Rozita Osman, Syaidatul Faraha Zainuddin and Siti Raihan Zakaria
Keywords: pineapples, chromatographic fingerprints, volatile, nonvolatile, chemometrics
Abstract: Pineapple (Ananas comosus L.) is one of the commercially important fruit crops in Malaysia and is listed as one of the special projects in the National Key Economic Agenda (NKEA) under the agriculture sector. Classification and quality control are based on morphological traits using manual inspection done by the agricultural officer. This approach is often biased and inconsistent as human perception and judgment are changing over time. 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 discriminating the fruits. The chromatographic fingerprints of volatile and nonvolatile 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 were conducted using quantitative descriptive analysis (QDA) showed the fruity aroma of pineapple was insignificant to differentiate between the pineapple varieties. Dealing with the chemical compositions (volatiles and non-volatiles) for the quality control of fruits involves a large set of data that requires effective statistical tools such as chemometric analysis such as cluster analysis (CA) and principal component analysis (PCA). This study showed that using sensory analysis alone could be biased and unreliable in discriminating pineapple varieties. The use of partial least square-discriminant analysis (PLS-DA) revealed the potential marker compounds for each pineapple variety permitting the unambiguous distinction between Morris, Josephine, MD2, and Sarawak pineapple. A combination of sensory attributes, volatile and non-volatile compounds provided useful information in discriminating pineapple according to their varieties.
