantly higher for red-fleshed genotypes than for white-fleshed genotypes. Similarly, a wider range of AOX activity (7.7-22.6 lmol Trolox equivalent g -1 ) has been reported by Joshi et al (2007) in apple cultivars. The difference observed among the genotypes studied in terms of antioxidant activity may probably be due to plant genotype because all plants were grown in the same location using similar horticultural practices.…”

Impact of Drying Processes on Bioactive Phenolics, Vitamin C and Antioxidant Capacity of Red-Fleshed Apple Slices

“…Air‐drying caused significant loss of catechin, epicatechin and phloridzin, which can be due to the exposure of apple slices to oxygen during air‐drying resulting in postcut enzymatic browning in apple slices (Funebo and Ohlsson 1998). It has been reported that catechin and epicatechin are the desirable substrates for polyphenol oxidase, which causes postcut enzymatic browning in apples (Joshi et al. 2007).…”

“…Air-drying caused significant loss of catechin, epicatechin and phloridzin, which can be due to the exposure of apple slices to oxygen during air-drying resulting in postcut enzymatic browning in apple slices (Funebo and Ohlsson 1998). It has been reported that catechin and epicatechin are the desirable substrates for polyphenol oxidase, which causes postcut enzymatic browning in apples (Joshi et al 2007). However, in the present study, the impact of drying on the color and browning of the apple slices could not be determined because of the interference of the color measurement due to the characteristic nonuniform red and white color distribution of the red-fleshed apple slices.…”

Colour and texture of apples high pressure processed in pineapple juice

“…4a and b ). The observed differences in the two apple varieties may be due to the differences in the susceptibility to browning of the apple varieties (Lozano-de-Gonzalez et al, 1993;Rocha & Morias, 2001;Ye, Heng, Yuan-peng, Feng & Shu-wei, 2007;Joshi et al, 2007), PPO activities and perhaps differences in polyphenol composition (Joshi, Rupasinghe, Pitts & Khanizadeh, 2007). In HPP (100-1000 MPa/−20°C to 60°C), cell walls and membranes are prone to disruption (Michel & Autio, 2001;Prestamo & Arroyo, 1998;Van Buggenhout, Messagie, Van Loey, & Hendrickx, 2005).…”