De-Oiling Method in the Manufacture of Low Oil Potato Chips

Abstract

A method of de-oiling potato slices, which have been coated in oil, the steps of the method including providing a plurality of potato slices that were pre-treated in oil; and randomly feeding the potato slices onto an elongate longitudinal conveyor which is permeable to oil, water and air. Further, the method includes spraying water downwardly and upwardly onto the plurality of potato slices on the conveyor to displace and lift surface oil from the potato slices. Then, directing air blades to blow a mixture of oil and water from the potato slices as these move along the conveyor.

1 . A method of de-oiling potato slices which have been coated in oil, the method comprising the steps of:
 (a) providing a plurality of potato slices, each slice having been pretreated in oil;   (b) randomly feeding the potato slices onto an elongate longitudinal conveyor which is permeable to oil, water and air;   (c) spraying water downwardly and upwardly from respective upper and lower water spray units onto the plurality of potato slices on the conveyor to cause the water to displace and lift surface oil on the potato slices; and   (d) thereafter directing upper and lower air blades downwardly and upwardly, respectively, onto the plurality of potato slices on the conveyor to cause the air blades to blow a mixture of oil and water from the potato slices, wherein the air blades comprise a plurality of pairs of upper and lower air blades spaced along the conveyor.   
     
     
         2 . A method according to  claim 1  wherein in step (b) the potato slices are fed onto the conveyor in a substantially non-overlapping configuration. 
     
     
         3 . A method according to  claim 1 , wherein the upper and lower water spray units are spaced a distance of from 50 to 150 mm, from the potato slices on the conveyor. 
     
     
         4 . A method according to  claim 1 , wherein the upper and lower water spray units are adapted each to spray from 0.72 to 1.2 litres of water per hour per kg of potato slices per hour, towards the conveyor. 
     
     
         5 . A method according to  claim 1 , wherein at least three pairs of parallel air blades are located in succession downstream of the water spray units. 
     
     
         6 . A method according to  claim 1 , wherein air blades are generated from respective air exit apertures having a width of from 0.5 to 1.5 mm. 
     
     
         7 . A method according to  claim 6 , wherein the air exit aperture is a distance from the conveyor of from 20 to 40 mm. 
     
     
         8 . A method according to  claim 1 , wherein the air blade has an air velocity of from 30 to 60 metres per second. 
     
     
         9 . A method according to  claim 8 , wherein the upper and lower air blades of a first pair of air blades located downstream of the water spray units have an air velocity of from 30 to 40 metres per second. 
     
     
         10 . A method according to  claim 9 , wherein the upper and lower air blades of a second pair of air blades located downstream of the first pair of air blades have an air velocity of from 40 to 50 metres per second. 
     
     
         11 . A method according to  claim 10 , wherein the upper and lower air blades of a third pair of air blades located downstream of the second pair of air blades have an air velocity of from 40 to 50 metres per second. 
     
     
         12 . A method according to  claim 1 , further comprising the step, between steps (b) and (c) of directing at least one primary air blade downwardly towards the potato slices on a primary conveyor. 
     
     
         13 . A method according to  claim 12 , wherein two primary air blades are provided which are longitudinally separated by a distance of from 100 to 300 mm. 
     
     
         14 . A method according to  claim 13 , wherein the primary air blades are each generated from a respective primary air exit aperture having a width of from 0.5 to 1.5 mm. 
     
     
         15 . A method according to  claim 14 , wherein the primary air exit aperture is a distance from the potato slices of from 20 to 40 mm. 
     
     
         16 . A method according to  claim 12 , wherein the primary air blade has an air velocity of from 30 to 60 metres per second. 
     
     
         17 . A method according to  claim 1 , wherein in step (a) the potato slices have an oil content of about 30 to 45 wt % oil, based on the dry weight of the final potato chip produced from the potato slice, and the potato slices after being de-oiled in step (d), have an oil content of about 10 to 15 wt % oil, based on the dry weight of the final potato chip produced from the potato slice. 
     
     
         18 . A method according to  claim 1 , further comprising holding the slices on the conveyor at least one of the air-blower station by an upper belt located above the conveyor, the slices being fed between the conveyor and the upper belt. 
     
     
         19 . A method of de-oiling potato slices which have been coated in oil, the method comprising the steps of:
 (a) lipophillically pretreating a plurality of potato slices in oil;   (b) randomly feeding the pretreated plurality of potato slices onto an elongate longitudinal conveyor which is permeable to oil, water and air;   (c) spraying water downwardly and upwardly onto the plurality of potato slices on the conveyor to cause the sprayed water to displace and lift surface oil off the potato slices; and   (d) directing upper and lower air blades onto the plurality of potato slices on the conveyor to cause the air blades to blow a mixture of oil and water from the potato slices, wherein the air blades comprise a plurality of pairs of upper and lower air blades spaced along the conveyor.   
     
     
         20 . A method according to  claim 19 , wherein after step (d) the plurality of potato slices have an oil content of about 10 to 15 wt % oil, based on the dry weight of a final potato chip product produced from the potato slice.