Influence Of Serving Temperature On Consumer Preference And Flavor Characteristics Of Huangjiu

Food temperature is an important factor affecting its flavor,which has an important influence on consumer preference and acceptance.Huangjiu is a traditional fermented wine in China,which has complex and unique flavor.At present,there is no report focused on the effect of serving temperature on preference and flavor characteristics of Huangjiu.In this research,consumers’preference for serving temperature of Huangjiu and its driving factors were analyzed.Then the effect of serving temperature on the sensory characteristics of semi-dry and semi-sweet Huangjiu was studied.And we discussed the reasons of temperature’s influence on the sensory characteristics of Huangjiu from three perspectives:the release of volatile components,basic taste and physicochemical indexes.At last,the effects of alcohol content and sugar content on the release of volatile flavor compounds in Huangjiu were further analyzed.The main research results are as follows:（1）The effects of serving temperature on sensory properties of semi-dry and semi-sweet Shaoxing Huangjiu were studied by using Check-All-That-Apply（CATA）and 9-point hedonic tests.The results showed that there were 13 sensory attributes of semi-dry and 12 sensory attributes of semi-sweet Huangjiu were affected by serving temperature.The results of penalty analysis showed that,for semi-dry Huangjiu,astringency and spicy were the key attributes that reduced the degree of consumers’liking,but no attribute could improve the degree of consumers’liking.Sweet and umami taste can enhance consumers’preference for semi-sweet Huangjiu,while bitterness,astringency and spicy can reduce consumers’preference.The Preference Mapping showed that more than 80%of consumers preferred to drink semi-dry Huangjiu at 4℃,10℃and 16℃.For semi-sweet Huangjiu,more than 80%of consumers like to drink it at 4℃,10℃and 16℃,and 40%-60%of consumers like to drink it at 36℃and above.（2）The effects of serving temperature on sensory characteristics of semi-dry and semi-sweet Huangjiu were studied by sensory quantitative descriptive analysis.There were 17sensory properties in both semi-dry and semi-sweet Huangjiu that were significantly affected by temperature.For semi-dry Huangjiu,the overall aroma intensity,nut aroma and almond aroma increased with the increase of temperature,while other aroma attributes showed a trend of increasing first and then decreasing.The intensity of flowery aroma and smoky aroma was the highest at 42℃,and the intensity of fruit aroma was the highest at 36℃.For semi-sweet Huangjiu,the higher the temperature,the stronger the overall aroma intensity and almond aroma.And the fruit aroma was the highest at 36℃,floral,nutty and smoky aroma at 42℃.The sour and umami taste increased with serving temperature,while the astringency decreased with it.Sweet taste first increased and then decreased with temperature,and it had the highest sweet taste intensity at 36℃.On the contrary,the bitterness decreased first and then increased with temperature,which was weakest at 36℃.By combining the results of sensory quantitative description analysis and CATA analysis,it was preliminarily determined that the suitable serving temperature of semi-dry Huangjiu was 16℃（cold drink）and 36℃（warm drink）,and that of semi-sweet Huangjiu was 10℃（cold drink）and 36℃（warm drink）.（3）The reasons for the influence of serving temperature on the sensory characteristics of Huangjiu were explored.41 volatile flavor compounds were identified by GC-IMS in the headspace of semi-dry and semi-sweet Huangjiu at different temperatures.The headspace content of 18 compounds,such as dimethyl disulfide,2-octanone,2-pentanone and benzaldehyde,increased faster than other compounds.By partial least square-discriminant analysis,22 key components which were significantly affected by temperature were screened out.By adding the above key components into Huangjiu and conducting sensory evaluation,the results verified the contribution of the volatilization of these components to the aroma difference of Huangjiu at different temperatures.The ionic strength of Huangjiu gradually increased with temperature,which may lead to the increase of H⁺and free amino acid concentration,which was manifested as the enhancement of taste properties such as sour,umami and bitter taste of Huangjiu.The viscosity of Huangjiu decreased with temperature,which was manifested as the decrease of the feel of viscosity in mouth.Electronic tongue was used to measure the basic taste of Huangjiu at different temperatures,and the sensor response values were linearly fitted with sensory data.The results showed that for semi-dry Huangjiu,the R² between the response values of sour,sweet,bitter,umami and astringency and sensory analysis results were 90.4%,91.6%,48.3%,86.4%and 89.5%,respectively.For semi-sweet Huangjiu,the R² was 95.2%,94.3%,5.7%,78.8%and 81.0%.The above data indicated that the electronic tongue could be used to predict the taste changes except bitterness of Huangjiu at different serving temperatures.（4）The effects of ethanol and glucose on the release of aroma compounds in Huangjiu at different temperatures were studied.The difference of ethanol and glucose concentration will change the coefficient（slope）of the release curve equation of the headspace content of aroma compounds in Huangjiu with the increase of temperature.When the ethanol concentration changed,the release coefficients of 17 compounds were significantly different with the change of temperature.The coefficients of 2-butanone,2,3-butanedione,butyraldehyde and isobutylaldehyde reached the maximum when the ethanol content was 5%vol,indicating that the headspace content of these substances increased fastest at this time.A total of 12substances,including 2-pentanone,2-heptanone and 2-octanone,had the maximum release coefficient at 15%vol,and only dimethyl disulfide had the maximum release coefficient at25%vol.When the glucose concentration changed,the release coefficient of 17 substances including 2-butanone,2-pentanone and so on reached the maximum when the glucose concentration was 40 g·L^-1.The results of 3-AFC showed that at 25℃and 48℃for sensory evaluation,there were significant differences in fruit and flower fragrance between 5%vol and 25%Vol simulation solution.At 48℃,there was a significant difference in the intensity of almond aroma between 40 g·L^-1 and 120 g·L^-1 simulated solution.This indicated that when the temperature was higher than 25℃,the change of ethanol and glucose concentration may lead to discernible differences in the sensory properties of the simulated solution.