Optimization, Modeling, and Online Monitoring of the Enzymatic Extraction of Banana Juice

Optimization of process parameters for mechanical extraction of banana juice using response surface methodology

Banana juice is traditionally processed under very basic conditions characterized by low efficiency and poor hygiene. Introduction of mechanical pressing has created opportunities for upgrading banana juice production, but more knowledge is needed about critical factors for juice release and about optimizing extraction for higher yield and quality. This study sought to identify and optimize important factors associated with juice release. This was done using an experimental design (Box-Behnken design of response surface methodology) involving three levels of three independent variables: blending speed (1000-3500 rpm), extraction time (30-240 s), and stage of ripeness (3-7). A second-order polynomial equation was created to describe the relationship between dependent and independent variables. The results showed that juice yield increased with blending speed, extraction time, and stage of ripeness, whereas the quadratic (squared) effect of these factors was a significant decrease in juice yield. Optimum juice yield (57.5%) was obtained at blending speed 2650 rpm, extraction time 162 s, and ripeness stage 5. Analysis of variance showed that stage of ripeness significantly (p ≤ 0.001) affected juice yield. This novel information on the underlying factors in banana juice extraction and on optimization of the process can be used to improve mechanical extraction of low-viscosity, clear banana juice and achieve scaling-up of banana juice processing.

Optimization of banana juice extraction using combination of enzymes

Banana juice extraction was optimized using central composite rotatable design with four numerical factors was employed to design the experiments. The numerical factors were incubation temperature (30-50 °C), and incubation time (20-60 min), cellulase concentration (0-0.4 g/100 g banana) and pectinase concentration (0-0.4 g/100 g banana). The optimum condition for extraction of banana juice were incubation temperature of 36.5 °C, incubation time of 29.33 min, cellulase concentration of 0.34% and pectinase concentration of 0.35%. The corresponding values of yield, viscosity, lightness, acidity, reducing sugar content and total soluble solids at the optimum condition were 74.15%, 101.14 mPa s, 30.06, 2.72%, 171.28 mg/100 g juice and 12.10 °Brix, respectively. Response surface analysis showed that yield increased with incubation time, and cellulase and pectinase concentration, and with temperature it initially increased and then decreased. The processing parameters had an opposite effect on viscosity. Reducing sugar content was also affected by all processing parameters.

Comparative study of the banana pulp browning process of 'Giant Dwarf' and FHIA-23 during fruit ripening based on image analysis and the polyphenol oxidase and peroxidase biochemical properties

This work presents a novel method to associate the polyphenol oxidase (PPO) and the peroxidase (POD) activities with the ripening-mediated color changes in banana peel and pulp by computational image analysis. The method was used to follow up the de-greening of peel and browning of homogenized pulp from 'Giant Dwarf' (GD: Musa AAA, subgroup Cavendish) and FHIA-23 (tetraploid hybrid, AAAA) banana cultivars. In both cultivars, the color changes of peel during the ripening process clearly showed four stages, which were used to group the fruit into ripening stages. The PPO and POD were extracted from pulp of fruit at these ripening stages, precipitated, and partially purified by gel filtration chromatography. Moreover, the pulp browning was digitally monitored after homogenization for a span time of up to 120 min. The browning level was higher for GD than FHIA-23 tissues. This fact correlated with an 11.7-fold higher PPO activity in the GD cultivar, as compared with that of FHIA-23. POD activity was 8.1 times higher for GD as compared that that of FHIA-23.

Effect of ultrasound and enzymatic pre-treatment on yield and properties of banana juice

Effect of ultrasound and enzymatic pre-treatments with cellulase and pectinase on yield and properties of banana juice were investigated. A two-level full factorial design was employed. The factors selected were ultrasonication time (0 and 30min), cellulase concentration (0 and 0.2%) and pectinase concentration (0 and 0.2%). The responses studied were yield, viscosity, clarity, total soluble solids (TSS) and pH. It was observed that pectinase was more effective in increasing the yield of juice compared to cellulase. Ultrasonic pre-treatment alone did not significantly increase the yield of juice. When ultrasound was combined with pre-treatment with both the enzymes maximum yield of 89.40% was obtained compared to 47.30% in the control. The viscosity of the juice decreased with addition of enzymes and with application of ultrasound. The clarity of the juice was not affected by cellulase treatment, but improved with pectinase treatment. Ultrasonication alone was found to be more effective than pectinase or cellulase treatment in improving the clarity of the juice. The TSS increased with enzymatic treatment, ultrasonication and their combination. pH was not affected by treatment type, but was found to be lower for the treated juices. Significant correlations were observed between the various responses.