An Overview on the Biological Production of Vinegar

theȱfermentableȱsugarȱandȱjuiceȱsolutionȱtoȱbeȱacetified.ȱTheȱprocessingȱ

differsȱ dependingȱ onȱ theȱ rawȱ materialȱ used.ȱ Inȱ general,ȱ fruitsȱ requireȱ

less preparation than seeds; however, seeds are more easily stored and

preserved after harvest. Fruits are highly perishable, rich in water, and

need to be processed very quickly. Therefore, basic safe food handling

practices, storage, and processing are essential to prevent the growth of

pathogenic microorganisms. These microorganisms could alter the quality

ofȱtheȱfinalȱproductȱorȱevenȱproduceȱdangerousȱtoxinsȱsuchȱasȱaflatoxin.ȱ

Processing has expanded the market of both fruit and vegetable products

(Singh and Verma 1995). The seasonal gluts are avoided by the utilization

of fruits/vegetables in processing industries for the preparation of various

value added products. In advanced countries, 70-75% of perishables are

processed before reaching the consumer’s table, whereas in India only

1-2% of the total produce is processed utilizing only 40% of the installed

processing capacity.

Microorganisms involved in the vinegar production

Afterȱrawȱmaterialȱpreparation,ȱtheȱalcoholicȱfermentationȱandȱacetificationȱ

processes play a key role in vinegar production. Depending on the

environmental factors (temperature, pH, water activity) or the nutrients

(carbon sources) and the microbial diversity present in the raw material,

differentȱbiotransformationsȱcouldȱtakeȱplace.ȱMicrobialȱspeciesȱinvolvedȱ

in fermentations may range from yeast and lactic acid bacteria (LAB)

to molds and AAB. The microorganisms involved in the elaboration of

vinegars are mainly yeasts and AAB. The former being responsible for the

alcoholicȱfermentation,ȱandȱtheȱlatterȱneededȱforȱtheȱacetificationȱ(Nandaȱ

et al. 2001; Haruta et al. 2006; Wu et al. 2010).

Yeasts

Yeasts are the most important microorganisms during alcoholic

fermentationȱbecauseȱtheyȱinfluenceȱfermentationȱspeed,ȱwineȱflavourȱandȱ

other wine qualities (Pretorius et al. ȱ2006).ȱYeastsȱareȱdefinedȱasȱ‘unicellularȱ

ascomycetous or basidiomycetous fungi, whose vegetative growth result

predominantlyȱfromȱbuddingȱorȱfission’.ȱYeastsȱdoȱnotȱformȱtheirȱsexualȱ

statesȱwithinȱorȱuponȱaȱfruitingȱbodyȱ(KurtzmanȱandȱFellȱ1998).

In 2009, Rainieri and Zambonelli optimized alcoholic fermentation as

a process where the sugar as a substrate was converted into ethanol in

presence of a yeast belonging to the Class Saccharomycetes; Phylum

Ascomycotaandwasresponsibleforfermentation(RainieriandZambonelli

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