香菇红外喷动床干燥品质表征及呈味物质动态变化

Characterization of quality and flavor substances dynamic changes in infrared spouted bed drying of shiitake mushrooms

该研究采用红外喷动床干燥香菇,研究其在不同出风风温(45、50、55、60℃)和风速(7.0、7.5、8.0、8.5 m/s)下的品质(色泽、粗多糖含量、单位能耗、微观结构、收缩率、复水比和质构特性)及在最佳干燥条件下呈味物质[5′-核苷酸、游离氨基酸和等鲜浓度(equivalent umami concentration,EUC)]的动态变化。结果表明,提高出风风温及风速能加快干燥速率,缩短干燥时间,降低单位能耗,样品蜂窝状结构更为均匀。综合对比得出,最佳干燥条件为出风风温55℃、出风风速8.0 m/s,在该条件下,L值和ΔE值分别取得最大值86.45和3.84,粗多糖含量取得最大值9.60 mg/g,单位能耗取得最小值98.74 kJ/g,微孔分布均匀,收缩率和复水比分别为81.43%和3.85,质构特性较好。在最佳干燥条件下,5′-核苷酸、Asp、Glu和Ser含量在干燥过程中持续增加(P<0.05),其余游离氨基酸含量及EUC值先增加后降低,游离氨基酸总量和EUC值分别在120 min和160 min时取得最大值110.02 mg/g和303.85 g/100g,且含量均高于鲜样。提高出风风温和风速能提升香菇的品质和干燥效率,在出风风温55℃、出风风速8.0 m/s条件下香菇品质佳、风味成分保留较多。该文可为香菇干制品加工和风味食品及调味品的开发利用提供理论参考。

In this study,the infrared spray bed was used for drying shiitake mushrooms to investigate the changes in quality indicators(color,crude polysaccharide content,unit energy consumption,microstructure,shrinkage rate,rehydration ratio,and textural characteristics)under different outlet temperature(45,50,55,60°C)and airflow speeds(7.0,7.5,8.0,8.5 m/s)and the dynamic changes of flavor substances(5′-nucleotides,free amino acids,and EUC values)under the optimal drying conditions.Results showed that increasing the outlet temperatures and airflow speeds could accelerate the drying rate,shorten the drying time,and reduce the unit energy consumption,and the honeycomb structure of the sample was more uniform.By comprehensive comparison,the optimum drying conditions were 55℃and 8.0 m/s.Under this condition,the maximum values of L andΔE were 86.45 and 3.84,respectively,and the maximum crude polysaccharide content was 9.60 mg/g.In addition,the minimum value of unit energy consumption was 98.74 kJ/g,the microporous distribution was uniform,the shrinkage rate and rehydration ratios were 81.43%and 3.85,respectively,and the texture properties were good.Under the optimal drying conditions,the contents of 5′-nucleotides,Asp,Glu,and Ser increased continuously during the drying process(P<0.05),and the remaining FAAs contents and EUC values first increased and then decreased.The total FAAs and EUC values achieved maximum values of 110.02 mg/g at 120 min and 303.85 g/100g at 160 min,respectively,which were better than those of fresh samples.Improving the outlet temperatures and airflow speeds could improve the quality and drying efficiency of the shiitake mushroom,and the quality of the shiitake mushroom was better and more flavor components were retained under the conditions of outlet temperature of 55℃and airflow speeds of 8.0 m/s.This paper provides a theoretical reference for the processing of dried shiitake mushroom products and the development and utilization of flavor food and condiments.