Abstract:
Cultivated pineapple varieties of Thailand are economic fruits and famous for Thai and foreign consumers due to their sweet and sour taste and unique scent. Each cultivar gives off a different smell. Therefore, the objective of this research was to analyze and compare the specific volatile components of 6 prominent cultivated pineapple in Thailand, such as Pattavia, Huai Mun, MD2 (Homsuwan), Trad Sithong, Phuket, and Phulae. When physico-chemical analysis of the pineapple pulp sample from each variety was performed, it was found that Trad Sithong had a statistically significant difference in the firmness from other 5 varieties and, from color measuring, MD2 and Huai Mun had the maximum lightness (L*), respectively. Trad Sithong had the highest redness (a*), whereas Pattavia had the lowest yellowness (b*). Besides, MD2 also had the maximum total soluble solids content (SSC) and titratable acidity (TA). However, the SSC/TA indicating the sweetness was found highest in Phuket. After the volatile components of 6 pineapple varieties were analyzed by headspace technique/gas chromatography-mass spectrometry (HS/GC-MS) and odor activity value (OAV) was calculated, it was revealed that there were 54 volatile components in total, including 33 esters, 2 aldehydes, 3 alcohols, 4 terpenes, 2 lactone, 2 amines, 3 miscellaneous, and 5 unknown. The highest volatile content was methyl 2-methylbutanoate (1.53-101.63 ng/gFW), follow by methyl hexanoate (1.69-39.63 ng/gFW) methyl octanoate (0.13-8.3 ng/gFW), and methyl butanoate (0.11-5.27 ng/gFW). There were 23, 13, 29, 15, 23, and 20 volatile components in Pattavia, Huai Mun, MD2, Trad Sithong, Phuket, and Phulae. The volatile substance most likely to produce a specific aroma in each cultivar was methyl 2-methylbutanoate, which gave an apple-like odor, fruity, and pineapple aroma and OAV from each cultivar was 17.76, 6.12, 406.52, 242.12, 116 and 151.68, respectively. Based on cluster analysis, Pattavia and Huai Mun had high similarity at 90.91 while Phulae and Trad Sithong had 58.73 similarities which correspond to the principal component analysis (PCA) that classified 6 pineapple varieties into 4 groups: (1) Phulae and Trad Sithong contained methyl 2-methylbutanoate, giving an apple-like odor, fruity, and pineapple aroma, (2) Pattavia and Huai Mun contained methyl butanoate, which gave a sweet smell and an apple-like odor, (3) Phuket contained ethyl 2-methylbutanoate and ethyl butanoate, which gave a fruity smell and pineapple aroma, and ethyl hexanoate, which gave a fruity smell and pineapple aroma and banana-like odor, and (4) MD2 contained methyl 2-methylbutanoate, which gave an apple-like odor, fruity, pineapple aroma, and 2,5-dimethyl-4-methoxy-3-(2H)-furanone which gave a cherry-like odor and caramel-like aroma. Thus, volatile component analysis can indicate the relationship of pineapple varieties and classify them, which is considered an odor classification that has never been reported before.