Effect of postharvest treatments and UVB-drying strategies on vitamin D2 content of some exotic mushrooms

Publication Type

Poster

Authors

Argyropoulos, D; Nölle, N; Palka, M; Biesalski, H:K:; Müller, J

Year of publication

2018

Published in

Book of Abstracts

Editor

ISEKI Food Association

Series/labeling

The food system appraoch: new challenges for education, research and industry

ISBN / ISSN / eISSN

978-3-900932-57-2

Conference name

5th International ISEKI Food Conference

Conference location

Stuttgart, Germany

Conference date

3 - 5 July, 2018

Keywords

drying, Exotic mushrooms, Qualität, UV-Behandlung, UVB light processing, Vitamin D

Cultivation of exotic mushroom species such as grey oyster (Pleurotus ostreatus), king oyster (Pleurotus eryngii), Shiitake (Lentinula edodes), Enoki (Flammulina velutipes), Nameko (Pholiota nameko) and Pioppino (Agrocybe aegerita) is steadily increasing in Europe. Mushrooms are a good source of dietary fibres, vitamin B complex, β-carotene, tocopherol and other valuable nutrients, including β-glucans and antioxidants. They represent the only non-animal-based food which could potentially contain vitamin D. The explanation for this is that their cell membranes are composed of ergosterol, which is converted by UV light into ergocalciferol (vitamin D2). Vitamin D deficiency is a major public health problem worldwide in all age groups, even in those residing in countries with low latitude. Cultivated mushrooms contain little to no vitamin D2 due to limited sunlight in the growing rooms. However, vitamin D2 content can be enhanced by exposure to natural or artificial UV-light (mainly UVB) during postharvest processing. Fresh mushrooms are highly perishable with short shelf life under ambient conditions of temperature and humidity. Drying represents an effective approach to maintain their quality, prolong their shelf life, improve their functionality and ensure their distribution. For instance, cost-effective and energy-efficient solar drying technologies and/or UVB light assisted drying systems could remarkably reduce the losses caused by surplus production, develop safe products with exceptional nutritional properties and enhance the income of mushroom growers. Few technical details are available about the various drying technologies used for industrial applications, and what details are available can be difficult to interpret by small scale or even micro growers. An overview of the capabilities and limitations of technical drying as well as the parameters influencing vitamin D formation in target exotic mushrooms will be presented.