Comparison of non-volatile compounds in fresh-squeezed juice from four lime cultivars using physicochemical and sensory properties

Abstract

Lime (Citrus aurantifolia) is classed as citrus fruit. In various Thai dishes, lime juice is one of the important ingredients due to its unique flavor (aroma and taste). The uniqueness of taste in citrus is from the balance of organic acids and sugars. Organic acids and sugars contribute sourness and sweetness in citrus while limonin and naringin contribute bitterness in citrus. Taste is one of the important criteria of eating quality and consumer acceptance. This study aimed to compare the fresh-squeezed juice from four lime cultivars i.e., ‘Pan Rumpai’, ‘Pan Puang’, ‘Pan Pichit’ (Citrus aurantifolia (Christm&Panz) Swingle ) and ‘Tahiti’ (Citrus latifolia Tanaka) using physicochemical properties and sensory evaluations. The analyses of non-volatile compounds i.e., organic acid (citric, malic, ascorbic, and succinic acids) contents, the sugar (sucrose, glucose, and fructose) contents, and the bitter compounds (limonin and naringin) were analyzed using liquid chromatography. Citric acid is the predominant acid in four lime cultivars, followed by malic, ascorbic, and succinic acids respectively. The predominant sugar is fructose followed by, sucrose and glucose. ‘Pan Puang’ and ‘Pan Rumpai’ had the highest organic acid contents and TA, while the highest sugar content, bitter compound (limonin) and TSS were found in ‘Tahiti’. ‘Pan Pichit’ had the lowest organic acids, sugars, bitter compound (limonin), TSS and TSS/TA. From Principal component analysis (PCA) and Hierarchical cluster analysis (HCA), fresh-squeezed lime juice samples could be separated into 3 clusters based on the similarity of samples; a cluster of ‘Tahiti’, a cluster of ‘Pan Pichit’ and a cluster of ‘Pan Puang and Pan Rumpai’. The higher organic acids content strongly associated with ‘Pan Puang’ and ‘Pan Rumpai’ cultivars than others. The higher sugar content, bitter compound, TSS, TSS/TA ratios and sweetness score were associated with ‘Tahiti’ lime than others, whereas ‘Pan Pichit’ cultivar negatively associated with the all non-volatile compound contents, physicochemical properties and sensory attributes from a descriptive analysis. From consumer acceptance test and preference ranking test performed by culinary students, ‘Pan Puang’ was the highest preference cultivar, while ‘Pan Pichit’ is the least preference cultivar.