Optimization of Enzymatic Peeling of Oranges and Pomelo

Optimization of vacuum infusion and incubation time for enzymatic peeling of ‘Thomson’ and ‘Mollar’ oranges

“…The surface of fruits was homogeneously perforated as outlined above and then placed in a vacuum tank containing 9 l of the Peelzym II solution (1 ml/l) without Chinese ink. The Peelzym II concentration used was the one found to be adequate according to previous experiments (data not shown), at 40 1C, which is the recommended temperature according to several authors (Pretel et al, 1997;Soffer & Mannheim, 1994), and exposed to vacuum conditions previously optimized. Thirty oranges of each variety were submerged in the tank with the enzymatic solution.…”

“…It is based on infusion, under vacuum, of an enzymatic preparation, which degrades the pectic substances present in the cell walls (Berry, Baker, & Bruemmer, 1988;Bruemmer, Griffin, & Onayami, 1978;Coll, 1996;McArdle & Culver, 1994;Pretel, Amoro´s, Botella, Serrano, & Romojaro, 2005;Pretel, Lozano, Riquelme, & Romojaro, 1997). There are many parameters to take into account to obtain good peeling effectiveness, such as type of enzymatic preparation and its concentration (Baker & Bruemmer, 1989;Bruemmer, 1981;Soffer & Mannheim, 1994), the design of the cuts of the flavedo (Pretel, Ferna´ndez, Martı´nez, & Romojaro, 1998a), and the vacuum conditions to allow the entrance of enzymatic solution towards the interior of the mesocarp (Baker & Wicker, 1996;Prakash, Singhal, & Kulkarni, 2001;Pretel et al, 1997). In addition, the morphologic characteristics of fruits, such as skin adherence and its thickness, and the degree of union between the segments, are also important factors which determine enzymatic peeling efficiency (McArdle & Culver, 1994;Pretel et al, 1997Pretel et al, , 2001.…”

“…In spite of the importance of vacuum pressure conditions for the enzymatic peeling process of citrus fruit at the industrial level, few studies have been carried out on this issue. Most authors do not measure the real vacuum pressure that is applied (Rouhana & Mannheim, 1994;Soffer & Mannheim, 1994) while others (Prakash et al, 2001) applying 93 kPa for 0.5-4 min. Using grapefruit, Bruemmer et al (1978), consider the absorption of 100 ml of solution in the albedo as a parameter to indicate peeling efficacy.…”

“…In addition, the morphologic characteristics of fruits, such as skin adherence and its thickness, and the degree of union between the segments, are also important factors which determine enzymatic peeling efficiency (McArdle & Culver, 1994;Pretel et al, 1997Pretel et al, , 2001. Finally, the effect of scalding, and the incubation time and temperatures on peeled fruit quality, may also be important (Prakash et al, 2001;Pretel et al, 1998a;Rouhana & Mannheim, 1994;Soffer & Mannheim, 1994).…”

“…Another important parameter in order to obtain a good quality product is the incubation time with the enzymatic solution at atmospheric pressure after the vacuum application (Prakash et al, 2001;Pretel et al, 1998a;Soffer & Mannheim, 1994). An incubation time above the optimum could cause the degradation of the juice vesicles from the surface and the softening of the segments (Pretel et al, 1997).…”