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Summer truffles (Tuber aestivum) collected from Italy were evaluated for changes in chemical composition and hence in vitro bioactivity on the basis of their maturity. Truffles were classified as immature and mature based on the colour of glebum. Water and methanol extracts of freeze-dried mature truffles demonstrated higher total phenolics, in vitro antioxidant activity, and lower tannins than immature truffle extracts. Phenolics and flavonoids were detected by liquid chromatography–mass spectroscopy (LC–MS) analysis. Gas chromatography (GC)–MS analysis of hexane extracts showed differences in fatty acid composition. Linoleic acid content was highest in both samples, and lauric and myristic acids were prominently detected in hexane extracts of mature truffles. The aroma profiling of truffles by headspace—GC showed an increase in alcohols and decrease in aldehydes. Thus this study comprehends altered chemical composition and its manifestation in in vitro bioactivity on maturation of summer truffles. This would aid in development of techniques for identification of maturity of truffles. [ABSTRACT FROM AUTHOR]

This paper reported for the first time the aroma profile and essential oil composition of eight species of Helichrysum endemic in South Africa but grown in Italy (CREA-Sanremo collection). The volatiles of all the studied Helichrysum were dominated by monoterpene hydrocarbons, except for H. basalticum , where sesquiterpene hydrocarbons was the main class of compounds with β-caryophyllene (13.7%) and α-guaiene (11.9%) as major components. Despite the great diversity of compounds obtained in the volatile emission (more than 130), only four compounds were responsible for at least 34% of the identified fraction. These compounds were: sabinene (16.0%), β-caryophyllene and α-guaiene in H. basalticum ; sabinene (57.7%) in H. foetidum ; (Z)-β-ocimene (34.6%), tricyclene (16.2%) and myrcene (10.0%) in H. incanatum ; myrcene (29.3%), tricyclene (21.5%) and limonene in H. indicum ; tricyclene (32.1%) and (E)-3-hexanol acetate (20.1%) in H. montanum ; limonene (10.3%), sabinene (8.9%), 1-decene (7.6%) and 1-hexanol (7.0%) in H. mutabile ; α- and β-pinene in H. patulum (27.6% and 44.9%, respectively) and α-pinene (36.3%) and α-fanchene(15.6%) in H. setosum. The EOs composition of these species was also different from each other with sesquiterpene compounds as the prevalent class. Valerianol (16.3%, os, in H. basalticum), ledol (16.3%, os, in H. foetidum), β-caryophyllene (11.0% and 13.4%, sh, in H. indicum and H. patulum , respectively), viridiflorol (18.3%, os, in H. montanum) and valerianol (30.1%, os in H. setosum) were found to be the main constituents. It is worthy to highlighting that the H. incarnatum EO showed a similar behaviour to that of the spontaneous emission with a predominance of monoterpene hydrocarbons (60.7% in EO vs 81.4% in VOC), both represented by (Z)-β-ocimene as main constituent. • First chemotaxonomic characterisation of eight South African Helichrysum spp. • These South African were grown in the same edaphic and climatic conditions. • Monoterpene hydrocarbons dominated VOC samples except for H. basalticum. • Sesquiterpenes had the highest percentage in seven EO samples. • Helichrysum incarnatum EO was characterised by high amount of monoterpenes. [ABSTRACT FROM AUTHOR]