instrumental techniques applied to mineralogy and geochemistry

90 Clemente Recio
beers. Some brands claiming to be “pure barley malt”, however, are suspicious of
misslabelling.
Other recent examples have to do with characterizing pork products. Traditional
breeding of the Iberian pig depends on the “Dehesa”, a distinctive ecosystem where the
animals are free ranging, feeding on natural resources all year long, with a major
contribution by acorns in the winter months. It is acorns that impart special
characteristics, both in terms of taste and healt benefits, to this class of pork, with
quantity and quality of the product mirroring the resources available. But modern market
demands are decoupled from natural cycles, which results in a modification of traditional
practices in order to satisfy demand, leading to an ever increasing number of animals
being reared on non-natural resources; mostly on formulated feed.
8
6
Pure Barley Malt
Barley and Wheat Malt
Added Corn, Rice, ...
4
Not clearly labelled
Bavarian Purity Law of 1516
2
0
-2
-4
-6
-29 -27 -25 -23 -21 -19 -17 -15
13 C PDB ,
FIGURE 1. Binary plot of 13 C vs 15 N measured on the dry extract of beer. Note two wellseparated
groupings, mostly determined by C isotopic values. Some samples gave values that, a
priori, do not correspond with the declared ingredients. Data from Cubides Castillo et al.
(2007).
The high quality of Iberian pork products -and subsequent consumer appreciation and
willingness to pay a corresponding high price- derives, however, from the traditional
breeding and feeding system, so a method to test for substantial acorn consumption is