METABOLITE PROFILES AND ACCEPTABILITY BY CLUSTERS OF DIFFERENT KEFIR TYPES FOR SOUTH AFRICAN CONSUMERS

Abstract

Kefir is an alternative fermented dairy product for low income South African consumers. However, it was shown that mass culturing of kefir grains leads to a loss of positive sensory attributes. Thus, this paper evaluates the chemical composition and the sensory acceptability for South African consumers of four variants of kefir (traditional kefir, mass-cultured kefir, Candi-kefir and Lacto-kefir).
Results showed that all variants of kefir contained key flavour compounds: acetaldehyde (7 – 45 mg.L-1), ethanol (186 – 1774 mg.L-1), diacetyl (5 – 12 mg.L-1), ethyl acetate (1,2 – 30 mg.L-1) and acetic acid (892 – 4 490 mg.L-1); with acidity (TA: 0,85 – 0,96%; pH: 4,13 – 4,25) comparable with ranges reported in literature.
Based on the liking of flavour of the variants of kefir, three clusters of consumers (N=85) were identified using Ward’s clustering. Cluster I was negatively sensitive to acidic products as indicated by the low scores (<5,30) given for liking of flavour. For Cluster II consumers, the main driver of liking of flavour was ethanol (r = 0,963; p < 0.05), therefore giving the best score (7,5) to traditional kefir the most ‘yeasty’ variant. For cluster III, acidity was a significant driver of liking (r = 0,999; p < 0.05). Thus, less acidic kefir products obtained better consumer liking scores ranging between 7,09 and 7,63.
The results of this study add to the understanding of sensory attributes which drive consumer preference for kefir. This important information can be used by the South African dairy industry to strengthen the current market through the appropriate production of kefir.