Keywords: Chemometrics; volatile compounds; phenolic compounds; chromatographic fingerprint; pineapple

Abstract

Classification and quality control of fruits in Malaysia is based on the morphological traits manual carried out by the agricultural officer. As this approach is based on human perception and judgment, it may be biased and inconsistent. The aroma of pineapple is made up of a wide range of volatile and non-volatile compounds depending on the varieties and maturity stages of the fruits and thus, can be valuable factors in classifying the fruits. The chromatographic fingerprints of volatile and phenolic compounds from pineapple pulp were obtained by using Gas Chromatography-Mass Spectrometry Detector (GC-MSD) and 2-Dimensional-Liquid Chromatography – Diode Array Detector (2D-LC-DAD), respectively. Sensory profiles, conducted using quantitative descriptive analysis (QDA), showed that the fruity aroma of pineapple were not able to differentiate between the pineapple varieties with scales of 4.13±2.07, 5.33±2.58, 3.87±2.07, and 3.00±0.00 for the Morris, Josephine, MD2, and Sarawak varieties, respectively. Thus, sensory analysis alone could be biased and unreliable in discriminating pineapple varieties. Chemometric techniques based on unsupervised (principal component analysis (PCA) and hierarchical cluster analysis (HCA)), and supervised (discriminant analysis (DA) and partial least squares discriminant analysis (PLS-DA) using 13 sensory attributes, 10 selected phenolic compounds, and 35 volatile compounds allowed the discrimination of these four pineapple varieties.