Fruit Quality and Antioxidant Activities of Yellow-Skinned Apple Cultivars Coated with Natural Sucrose Monoesters

Abstract

Yellow-skinned ‘Tsugaru’, ‘Summer King’, and ‘Shinano Gold’ apples (Malus × domestica Borkh.) were coated with a mixture of edible sucrose monoesters of fatty acid and ethanol that had never been applied in those apple fruits, for up to 28 days after room temperature storage (DAS) to evaluate their morphological characteristics, fruit qualities, and antioxidant concentrations. The coating treatment significantly reduced respiration rates of ‘Tsugaru’ and ‘Summer King’ apples at both 14 and 28 DAS, and ‘Shinano Gold’ at 28 DAS. The coated ‘Tsugaru’ and ‘Summer King’ apples were found in greater coverage with fragments of the sucrose esters than those of ‘Shinano Gold’, exhibiting greater skin greasiness and thickness. The coated ‘Tsugaru’ and ‘Summer King’ apples mostly maintained high fruit firmness, peel color, vitamin C, total polyphenol concentrations, and 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity. The recent developed coating material contributed to improving shelf-life of the ‘Tsugaru’ and ‘Summer King’ apples and fruit defense systems as a novel post-harvest technology for sustainable food security.

Assessing the Effectiveness of Natural Coating Application in Prolonging Shelf-Life in Plumcot Fruits

“…Fruit samples collected after 0 d CS and after 7 d CS were dipped into water as a control (uncoated control) and into a solution of 2.0% edible additives based on a mixture of sucrose monoesters of fatty acid (Naturcover Conservation Extra, Decco, Inc., Valencia, Spain) for 5 min as a coating, and then air-dried according to the method of Jung and Choi [25]. The coating material consisted of 15.0% (w/v) ethanol, 5.0% (w/v) alpha-D-Glucopyranoside, beta-D-fructofuranosyl, mixed palmitates and stearates, and 2.0% water (w/v) [25].…”

“…Peel samples from control and coated fruits were taken for observation of their morphological structure at 6 DAS according to the method of Jung and Choi [25]. The epicuticular structure (5 × 5 × 2 mm) from a 2 mm thick section of peel was analyzed under scanning electron microscopy (SEM; SU-3500, Hitachi Co., Ltd., Tokyo, Japan), with a voltage of 10 kV and at 50, 100, and 500× zoom.…”

“…Each fruit was kept in a 3000-mL plastic film bag containing a digital CO 2 electronic sensor capable of measuring between 0-1000 mL −1 kg −1 h −1 (XE-2000 Multi-function, XEAST Co., Ltd., Shenzhen, China) that was placed inside for one hour to monitor concentrations of CO 2 inside the fruit tissue [25].…”

“…The components of edible films are mainly based on natural biopolymers, protein, polysaccharide, and lipid compounds, which create a thin layer on the fruit surface and have been shown to extend the shelf-lives of early apple cultivars as well as those of citrus, European pears, pineapple, papaya, grapes, strawberry, and stone fruit [10][11][12][13][14][15][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32]. The natural coatings limit moisture and solute migration into the fruit tissue but do not consistently regulate diffusion of CO 2 gas across various fruit species [10][11][12][13][14][15][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32], with no data available for the the post-harvest behavior of coated plumcots. A sucrose monoester coating mixed with palmitate and stearate has been observed to form a semi-permeable modified atmosphere, successfully reducing fruit quality loss in early apple culti...…”

“…The natural coatings limit moisture and solute migration into the fruit tissue but do not consistently regulate diffusion of CO 2 gas across various fruit species [10][11][12][13][14][15][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32], with no data available for the the post-harvest behavior of coated plumcots. A sucrose monoester coating mixed with palmitate and stearate has been observed to form a semi-permeable modified atmosphere, successfully reducing fruit quality loss in early apple cultivars for up to 28 days, mitigating anaerobic conditions and off-flavors [22,25].…”