Page 59 - Analytical method for food addtives

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E160b: Annatto extracts

5.1 Introduction
The major food groups contributing to dietary intake of annatto extracts are such
items as various cheeses, and snacks. The maximum permitted level of 50 mg/kg
is allowed in Red Leicester cheese, 10–25 mg/kg in snacks and 10 mg/kg in
liqueurs. The acceptable daily intake (ADI) for annatto extracts (as bixin) is
0.065 mg/kg body weight.

5.2 Methods of analysis
Annatto is a natural food colour and can be identified by characteristic colour
reactions. In ‘flavoured’ milk it can be detected by pouring a few millilitres of milk
into a flat dish, adding sodium bicarbonate solution and then inserting a strip of
filter paper. After a few hours the paper is stained brown in the presence of annatto
and turns pink on the addition of a drop of stannous chloride solution. In butter,
annatto can be detected by the following method: divide an ethereal solution of
isolated butterfat into two tubes. To one tube (A) is added 1–2 mL hydrochloric
acid (1+1) and to (B) 1–2 mL 10 % sodium hydroxide solution. If annatto or other
vegetable colour is present there is no colour in A, but a yellow colour appear in B. 1
There are several methods published for the determination of annatto in
foodstuffs. The traditional methods developed for annatto depend on its character-
2–7
1,2
istic colour reactions. More recently HPLC, TLC and photoacoustic
8,9
10
spectrometry (PAS) methods have been developed. A summary of these methods
is given in Table 5.1, together with the matrices for which the methods are
applicable. If statistical parameters for these methods were available these have
been summarised in Table 5.2.