Impact of Pleurotus ostreatus ß-Glucans on Oxidative Stability of Active Compounds Encapsulated in Powders during Storage and In Vitro Digestion.

Polyunsaturated fatty acids and α-tocopherol were encapsulated in powders by spray drying using maltodextrins DE 12 as wall material and different emulsifiers (Tween®20, acacia gum or ß-glucans-rich extracts from Pleurotus ostreatus). The aim was to study the effects of the surfactants on: (a) the oil droplet size distribution and α-tocopherol stability during in vitro digestion, and (b) the oxidative stability during 15 days of accelerated storage. Acacia gum sample had the most stable particle size distribution up to the gastric phase, but showed a significant α-tocopherol degradation prior to the intestinal stage. On the contrary, ß-glucan-samples displayed a bimodal distribution in the oral and gastric phases but retained α-tocopherol up to the beginning of the intestinal stage. At the end of intestinal stage, no α-tocopherol was found in the samples. The storage study showed that ß-glucans improved the oxidative stability of the powders, which displayed 82% α-tocopherol retention after 5 days under accelerated conditions (60 °C), corresponding to 310 days at 20 °C, while acacia gum and Tween® 20 did not delay α-tocopherol degradation. Results highlight the potential antioxidant activity of ß-glucans used as emulsifying agents during in vitro digestion and accelerated aging conditions.

The Effect of UV Irradiation on Vitamin D2 Content and Antioxidant and Antiglycation Activities of Mushrooms.

Mushroom irradiation has been considered a sustainable process to generate high amounts of vitamin D2 due to the role of this vitamin for human health and of the global concerns regarding its deficient or inadequate intake. Mushrooms are also receiving increasing interest due to their nutritional and medicinal properties. However, there is still a knowledge gap regarding the effect of UV irradiation on mushroom bioactive compounds. In this study, two of the most cultivated mushroom species worldwide, Agaricus bisporus and Pleurotus ostreatus, were irradiated with UV-B, and the effect of processing was investigated on the contents of vitamin D2 as well as on antioxidant and antiglycation activities. UV irradiation increased vitamin D2 up to 57 µg/g d.w, which is an adequate level for the fortification of a number of target foods. UV irradiation decreased the antioxidant activity when measured by the Folin-Ciocalteu reagent, the 2,2-diphenyl-1-(2,4,6 trinitrophenyl) hydrazyl radical assay and the ferric ion-reducing antioxidant power assay, but did not decrease the mushroom's ability to inhibit glycation of a target protein. These results open up a new area of investigation aimed at selecting mushroom species with high nutraceutical benefits for irradiation in order to maintain their potential properties to inhibit oxidative and glycation processes responsible for human diseases.

Effect of Vitamin D2 Fortification Using Pleurotus ostreatus in a Whole-Grain Cereal Product on Child Acceptability.

Vitamin D2 deficiency is one of the most common micronutrient insufficiencies among children. Few foods, mainly those derived from animal sources, naturally contain this vitamin. The basidiomycete mushroom Pleurotus ostreatus could be used as an innovative and sustainable ingredient for food fortification with vitamin D2. This study was aimed at exploring children's acceptance of a whole-cereal-based product (breadsticks) combined with increasing concentrations of P. ostreatus powder rich in vitamin D2. The food neophobia trait (fear of trying unfamiliar and new food) on sample acceptability was also investigated. One hundred and three children (47 girls and 56 boys, aged 9-11 years) were recruited, and breadstick-liking was studied in relation to gender and neophobic traits. Results showed that the samples enriched in vitamin D2 were well accepted by children even if liking decreased with increasing concentration of mushroom powder. Generally, neophilic subjects gave higher liking scores compared with the neophobic ones, especially for the modified samples. New, well-accepted fortified products could be developed using an adequate concentration of mushroom powder to deal with the increasing vitamin D2 deficiency among children.

Circular reuse of bio-resources: the role of Pleurotus spp. in the development of functional foods.

The basidiomycetes fungi belonging to the genus Pleurotus could make an important contribution to sustainable functional food design because they possess an elevated protein content with a valuable essential amino acid scoring pattern, a unique dietary fibre profile, mainly comprised of branched ß-glucan, high levels of some vitamins of the B group, vitamin D, Fe, Zn, Cu, Se and some bioactive mycochemicals, while the Na and fat contents are low. Moreover, Pleurotus spp. can grow efficiently on various clean by-products of food processing, such as wheat straw, wheat stalk and spent beer grain, thus representing a sustainable food source. This review illustrates the compositional variability of Pleurotus spp. grown on various by-products, in order to clarify its potential ability to address the needs of populations with endemic nutritional deficiencies as well as those populations at risk or affected by some chronic diseases. The perspectives for Pleurotus applications in functional foods decisively depend on consumers' acceptability. Hence, the sensory properties of Pleurotus spp. are also clarified herein. Lastly, the three main strategies of functional food development using Pleurotus spp. are summarized, namely its use as a fortifying agent, high-cost protein replacer and prebiotic ingredient.