Mushrooms as a source of high-value bioactive moleculesconversion of ergosterol into vitamin D2, extraction, stabilisation, and a study using bakery products

Resumen

Many factors put Europe at risk of vitamin D deficiency. This deficiency causes the body to absorb less calcium and phosphate, and if there is not enough calcium and phosphate to keep the body healthy, it can cause several serious health disorders. Natural (unenriched) foods by themselves rarely provide sufficient vitamin D to prevent deficiency. Vitamin D-enriched foods and vitamin D supplements can help prevent deficiency when sun exposure is inadequate, but most of them are from synthetic sources. So, vitamin D from a natural source would be an alternative to overcome the problems of synthetic additives and help provide health benefits. The food industry is constantly searching for ingredients from natural sources due to their multifunctional properties, competitive efficacy, and lower toxicity effects, which can be used as a food fortifier. Mushrooms have been an essential part of our diet for many years due to their rich nutritional content and abundance in biomolecules, specifically ergosterol, a provitamin D2. However, reaching a more significant number of individuals is necessary. Consequently, it has been necessary to choose a food matrix consumed by a large proportion of the world's population, such as cereals, mainly wheat, whose flour is used to develop many food products worldwide. Further, to obtain vitamin D from a natural source (mushrooms - vitamin D2) is necessary to develop several methodologies, from producing mushrooms to obtaining vitamin D2. After obtaining vitamin D2, its stabilisation is also essential, so encapsulation methodologies are a choice to ensure the properties of vitamin D2 when incorporated into the final product. Vitamin D is essential for many functions in the body, but mainly for the bones, so validating the concept that vitamin D2 promotes calcium absorption is needed. The following description shows that it is possible to obtain and stabilise natural vitamin D2 from mushrooms and incorporate it into a flour matrix using innovative extraction, irradiation, and encapsulation technologies. As a result, in order to maximize the bioactive compounds, present in mushrooms, a study has been done to supplement mushroom substrates with calcium silicate. This supplementation has been linked to increased resistance against insect pests. However, few studies show the impact of this supplementation on the different agronomic parameters of oyster mushrooms (Pleurotus ostreatus var. florida) or even their chemical and bioactive composition (antioxidant, antibacterial and antifungal activities). Considering the increased production and consumption of mushrooms, the high perishability represents a significant commercial drawback. In addition to increasing the product's shelf life, preservation processes should be harmless to consumers. Therefore, the effects of gamma radiation and electron beam on the chemical and nutritional composition of fresh and dried samples of Agaricus bisporus Portobello was evaluated. A study illustrating the possibility of adding value to bioresidues left over from the mushroom cultivation industry was done. In essence, unused mushroom parts were subjected to extraction and UV-C irradiation to increase the vitamin D2 content and validate its extraction. The concentration of vitamin D2 in three different mushroom species (Agaricus bisporus, A. bisporus Portobello, and Pleurotus ostreatus) was determined by high-performance liquid chromatography (HPLC) using an ultraviolet (UV) detector. These results are good indicators of the viability of industrial mushroom surpluses as sustainable food sources of vitamin D2, and also help to reinforce the circularity principles associated with the mushroom production chain. Studies were continued with the best irradiation conditions and the mushroom that presented the best vitamin D2 content (A. bisporus Portobello). In this sense, the Portobello mushroom was subjected to extraction (use of more environmentally friendly methodologies (UAE) and solvents (ethanol)) to obtain the extract rich in ergosterol, which was then irradiated to convert the ergosterol into vitamin D2. New fortified foods open the opportunity to design new tailor-made products that not only feed and nourish but also provide bioactive compounds necessary for the proper functioning of the body, avoiding dependence on the intake of drugs or supplements with synthetic contents. In this context, vitamin D2 is a suitable candidate to be ingested in a simple way in the daily diet, namely in bread. One of the strategies to ensure the protection of bioactivity during the production of fortified bread involves its encapsulation to be incorporated in the form of particles, facilitating a homogeneous distribution in the bread dough. In this proof of concept, stabilization studies were performed where particles containing vitamin D2 were prepared using k-carrageenan polymers, through solid dispersion technology. The qualitative and quantitative characterization of vitamin D2 encapsulation allowed corroborating the effectiveness of the solid dispersion process for the formulations. Moreover, the methodology allowed the development of a final formulation with the VitD2-enriched extract (KC-Bioactive) and the incorporation in the bread of specific amounts of vitamin D2, which were subsequently identified and quantified, validating the proof of concept of the developed fortified bread. Furthermore, the promising extract (UAE) was subjected to proof-of-concept evaluation of increased calcium absorption by osteoblast bone cell line (h-FOB 1.19) by in vitro assay. The results indicated that the VitD2-enriched extract increased calcium absorption by h-FOB 1.19 cell lines. Finally, seven types of wheat and rye flour were studied for their physical and chemical properties as well as the presence of mycotoxins and microorganisms. In this sense, increasing the confidence of the European consumer, and the Portuguese in particular, in the products they buy and consume daily. To our knowledge, this is the first characterization of wheat and rye flour for Portuguese consumers. Studies on flour made from cereal by-products characterize them as sustainable ingredients for developing new bakery products and functional foods and contribute to better use of biological resources, efficiency, and circularity. Cereal by-products (wheat germ, corn bran-germ blend, rye bran, and wheat bran) from the flour milling industry were characterised for their nutritional value and chemical composition, as well as antioxidant and antibacterial activities. All the flour mentioned above can serve as a food matrix fortified with vitamin D2. The final products (flour and bread) were developed using one of the flours mentioned above (wheat flour type 65). The sensory evaluation of the samples was examined by comparing the performance of flour and bread samples fortified with KC-Bioactive and free form (VitD2-enriched extract) with the unfortified (control) samples.