Phenolic, polysaccharidic and lipidic fractions of mushrooms from northeast Portugal: chemical compounds with antioxidant properties

Mushrooms do not constitute a significant portion of the human diet, but their consumption continues to increase due to their functional benefits and presence of bioactive compounds. Some of those compounds can be found in the phenolic, polysaccharidic and lipidic fractions of edible and inedible species. Herein, those fractions of five wild mushrooms (Coprinopsis atramentaria, Lactarius bertillonii, Lactarius vellereus, Rhodotus palmatus and Xerocomus chrysenteron) from Northeast Portugal were studied for their chemical composition and antioxidant properties. Protocatechuic, p-hydroxybenzoic, p-coumaric and cinnamic acids were found in the phenolic fraction, ramnose, xylose, fucose, arabinose, fructose, glucose, manose, mannitol, sucrose, maltose and trehalose were quantified in polysaccharidic fraction, linoleic and stearic (only in Lactarius sp.) acids, and β- and γ-tocopherols were the main compounds in the lipidic fraction. C. atramentaria and X. chrysenteron phenolic fractions gave the highest free radical scavenging activity, reducing properties and lipid peroxidation inhibition in brain homogenates, which is in agreement with its highest content in total phenolics. Furthermore, among the polysaccharidic fractions C. atramentaria also gave the highest antioxidant activity, which is accordingly with its highest total polysaccharides content and sugars obtained after hydrolysis.The authors are grateful to Fundação para a Ciência e a Tecnologia (FCT, Portugal) and COMPETE/QREN/EU (research project PTDC/AGR-ALI/110062/2009) for financial support. L. Barros (BPD/4609/2008) and S.A. Heleno (BD/70304/2010) also thank FCT, POPH-QREN and FSE. The GIP-USAL is financially supported by the Spanish Ministerio de Ciencia e Innovación through the Consolider-Ingenio 2010 Programme (FUN-C-FOOD, CSD2007-00063), and Junta de Castilla y León (Grupo de Investigación de Excelencia, GR133)

Effect of jenny milk addition on the inhibition of late blowing in semihard cheese

The occurrence of late blowing defects in cheese produces negative effects on the quality and commercial value of the product. In this work, we verified whether the addition of raw jenny milk to bulk cow milk reduced the late blowing defects in semihard cheeses. During cheesemaking, different aliquots of jenny milk were poured into 2 groups of 4 vats, each containing a fixed amount of cow milk. A group of cheeses was created by deliberately contaminating the 4 vats with approximately 3 log10 cfu/mL milk of Clostridium tyrobutyricum CLST01. The other 4 vats, which were not contaminated, were used for a second group of cheeses. After 120 d of ripening, some physical, chemical, and microbiological parameters were evaluated on the obtained semihard cheeses. Differences in sensory properties among cheeses belonging to the uncontaminated group were evaluated by 80 regular consumers of cheese. Our results showed that the increasing addition of jenny milk to cow milk led to a reduction of pH and total bacterial count in both cheese groups, as well as C. tyrobutyricum spores that either grew naturally or artificially inoculated. We observed a progressive reduction of the occurrence of late blowing defects in cheese as consequence of the increasing addition of jenny milk during cheese making. Moreover, the addition of jenny milk did not affect the acceptability of the product, as consumers found no difference among cheeses concerning sensorial aspects. In conclusion, the important antimicrobial activity of lysozyme contained in jenny milk has been confirmed in the current research. It is recommend for use as a possible and viable alternative to egg lysozyme for controlling late blowing defects in cheese