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Effect of temperature and time on free amino acid profile in Thai chicken bone soup stock preparation
Author(s)
Chotechuang, Nattida
Lokkhumlue, Matichon
Deetae, Pawinee
Date Issued
January 1, 2018
Type
Article
Abstract
Introduction: Soup stock is the basic material for cooking various types of food, including Thai food. The general practice to prepare good quality Thai soup stock is to gently boil chicken bone at 85-95°C for 1-3 h. Free amino acids (AAs) including essential AA (EAA) present in the soup stock play an important role for the supply of nutrients and the modulation of taste and palatability. Chicken bone contains key taste-active compounds such as glutamate (Glu) which is responsible for the umami taste. However, no data have been reported on the content of free AA and the changes in its concentration in chicken bone soup stock as a function of boiling time. Method: Therefore, this study aimed to investigate the effect of temperature and boiling time on the AA profile and their concentrations during soup stock production. The concentrations of free AA during the heating of the chicken bone soup stocks at three different temperatures (85°C, 90°C, and 95°C) for 30, 60, 120, and 180 min were analyzed by high-performance liquid chromatography. Results and Conclusion: The results showed the compositions of AA (19 AA) in Thai chicken bone stock prepared in each condition were similar, and major free AAs in the stock were Glu and alanine. The total free AA concentration slowly rose with increasing temperature and heating time, except for glutamine. The total AA concentration was the highest in soup stock boiled at 90°C and 95°C for 180 min (143.14 ± 3.30 and 145.99 ± 9.20 mg/100 ml, respectively) and was significant higher than those at 85°C, 180 min. The concentration of Glu was also found to be highest when the stock was boiled at 90 and 95°C, 180 min (28.61±1.0 and 28.80±2.21 mg/100 ml, respectively), whereas the concentration of EAA (52.00 ± 2.96 mg/100 ml) was significantly highest in the soup stock cooked at 95°C for 180 min. Sensory evaluation demonstrated that boiling time, but not temperature, improved sensory attributes of the soup stocks. Those boiled for 120 and 180 min obtained significantly higher scores for taste, color, thickness, and overall liking than those boiled for 30 and 60 min. This result corresponded to a significant increase of Glu concentration from 120 min of heating. This revealed that the palatability of Thai chicken bone soup stock might be affected by Glu, an umami taste substance. This finding might suggest that the condition to obtain good quality chicken bone stock in terms of taste and nutritional values, especially EAA content, is to gently boil at 90-95°C for 180 min.
Citation
Thai Journal of Pharmaceutical Sciences, 42(3), 110-117, 2018