A Study of Fermentation Time in Development of Fermented Pineapple Beverage

Chang, Chin Pang (2018) A Study of Fermentation Time in Development of Fermented Pineapple Beverage. Final Year Project (Bachelor), Tunku Abdul Rahman University College.

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Abstract

A study of fermentation time (0 to 72 hours) in development of alcoholic beverage was conducted with the use of basic ingredients: distilled water, brown sugar, Sarawak pineapple and baker yeast. Single factor experiment design (fermentation time: 0 to 72 hours) was used to conduct formulation trials and analysis tests in triplicate. Responses collected involved yeast population, pH, total soluble solids (ºBrix), specific gravity, alcohol content, total titratable acidity and sensory analysis (Quantitative Descriptive Analysis (QDA), Hedonic Test and Preference Test). The results showed that yeast population, pH, total soluble solid and specific gravity dropped over 3 days fermentation time whereas alcohol content and titratable acidity increased gradually. Initially, 8.97 ± 0.03 log CFU/mL of yeast, 17.4 ± 0.2 ºBrix (depend on maturity of Sarawak pineapple) and pH: 4.06 ± 0.01 were presented in Day 0 sample and after 3 days fermentation time, it decreased gradually to 7.98 ± 0.46 log CFU/mL, 9.5 ± 0.3 ºBrix and pH: 3.62 ± 0.01 respectively which may due to sugar depletion and organic acid production. Furthermore, the specific gravity is highly related to the alcohol content as sugar depletion will lower down the density of the sample and the estimated alcohol content is increased consistently (~2.5 % v/v per day). The total titratable acidity is a measure of amount predominant acid in the fermented sample and it increased steadily from 0.12% ± 0.01 to 0.35% ± 0.01 as citric acid. QDA was conducted based on the sample’s appearance, aroma, taste and mouthfeel and significant changes (p < 0.05) in colour (only Day 0 and Day 3), fruity aroma, yeasty odour, alcohol odour, sweetness, sourness, bitterness, bitter aftertaste, fruity flavour, alcohol flavour and astringency were detected by trained panels. Moreover, the flavour of the sample changed from cider taste to beer over 3 days fermentation time as described by trained panels. The results in the hedonic test shown that Day 1 sample acquired the highest overall acceptability (average scores: 7.10) compared with Day 2 sample and commercial product and 70% of panels preferred Day 1 sample.