Carla Sousa e Silva

TL;DR: The main effects of trace elements in human health, namely iron, zinc, copper, manganese and fluorine are reviewed, focusing on the physiopathology and consequences of lack or excess of these elements.

Abstract: Coffee is one of the most popular and consumed beverages in the world, which leads to a high contents of solid residue known as spent coffee grounds (SCG). As is known, coffee beans contain several classes of health related chemicals, including phenolic compounds, melanoidins, diterpenes, xanthines and carotenoids which are associated with therapeutic and pharmaceutical effects, due to antimicrobial, antioxidant, anti-infectious and antitumour activities. Considering that this coffee industrial waste has no commercial value and are currently disposed as a solid waste or employed as fertilizers, we intend to highlight the use of SCG as a raw material with potential interest to the food and pharmaceutical industries. Moreover, this work seems to be valuable to promote the use of SCG as natural and an inexpensive food supplements or pharmaceutical additive. The phytochemical compounds content among the crude aqueous extracts of SCG followed this order: phenolics > flavonoids > carotenoids (mg/ g dry waste), respectively. Caffeine content found in SCG was ~ 0.82 g/ 100 g dry waste, 70 % lower than coffee roasting beans. Coffee ground extracts showed inhibition to S. aureus and E. coli growth for concentrations of 1.0 mg/ mL and a stronger inhibition was also observed against C. albicans, C. krusei and C. parapsilosis growth using lower concentration (0.5 mg/ mL).

TL;DR: The hydroalcoholic extract of dried Stevia rebaudiana leaves showed high in vitro antioxidant activity, besides a positive correlation between total phenolic compounds and the DPPH and FRAP assays, and is likely to become a major source of natural sweetener for the growing food market.

TL;DR: The main effects of ultra-trace elements in human health, namely selenium, chromium, molybdenum, cobalt, boron and iodine are reviewed, focusing on the physiopathology and consequences of deficiency and/or excess of these elements.