The production of plant-based fermented beverages has been currently focused on providing a functional alternative to vegan and/or vegetarian consumers. This study primarily targeted the development and characterization of fermented beverages made up of hydrosoluble extracts of oats, almonds, soybeans, Brazil nuts, and rice. The fermentation was carried out by lactic cultures of Bifidobacterium BB-12, Lactobacillus acidophilus LA-5, and Streptococcus thermophilus. Plant extracts were fermented at 37 °C for 12 h, with and without sucrose supplementation. The physicochemical and microbiological stability of the extracts was monitored for 28 days at 5 ± 1 °C. The composition of the fermented beverages was subsequently determined. The pH values measured at the beginning and the end of the extracts’ fermentation ranged between 6.45 and 7.09, and 4.10 to 4.97, respectively. Acidity indices, expressed as a percentage of lactic acid, ranged from 0.01 to 0.06 g/100 mL at the beginning of the fermentation, and from 0.02 to 0.33 g/100 mL upon fermentation being concluded. Most fermented extracts achieved viable lactic acid bacteria counts exceeding 106 CFU/mL during storage. Sucrose supplementation did not alter the rate of bacterial growth. The findings showed that the complete replacement of dairy ingredients with water-soluble plant extracts is a potential alternative for developing a functional fermented plant-based beverage.
19 June 2017 in International Journal of Food Science and Technology
The shelf life of fresh sugarcane juice is quite limited due to the high rates of microbiological and enzymatic reactions which take place after extraction. In order to evaluate the impact of pasteurization temperature on quality and stability of sugarcane juice with passion fruit pulp, nine batches of sugarcane juice with 4g/100g passion fruit pulp were processed at 85, 90 and 95 °C for 30 s, in triplicate. The pasteurized beverage was aseptically packaged in polyethylene terephthalate (PET) bottles and stored at 7 °C in the dark. The beverage was characterized by physicochemical tests. Activities of polyphenol oxidase (PPO) and peroxidase (POD) were determined before and after processing. Coliforms and Salmonella tests were carried out to assure the beverage´s microbiological safety. Color parameters were measured in the processed juice throughout the storage period. Fifty panelists evaluated the beverage's appearance, aroma, flavor, and overall impression using seven-point hedonic scale tests. Sensory stability was estimated by considering score averages above four and percentages of acceptance above 60%. The pH, soluble solids and titratable acidity of end product ranged from 3.96 to 4.19, 19.7 to 20.1 ºBrix, and 0.163 to 0.175 g/100g citric acid, respectively. The three processing binomials were effective for PPO inactivation; however, complete POD inactivation was reached at 95 °C/30 s only. The estimated sensory shelf-lives for sugarcane juice with passion fruit pulp processed at 85, 90 and 95 °C/30 s were 30, 40 and 50 days, respectively. Thus, the increase of pasteurization temperature had a positive effect on product's stability.
Sugarcane juice with passion fruit pulp was clarified using microfiltration under different T (temperature), P (pressure), and V (tangential velocity). The effects of these processing parameters were evaluated applying a rotational central composite experimental design (RCCD) and response surface methodology (RSM). The tests were performed at a filtration pilot plant using a polyamide hollow-fiber membrane with an average pore diameter of 0.4 µm and filtration area of 0.723 m². In addition, the resistances to the permeate flux during the microfiltration were investigated according to the series resistance. The final permeate flux ranged from 7.05 to 17.84 L·h- 1·m- 2. There was a rapid decline in flux (50%) in the initial stages of microfiltration. T and V were the major variables responsible for the flux increase. The concentration polarization showed the greatest influence on the flux decline, and highest values for the flux decline rate (λ) were found when low pressures were used. In the clarified juice there was a reduction in the contents of total solids, proteins, vitamin C, and acidity, while the soluble solids, pH, and ash contents did not change. Finally, membrane process could produce high quality filtered sugarcane juice with substantial flux and increased luminosity improving organoleptical properties