Computational modelling approach for the optimization of apple juice clarification using immobilized pectinase and xylanase enzymes

Shady S Hassan; Gwilym A Williams; Amit K Jaiswal

doi:10.1016/j.crfs.2020.09.003

Computational modelling approach for the optimization of apple juice clarification using immobilized pectinase and xylanase enzymes

Curr Res Food Sci. 2020 Oct 14:3:243-255. doi: 10.1016/j.crfs.2020.09.003. eCollection 2020 Nov.

Authors

Shady S Hassan^{1

2

3}, Gwilym A Williams³, Amit K Jaiswal^{1

2}

Affiliations

¹ School of Food Science and Environmental Health, College of Sciences and Health, Technological University Dublin - City Campus, Grangegorman, Dublin 7, Ireland.
² Environmental Sustainability and Health Institute, Technological University Dublin - City Campus, Grangegorman, Dublin 7, Ireland.
³ School of Biological and Health Sciences, College of Sciences and Health, Technological University Dublin, Kevin Street, Dublin 8, Ireland.

Abstract

Apple juice is typically marketed as a clear juice, and hence enzymatic treatments are common practices in juice industry. However, enzymatic treatments have been shown to face some challenges when process efficiency, and cost effectiveness are concerned. Therefore, it is necessary to optimize the enzymatic treatment process to maximize efficiency, and reuse enzymes to minimize the overall cost via immobilization. In this context, the present work features the immobilization of pectinase and xylanase from M. hiemalis on genipin-activated alginate beads, with subsequent evaluation of its efficacy in apple juice clarification. A central composite rotatable design (CCRD), coupled with artificial neural network (ANN) for modeling and optimization was used to design the experiments. Deploying a coupling time up to 120 min, and an agitation rate of 213 rpm (pectinase) - 250 rpm (xylanase), a maximum fractional enzyme activity recovered was observed to be about 81-83% for both enzymes. Optimum enzyme loading and genipin concentration were found to be 50 U/ml and 12% (w/v), respectively. The immobilized enzyme preparations were suitable for up to 5 repeated process cycles, losing about 45% (pectinase) - 49% (xylanase) of their initial activity during this time. The maximum clarity of apple juice (%T₆₆₀, 84%) was achieved at 100 min when pectinase (50 U/ml of juice) and xylanase (20 U/ml of juice) were used in combination at 57 °C. The immobilized enzymes are of industrial relevance in terms of biocompatibility, recoverability, and operational-storage stability.

Keywords: Alginate beads; Apple juice clarification; Artificial neural network (ANN); Central composite rotatable design (CCRD); Mucor hiemalis; Pectinase; Xylanase.