PROPOSED CHEMICAL SUBSTANCES AS QUALITY PARAMETERS OF CHOCOLATE
Date Issued
2022-09-22
Author(s)
Jovanov, Stefan
Nestorovski, Tome
Abstract
Rich, unique and sweet taste is what makes chocolate one of the favorite and
commonly used food. Ingredients such as cocoa, fats, milk and sugar play an important
role in chocolate’s quality. In this study we propose several chemical indicators as
parameters for chocolate’s quality. A total of 24 samples were analysed, 5 declared as dark
chocolates, 16 milk chocolates and 3 composite chocolates. Naturally present substances
like methylxanthines, caffeine and theobromine, are used to estimate the amount of cocoa
in chocolate. These substances were determined using HPLC-DAD method with isocratic
elution with PBS 12.5 mM pH=3.5: ACN (90:10 V/V) and RP-C18 column. Same HPLC
method was also used for the analyzing the presence of artificial sweeteners, aspartame,
Na-saccharin, acesulfame-K and the preservatives, Na-benzoate and K-sorbate. The results
showed that none of the analyzed samples contained these substances. The concentration
range of caffeine and theobromine were from 9.94 mg/L to 2129.2 mg/L and from 473.20
mg/L to 5565.6 mg/L respectively. Composite chocolates contained the lowest amount of
methylxanthines, while the dark chocolates had the highest. Fatty acids composition was
determined as methyl esters using GC-FID with capillary column. These results indicated
the content of dairy fat, cocoa butter or other vegetable fat, like palm or coconut oil, in the
total fat content of the samples. Dark chocolates contained only cocoa butter, the dairy fat in
milk chocolates and composite chocolates ranged from 8.23% to 19.57% and from 5.74%
to 18.55% respectively, while the rest of the fat was cocoa butter. Two milk chocolate
samples were dairy fat free, while the total fat content in one of the samples consisted
from 92.11% palm oil and 7.89% coconut oil, in the other sample was determined 47.23%
cocoa butter and 52.77% coconut oil. Present sugars, sucrose and lactose, were examined
with HPLC-RID method using a commercial amino-column. All milk and composite
chocolates contained lactose from 4.98% to 13.70% which is indication for used milk or
milk powder, while none of the dark chocolates contained lactose. The concentration range
for saccharose for all samples was from 29.82% to 59.51%, and it is not correlated to the
type of the chocolate.
commonly used food. Ingredients such as cocoa, fats, milk and sugar play an important
role in chocolate’s quality. In this study we propose several chemical indicators as
parameters for chocolate’s quality. A total of 24 samples were analysed, 5 declared as dark
chocolates, 16 milk chocolates and 3 composite chocolates. Naturally present substances
like methylxanthines, caffeine and theobromine, are used to estimate the amount of cocoa
in chocolate. These substances were determined using HPLC-DAD method with isocratic
elution with PBS 12.5 mM pH=3.5: ACN (90:10 V/V) and RP-C18 column. Same HPLC
method was also used for the analyzing the presence of artificial sweeteners, aspartame,
Na-saccharin, acesulfame-K and the preservatives, Na-benzoate and K-sorbate. The results
showed that none of the analyzed samples contained these substances. The concentration
range of caffeine and theobromine were from 9.94 mg/L to 2129.2 mg/L and from 473.20
mg/L to 5565.6 mg/L respectively. Composite chocolates contained the lowest amount of
methylxanthines, while the dark chocolates had the highest. Fatty acids composition was
determined as methyl esters using GC-FID with capillary column. These results indicated
the content of dairy fat, cocoa butter or other vegetable fat, like palm or coconut oil, in the
total fat content of the samples. Dark chocolates contained only cocoa butter, the dairy fat in
milk chocolates and composite chocolates ranged from 8.23% to 19.57% and from 5.74%
to 18.55% respectively, while the rest of the fat was cocoa butter. Two milk chocolate
samples were dairy fat free, while the total fat content in one of the samples consisted
from 92.11% palm oil and 7.89% coconut oil, in the other sample was determined 47.23%
cocoa butter and 52.77% coconut oil. Present sugars, sucrose and lactose, were examined
with HPLC-RID method using a commercial amino-column. All milk and composite
chocolates contained lactose from 4.98% to 13.70% which is indication for used milk or
milk powder, while none of the dark chocolates contained lactose. The concentration range
for saccharose for all samples was from 29.82% to 59.51%, and it is not correlated to the
type of the chocolate.
Subjects
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