Membrane technology has emerged as a substitute to traditional juice clarification and concentration processes as they require less manpower, reduce operating cost and low temperature. It is a low temperature process in which the organoleptic quality of the juice is almost retained. The advantages of these membrane processes over traditional methods are lower thermal damage to product, increase in aroma retention, less energy consumption, and lower equipment costs. Membrane concentration of fruit juice not only provides microbiological stability but also permits economy in packaging and distribution of the finished product due to a reduction in bulk by weight and volume. The biggest problem in the use of membrane based processes for the clarification/concentration of fruit juices is membrane fouling. Membrane fouling manifests itself as a decline in flux with the time of operation, reducing the membrane permeability. The degree of membrane fouling determines the frequency of cleaning, the lifetime of the membrane, the membrane area needed and consequently costs, design and operation of membrane plants. In this review, different membrane separation methods including microfiltration, ultrafiltration, nanofiltration and reverse osmosis for fruit juice clarification/concentration reported in the literature in the last fifteen years are discussed. Membrane Distillation methods for juice concentration is also covered in this review.

Fruit juice processing using membrane technology: A review

A plethora of solid substrates, cultivation conditions and enzyme assay methods have been used for efficient production and estimation of polygalacturonase and pectin methylesterase enzymes. Recent developments in industrial biotechnology offer several opportunities for the utilization of low cost agro-industrial waste in Solid State Fermentation (SSF) for the pectinolytic enzyme production using fungi. Fruit waste mainly citrus fruit waste alone and along with other agro-industrial waste has been explored in SSF for enzyme production. Agro-industrial waste, due to the economic advantage of low procuring cost has been employed in SSF bioreactors for pectinolytic enzyme production. Acidic pectinases produced by fungi are utilized especially in food industries for clarification of fruit juices. This review focuses on the recent developments in SSF processes utilizing agro-industrial residues for polygalacturonase and pectin methylesterase production, their various assay methods and applications in fruit juice industries.

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Pectinolytic enzymes-solid state fermentation, assay methods and applications in fruit juice industries: a review

Recent developments in microfiltration and ultrafiltration of fruit juices

Modeling and optimization of pectinase-assisted low-temperature extraction of cashew apple juice using artificial neural network coupled with genetic algorithm.

Beverage industry for its fruit juice products and fruit softening has been using cell wall degrading enzymes such as pectinases, cellulases, and proteases. The pectin in the middle lamella of plant tissues is enzymatically degraded by protopectinase, pectin methylesterase, pectin lyase, and polygalacturonase to completely hydrolyze the galacturonan polymer to its constituent galacturonic acid. This improves the yield and clarification of various fruit juices. The acidic pectinases are used extensively in fruit juice manufacturing individually or synergistically with cellulases and proteases. Various microbial—fungal and bacterial—sources have been employed for production of pectinases using solid state as well as submerged fermentation. The purified or partially purified polygalacturonase and pectin methylesterase have been employed for clarification of various fruit juices in solutions or by using bioreactors. Pectinases are an important biochemical tool for fruit liquefaction, pressing, clarification, and production of clear concentrated fruit juices. This chapter contemplates the pectin structure, the hydrolyzing enzymes, their sources, production, and their application in the beverage industry.

Salma Jallouli Drira

Papers

Lemon juice clarification using fungal pectinolytic enzymes coupled to membrane ultrafiltration