Food & Function PAPER Cite this: Food Funct., 2018, 9, 3166 Received 13th March 2018, Accepted 9th May 2018 DOI: 10.1039/c8fo00482j rsc.li/food-function Incorporation of tocopherol-rich extracts from mushroom mycelia into yogurt Chaima Bouzgarrou,† a,b Khira Amara,† a,b Filipa S. Reis, a João C. M. Barreira, a Fethia Skhiri, b Noureddine Chatti, b Anabela Martins, a Lillian Barros a and Isabel C. F. R. Ferreira * a Consumers are well-informed about food additives and it is likely that they prefer natural additives over their synthetic analogues. Antioxidants represent a major class of food preservatives, among which toco- pherols stand out as one of the most important examples. Interestingly, these compounds are present in relevant amounts in the mycelia of in vitro cultured mushrooms. Accordingly, the mycelia from Ganoderma lucidum, Pleurotus ostreatus and Pleurotus eryngii were used as alternative sources of toco- pherols. These extracts were incorporated into different yogurt formulations, which were further com- pared among each other and with yogurts containing commercial α-tocopherol (E307), regarding their nutritional parameters, fatty acid profile and antioxidant activity. The proposed approach was validated as an effective functionalization strategy, particularly in the case of the G. lucidum mycelium, which showed the highest antioxidant potential, most likely as a result of its tocopherol profile. Furthermore, yogurts pre- pared with each mycelium extract allowed maintaining the nutritional properties observed in the “blank” yogurt formulation. Introduction In the food industry, the use of artificial additives is mainly justified by potential improvements in the properties of pro- cessed foods. However, their excessive consumption has been associated with gastrointestinal, respiratory and dermatologi- cal adverse reactions. 1,2 Furthermore, consumers are becom- ing more well-informed about food additives and it is likely that they choose natural additives over their synthetic ana- logues. Among these additives, antioxidants naturally present in plants, algae and mushrooms, are intensely sought by con- sumers. 3,4 Vitamin E is considered a major natural antioxidant in vegetable oils, being classified as “Generally Recognized as Safe” (GRAS) and widely used in food products. 5 Nevertheless, besides vegetable oils, there are other alternative sources of this vitamin, from which it could be obtained at a low cost. Mushrooms are widely recognized for their organoleptic pro- perties, nutritional composition and bioactivity, 6–10 but they would not be (considering the lipophilicity of vitamin E) an obvious choice as such an alternative. However, the mycelia remaining from mushroom production contain relevant levels of this vitamin, thereby raising its potential use as an in- expensive source of this bioactive compound. 11 Owing to its biological effect, the inclusion of vitamin E in food products, where it is not naturally present, could rep- resent an added-value to the product. Yogurt, for instance, has been recognized as having essential nutrients with health benefits, as well as non-nutritional components that prevent or delay the onset of chronic illnesses associated with age. 12,13 However, it does not contain (except when mixed with nuts or seeds) vitamin E, so the supplementation with this component could increase its bioactive value, similar to what has been done in other functionalization approaches using hazelnut skins, 14 chamomile, fennel 15 and elmleaf blackberry. 16 Herein, the mycelia of Pleurotus ostreatus (Jacq. ex Fr.) P. Kumm., Pleurotus eryngii (DC.) Quél., acknowledged as rich sources of bioactive phenols, polysaccharides 17 and tocopher- ols, 18 and Ganoderma lucidum (Curtis) P. Karst, also reported for different bioactivities, 19–21 inclusively in its mycelium, 22–25 were used as alternative tocopherol sources in yogurts. The functionalized yogurts were further compared with a “blank” formulation (yogurt free of any additive), and with a fifth yogurt formulation incorporating synthetic α-tocopherol (E307). The evaluated parameters included nutritional compo- sition, free sugars, fatty acid profile and antioxidant activity and were evaluated in two different times: preparation day and † Both authors contributed equally. a Centro de Investigação de Montanha (CIMO), Instituto Politécnico de Bragança, Campus de Santa Apolónia, 5300-253 Bragança, Portugal. E-mail: iferreira@ipb.pt; Fax: +351-273-325405; Tel: +351-273-303219 b University of Monastir, High Institute of Biotechnology of Monastir, Genetics, Biodiversity and Valorization of Bioresources Laboratory, Street Tahar Haddad, 5000 Monastir, Tunisia 3166 | Food Funct., 2018, 9, 3166–3172 This journal is © The Royal Society of Chemistry 2018 Published on 10 May 2018. Downloaded by Instituto Politecnico de Braganca on 7/26/2018 4:23:32 PM. View Article Online View Journal | View Issue