基于电子舌的氯吡脲对草莓风味影响的研究

在草莓“甜查理”盛花后一周，喷施清水及4个浓度（2.5、5.0、10、20 mg/L）的氯吡脲，检测由此产生的草莓果实可溶性固形物、总酸、游离氨基酸、单宁等风味营养品质含量，电子舌分析技术检测酸、甜、苦、鲜、咸、涩味、苦味回味、涩味回味等味觉指标，评价氯吡脲的使用及浓度水平对草莓风味营养品质和滋味的影响，并分析电子舌在检测氯吡脲对草莓滋味影响方面运用的优势。结果表明：氯吡脲能够提高草莓果实的可溶性固形物的含量，降低总酸含量，提高固酸比值，降低游离氨基酸种类和游离氨基酸总量；低浓度（2.5、5.0 mg/L）的氯吡脲处理能降低草莓单宁含量，而高浓度（10、20 mg/L）处理会使单宁含量显著升高；电子舌味觉分析结果表明低浓度氯吡脲处理可使草莓甜味增加，酸味降低，但是咸味和鲜味及与其高度相关（相关系数均为0.99）的苦味也相应降低；游离氨基酸总量与鲜味值、单宁含量与涩味回味值、总酸含量与酸味值、固酸比与甜味值均呈正相关性。低浓度氯吡脲使用对草莓的甜味、酸味等滋味和风味组成具有正面影响，而无论氯吡脲浓度使用高低对咸味和鲜味等滋味和风味组成均有负面影响。

Electronic Tongue-based Study on the Effect of Clopidogrel Phenyl Urea (CPPU) on the Flavor Quality of Strawberry

One week after the ''Sweet Charlie'' strawberry trees produced flowers, they were sprayed with water or CPPU at either of the four concentrations (2.5, 5.0, 10, 20 mg/L). The contents of soluble solids, total acid, free amino acids, and tannins of the resultant strawberry fruits were measured. The taste indicators such as sourness, sweetness, bitterness, umaminess, saltiness, astringency, and aftertaste of bitterness and astringency were analyzed by the electronic tongue technique, to evaluate the effect of CPPU and its concentration on the flavor, nutritional quality and taste of strawberry, as well as the advantages of using electronic tongue to investigate the effect of CPPU on the taste of strawberries. The obtained results showed that the use of CPPU could increase the content of soluble solids, reduce the total acid content, increase the solid-to-acid ratio, and reduce the number of species and total amount of free amino acids in strawberry fruits. Low concentrations (2.5 or 5.0 mg/L) of CPPU could reduce the tannin content of strawberries, whilst high concentrations (10 or 20 mg/L) could increase significantly this content. The results of the electronic tongue analysis, the CPPU treatment at low concentrations could increase the sweetness and reduce sourness, with the corresponding reduction in the saltiness and umaminess along with their highly correlated bitterness (correlation coefficient: 0.99). There were positive correlations between the total amount of free amino acids and umaminess, the tannin content and astringency, the total acid content and sourness, the solid-to-acid ratio and sweetness. The CPPU treatments at low concentrations had a positive impact on the sweetness and sourness and associated flavor composition of strawberry. However, a CPPU treatment, regardless of its concentration, had a negative impact on salty and umami tastes and associated flavor composition.