Vitamin D2 enrichment in mushrooms by natural or artificial UV-light during drying

• Published in: Food science & technology 2017-11, Vol.85, p.400-404
• Main Authors: Nölle, Nils, Argyropoulos, Dimitrios, Ambacher, Stefan, Müller, Joachim, Biesalski, Hans Konrad
• Format: Article
• Language: English
• Subjects: Agaricus bisporus; Ergocalciferol; Processing; Solar drying; UVB
• ISSN: 0023-6438; 1096-1127
• DOI: 10.1016/j.lwt.2016.11.072

This paper investigates the effect of direct sunlight during natural sun drying and solar drying in a forced convection type solar dryer on vitamin D2 content of brown button mushrooms (Agaricus bisporus). Commercial UVB light, sample processing and drying methods on vitamin D2 content were also studied via different UVB-drying strategies. Mushrooms of the same flush were divided in different groups: i) slices were dried under the sun and in an innovative solar dryer, ii) slices were UVB-treated and dried either by freeze- or convective drying, iii) whole fruit bodies were UVB-treated, sliced and freeze-dried, iv) freeze dried samples were UVB-treated in the form of slices or powder. UVB-treatment of whole mushrooms led to remarkable vitamin D2 enrichment (45 μg/g dry matter), while slicing of mushrooms prior to UVB exposure resulted in a ten-fold increase in D2 content (406 μg/g). UVB light exposure of already dried slices and powder also induced high vitamin D2 generation. Sun-dried and solar-dried mushrooms contained 36 and 39 μg/g dry matter vitamin D2, respectively. Although commercial UVB light boost D2 synthesis in mushrooms, solar drying represents a viable method for the natural formation of ergocalciferol in mushrooms and an excellent vitamin D source for vegans. •Solar drying and natural sun drying produced astonishing vitamin D contents.•Sun dried and solar dried mushrooms represent an excellent source of dietary vitamin D.•Whole UVB-treated brown button mushrooms contained high vitamin D2 content.•Slicing of mushrooms prior to UVB induced a ten-fold increase in vitamin D2 content.•UVB-treatment of previously dried slices and powder could also boost vitamin D2 formation.