NUT SHELL COATINGS FOR IMPROVED PROCESSING AND STORAGE
20180184676 ยท 2018-07-05
Inventors
Cpc classification
A23V2002/00
HUMAN NECESSITIES
International classification
Abstract
The present invention is directed to an integrated system of improving nut product safety, quality and production costs. Formulations and methods are provided for reducing pathogen contamination of nuts, improving storage stability of stored nuts and reducing refrigeration costs, and enhancing shelling operations by improving the contrast between nut shell fragments and nutmeats. The formulations may be used individually or in combination to provide all three commercial benefits of reduced bioburden, enhanced storage stability, and greater sorting efficiency of nutmeat from shell. The materials for the formulations disclosed herein are mostly derived from the waste materials of the species of tree that nut is harvested from and/or from other natural sources.
Claims
1. An antimicrobial composition for coating nuts comprising Yucca extract, methyl cellulose, walnut shell powder and walnut ink.
2. The antimicrobial composition of claim 1 comprising 1-5% Yucca extract concentrate@40% Brix.
3. The antimicrobial composition of claim 2 comprising about 5% Yucca extract concentrate@40% Brix, about 4 g methyl cellulose, about 15.9 g of ground walnut shell powder, and about 3.2 ml of walnut ink per 100 ml aqueous solution.
4. An aqueous antioxidant barrier coating for nuts comprising carboxymethyl cellulose at a concentration of about 0.5% to about 3.0%, propylene glycol at a concentration of about 0.5% to about 3.0%, sodium gluconate at a concentration of about 0.001% to about 0.5%, sorbitol at a concentration of about 0.1% to about 1%, lecithin at a concentration of about 0.05% to about 1% and alpha tocopherol at a concentration of about 0.01% to about 1%.
5. The aqueous antioxidant barrier coating of claim 4 wherein the concentration of carboxymethyl cellulose is about 2.0%, the concentration of propylene glycol is about 3.0%, the concentration of sodium gluconate is about 0.1%, the concentration of sorbitol is about 0.5%, the concentration of lecithin is about 0.2%, and the concentration of alpha tocopherol is about 0.5%.
6. A shelling processing aid for improving the optical contrast between nutshells and nutmeats comprising materials derived from the nut husks of the nuts to be processed and a polyvalent metal ion containing compound.
7. The shelling processing aid of claim 6 wherein the nut husks are selected from the group comprising pecan husks, walnut husks, macadamia nut husks and almond nut husks.
8. The shelling processing aid of claim 6 wherein the nut husks are pecan husks.
9. The shelling processing aid of claim 6 wherein the polyvalent metal ion containing compound is an iron polyvalent metal ion.
10. The shelling processing aid of claim 6 wherein the polyvalent metal ion containing compound is an iron(II) polyvalent metal ion.
11. The shelling processing aid of claim 6 wherein the polyvalent metal ion containing compound is iron(II) sulfate heptahydrate.
12. The shelling processing aid of claim 6 wherein the nut husks are pecan husks and the polyvalent metal ion containing compound is iron(II) sulfate heptahydrate.
13. The shelling processing aid of claim 12 wherein the materials form the pecan husks and iron(II) sulfate heptahydrate are in a mass ratio of about 1:2 to about 1:10.
14. The shelling processing aid of claim 13 wherein the materials from the pecan husks and iron(II) sulfate heptahydrate are in a mass ratio of about 1:7.
15. The shelling processing aid of claim 14 wherein the shelling processing aid is added to water at a concentration of about 1 g/liter, forming a working solution for contrast improvement for pecans.
16. An integrated process for improving the product quality of pecan nutmeat comprising the steps of i) coating the nuts with the anti-salmonella composition of claim 3, ii) further coating the nuts with the shelling processing aid of claim 15, iii) subsequently coating the nuts with the anti-rancidity of formula of claim 5, iv) storing the nuts as needed, v), pasteurizing the nuts, and vi), shelling and optically sorting the nuts to separate nutshell from nutmeat.
17. A nut shell mordant mixture for coloring nut shells, comprising nut husks and a polyvalent metal ion mordant.
Description
BRIEF DESCRIPTION OF FIGURES
[0049]
[0050]
[0051] The present invention will now be more fully described with reference to the accompanying examples. It should be understood, however, that the following description is illustrative only and should not be taken in any way as a restriction on the generality of the invention specified above.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0052] As described, herein, bacterial pathogens that are of relevance to the invention are those associated with foodborne illness, generally, including but not limited to Campylobacter jejuni, Clostridlum botulinum, Clostridium perfringens, Cryptosporidium, enterohemorrhagic Escherica coli (including Escheria coli O157:H7), Listeria monocytogenes, Salmonella and its multiple types, Shigella and its multiple types, Staphylococcus aureus and Vibrio vulnificus. Pathogens that are of particular relevance to nut processing industry are recognized to be Salmonella and its multiple types and enterohemorrhagic Escherica coli.
[0053] As used herein, Yucca Extract or Yucca Extract Concentrate is the natural extract of the Mohave Yucca Plant (Yucca schidegera). In a preferred embodiment, the concentration is 40 Brix. Mohave Yucca (Yucca schidigera) is approved for use in food and beverages by the FDA under CFR 172.510, FEMA number 3121 and allowed for use in organic production without preservatives under 7 U.S.C 605 and N.O.P. 205.602. Yucca Extract is exempt from the requirement of a tolerance as specified in 40 CFR 180.100.
[0054] Antioxidants generally are substances that prevent or inhibit the oxidation of susceptible substances either by direct chemical interaction or by functioning to prevent the exposure of the other substance to oxygen. As used herein, an antioxidant is a substance that inhibits oxidation, especially one used to counteract the deterioration of stored nut stuffs, either by direct chemical action or as a physical barrier to oxygen diffusion. Many synthetic antioxidants such as propyl gallate, tertiarybutylhydroquinone, butylated hydroxyl anisole and butylated hydroxytoluene and others are well known to the artisan and are considered within the scope of the invention. However, natural, non-synthetic antioxidants such as Vitamin C (ascorbic acid) and alpha-tocopherol and related tocopherols are preferred examples of antioxidants useful for the invention. Fat soluble antioxidants such as alpha tocopherol function to prevent rancidity by preferentially reacting with oxygen free radicals, thereby inhibiting the oxidation of fatty substances in the food or nut.
[0055] GRAS compounds are preferred compounds for use with the invention. GRAS is an acronym for the phrase Generally Recognized As Safe. Under sections 201(s) and 409 of the Federal Food, Drug, and Cosmetic Act, any substance that is intentionally added to food is a food additive, that is subject to premarket review and approval by FDA, unless the substance is generally recognized, among qualified experts, as having been adequately shown to be safe under the conditions of its intended use, or unless the use of the substance is otherwise excluded from the definition of a food additive.
[0056] Under sections 201(s) and 409 of the Act, and FDA's implementing regulations in 21 CFR 170.3 and 21 CFR 170.30, the use of a food substance may be GRAS either through scientific procedures or, for a substance used in food before 1958, through experience based on common use in food.
[0057] Without limitation, all agriculturally useful nuts, such as pecans, walnuts, pine nuts, hazel nuts, macadamias, almonds, cashews, Brazil, cacao, chestnuts, peanuts, and soy nuts are within the scope of the invention.
Anti-Microbial Shell Coating
[0058] In one embodiment of the invention a coating composition effective for reducing the surface burden of Salmonella of walnuts is disclosed and other nuts. The composition comprises Yucca extract, methyl cellulose, walnut shell powder and walnut ink.
Example 1
[0059] The coating of Table 1 is prepared and applied to nut shells by dipping or other means. The amounts listed are in water, per 100 ml total volume.
TABLE-US-00001 TABLE 1 Exemplary Composition Antimicrobial Coating per 100 ml Water a) 5 ml Yucca Extract Concentrate @ 40% Brix b) 4.0 g methyl cellulose c) 15.9 gram of ground walnut shell powder, WF-7 #325. d.) 3.2 ml walnut ink.
[0060] Walnut ink is available from Shellac.net Wood Finish Supply, 2325 #A, First Street, Napa, Calif. 94559. Walnut powder (WF-7 #325) is available from Composition Materials Co., Inc., 249 Pepes Farm Road, Milford, Conn. 06460.
[0061] According to the invention, the composition is useful over a concentration range of about 0.5% to about 5% yucca extract concentrate @ 40% Brix.
[0062] According to the invention, the nuts are dipped into the coating of Table 1 and dried at 40 C. for 1 hour. Alternatively, the nuts may be rapidly dried in a heating tunnel. When tested for Salmonella, a 2 decade reduction (1/100) of Salmonella levels may be obtained.
[0063] Before cracking, the nuts may be washed in running water for 45 seconds to remove the coating. A five decade reduction (1/100,000) in salmonella level may be achieved thereby.
[0064] As the antimicrobial composition is expected to act directly on the pathogenic organism, and not to be significantly affected by the nut surface, it is expected that the disclosed composition will have utility for other nut types and pathogens other than Salmonella.
Anti-Oxidant Barrier Coating
[0065] A barrier coating for inhibiting the rancidity of nuts or nutmeats is another embodiment of the invention. It is supposed that the barrier coat of the invention decreases rancidity by providing a barrier against oxygen diffusion through the nut shell into the nutmeat, or if the nutmeat is coated, into the nutmeat. The composition is expected to decrease the need for refrigeration, that to slow the development of rancidity when nuts are stored at higher temperatures.
[0066] The coating composition comprises the following components, useful in the ranges given, based upon weight/volume (g/100 ml) fraction in water: carboxymethyl cellulose, from about 0.5% to about 3.0%; propylene glycol, from about 3% to about 5%; sodium gluconate, from about 0.001% to 0.5%; sorbitol, from about 0.1% to about 1%; lecithin from about 0.05% to 1%; and alpha tocopherol, from about 0.01% to 1%.
Example 2
[0067] A preferred, exemplary composition of the antioxidant coating is shown in Table 2.
TABLE-US-00002 TABLE 2 Concentration (wt %) Component in water Function carboxymethyl cellulose 2.0% oxygen barrier propylene glycol 3.0% edible plasticizer sodium gluconate 0.1% natural chelator sorbitol 0.5% edible plasticizer lecithin 0.2% surfactant, emulsifier alpha-tocopherol 0.5% antioxidant
[0068] The exemplary formula comprises sodium gluconate, a natural chelator of metal ions. Sodium gluconate assists in preventing rancidity, instead of, for example, EDTA, a synthetic compound.
[0069] The composition is prepared by mixing the carboxymethyl cellulose in hot water at 100 C. to make a 10% wt % solution, which is diluted into cold water. Sodium gluconate and sorbitol are next added with stirring. Lecithin and alpha tocopherol are added last. Water in sufficient quantity is added to the mixture to bring the composition to the final concentrations.
[0070] The mixture may be de-aerated under vacuum at 20 mm Hg to remove entrapped bubbles. The coating solution is best stored at 4 C.
[0071] The mixture may be applied to the nuts by spraying or dipping or by other means known to the artisan.
Product Processing Product (PPP) Contrast Aid
[0072] In another embodiment of the invention, herein is disclosed a new processing aid mixture (Product Processing Product, PPP, or alternatively, shelling processing aid) comprising natural husk material and an FDA-approved processing aid for the improved optical separation of the shells (husks) of seeds and nuts from their respective meats. Surprisingly, the invention meets most, if not all of the criteria listed above in [0022] for improving shelling operations by optical sorting.
[0073] Upon treatment of the nuts with the processing aid mixture, the PPP improves the optical contrast between husk shell and meat and allows more efficient optical sorting between husk and meat.
[0074] The PPP comprises materials from recycled nut husks and one or more polyvalent metal cations. It is theorized that the polyvalent metal cations act as mordants. In the prior art, a polyvalent metal ion, such as ferrous ion, is often used to attach a dye to a product or material. A polyvalent metal ion or mordant forms a coordination complex between a coloring agent and the product that takes up the color. Additionally, a mordant can intensify a colors from husks derived from natural products like husks, and other natural products.
[0075] In one preferred embodiment of the invention, the PPP may be added to the microbial kill step tank which is routinely used in nut processing operations.
[0076] In one preferred embodiment the PPP comprises the natural husk material (0.4 Kg) from the specific nut that is being processed, combined with a FDA-approved processing aid (2.9 Kg) material comprising a polyvalent metal cation.
[0077] In one embodiment, the FDA-approved processing aid is ferrous ion, obtained from ferrous sulfate heptahydrate, FeSO.sub.4.7H.sub.2O, CAS Reg. No. 7782-63-0. The amount of processing aid may be modified depending on identity, mass and charge of the polyvalent ion mordant. In other preferred embodiments, the nuts for processing with the PPP are pecan, walnut, macadamia and almond nuts.
[0078] Other examples of mordant compounds useful for the invention are potassium aluminum sulfate K(Al)(SO.sub.4).sub.2, potassium aluminum sulfate dodecahydrate, K(Al)(SO.sub.4).sub.2.12(H.sub.2O), and stannous chloride, SnCl.sub.2,
[0079] In another embodiment the nuts in the shells can be sterilized by heating in an oven and the PPP can be added to the nuts before or after oven sterilization by dipping in water based solution or spray applied to the nuts before or after sterilization.
[0080] In the PPP, a ratio of husk material to polyvalent cation compound of about 1:7 is preferred. In a preferred embodiment, PPP is added directly to microbial kill water bath, typically at 190 F., a temperature used in many shelling operations.
[0081] In one embodiment, about 14.4 Kg of processing aid mixture is added to about 5,000 gallons of water (at ratio of about 0.8-1.1 grams/liter of water).
[0082] In accordance with 21 CFR 184.1(b)(1), the ingredients of the present invention are used in food as nutrient supplements as defined in 21 CFR 170.3(o)(20) of that chapter and as a processing aid as defined in 21 CFR 170.3(o)(24), with no limitation other than usage under current good manufacturing practices. The natural husk mixture used in the processing aid is waste product from the specific species from the nut material tree or stalk from which the nut is removed and therefore is a natural product and contains natural materials.
[0083] Ferrous sulfate is an affirmed GRAS compound (21 CFR 184.1315 Ferrous sulfate).
[0084] In a preferred embodiment the nut husk material is 1 (0.4 Kg) husk material to (2.9 Kg) processing aid and the processing aid is ferrous sulfate heptahydrate (iron (II) sulfate heptahydrate, FeSO.sub.4.7H.sub.2O. The composition is diluted to a preferred concentration of 1.0 grams per 1 liter of water.
[0085] Examples of polyvalent cations which may be useful for the invention are shown below in Table 3:
TABLE-US-00003 TABLE 3 Aluminum Al.sup.3+ Barium Ba.sup.2+ Calcium Ca.sup.2+ Copper(II) Cu.sup.2+ Cupric Iron(II) Fe.sup.2+ Ferrous Iron(III) Fe.sup.3+ Ferric Magnesium(II) Mg.sup.2+ Manganese(II) Mn.sup.2+ Manganous Tin(II) Sn.sup.2+ Stannous Tin(IV) Sn.sup.4+ Stannic Zinc Zn.sup.2+
Example 3
[0086] In a preferred embodiment the nut husk material is in the amount of 0.4 Kg husk material to 2.9 Kg processing aid, and the processing aid is ferrous sulfate heptahydrate (iron (II) sulfate heptahydrate, FeSO.sub.4.7H.sub.2O. The composition is diluted to a preferred concentration of 1.0 gram per 1 liter of water (1 concentration), a mixture into which the nuts are placed for testing contrast development.
[0087] When this embodiment is used as a processing aid, as shown in Table 4 below, this mixture produces an average light to dark value (L=100, white; L=0, black) on the nut of L=32 with a standard deviation of 1.59 (obtained with a Hunter Instruments, Model Ultrascan/Vis EasyMatch Software Reston, Va.). Lower L values correspond to greater contrast, which is desired. Increasing the concentration 3, 10 does not significantly improve the dark values (giving L=35 and 32 respectively). Therefore, increasing the concentration above 1 does significantly improve the dark value on the nut. Alternatively, decreasing the concentration of PPP degrades the dark value on the nut. Concentrations of (0.33) and 0.1 result in dark values increasing to 37 and 40 respectively. No good processing products have L (dark values) of 40.
[0088] Additionally, the standard deviation of the 0.33, 0.1 and no processing product (0), is significantly higher than 1 concentrations. Developing a consistent shell processing L value allows for the scanner/separator to be set to exclude shell parts.
TABLE-US-00004 TABLE 4 Processing Product Shell 1 Shell 2 Shell 3 L* a* b* L* a* b* L* a* b* Water 1 41.62 11.26 16.83 44.31 8.57 15.74 40.93 9.06 15.08 2 42.13 9.66 15.97 39.36 10.28 15.83 40.25 10.93 16.56 3 41.07 9.52 16.64 39.53 5.27 9.65 37.38 6.31 10.88 4 39.12 11.49 16.83 36.78 11.38 14.46 38.29 11.46 16.14 5 39.72 11.87 17.6 34.44 7.28 11.88 42.24 10.81 17.45 6 41.87 8.02 14.61 40.29 8.02 14.41 42.33 8.97 14.99 Avg 40.09 9.45 15.09 St Dev 2.35 1.93 2.22 1/10 1 38.39 7.84 14.03 39.55 9.28 14.27 38.18 9.74 15.59 2 40.94 10.58 16.15 36.21 8.95 14.14 43.52 11.39 18.71 3 45.39 12.25 20.04 40.13 7.86 13.78 42.1 10.72 16.52 Avg 40.49 9.85 15.91 St Dev 2.69 1.44 2.09 1 32.58 5.63 8.86 39.16 9.67 14.56 33.81 5.49 9.48 2 37.3 9.39 14.3 41.79 8.95 14.63 39.62 9.54 14.9 3 38.5 10.37 15.28 36.92 9.24 13.15 35.36 6.57 9.75 Avg 37.23 8.32 12.77 St Dev 2.76 1.77 2.48 1 1 29.66 1.19 4.66 32.12 1.03 6.41 29.1 0.68 4.55 2 31.96 0.88 6.77 31.53 2.61 8.55 32.32 0.51 5.45 3 33.24 1.43 7.07 34.39 1.13 6.77 33.1 1.78 7.68 Avg 31.94 1.25 6.43 St Dev 1.59 0.60 1.26 3 1 32.62 2.16 8.69 34.05 1.54 7.43 30.66 1.27 7.5 2 33.2 0.78 6.03 35.65 2.56 10.81 35.05 1.3 8.1 3 38.23 2.45 9.35 37.11 1.57 6.81 36.89 1.77 8.21 Avg 34.83 1.71 8.11 St Dev 2.29 0.55 1.33 10 1 34.54 1.75 7.41 31.31 0.54 4.77 28.55 1.26 5.05 2 31.06 1.07 5.6 31.16 0.89 5.84 29.14 1.11 5.57 3 35.39 1.44 7.16 35.05 1.66 7.03 31.12 1.01 6.26 Avg 31.92 1.19 6.08 St Dev 2.36 0.36 0.89 Averages Color [PPP] L* a* b* Concentration 0 40 9 15 0.1 40 10 16 0.33 37 8 13 1 32 1 6 3 35 2 8 10 32 1 6 L* = Light to Dark value (White = 100, Black = 0) a* = Green to Red Value b* = Blue to Yellow Value
[0089] The average L value for each concentration of processing aid is graphed in
[0090] Another example of existing optical equipment that may be used for optical sorting is the Scan Master II (Satake), SMII DE/XE 800/400/200 Series color sorting machinery.
Example 4
[0091] A working batch of PPP was prepared and used to colorize pecan nutshells in a pasteurization tank in advance of sorting. Thereby 100 lbs. (45.3 kg) of ferrous sulfate heptahydrate and 6.355 kg of ground pecan husk containing 14% moisture were mixed for 10 minutes in a rotating mixer. The working batch of PPP was divided into containers, each container holding 3.255 kg of PPP.
[0092] Four containers (13.02 kg) of PPP was placed into 11,420 liters (L) of water to charge the system to give a concentration of 1.1 g/L. The water was heated to 190 F. to obtain pasteurization temperatures. 300 pounds of pecans were placed in the pasteurization tank every 10 minutes. The pasteurization tank was refreshed with two containers of PPP every 3 hours to maintain the concentration of PPP in the tank.
[0093] The optical darkness, L, of the nuts obtained thereby was approximately 30 L as measured by the Hunter instrument (Hunter Instruments, Model Ultrascan/Vis, EasyMatch Software Reston, Va.). Pecans or nuts without the PPP treatment have an L value of 40-50 L.
[0094] In preferred embodiments of the invention the nuts used with PPP are: pecans, walnuts, almonds, and macadamia nuts.
[0095] Pasteurization, sterilization processes for nuts include: steam (water bath in the preferred embodiment we added the PPP to the water bath at temperatures above 184 F., preferably between 190 and 194 F.). A time longer than 7 minutes is used to kill salmonella. However, in the current invention a time between 9-14 minutes was used in the water bath to coat the shells with PPP.
[0096] It is envisioned that the PPP mixture will enhance the microbial effectiveness of the kill step when added at this stage. One mechanism for this activity would be redox cycling of the polyvalent transition metal producing toxic oxygen radicals.
[0097] Sterilization processes can also include oil bath emersion of the nuts in the shell or dry. In another embodiment the oily husks of the plant material are extracted in oil and the nuts are passed through the oil bath containing the oil and the extracted husk material.
[0098] In another embodiment, the nuts in the shells can be sterilized by heating in an oven and the PPP can be added to the nuts after before oven sterilization by dipping in water based solution or spray applied to the nuts before or after sterilization.
[0099] In other embodiments, the processing aid may be sprayed on the nuts during dry roasting. In other embodiments of the invention, the processing aid mixture may be sprayed on the nuts during dry sterilization. In yet other embodiments of the invention, the processing aid mixture may be part of an oil or oil in water mixture.
Example 5
[0100] In a preferred embodiment of the invention, the processing aid mixture can be removed from the waste stream from the heat kill step along with other waste products by forming pH dependents in the waste stream. (
[0101] Referring to
[0102] The precipitation effect is pH dependent. Acidic pH does not induce precipitate formation. The amount of precipitate from the waste water treated with acid and base starting at pH 2.0 and ending at pH 13.0 was tested. The pH between 2.0 to 9.0 did not cause precipitation formation. However, pH values higher than 10 and especially a pH range between 11 and 13 induced a rapid precipitation of materials in the waste water. Thus, this precipitate method pulls down additional products from the waste stream.
[0103] On a large scale, lime or slaked lime could be added to the mixing tank shown in
[0104] One advantage of this precipitation step is that it increases the quality of the water being pumped out of the microbial/kill waste water for large volume processing operations.
[0105] Different sources of water need different coagulants, but the most commonly used coagulants are alum and ferric sulfate:
##STR00001##
[0106] The following coagulant and coagulant aids, shown in Table 5, are useful in embodiments of the invention.
TABLE-US-00005 TABLE 5 Primary Coagulant Chemical Name Chemical Formula Coagulant Aid Aluminum sulfate (Alum) Al.sub.2(SO.sub.4).sub.314H.sub.2O X Ferrous sulfate FeSO.sub.47H.sub.2O X Ferric sulfate Fe.sub.2(SO.sub.4).sub.39H.sub.2O X Ferric chloride FeCl.sub.36H.sub.2O X Cationic polymer Various X X Calcium hydroxide (Lime) Ca(OH).sub.2 X X Calcium oxide CaO X X (Quicklime) Sodium aluminate Na.sub.2Al.sub.2O.sub.4 X X Bentonite Clay X Calcium carbonate CaCO.sub.3 X Sodium silicate Na.sub.2SiO.sub.3 X Anionic polymer Various X Nonionic polymer Various X
[0107] In accordance with 21 CFR 184.1(b)(1), the ingredients of the embodiment are used in food as nutrient supplements as defined in 21 CFR 170.3(o)(20) and are processing aids as defined in 21 CFR 170.3(o)(24), with no limitation other than current good manufacturing practices. The natural husk mixture is waste product from the specific species from the nut material tree or stalk from which the nut is removed and therefore is a natural product and contains natural materials.
Integrated Processing of Nuts
[0108] In an embodiment of the invention, an integrated method for improving nut processing whereby the microbial burden of the nut and nutmeat is reduced, storage stability of the unshelled nut is enhanced, and shell contamination of the nutmeat after shelling is diminished is envisioned. The integrated process comprises the steps of i) coating the nuts with the anti-salmonella composition of Example 1, ii) further coating the nuts with the PPP of Example 3, iii) subsequently coating the nuts with the anti-rancidity of formula of Example 2, iv) storing the nuts as needed, v), pasteurizing the nuts, and vi) shelling and optically sorting the nuts to separate nutshell from nutmeat.
[0109] Many other variations of the present invention will be apparent to those skilled in the art and are meant to be within the scope of the claims appended hereto.