Blue Light Does Not Affect Fruit Quality or Disease Development on Ripe Blueberry Fruit During Postharvest Cold Storage

Yi-Wen Wang,Helaina Ludwig,Savithri Nambeesan,Marc Van Iersel,Harald Scherm

doi:10.3390/horticulturae6040059

Abstract

Blueberry fruit are perishable after harvesting due to fruit softening, water loss and susceptibility to pathogens. Light, especially blue light, increases the accumulation of anthocyanins and reduces postharvest decay in some fruits, but the effect of blue light on postharvest fruit quality attributes in blueberries is unknown. In this study, we evaluated the effect of blue light on fruit quality, anthocyanin accumulation and disease development during postharvest cold storage (2 °C–4 °C) in two experiments with southern highbush blueberry ‘Star’ and rabbiteye blueberry ‘Alapaha’. Overall, diurnal blue light did not affect postharvest fruit quality attributes, such as visual defects, fruit compression, skin puncture, total soluble solid content and titratable acidity, in the two cultivars compared with their respective controls (diurnal white light or continuous darkness). Further, there was no effect of blue light on fruit color and anthocyanin accumulation. Fruit disease incidence in ‘Star’ ranged from 19.0% to 27.3% after 21 days and in ‘Alapaha’ from 44.9% to 56.2% after 24 days in postharvest storage, followed by 4 days at room temperature, but blue light had no consistent effect on postharvest disease incidence for either cultivar. Disease progression following artificial inoculations with Alternaria tenuissima and Colletotrichum acutatum in ‘Star’ was not influenced by light treatment prior to inoculation and during fruit storage. In a separate experiment, we tested the effect of blue light on color development in ‘Farthing’, a southern highbush blueberry cultivar with fruit prone to non-uniform ripening, whereby the stem-end remains green as the rest of the fruit turns blue. Although green stem-end spots turned blue over time, there was no statistically significant effect of the blue light treatment. Overall, these data indicate that blue light does not affect fruit quality attributes or disease development in ripe blueberry fruit during postharvest storage in the conditions investigated here.

Highlights

Blueberries are native to North America, with the United States being the largest producer, accounting for almost half of the global production [1]
The blue light source consisted of flexible light-emitting diodes (LEDs) strips (5630 blue LEDs, BZONE International, Taipei, Taiwan) with a peak wavelength of ~430 nm at an intensity of 40 μmol m−2 s−1
Blue light did not affect the development of visual defects such as bruising and leakiness of blueberry fruit during storage (Figure 1)

Summary

Introduction

Blueberries are native to North America, with the United States being the largest producer, accounting for almost half of the global production [1]. The commercially important species cultivated in the northern parts of the United States include lowbush (Vaccinium angustifolium Ait.) and northern highbush blueberries (V. corymbosum L.). The main cultivated species include rabbiteye (V. virgatum Ait.) and southern highbush blueberries (hybrids of V. corymbosum, V. virgatum and V. darrowii Camp.) [2,3]. Blueberries have a shelf-life of 1 to 8 weeks depending on the genotype, method of harvest and storage regime [7,8,9]. Other potential postharvest treatments to prolong shelf-life and reduce fungal growth include natural edible coatings such as chitosan, as well as irradiation [7,9,14,15,16,17]

Objectives

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Results

Conclusion