Antioxidant Properties of Fermented Camel Milk Prepared Using Different Microbial Cultures

Abstract

This study investigated the effect of using different combinations of commercial starter culture and lactobacilli strains on the antioxidant properties of fermented camel milk for 14 days. The bacterial strains included Lb. casei subsp. casei B-1922, Lb. paracasei subsp. paracasei B-4560, Lb. rhamnosus B-442 and Lb. rhamnosus B-1445. The antioxidant activity of fermented milk was estimated using DPPH radical scavenging activity, ferrous ion chelating activity (FCA) and ferric reducing power assays. The total phenolic content (TPC), titratable acidity, proteolysis degree and sensory acceptability of samples were also evaluated. The results showed that all the studied parameters were affected by both the type of starter culture and storage. Samples containing the commercial starter and Lb. rhamnosus B-1445 had the highest DPPH radical scavenging activity and TPC throughout storage. Fermented milks prepared using the commercial starter and Lb. rhamnosus B-442 or Lb. paracasei retained their high FCA and reducing power throughout storage compared to the other samples. Fermented milk containing the commercial starter and Lb. casei showed the lowest antioxidant activity. The DPPH scavenging activity for all fermented milks decreased sharply during storage, while the change in FCA, reducing power and TPC differed among the samples during storage. The highest acidity was observed in the samples containing the commercial starter and Lb. paracasei, while fermented milk prepared using commercial starter and Lb. rhamnosus B-1445 had the lowest acidity. Samples containing the commercial starter and Lb. casei had the greatest proteolysis during the first week of storage, while samples containing the commercial starter and Lb. rhamnosus B-1445 had the highest proteolysis on day 14. Fermented milks with commercial starter and Lb. rhamnosus B-1445 or Lb. paracasei were the most acceptable products, while samples containing the commercial starter and Lb. casei were less acceptable.