Volatile Compounds of Re-Heated Frozen Prepared Chicken Soup Evaluated by Pareto Chart Combined with Principal Component Biplots
HUI Teng, LIANG Zhihong, DAI Ruitong*
Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China
Abstract：The aim of this study was to evaluate the impact of re-heating methods (85 ℃ water-bath re-heating vs boiling water steam re-heating) and re-heating core temperatures ((65 ± 5) vs (75 ± 5) ℃) on the overall and key volatile compounds of frozen prepared stewed chicken soup by pareto chart combined with principal component biplots. A total of 47 kinds of odor threshold compounds and 5 kinds of compounds without odor thresholds reported were detected. 1-octen-3-one, hexanal, phenylacetaldehyde, (Z)-beta-ocimene, nonanal, linalool, (E)-citral, (E)-beta-ocimene, (Z)-citral, beta-myrcene, butyl acetate, 1,8-cineole, and zingiberene were the key volatile compounds, which contributed to nearly 100% cumulative odor. Re-heating method and re-heating core temperature had a significant effect on the generation of 1-octen-3-one, phenylacetaldehyde, and butyl acetate, which made a 41.6%, 13.4%, and 1.1% odor contribution, respectively. The re-heating core temperature of (65 ± 5) ℃ promoted the degradation of linoleic acid and then gave rise to the generation of more 1-octen-3-one. However, increasing re-heating temperature to (75 ± 5) ℃ accelerated aldehyde-amine condensation in the late stage of the Maillard reaction, resulting in a reduction of 1-octen-3-one. The increase in re-heating core temperature also promoted the Maillard reaction between some amino acids and reducing sugars in the chicken soup to generate the Strecker degradation aldehyde phenylacetaldehyde. Long-time re-heating led to an obvious increase in phenylacetaldehyde generation though accumulation of lipid oxidation products in the soup. Biplots results showed that re-heating had a significant effect on the overall flavor of the soup. The water bath re-heating and the control treatments had higher similarity in the kinds and contents of volatile flavor compounds, and 85 ℃ water bath re-heating to (65 ± 5) ℃ exhibited the most similar overall flavor and key volatiles contents to those of the control group, suggesting that lower heat transfer rate and re-heating core temperature could maintain the flavor of frozen prepared stewed chicken soup during the re-heating process.
2019, Vol. 33 
