关键词: 甜面酱, 非挥发性有机酸, 气相色谱-质谱法, 酸味

Abstract:

The non-volatile organic acids in 7 kinds of sweet sauces were determined by gas chromatography-mass
spectrometry (GC-MS). The acid components were esterified with 12.5% (V/V) H2SO4-CH3OH solution and extracted by
CH2Cl2. Identification of these organic acids was assessed by comparing their retention indexes (RI) with those of authentic
standards using double-column method, and semi-quantification was conducted by using methyl tridecanoate as the internal
standard. Totally 37 non-volatile organic acids were separated by a strong polar column and a weak polar column and their
chemical structures were identified, including 18 higher fatty acids, 10 polybasic acids, 3 aromatic acids and 6 other types.
The content of the higher fatty acids accounted for 86.62%–95.12% of the total organic acids, and their carbon numbers
mainly ranged from 14 to 22. The major acid components in 5 kinds of sweet sauces commercialized in Beijing were linoleic
acid (52.14–53.46 mg/100 g), palmitic acid (17.33–18.09 mg/100 g), oleic acid (11.53–13.54 mg/100 g), levulinic acid
(2.93–4.03 mg/100 g), α-linolenic acid (2.65–2.91 mg/100 g), citric acid (1.61–3.61 mg/100 g), sorbic acid (1.18–1.83 mg/100 g)
and stearic acid (0.90–1.21 mg/100 g). It was also found that the types of organic acids in sweet sauces from different origins
were basically the same. However, the content of each compound showed a significant difference. Compared with previous
results obtained by electronic tongue analysis, citric acid provided the biggest contribution to the sourness of sweet sauce.
However, no appreciable relevance between content of organic acids and sourness intensity was observed in this work.

Key words: sweet sauce, non-volatile organic acids, gas chromatography-mass spectrometry (GC-MS), sourness