The present research work was carried out at the Laboratory of Dairy Microbiology and Biotechnology, Department of Dairy Science, Bangladesh Agricultural University (BAU), Mymensingh-2202, Bangladesh. Preparation of chhana whey and pineapple juice: Raw cow milk was collected from BAU Dairy Farm. The whey was prepared following the procedure recommended by Baljeet. Raw cow milk (4% fat, 3.5% protein and 8.5% solids-not-fat) was heated at 70 ºC for 30 min in a glass vessel using a water bath. Afterward, 1% Citric acid (Merck, India) was added to the milk slowly to a pH 5.1 until greenish whey emerged. Then the coagulum was filtered by using a muslin cloth to drain and collect the whey produced. Fresh pineapples (Honey queen variety) were collected from the local market and then de-crowned and sliced into small pieces. The fruit pieces were ground in a blender (Siemens, Germany) and the resulting juice was passed through a double layer muslin fabric to collect the juice. Subsequently, the juice was pasteurized at 85 ºC for 30 min in a hot air oven to inactivate the microbes and bromelain enzyme. The physic-chemical and microbiological analysis of raw cow milk and pineapple juice was performed initially. Probiotic culture conditioning: The probiotic culture Lactobacillus acidophilus LA-5 (ATCC 4356) was obtained from Chr. Hansen A/S (Hrrsholm, Denmark) in lyophilized form. For the activation, 0.1 g of L. acidophilus was added to 9.9 mL of sterilized skim milk medium (10% w/v, Himedia, India) and then incubated at 37 ºC for 24 h [30]. This culture was used as inoculum to the blends fermentation. Preparation of whey-pineapple beverage: Four different beverages were prepared by different blends of whey and pineapple juice coded as A (0% whey & 100% pineapple juice, considered as the control sample), B (15% whey & 85% pineapple juice), C (25% whey & 75% pineapple juice) and D (35% whey & 65% pineapple juice), and all have 8% sugar. Five mL of activated L. acidophilus (9.8 - 109 CFU mL1 ) was inoculated into 450 mL of pasteurized fruit juice and whey blends in sterilized glass bottles. Finally, the blends made were incubated at 37 ºC for 5 h. Sensory evaluation: The sensory parameters such as color & appearance, flavor, mouthfeel, sweetness and overall acceptability were evaluated by 15 persons comprising faculty members and post-graduate students of the Department of the Dairy Science, Bangladesh Agricultural University, Mymensingh2202, Bangladesh. A 5-point hedonic scale was used for this purpose. The panelists were asked to evaluate the sensorial attribute, based on the 5- point hedonic scale; 5 ¼ Like a lot, 4 ¼ Like a little, 3 ¼ Neither like or dislike, 2 ¼ Dislike a little, and 1 ¼ Dislike a lot. 2.5. Physico-chemical analysis Chemical composition of all the whey-pineapple-based beverages was analyzed for total solids, ash, acidity and total dietary fiber (TDF); protein content by Micro-Kjeldahl method; carbohydrate content as per Ranganna and pH by using a digital pH meter (Hanna, Romania). The TDF content was assessed by following the enzymatic-gravimetric procedure [14]. In short, the samples were first gelatinized with heat stable α-amylase (Himedia, India). Once gelatinization finished, the samples were digested with the protease and amyloglucosidase (Sigma-Aldrich, Germany). Sequentially, warm distilled water (60 ºC) was used filter and wash insoluble dietary fiber (IDF). In contrary, to precipitate the soluble dietary fiber (SDF) the filtrate and washed water were combined with 4 vol of ethanol (95%) at 60 ºC. Afterward, the residues were dried at 105 ºC for overnight in a hot air oven and weighed. Finally, the sum total of IDF and SDF was considered as total dietary fiber (TDF) content. 2.6. Total phenolic compounds To determine total phenolic compounds (TPC) the sample extracts prepared according to Chandra [16]. In brief, the beverage samples were dried at 105 ºC overnight. Then 10 g sample were extracted with 75 mL (95% v/v) ethanol at 40 ºC for 10 min. The extract with solvent was kept at 60 ºC for evaporation. About 50 mg of the extract was dissolved in 5 mL methanol for 45 min at 40 ºC followed by centrifugation at 1000-g for 10 min at room temperature and collected supernatant. The sample extracts (500 μL) were inserted into test tubes accompanied by the addition of the Folin–Ciocalteu reagent (2.5 mL) (Merck, India; diluted 10 times with water) and sodium carbonate (2 mL) (7.5% w/v). Afterward, the samples in the tubes were mixed gently by vortexing and incubated for 5 min at 50 ºC. By using a UV-VIS spectrophotometer (Hitachi, Japan), the absorption was measured at the wave length of 760 nm. Finally, the obtained results were presented as the mg of gallic acid equivalents (GAE) per 100 g (on a fresh basis). Microbiological analysis: The total viable count (TVC) (Log10 CFU mL1 ) was assayed using the standard plate count technique according to the method of Vanderzant. At first, the plate count agar media and sterile saline solution of 0.9% NaCl (w/v) were prepared. The samples (1 mL) were shifted into the sterile saline solution and each serial dilution carried out up to five folds (105 ), then set into the plate and poured agar (10–15 mL) and left for solidification. After solidification, the plates were placed in incubation at 32 ºC for 48 h. The colonies were enumerated from plates having 30–300 colonies. In all cases, duplicate-counting plates were prepared for appropriate dilutions. Statistical analysis: One-way analysis of variance was done to compare the group means and the means were separated (in case of significant difference among them) by using DMRT. Pearson correlation was done to see the relationship among the physicochemical attributes. The probiotic survivability was predicted by the multiple linear regressions and to predict the shelf-life of the beverage Poisson regression was performed.