Novel insights into ascorbate retention and degradation during the washing and post-harvest storage of spinach and other salad leaves

•Salad leaves lost 35–86% of their ascorbate during 10d storage at 4°C.•Water-washing of spinach leaves and leaf discs increased ascorbate loss.•Washing in presence of hypochlorite did not significantly increase ascorbate loss.•Mechanical agitation of spinach leaves during washing exacerbated ascorb...

Full description

Saved in:
Bibliographic Details
Published in:Food chemistry 2017-10, Vol.233 (C), p.237-246
Main Authors: Dewhirst, Rebecca A., Clarkson, Graham J.J., Rothwell, Steve D., Fry, Stephen C.
Format: Article
Language:English
Subjects:
Ascorbic Acid
BASIC BIOLOGICAL SCIENCES
Chlorine
Lactuca
Oxalic acid
Plant Leaves
Post-harvest storage
Salad leaves
Spinach
Spinacia oleracea
Vegetables
Vitamin C
Washing
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:•Salad leaves lost 35–86% of their ascorbate during 10d storage at 4°C.•Water-washing of spinach leaves and leaf discs increased ascorbate loss.•Washing in presence of hypochlorite did not significantly increase ascorbate loss.•Mechanical agitation of spinach leaves during washing exacerbated ascorbate loss.•Oxalate was the major [14C]ascorbate by-product, indicating oxidative stress. Post-harvest treatments of pre-packaged salad leaves potentially cause l-ascorbate loss, but the mechanisms of ascorbate degradation remain incompletely understood, especially in planta. We explored the extent and pathways of ascorbate loss in variously washed and stored salad leaves. Ascorbate was assayed by 2,6-dichlorophenolindophenol titration, and pathways were monitored by 14C-radiolabelling followed by high-voltage electrophoresis. All leaves tested showed ascorbate loss during storage: lettuce showed the greatest percentage loss, wild rocket the least. Spinach leaves were particularly prone to losing ascorbate during washing, especially with simultaneous mechanical agitation; however, washing in the presence of hypochlorite did not significantly increase ascorbate loss. In spinach, [14C]oxalate was the major product of [14C]ascorbate degradation, suggesting that commercial washing causes oxidative stress. This study highlights that ascorbate/dehydroascorbic acid are lost via the oxidative pathway during washing and post-harvest storage of salad leaves. Thus changes to washing procedures could potentially increase the post-harvest retention of ascorbate.
ISSN:0308-8146
1873-7072
DOI:10.1016/j.foodchem.2017.04.082