Microbial viability, physico-chemical properties and sensory evaluation of pineapple juice enriched with Lactobacillus casei, Lactobacillus rhamnosus and inulin during refrigerated storage

The effect of enrichment of pineapple juice with Lactobacillus casei (108 CFU/mL) or Lactobacillus rhamnosus (108 CFU/mL) and inulin (20 g/L) as prebiotic compound, on physicochemical characteristic, cell viability and sensory properties of the juice during 28 days of refrigerated storage was studied. A comparison between the samples containing sucrose and those with inulin (as sugar substitute) indicated identical physicochemical characteristics (except for fat content), acidity and Brix; however, density and turbidity were higher and lightness value (L*) and pH were lower in the samples containing inulin. Viable cell count was significantly higher in the samples incorporated with L. casei (5.22 ± 0.08 log CFU/mL) than those with L. rhamnosus (4.54 ± 0.16 log cfu/mL) (p < 0.05). Difference between viable cell counts after 21 and 28 days of storage was significant among all samples (p < 0.05). Pineapple juice sample with inulin and L. casei had highest cell counts with 6.74 and 6.45 (log CFU/mL) after 21 and 28 days of storage, respectively, while the sample containing L. rhamnosus had the lowest with 5.41 and 4.53 (log CFU/mL) after 21 and 28 days of storage, respectively. Sensory evaluation indicated that, regarding flavor, the juice with sucrose and the one with inulin were the most acceptable samples while the juice containing L. casei was the least acceptable one. Therefore, inulin can be used as a compound effective on the viability of L. casei (108 CFU/mL) or L. rhamnosus in pineapple juice and is suggested to substitute sucrose in the juice.