谷胱甘肽型酵母抽提物不同pH值条件热反应风味分析

Thermal Reaction Flavor Analysis of Glutathione Yeast Extracts under Different pH Conditions

为研究不同pH值条件对谷胱甘肽型酵母抽提物热反应风味差异的影响,采用顶空固相微萃取-气相色谱-质谱联用技术检测热反应后的风味物质,并通过风味分析与检测结果进行对比分析。结果表明,在酸性和碱性条件下,谷胱甘肽型酵母抽提物热反应的特点和风味物质具有较大差异,酸性反应条件下苏氨酸、酪氨酸、谷氨酸为主要消耗氨基酸,碱性条件下脯氨酸、苏氨酸、酪氨酸、蛋氨酸为主要消耗氨基酸;pH5时主要是酸类化合物,pH8时吡嗪类化合物的含量最高,含硫化合物在pH6时生成挥发性化合物含量最高;风味上,pH5时,酸类物质较多,风味较差,pH6时肉风味最强,但是存在硫味,pH7时肉风味弱且不协调,pH8时主要为烤肉风味且协调性较好,但是存在少量氨味。综上所述,谷胱甘肽型酵母抽提物在偏碱性条件下,形成的吡嗪可以抑制含硫化合物的异味,因此在风味上较好,但是会出现少量氨味,后期可通过工艺优化来避免。

In order to study the effect of different pH conditions on the flavor differences of glutathione type yeast extracts during thermal reaction,headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-PME-GC-MS) technology was used to detect the flavor substances after thermal reaction,and flavor analysis and detection results were compared and analyzed.The results showed that under acidic and alkaline conditions,there were significant differences in the thermal reaction characteristics and flavor substances of glutathione type yeast extracts.Under acidic reaction conditions,threonine,tyrosine,and glutamic acid were the main amino acids consumed,while under alkaline conditions,proline,threonine,tyrosine,and methionine were the main amino acids consumed.At a pH of 5,the main compounds are acidic compounds.At a pH of 8,the content of pyrazine compounds is highest,while sulfur-containing compounds generate the highest volatile compounds at pH 6.In terms of flavor,when the pH is 5,there are more acidic substances and a poorer flavor.When the pH is 6,the meat flavor is strongest,but there is a sulfur flavor.When the pH is 7,the meat flavor is weak and uncoordinated.When the pH is 8,the main flavor is roasted meat with good coordination,but there is a small amount of ammonia flavor.In summary,the pyrazine formed by glutathione type yeast extract under alkaline conditions can inhibit the odor of sulfur-containing compounds,resulting in better flavor.However,there may be a small amount of ammonia odor,which can be avoided through process optimization in the later stage.