Assessment of the Applicability of Coconut and Skim Milk Powder as a Carrier for Lactic Acid Bacteria on Their Performance During Production of <i>Ting</i>

The demand for dried starter cultures that are specific to indigenous fermented food products is increasing. In most cases, skim milk (SM) powder is used as a cryoprotectant for microbial cell protection during the preparation of starter cultures. However, the extent of cell protection during freeze-drying and the fermentation efficacy of dried cultures are dependent on the type of microbial strain and carrier media, hence the need to investigate the protective effects of alternative carrier media. This study evaluated the fermentation potential of lactic acid bacteria (LAB) preserved in coconut (CCN) powder and SM powder during <i>ting</i> (traditional fermented sorghum) production. <i>Ting</i> was fermented with single and mixed strains of <i>Lactobacillus plantarum</i> and <i>Lactobacillus brevis</i>. The pH, total titratable acidity (TTA), functional groups (Fourier transform infrared spectroscopy [FTIR]), microbial quality, and consumer acceptability were monitored during fermentation. <i>Ting</i> prepared with LAB strains preserved in SM had a more rapid reduction (<i>p</i> > 0.05) in pH and lower final pH than <i>ting</i> prepared with LAB preserved in CCN. Mixed LAB strains showed a rapid reduction in pH of <i>ting</i> compared to single LAB strains and <i>ting</i> prepared with spontaneous fermentation. The highest TTA (3.57%) was observed with mixed LAB after 48 h on both SM and CCN <i>ting</i>. FTIR showed similar functional groups corresponding to O-H and phenolic compounds for both SM and CCN <i>ting</i>. The highest increase in LAB counts (up to 10 log CFU/mL) occurred in <i>ting</i> prepared with mixed strains of both CCN and SM, while the least increase occurred with spontaneously fermented <i>ting</i>. Enterobacteriaceae, yeasts, and molds were not detected in all the fermented samples. With consumer acceptability, CCN <i>ting</i> was the most preferred sample with the highest overall score (6.95), followed by the SM <i>ting</i> sample (5.67). In conclusion, this work indicates that the LAB strains preserved in CCN result in comparable fermentation performance to that of SM and produce <i>ting</i> that is preferred by consumers. Therefore, CCN should be considered as a carrier medium for the development of <i>ting</i> starter cultures.