A value-added functional beverage is formulated utilizing; unprocessed liquid whey. Whey has excellent nutritional qualities and bland flavors; it is easy to digest and has a unique functionality in a beverage system. The ready-to-drink beverage is formulated with concentrated whey, orange juice along with an adequate amount of sugar, stabilizer, citric acid and flavor. Orange juice is used since the acidic flavor of whey is compatible with citrus flavors and particularly orange. The health and nutritional benefits of orange further imparts the value to the formulated beverage. Nine blend formulations are prepared by varying the dry matter of whey, fruit juice and sugar content. Based on a statistical analysis of the sensory evaluation of the drinks, the optimal formulation is found to have a ratio 3:2 for concentrated liquid whey and orange juice followed by an addition of 8% sugar (w/v) and 0.1% stabilizer ( w/v). The shelf-life of the final product is carried out both at room temperature (30±2°C) and refrigeration temperature (7±1°C) with and without addition of preservatives. The product remains in good condition up to eleven days at room temperature and up to three months under refrigeration condition with addition of 150 ppm of sodium benzoate.

Se realizó una bebida funcional de valor agregado, utilizando suero líquido sin procesar. El suero tiene excelentes cualidades nutricionales y sabores insulsos; es fácil de digerir y posee una funcionalidad única en un sistema de bebidas. La bebida preparada se formuló con suero de leche concentrado, zumo de naranja, una cantidad adecuada de azúcar, estabilizador, ácido cítrico y saborizante. Los beneficios nutricionales y saludables de la naranja le imparten aún más el valor a la bebida formulada. Nueve formulaciones de mezcla se prepararon mediante la variación de la materia seca de suero de leche, jugo de fruta y el contenido de azúcar. Basado en un análisis estadístico de la evaluación sensorial de las bebidas, se encontró que la formulación (óptima tiene una relación de 3:2 para el suero líquido concentrado y jugo de naranja, seguido por la adición del 8% (w/v) de azúcar y 0.1% de estabilizador (w/v). El tiempo de almacenamiento del producto final se llevó a cabo tanto a temperatura ambiente (30±2°C) y temperatura de refrigeración (7±1°C) con y sin la adición de conservadores. El producto se mantiene en buenas condiciones hasta once días a temperatura ambiente y hasta tres meses bajo condiciones de refrigeración con la adición de 150 ppm de benzoato de sodio.

AbstractThe introduction of flow instabilities into a microfiltration process can dramatically change several elements such as the surface-renewal rate, permeate flux, specific cake resistance, and cake buildup on the membrane in a positive way. A recently developed surface-renewal model for constant-pressure, cross-flow microfiltration (Hasan et al., 2013) is applied to the permeate-flux data reported by Mallubhotla and Belfort (1997), one set of which included flow instabilities (Dean vortices) while the other set did not. The surface-renewal model has two forms - the complete model and an approximate model. For the complete model, the introduction of vortices leads to a 53% increase in the surface-renewal rate, which increases the limiting (i.e., steady-state) permeate flux by 30%, decreases the specific cake resistance by 14.5% and decreases the limiting cake mass by 15.5% compared to operation without vortices. For the approximate model, a 50% increase in the value of surface renewal rate is shown due to vortices, which increases the limiting permeate flux by 30%, decreases the specific cake resistance by 10.5% and decreases the limiting cake mass by 13.7%. The cake-filtration version of the critical-flux model of microfiltration (Field et al., 1995) is also compared against the experimental permeate-flux data of Mallubhotla and Belfort (1997). Although this model can represent the data, the quality of its fit is inferior compared to that of the surface-renewal model.

Abstract This work examines the influence of the residence-time distribution (RTD) of surface elements on a model of cross-flow microfiltration that has been proposed recently (Hasan et al., 2013). Along with the RTD from the previous work (Case 1), two other RTD functions (Cases 2 and 3) are used to develop theoretical expressions for the permeate-flux decline and cake buildup in the filter as a function of process time. The three different RTDs correspond to three different startup conditions of the filtration process. The analytical expressions for the permeate flux, each of which contains three basic parameters (membrane resistance, specific cake resistance and rate of surface renewal), are fitted to experimental permeate flow rate data in the microfiltration of fermentation broths in laboratory- and pilot-scale units. All three expressions for the permeate flux fit the experimental data fairly well with average root-mean-square errors of 4.6% for Cases 1 and 2, and 4.2% for Case 3, respectively, which points towards the constructive nature of the model - a common feature of theoretical models used in science and engineering.

A mathematical model using classical cake-filtration theory and the surface-renewal concept is formulated for describing cross-flow microfiltration under dynamic and steady-state conditions. The model can predict the permeate flux and cake buildup in the filter. The three basic parameters of the model are the membrane resistance, specific cake resistance and rate of surface renewal. The model is able to correlate experimental permeate flow rate data in the microfiltration of fermentation broths in laboratory- and pilot-scale units with an average root-mean-square (RMS) error of 4.6%. The experimental data are also compared against the critical-flux model of cross-flow microfiltration, which has average RMS errors of 6.3, 5.5 and 6.1% for the cases of cake filtration, intermediate blocking and complete blocking mechanisms, respectively.

Natural vinegar is one of the fermented products which has some potentiality with respect to a nutraceutical standpoint. The present study is an optimization of the fermentation conditions for palm juice vinegar production from palm juice (Borassus flabellifer) wine, this biochemical process being aided by Acetobacter aceti (NCIM 2251). The physical parameters of the fermentation conditions such as temperature, pH, and time were investigated by Response Surface Methodology (RSM) with 2³ factorial central composite designs (CCD). The optimum pH, temperature and time were 5.5, 30 °C and 72 hrs for the highest yield of acetic acid (68.12 g / L). The quadratic model equation had a R² value of 0.992. RSM played an important role in elucidating the basic mechanisms in a complex situation, thus providing better process control by maximizing acetic acid production with the respective physical parameters. At the optimized conditions of temperature, pH and time and with the help of mathematical kinetic equations, the Monod specific growth rate ( µ max= 0.021 h-1), maximum Logistic specific growth rate ( µ 'max = 0.027 h-1) and various other kinetic parameters were calculated, which helped in validation of the experimental data. Therefore, the established kinetic models may be applied for the production of natural vinegar by fermentation of low cost palm juice.