Efficacy of xylanase purified from Aspergillus niger DFR-5 alone and in combination with pectinase and cellulase to improve yield and clarity of pineapple juice

Abstract

Pineapple is one of the fruits having xylan rich hemicellulose content more than pectin. Therefore, the efficacy of absolutely purified xylanase from A. niger DFR-5 alone and in combination with pectinase and cellulase on juice yield and clarity was studied. Xylanase provided maximum yield (71.3%) and clarity (64.7%) of juice in comparison to control responses (61.8% yield and 57.8% clarity). When used together, a synergistic effect of xylanase, pectinase and cellulase on process responses was observed indicating the necessity of a cock-tail of hydrolytic enzymes for complete cell wall degradation. Overall, an increase in juice yield by 52.9% was observed. The process was numerically optimized with the constraint of 'minimum' pectinase and cellulase and 'maximum' xylanase and incubation time for 'maximum' juice yield and clarity. The closeness of observed response (90.2% yield and 80.9% clarity) to the predicted one (89.6% yield and 80.3% clarity) indicated the validity of developed model.

Keywords: Aspergillus niger; Juice yield; Pineapple; Statistical design; Xylanase.

Fig. 1

Individual effect of cell wall hydrolytic enzymes on yield and clarity of pineapple juice (n = 3)

Fig. 2

Effect of xylanase and pectinase on a yield and b clarity of pineapple juice

Fig. 3

Effect of xylanase and cellulase on a yield and b clarity of pineapple juice

Fig. 4

Effect of xylanase and incubation time on a yield and b clarity of pineapple juice

Fig. 5

Perturbation graph showing the effect of independent variables on a yield and b clarity of pineapple juice (A = xylanase, B = pectinase, C = cellulase and D = incubation time)