Effect of blanching time and salt concentration on pectolytic enzymes, texture and acceptability of fermented green beans

Effect of blanching time, salt concentration and fermentation on texture of green beans (var. Tuf) was determined. Beans were blanched at 90 degrees C for 1, 10 or 20 minutes and fermented with brine containing 3.08 and 4.6% salt (corresponding to 1.2 and 1.8% salt in the finished product). The bean s were assessed for texture mechanically using Universal Testing Machine (M odel 1011, Instron). Sensory evaluation was carried out to assess the taste , texture and overall acceptability of the products. Pectolytic enzyme (pec tinestarase and exopolygalacturonase) activities were determined in fresh a nd fermented beans. Increase in blanching time improved the texture signifi cantly. Significant (p < 0.05) decreases in shearing energy of the beans we re observed in the first two days of fermentation and, thereafter, there we re no significant (p > 0.05) changes except for samples blanched for one mi nute. Salt concentration showed a small but significant effect on texture o nly in samples blanched for one minute and this was probably due to activat ion by salt of residual pectolytic enzymes in the beans. Most acceptable be ans were those blanched for 20 minutes and fermented with 1.2% salt brine.