Patent Application
20120076904
The present invention relates to the field of physical separation, concentration and drying of bioactive color fraction containing anthocyanins and phenolics from the juices of berries, fruits and vegetables.
In addition to vitamins, minerals, fibers and energy giving nutrients like sugar, carbohydrates, lipids and proteins, fruits and vegetables contain bioactive phenolic and polyphenolic compounds which are not energy giving nutrients, but which are believed to have beneficial physiological and cellular roles, and modify risk of chronic diseases. Consumed over an extended period as a part of a regular diet, these naturally occurring bioactive phenolic and polyphenolic plant constituents can confer a wide range of physiological benefits as natural antioxidants, antiallergic, anticarcinogenic, antiinflammatory, etc.
The phenolic and polyphenolic compounds of dietary significance are polycyclic structures consisting of 15 carbon atoms based on C6-C3-C6 skeleton, and include:
a) Flavonols (e.g. quercetin in apples, cherries)
b) Flavones (e.g. apigenin in celery)
c) Flavan-3-ols (e.g. proanthocyanidin A or PAC in cranberries having antiadhesion role)
d) Flavanones (e.g. naringenin in citrus),
e) Anthocyanins (color pigments of fruits, vegetables and flowers)
f) Isoflavones (present in soy products)
The non-flavonoid polyphenolic compounds having dietary significance include:
a) The C6-C1 Phenolic acids (e.g. gallic acid, ellagic acid in raspberries)
b) The C6-C3 Hydroxy cinnamates (e.g. chlorogenic acid in cherries)
c) The C6-C2-C3 Stilbene (e.g. resveratrol in red wine, pterostilbene in blueberries)
In nature phenolic compounds are commonly found conjugated to sugars and organic acids, and have antioxidant properties as determined by their oxygen Radical Absorbance Capacity (ORAC). The in vitro ORAC test was developed as a relative measure of antioxidant capacity. Fruits and vegetables products rich in health promoting constituents have many benefits and uses including as dietary supplements.
The essentially water soluble anthocyanins are a significant component of some fruits, vegetables and flowers, and bestow them with their red, blue and purple colors. The known anthocyanins exist as the glucosides of polyhydroxy and/or polymethoxy derivatives of the flavylium cation like, cyanidin (red color), pelargonidin (orange-red), peonidin (red-rose), delphinidin (blue-violet), petunidin (blue-purple) and malvidin (purple). Anthocyanins in red tart cherries have been suggested to benefit people suffering from joint pain and inflammation because of their potential role in inhibiting cyclooxygenase enzymes (Cox-1 and Cox-2) which are reported to catalyze the conversion of arachidonic acid to prostaglandins (PGs) which contribute to pathogenesis of inflammation. In rheumatoid arthritis and other inflammatory joint diseases, high concentration of PGs has been detected.
The molecular weight of these bioactive phenolic compounds can range from about 300 to about 700 Daltons. Sugars such as glucose and fructose (C6H12O6) which are the predominant components of fruit juices have molecular weight of 180 Dalton; the fruit juices also contain a small amount of sucrose (C12H22O11) having a molecular weight of 342 Dalton. The organic acids (such as citric acid, C6H8O7; malic acid C4H6O5, tartaric acid, C4H6O6, quinic acid, C7H12O6) in fruits juices can range in molecular weight from 134 to 192 Dalton. Resin separators and high pressure liquid chromatography have been used, but these are chemical processes and often not as economically viable for commercial scale up in separation of bioactive flavanoids from the sugars and food acids of the juices.
The present invention is a method for physical separation and purification of bioactive phenolics from fruits, berries and vegetables by subjecting a fruit, berry or vegetable extract solution having a Brix of from about 1 to about 4 to ultrafiltration using an about 2,000-6,000 Dalton cutoff ultrafiltration membrane under a pressure of about 30-120 psi, and a temperature of about 80-110° F., followed by subjecting the resulting retentate to diafiltration-ultrafiltration with the co-injection of water, using an about 2,000-6,000 Dalton cutoff ultrafiltration membrane under a pressure of about 30-120 psi, and a temperature of about 80-110° F., and recovering the diafiltered retentate containing the separated bioactive phenolics.
The presence of the bioactive phenolics in the retentate is evident from the analysis of the freeze dried product prepared from the retentate. It is surprising that the bioactive phenolics, which have molecular weights of less than a thousand, are captured and concentrated in the retentate, using specific higher molecular weight cut off membranes.
In the preferred embodiment, the process comprises the following steps:
The resulting anthocyanins and phenolic concentrated retentate can be used a high antioxidant product, or as a phenolic concentrated product, or can be freeze dried at about 26° F.
Step 1 is a juice extraction and clarification step. One obtains a clarified, extracted juice within about 1 to about 4 Brix range. The Brix of the “as extracted” juice can be adjusted by further concentration, or dilution, as necessary.
In the ultrafiltration step (step 2 above), extracted, clarified juice held in a feed reservoir 10 is pumped by pump 20 through feed line 11, to ultrafiltration unit 30. (
The retentate from ultrafiltration unit 30 recirculated through recirculation line 12 to feed reservoir 10, from which it is again pumped by pump 20, along with added original feedstock, to ultrafiltration unit 30. The permeate passing through ultrafiltration unit 30 is collected in a permeate receiver 50, and subsequently processed. When the flow rate through ultrafiltration unit 30 slows to about 4 liters per square meter of membrane area per hour or 4.0 LMH, recirculation is stopped.
The reservoir 10 then contains essentially retentate (probably with some small amount of original feed stock), in a volume from about 1/12 to about 1/22 of the volume of original feed stock processed. This is reflected in examples 1 to 3 below as the “volume concentration factor,” which is the volume of original feedstock processed divided by the final volume of retentate obtained. A desirable volume concentration factor is thus from about 12 to about 22.
With the flow rate thus reduced, the ultrafiltration-diafiltration step (step 3 above) is initiated by stopping the flow of original feedstock into feed reservoir 10. Retentate only, with whatever small amount of original feed stock may be present, is pumped and recirculated through filter unit 30 by pump 20, with water from source 40 being co-injected to the retentate stream. Water is added at a rate of about one quarter to about one half liter of water per liter of retentate. The retentate is recirculated with dilution as indicated until the total distilled water used is about 1 and ½ to about 3 times the volume of the original retentate.
The filter membrane may be either cleaned or replaced prior to initiating the ultrafiltration-diafiltration step. One of the advantages of ultrafiltration diafiltration at this point is that it is not necessary to do either of the above as the diafiltration process minimizes membrane fouling, while further separating sugars and food acids into the permeate, and further concentrating anthocyanins and other phenolics into the retentate.
Nevertheless in one embodiment of the invention, the two 4,000-6,000 Dalton cutoff filter membranes are replaced with two 2,000-4,000 Dalton, preferably about 3000 Dalton molecular weight cutoff tight spiral wound polyethersulfone (PES) ultrafiltration membranes used in parallel, prior to initiating the recirculation/dilution process.
Examples 1-3 below show the results obtained using the process of the preferred embodiment on the extraction of red tart cherry juice, wild blueberry juice and cranberry juice.
The volume of feedstock used in each of the examples, the initial Brix and the calculated soluble solids are indicated under “I. Feed,” (I a-c). The operating parameters are shown under item II A pressure of 45 psi was used for cherry juice and blueberry juice, while 100 psi was used for cranberry.
The progress through the initial ultrafiltration step is reported at item III. In Examples 1 and 2, more than 85% of the soluble solids have passed through with the permeate. In the cranberry example 3, almost 70% are in the permeate. While the Brix of the retentate has increased in all of the examples, it is a function of the concentration of the retentate. The retentate volume at this point is well under 10% of the starting volume.
In Example 1, 71 liters of retentate from red tart cherry juice was collected in the ultrafiltration only step (III A. a). This retentate was recycled with diafiltration eight times, adding approximately 20 liters of water to the recycled retentate on each pass. Thus, 160 liters of water were added during the ultrafiltration-diafiltration step (IV A.a). In Example 2, wild blueberry juice, 37 liters of retentate (III.A.a) were ultimately diluted with an additional 120 liters of water during six passes of the ultrafiltration-diafiltration process (IV.A.a). In Example 3, 80 liters of cranberry juice retentate (III.A.a) were recirculated four times with 20 liter injections until a total of 80 liters of water had been used to dilute the retentate (IV.A.a). As a result of the diafiltration-ultrafiltration step, additional sugar has been eliminated from the retentate and passed into the permeate (IVA, b and c, compared to III A, b and c; or IV B e to III B d).
The resulting retentate quantities were freeze dried at 26° C. (V). The degree of concentration of phenolics can be seen by comparing the anti-oxidant capacity (ORAC Value in micromoles TE per 100 grams) of the concentrates obtained, as compared to the ORAC Values for the original fruit:
1Source: USDA, 2007, except for Red Tart Cherries, for which the source is the Cherry Marketing Institute of Michigan.
2Source: Examples 1 to 3.
The total phenolics obtained in examples 1-3 comprise 40.79%, 36.08% and 21.48% of the freeze dried diafiltered retentate color fraction. The anthocyanins content of the Examples 1-3 are 9.27%, 14.19%, and 9.121%, respectively.
It is surprising that these quantities of bioactive phenolics, comprised of significant quantities of compounds having molecular weights well below the molecular cut-off of the ultra-filters used, have been retained in the retentate, and have not passed through with the sugars and food acids contained in the permeate.
Of course, it is understood that various changes and alterations can be made to the preferred embodiments disclosed herein without departing from the spirit of the invention as set forth in the appended claims.
