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< prev - next > Food processing Pickles and vinegars KnO 100282_Pineapple peel vinegar (Printable PDF)
This product enables the utilisation of pineapple peels, which are usually discarded during the
processing or consumption of the fruit. The product has a distinct, very light pineapple flavour
and has the same uses as any commercial vinegar.
Raw material preparation
The peels should be from very well washed ripe pineapples (damaged, rotten or infected fruits
should not be used as a source of peels). Use only the peels, not the leaves or stems. The water
used should be potable water, boiled if necessary. All the equipment should be well cleaned, as
well as the bottles, which should also be steam-sterilised before use.
The peels should be cut into thin strips and put into clay or pewter pots. Aluminium or iron pots
should not be used.
Sugar and clean water are added. Each pot is then inoculated and covered with a clean cotton
cloth, held around the pot with an adhesive tape, to prevent contamination by insects or dust.
The inoculated pineapple is fermented at room temperature (about 20-220C) for about eight
days. The acidity should be checked daily. The water level should be maintained during this
period. The product should be increasingly acid and by the eighth day it should have the
required concentration of 4 per cent acetic acid in vinegar. If higher acidity is desired the
product is left to ferment for another one or two days.
The development of acidity should be checked by tasting the product during fermentation.
The residual bacteria removed may be reused as a residue inoculum two or three times more.
The traditional process may be improved by a two-stage fermentation in which alcohol is first
formed by yeast (Saccharomyces cerevisiae) and the ‘must’ is then inoculated with acetic acid
bacteria (Acetobacter pasteurianus). In outline, the process involves liquidising the peels and
diluting with water (water:pulp is 4:1), adjusting the pH to 4.0 using sodium bicarbonate and
adding yeast nutrient (ammonium phosphate) at 0.14g per litre. A starter culture is added at
2.7g per litre and the fermentation allowed to take place at 250C for two days. The ‘must’ is
then filtered and inoculated with acetic acid bacteria and allowed to ferment for eleven days with
aeration of the ‘must’. Other parts of the process are similar. Additional equipment includes a
pH meter, refractometer, liquidiser, fermentation locks and equipment for preparing the starter
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