米茶焙炒挥发性气味的形成与特征研究

以籼米为原料,经浸润、焙炒等工序制得米茶。采用电子鼻、顶空固相微萃取(HS-SPME)和气相色谱-质谱联用技术(GC-MS),研究焙炒过程中米茶挥发性成分的形成,为揭示谷物饮料的香气形成提供理论参考。大米的挥发性气味物质主要是己醛、壬醛等醛类,右旋萜二烯、酯类及烷烃类,随着焙炒时间的延长,挥发性物质种类和浓度逐渐丰富,米茶挥发性物质组成以醛、烷烃和杂环类为主,兼有较大比例醇、酯和酮类。焙炒米茶的香气成分主要是2-戊基呋喃、2-戊基吡啶和3-乙基-2,5-二甲基吡嗪等杂环物质。建立的基于电子鼻传感器的米茶香气成分预测模型具有很高的拟合精度。

The formation and characteristics of volatile odor in roasted rice tea

In order to provide a theoretical basis for revealing the formation of the aroma of cereal beverage, the indica rice was used as raw material to make rice tea after soaking and roasting, and the process of the formation of roasted rice tea volatile components was studied by using electronic nose, headspace solid phase micro-extraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS). The results showed that the volatile odorants in raw rice are mainly hexanal, nony aldehydes, dexteose limonene, esters and alkanes. With the extension of the roasting time, the type and concentration of volatile substances gradually enriched. The volatile composition of rice tea was given priority to aldehydes, alkanes and heterocyclic, and also with a larger proportion of both alcohols, esters and ketones. The main aroma components of roasted rice tea were 2 - pentyl furan, 2 - pentyl pyridine and 3 - ethyl - 2, 5 - dimethyl pyrazine. The mathematical prediction models based on e-nose sensors have high fitting precision and can better describe the aroma of rice tea.