Abstract:
The microbiological and physicochemical characteristics of both pineapple and pawpaw fruits during production of wine were investigated. Apparently healthy fruits were collected and blended in different ratio and fermented for five days using indigenous organisms as starter cultures. The microorganisms isolated from the fermented samples include: Bacilus subtilis, Lactobacillus delbrueckii, Leuconostoc mesenteroides, Staphylococcus aureus, Citrobacter fruendi, Aspergillus niger, Rhizopus species, Fusarium oxysporium and Saccharomyces cerevisiae. There was an increase in microbial load of the fermenting samples especially within the first three days of fermentation as a result of hydrolysis of carbohydrate by fermenting microorganisms. The dominant lactic acid bacteria (Lactobacillus delbrueckii), Leuconostoc mesenteroides and yeast (Saccharomyces cerevisiae) isolated from spontaneous fermentation were used as starter cultures, singly and in combination for controlled fermentation in the production of the wine. The wine was produced using the mixture of the fruits in ratio 1:1, 1:3 and 3:1 was evaluated for pH and total titratable acidity on daily basis, in each case. The proximate, anti-nutrient, alcohol and mineral contents were determined before and after the 5 days of fermentation. There was a significant drop in pH of the wine produced by single starter cultures and by the mixed culture. At ratio 1:1 the single starter culture of Leuconostoc. Mesenteroides, Lactobacillus delbruecki or Saccharomyces. cerevisiae reduced the pH from 6 to 4.3, 4.1 or 3.6 respectively. The mixed culture gave a pH value of 3.5 after the fifth day fermentation. The wine produced from the mixed cultures gave the highest protein content of 16%. There was reduction in the tannin content from 3.40 mg/100ml to 2.50 mg/100ml and oxalate content from 2.6 mg/100 ml to 1.80 mg/100 ml by the mixed culture on 1:1 blended sample. The alcohol content of the wine was 3.30%. The wine produced from the ratio 1:1 fermented with the mixed culture was rated best in terms of acceptability and differed from other products. This study has shown that the fruits of pineapple and pawpaw can be used for the production of wine and the use of indigenous starter cultures in its production gave the best quality of the wine in terms of sensory, uniformity and nutritional values.
