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US 4,959,237 AGranted
Reverse osmosis concentration of juice products with improved flavor
AssigneeE. I. Du Pont de Nemours and Company
InventorJames B. Walker
Life of this patent
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Abstract
A membrane process for producing an improved product quality comprising feeding a clarified serum at an elevated pressure to a plurality of reverse osmosis units in two stages--the first having high-rejection polyamide membranes and the second having low-rejection membranes, wherein the permeate from the low-rejection membranes is recycled to the high-rejection feed.
Claims15
A membrane process for preparing a concentrated superior-tasting food juice comprising the steps of:
- (a) feeding a clarified serum to a multistage reverse osmosis (RO) system, wherein the serum is fed at a trans-membrane pressure of 1000 psig or greater to the first stage of the system which comprises one or more RO units having high-rejection polyamide membranes in which the retentate of one unit is fed to the subsequent unit if there are more than one;
- and
- (b) feeding the retentate from the last of the high-rejection RO units at a trans-membrane pressure of 1000 psig or greater to the second stage which comprises one or more RO units having low-rejection membranes, wherein the retentate of each low-rejection RO unit is fed to the subsequent unit if there are more than one and wherein all permeates from the second stage are ultimately recycled to the first stage.
A membrane process for preparing a concentrated storage-stable superior-tasting food juice comprising the following steps:
- (a) providing from a juice-bearing fruit or vegetable a juice suitable for ultrafiltration;
- (b) permeating said juice first through an ultrafiltration stage which stage is equipped with a porous membrane having a pore size larger than the size of desirable flavor and aroma components but smaller than undesirable microorganisms to form a permeate stream containing flavor and aroma components and a retentate stream containing undesirable microorganisms;
- (c) treating retentate from (b) above to inactivate a sufficient number of undesirable microorganisms to inhibit spoilage of juice under storage conditions;
- and
- (d) feeding permeate from (b) to a multi-stage reverse osmosis (RO) system, wherein the serum is fed at a trans-membrane pressure of 1000 psig or greater to the first stage of the system which comprises RO units having high-rejection polyamide membranes in which the retentate of one unit is fed to the subsequent unit and the retentate from the last of the high-rejection RO units is fed at a trans-membrane pressure of 1000 psig or greater to the second stage which comprises RO units having low-rejection membranes,
- wherein the retentate of each low-rejection RO unit is fed to the subsequent unit and wherein all permeates from the second stage are ultimately recycled to the first stage;
- to produce a concentrated RO retentate which is combined with the treated retentate of step (c) to produce a storage-stable superior-tasting concentrated product.
4 more elements
A membrane process for preparing a concentrated storage-stable superior-tasting food juice comprising the following steps:
- (a) providing from a juice-bearing fruit or vegetable a juice suitable for ultrafiltration;
- (b) permeating said juice first through a microfiltration stage which stage is equipped with a porous membrane having a pore size substantially larger than the size of desirable flavor and aroma components but smaller than undesirable microorganisms to form a permeate stream containing flavor and aroma components and a retentate stream containing undesirable microorganisms;
- (c) feeding said retentate stream to an ultrafiltration stage which stage is equipped with a porous membrane having a smaller pore size than the microfilter in (b) above to separate a permeate and retentate stream;
- (d) treating retentate from (c) above to inactivate a sufficient number of undesirable microorganisms to inhibit spoilage of juice under storage conditions;
- and
- (e) feeding recombined permeate from (b) and (c) to a two-stage reverse osmosis (RO) system, wherein the first stage comprises RO units having high-rejection membranes in which the retentate of one unit is fed to the subsequent unit with the retentate from the last of the high-rejection RO units being fed to the second stage which comprises RO units having low-rejection membranes, the pore size of which being more open in each subsequent unit, wherein the retentate of each low-rejection RO unit is fed to the subsequent unit and the permeate from each subsequent unit is fed to the feed side of the preceding RO unit;
- to produce a concentrated RO retentate which is combined with the treated retentate of step (d).
4 more elements
Dependencies are inferred from the claim text.