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Hot water treatment in combination with calcium ascorbate dips increases bioactive compounds and helps to maintain fresh-cut apple quality

journal contribution
posted on 2023-05-18, 16:49 authored by Aguayo, E, Requejo-Jackman, C, Roger StanleyRoger Stanley, Woolf, A
Fresh-cut ‘Braeburn’ apple slices were dipped into cold water (4 °C for 2 min) or hot water (HWT, 48 °C or 55 °C for 2 min) followed by dips into 0 or 6% w/v aqueous calcium ascorbate (CaAsc, 2 min, 0 °C) and stored in air up to 28 d at 4 °C. Microbial counts, changes in browning and sensory acceptance were determined to indicate changes in quality. Changes in antioxidant levels were measured using free radical scavenging activity (DPPH), reducing activity (FRAP), ascorbic acid content (AA) and polyphenolic content (by HPLC). CaAsc dips had a strong impact reducing the browning through increasing the flesh luminosity and hue angle. 6% CaAsc in fresh-cut apples extended the overall acceptability from less than 7 d to 14 d. Immediately after CaAsc treatment, AA content was 5 fold higher (0.25–1.25 g kg−1) than those not dipped into CaAsc. However, the combination of HWT treatments and CaAsc dips led to seven fold increased levels of AA inside the apple tissue (0.25–1.85 g kg−1) and consequently increased the antioxidant activity. HWT did not increase the AA content when not combined with CaAsc dips. The HWT CaAsc dip extended the overall acceptability to 21 d compared to 14 d for samples not heated but dipped into CaAsc. Shelf life was ultimately limited by sensory quality. At day 28, total plate counts were reduced from 5.3 log cfu/g (untreated slices) to 4.6 log cfu/g in the 6% CaAsc dips and further to 3.9 log cfu/g with the combination of HWT and CaAsc dip. Changes in the content of phenolic compounds with time, HWT and CaAsc dip were generally not significant except for slightly increased quercetin and phloridzin levels and decreased p-coumaric and procyanidins over time. The combination of HWT at 48 °C for 2 min followed by 6% CaAsc dip would be best for preserving the eating quality of apple slices.

History

Publication title

Postharvest Biology and Technology

Volume

110

Pagination

158-165

ISSN

0925-5214

Department/School

Tasmanian Institute of Agriculture (TIA)

Publisher

Elsevier Science Bv

Place of publication

Po Box 211, Amsterdam, Netherlands, 1000 Ae

Rights statement

Copyright 2015 Elsevier

Repository Status

  • Restricted

Socio-economic Objectives

Processed fruit and vegetable products (incl. juices)

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