Microfluidization of juice extracted from partially granulated citrus fruits: Effect on physical attributes, functional quality and enzymatic activity

Abstract

Citrus juice sac granulation reduces the yield of extractable juice and impairs its nutritional and functional quality. Therefore, present study was carried out to improve the physico-functional quality of juice extracted from partially granulated ‘Dancy’ tangerine. Juice was passed through microfluidizer under varying pressure (41, 62, 83, 103, 124 MPa) for different number of passes (1, 2, 3). The microfluidized juice was evaluated for different quality attributes, viz. cloud value, fractal dimension, lacunarity, colour attributes and pectin methyl esterase (PME) activity. Naringin and hesperidin were quantified through HPLC. Control juice exhibited the highest fractal dimension (18.89), indicating irregular cell structure, while 103MPa/3 passes (1.04) displayed the lowest indicating uniformity in juice. Microfluidized juice showed improved opalescence stability, greater hue, low PME activity and augmented hesperidin and naringin contents. Juice treated at 103 MPa for a single pass exhibited the best organoleptic quality. The high pressure applied during microfluidization can drastically improve the quality of otherwise low quality juice extracted from granulated citrus fruits. Application of appropriate processing pressure and number of passes through the microfluidizer yields citrus juice possessing enhanced bioactive constituents, reduced enzymatic activity with good organoleptic acceptability.

Keywords

• Citrus juice
• Microfluidization
• Fractal dimension
• Hesperidin
• Naringin
• Pectin methyl esterase