Chocolate is an ingredient usually used in the
preparation of several foods (cakes, cookies, breads, ice
creams, etc.), which are consumed mainly by children.
Thus, the mineral content of this ingredient has great
value for nutritional control of the foods. However, the
determination of metals in such samples involves a
difficult step of digestion, considering that its matrix
contains high contents of organic compounds [1].
Chocolate is a vastly nutritious energy source, with a
fast metabolism and good digestibility. The presence of
cocoa, milk and sugar in its composition can be the
warranty of proper ingestion of proteins, carbohydrates,
fats, minerals and vitamins [2]. It is therefore necessary
to monitor human exposure to TMs present in the food
chain [3].
Toxicity of Cd came in the headlines after the
Itai-Itai disease was found to be caused by high intake
of Cd in Japan. When Cd is ingested in excess amounts,
it induces toxicity symptoms like gastrointestinal pains,
nausea, respiratory distress, diarrhoea, impaired
reproductively, kidney damage and hypertension [4-6].
Lead contamination in chocolates and candies
is a very old problem that has evolved with time. Since
the middle of the 19th century, various measures
including regulations and public education were
implemented to minimize the contamination of
chocolates and candies from such sources [7].
Nowadays, industrial activities dominate the global flux
of lead in the environment [8, 9] and have become the
predominant sources of lead in many food items,
including candies [10].
Nickel occurs naturally more in vegetables
than in animal flesh [11]. However, nickel toxicity in
humans is not a very common occurrence because the
intestinal absorption of nickel is very low [12]. Apart
from environmental contamination sources of nickel in
foods, this metal may also be derived in foods from
processing activities such as drying, cooking and
canning in nickel-containing vessels [13].