The aim of the present study was to perform simultaneous alcoholic and malolactic wine fermentations using free or immobilized kefir culture at a wide temperature range (5-45 °C). Repeated batch fermentations were carried out for a period up to 29 months, suggesting a high operational stability of the systems, while malic acid conversion and ethanol productivity up to 70.9% and 36.9 g/(Ld) were noted. Volatile acidity was at levels typically found in wines (<1.0 g acetic acid/L) in most cases, although increased values were recorded in wines produced at 5 °C, but no vinegar taint was detected. Fusel alcohols were at levels usually found in wines, but were reduced at 5 °C. Application of PCA to minor volatiles showed that the fermentation temperature rather than the nature of kefir culture had a significant effect. Noticeably, all products were accepted by the panel during the preliminary sensory evaluation.
Keywords: 1-Hexanol (PubChem CID: 8103); 2-Methyl-1-propanol (PubChem CID: 6560); 2-Phenylethanol (PubChem CID: 6054); Acetaldehyde (PubChem CID: 177); Acetic acid (PubChem CID: 176); Apple; Delignified cellulosic material; Ethanol (PubChem CID: 702); Ethyl acetate (PubChem CID: 8857); Grape skins; Kefir culture; Lactic acid (PubChem CID: 612); Methanol (PubChem CID: 887); Sensory evaluation; Volatiles; Wine; l-Malic acid (PubChem CID: 222656).
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