Pleurotus species as a source of bio-preservatives

• Main Author: Bouzgarrou, Chaima
• Publication Date: 2017
• Other Authors: Reis, Filipa S., Barros, Lillian, Chatti, Noureddine, Ferreira, Isabel C.F.R., Martins, Anabela
• Language: eng
• Source: Repositórios Científicos de Acesso Aberto de Portugal (RCAAP)
• Download full: http://hdl.handle.net/10198/16162
• topic: Pleurotus sp.; In vitro culture; Tocopherols; Natural preservers

Mushrooms are consumed worldwide not only as a part of the normal diet, but also as a delicacy due to their highly desirable taste and aroma. In addition to their nutritional value, mushrooms have been considered functional foods [1] and even as adjuvants in some therapies, namely chemotherapy [2]. This is because they are natural matrices rich in bioactive molecules, such as phenolic compounds, tocopherols, ascorbic acid, or carotenoids. In particular, tocopherols are powerful antioxidants that can be explored as natural food preservatives, in order to replace the widely used synthetic counterparts. With these aspects in mind, and given the evidence that the in vitro culture of mushrooms promotes the production of tocopherols [3], the present work aimed to sub-culture two different mushroom species by in vitro techniques, in order to enhance the production of tocopherols, and use the mycelium as sources of preservative ingredients for foodstuff. The species chosen for the study were two of the most consumed species worldwide, Pleurotus ostreatus (Jacq. ex Fr.) P. Kumm. and Pleurotus eryngii (DC.) Quél. Firstly, both mushroom species were cultivated in different culture media (i.e., MMN complete, MMN incomplete and PDA), in order to optimize the ideal growth conditions. Since the best growth was obtained on PDA medium, both species were cultivated in PDB liquid medium, in order to obtain the amount of biomass required for the assays. After a period of approximately five weeks, the mycelia were recovered, freeze-dried and stored until further analyses. The tocopherols content was evaluated by high performance liquid chromatography coupled with a fluorescence detector. A formulation enriched in tocopherols will be prepared by extraction from the mycelium and further incorporated in cakes. Its preservative capacity will be assessed, through the evaluation of the antioxidant and antimicrobial properties before and after incorporation in the foodstuff. The results will be compared with commercial available and used preservatives (i.e., ascorbic acid- natural antioxidant and potassium sorbate- synthetic preservative).