Analytical apparatus and process
Contents
1. to 50 C and more preferably 35 to 45 C and the temperature as charged of the sample for volatiles moisture or solids determination is within the range of 1 to 30 C prefer ably 2 to 10 C e g about 5 C Preferably the density characteristic measured is the period but frequency or other relatable property can be measured instead Simi larly instead of solids content moisture content may be employed In such cases the computer instructions will be modified accordingly For simplicity various refer ences herein will be to period as the characteristic cor responding to density and to solids content but utiliz ing frequency and volatiles content are also within the described invention The invention will be readily understood by refer ence to this specification including illustrative working examples thereof taken in conjunction with the draw ing in which FIG 1 is a front perspective view of the apparatus of this invention FIG 2 is a schematic diagram of the components of the automatic volatility computer portion of this inven tion shown interfacing with the electronic density mea suring apparatus and 20 40 45 60 65 4 FIG 3 is a diagrammatic elevational view of the mechanical oscillator or mechanical oscillator forma tion of the density determining device portion of this invention In the embodiment of the invention illustrated in FIG 1 automatic volatility computer 11 include2. Difference 96 1 38 48 10 19 10 29 10 2 39 78 10 73 10 73 0 3 38 85 11 89 11 99 10 4 38 85 10 40 10 30 10 5 39 13 11 98 11 90 08 6 39 70 12 47 12 48 01 7 39 85 12 18 12 16 02 8 38 86 12 34 12 23 11 9 38 68 12 23 12 26 03 10 39 36 11 83 12 00 17 11 38 70 12 69 12 77 08 12 37 79 9 85 9 84 01 13 38 75 10 26 10 27 01 14 38 27 10 42 10 44 02 15 40 64 11 13 11 13 0 4 The experiment of Example 3 is repeated using va nilla ice cream mixes The same equation is in the com puter program as was employed in Example 3 Table 4 gives the data obtained using fifteen different vanilla ice cream mixes It is clear that the invented apparatus and method work equally well on chocolate and vanilla ice cream mixes This is important because other electronic fat analysis methods such as infrared techniques often give erroneous readings for chocolate mixes or require dilutions of such mixes which are not necessary when practicing the present invention EXAMPLE 5 An experiment like those of Example 1 4 is run on a sample of condensed milk The solids content is found to be 41 05 the fat content is found to be 12 53 and T T 0 09717 The standard error of fit is 0 131596 In Table 5 the data from fifteen runs on different condensed milk samples are given confirming the prac ticality of the invented apparatus and method for ana lyzing such product for fat content TABLE 5
3. determined by regression analysis will be given below Other formulas have also been developed for other dairy products such as cottage cheese con densed milk pasteurized milk reconstituted milk from milk powder and butter but it is considered that the four formulas are representative and sufficiently illus trate the invention For raw milk the percent of fat therein F 100 0 86427 solid _ 7 48999 T Tw wherein is the period of resonant oscillation reso nant period for the sample and T is the resonant per iod for the water both being tempered to the same temperature 40 C Corresponding formulas for the 15 20 25 35 40 45 50 65 10 fat contents percentages of cream ice cream mix and condensed milk respectively are F 0 86852 sid _ 1 36934 T sore F E solid 55736 T Tw and F 10 0 58858 x solid _ 1 34632 T Ty 0 01451 The formulas given were obtained by regression analy ses based on a preliminary assumption that for the de scribed products the product density is a function of the densities of three main components fat water and other materials mainly protein and sugar and the percent ages thereof present Although the other materials include both water soluble and water insoluble com pounds it has been found that the derived relationships give accurate fat analyses In
4. a similar manner formulas relating volatiles content or solids content to contents of other components of other products which compo nents are of different densities may be derived and the analyses of such products may be undertaken in similar manner Because the density measuring or resonant period measuring apparatuses that may be employed in the following examples cannot have identical mechanical oscillation characteristics the relationships set for the above four determinations of fat contents have been established for the particular apparatus employed Each other apparatus is standardized against the first one using water and an appropriate standard sample which sample is preferably about the density of the product to be analyzed Thus for analyses of raw milk which has a density of about 1 055 g ml at 40 C an aqueous copper sulfate solution of such density about 9 is employed as the test sample In such case if for example T T for the standard copper sulfate solution and water measured by the first apparatus was 0 0283943 and if for the second apparatus it was 0 0278512 the computer of the AVC 80 apparatus used with the second density measurer would be pro grammed at the factory to correct the T Ty by multiplying by 0 0283943 0 0278512 or 1 0195 Using such a correction factor the same equations for fat con tent may be used for all the apparatuses which is an important attribute of
5. desired 4 minutes and 30 seconds operation or 3 30 of the magnetron 4 30 is pressed Then the display reads Condensed Fat Y Rdy N Chg Because this is not the desired category the change button is pressed The next display is similar but is for Homogenized Fat Again the change button is pressed and the next display is for Raw Milk Fat Because this is the type of test being run the Rdy or the Y button is pressed Next on the display will appear sequentially indications of the constants which can be changed if desired but because they were properly set in the computer they were not changed Accordingly for all four constants the ready button is pressed Note that the fourth constant is not being employed and therefore is zero but provision has been made for further improving the regression formu las by allowing the insertion of a fourth constant if that should be considered desirable in the future The dis play then indicates Solids Bias to allow for different fat analyses to be used as comparisons but no bias is needed so Rdy is pressed Water calibration of the density meter is made at the beginning of each day of operation Such is begun by pressing the water solids button of the AVC 80 key board First the display appears as Cal Units Rdy CU 0 0000 At this point the tempered distilled water at 40 C is injected into the U tube of the mechanical oscillator formation of the density meter and two to three minutes i
6. may be reused An apparatus that accomplishes this the CEM Fat Ana lyzer and or the CEM Fat Oil Analyzer is manufac tured by CEM Corporation Indian Trail N C and when used in conjunction with a moisture solids analy zer made by the same company typically provides a moisture and fat content analysis of a small sample of a product within about 6 to 8 minutes with such analyti cal results being reported on a display screen of the moisture solids analyzer Such fat and oil analyzing apparatus is described in U S Pat No 4 554 132 and in a bulletin entitled The CEM Fat Analyzer copyrighted in 1981 by CEM Corporation Although the speedier solvent extraction technique mentioned above has advanced the analytical art signifi cantly sometimes it has been considered to be prefera 20 25 30 35 40 45 50 55 60 ble to avoid the employment of extraction solvents Use of such solvents may be objected to by some for eco nomic environmental and health reasons Also because some of the fats present in dairy products often about 2096 is tightly bound and not readily removable by single solvent extraction a plurality of solvents or spe cial treatments may be needed with resulting complica 65 2 tions of the extraction apparatus and process For those and or other reasons efforts have been made to employ other techniques preferably physical or mechanical and different from chemical and extraction operat
7. oscillator formation containing a sample of the dairy product in liquid state and an automatic volatility computer for determining the moisture and or solids content of the sample of the dairy product Although a separate computer can be employed to convert the electronic signals from both apparatus components to a readable display or print out of the fat content of the sample the computer will pref erably be located in either the density or volatility appa ratus more preferably in the latter It is also preferable for the computer to be programmed as by a plurality of circuits in a chip or in a plurality of chips so as to be capable of selectively computing fat contents of differ ent types of dairy products and sometimes of other materials too Also within the invention is a process for determining the fat content of a food which comprises automatically measuring a density characteristic of a food and produc ing an electronic signal corresponding to the density of the food automatically measuring a solids content char acteristic of a food and producing an electronic signal corresponding to the solids content of the food trans mitting the electronic signals to a computer automati cally computing with the computer the fat content of the food from the electronic signals and reporting the fat content of the food The temperature of the sample undergoing density measurement is normally in the range of 10 to 55 C preferably 30
8. oscillator formation container due to circulation about it of the water or other fluid from the temperature con troller After the test sample is at the desired tempera ture for insertion into the oscillator formation a sample is drawn into a syringe from a sealed vial thereof and is injected into the oscillator formation tube Because such tube is of relatively small volume normally being from 0 5 to 1 ml excess sample passes through the tube eliminating any gas contained therein or in the lines and some is intentionally left in the syringe so that no air enters the tube from the syringe A numeral related to the density of the sample the resonant period will be displayed by the density meter and or by the display of the AVC 80 or other computer When such numeral is constant and when the solids determination by the AVC 80 has been completed the percentage of solids content and the percent fat will be displayed by the AVC 80 or other computer and or printed by the printer Prior to injection of the test sample into the density meter a similar run would have been made using water at the same temperature as would be employed for the sample When the resonant period or frequency reading characteristic of the density of the water is constant that figure is entered into the computer and the difference between it and the reading for the sample is that which is relatable to the difference between the densities of the sample and water After co
9. solids content of the dairy product and utilizing a computer to calculate the fat content of the dairy product from the relevant signals and automatically to display print transmit and or store such result By means of the present inven tion the fat contents of dairy products as well as con tents of comparable components of other materials may be rapidly and accurately determined from small sam ples of such materials thereby facilitating rapid evalua tions production controls and standardizations of such 4 651 285 3 materials leading to important savings of time and money In accordance with the present invention an appara tus for determining the fat content of a food comprises means for automatically measuring a density character istic of a food and producing an electronic signal corre sponding to the density of the food means for automati cally measuring a solids content characteristic of a food and producing an electronic signal corresponding to the solids content of the food computer means to determine the fat content of the food from the electronic signals means for transmitting the electronic signals to the com puter means and means for reporting the fat content of the food Preferably the apparatus is adapted to deter mine the fat content of dairy products such as milk cream condensed milk ice cream mixes ice cream and cottage cheese by use of a density determining appara tus which includes a mechanical
10. the invention The following examples illustrate but do not limit the invention Unless otherwise indicated all parts are by weight and all temperatures are in C in the examples and throughout the specification EXAMPLE 1 The temperature controller is set at 40 C for both the water circulating to the density meter and for the tempering water used to raise the temperature of sealed vials of test samples of dairy products The AVC 80 volatility computer and the density meter are turned on and after heating of the temperature controlled water to 40 C it is circulated through the density meter and is 4 651 285 11 also employed to raise the temperature of the sealed vials of samples to 40 C Although the vials are sealed provision is made to allow the escape of any dissolved gas therein It takes about 5 to 7 minutes for the temper ature of the samples to be raised to 40 C When the AVC 80 digital display is turned on the mode is set for Section No 7 and the display reads Mode Section 7 Solids Fat Analysis The date is indicated by 00 00 00 and instructions appear to insert the correct date by means of the keyboard After the date is inserted the display indicates that the percent of solids will be dis played The ready button is pressed at which time the display reads Power P At this time 90 is inserted by pressing 9 and 0 on the keyboard to set the AVC 80 unit for 90 power Then time T 00 00 appears and for the
11. to the solids content thereof transmit ting the electronic signals to a computer and automati cally computing with the computer the component content of the material fromthe electronic signals 5 A process according to claim 4 for use in determin ing the fat content of a food which comprises automati cally measuring a density characteristic of a food and producing an electronic signal corresponding to the density of the food automatically measuring a solids content characteristic of the food and producing an electronic signal corresponding to the solids content of the food transmitting the electronic signals to a com puter and automatically computing with the computer the fat content of the food from the electronic signals k g
12. 446 hollow glass U tube 67 in which the sample to be tested for density is present during the test is connected by inlet and outlet glass tubing only inlet tubing 69 is shown to a source of sample to be tested Line 69 shown supported by a wail 71 communicates with an inlet for insertion of a sample into U tube 67 only one side of the U is shown but the usual means employed for inserting the sample into the tubing a syringe and a tubing seal are not illustrated Also not illustrated is a drain from the return tubing not shown to a waste holding pan not shown which facilitates insertion of sample into the U tube free of air The oscil lator illustrated incorporates a small rod like perma nent magnet 73 which can be inserted into two opposed coils 75 and 77 Coil 77 which constitutes a pick up coil is connected to coil 75 a driver coil by excitation am plifier 79 More details about the automatic volatility computer and the electronic density measuring apparatus of this invention and their operations will now be given While the temperature controller is important to the proper 20 25 30 40 45 60 65 6 operation of the invention it is considered that its func tion is apparent from the drawing in the previous de scription However the volatility computer and density measurer are more complex units and will be described further The density measuring apparatus 13 as illustrated includes a filling acc
13. C 80 and in the CEM Corporation operation and service manual entitled Automatic Volatility Computer Model AVC TM 80 both of which were previously referred to in this specification Such an automatic volatility com puter is described in U S Pat No 3 909 598 previously mentioned Also of interest is a one page publication from CEM Corporation entitled CEM Serial Dot Ma 4 651 285 7 trix Printer 80 Column which describes a printer that may be used with the AVC 80 analyzer The described apparatus may be assembled from a CEM Corporation AVC 80 Automatic Volatility Com puter with built in computer a CEM Corporation printer of the type mentioned above a Paar DMA 40 Digital Density Meter of the type described in the in struction manual previously referred to and in a four page publication entitled Digital Density Meter for Liquids and Gases DMA 40 which density meter may be suitably modified as by moving the sample inlet to the front thereof or may have only the mechanical oscillator formation employed or a Paar DPA 2000 Density Meter and a suitable water bath such as Exa cal Model EX 100B The density meter and the AVC 80 are electronically connected together using serial or parallel data transmission When the equipment has been set up with the proper chip or integrated circuitry in the AVC 80 unit to allow computation of the fat content of the product from its density and moisture content this is mode no 7 of the A
14. Instead of the Paar type density meter being em ployed other devices for determining density which can be modified to emit a characteristic electrical signal for the density may also be utilized While the invented technique as described is so easy to practice in a short time so that results are often obtainable within five or ten minutes or less exclusive of preliminary heating or tempering and very often will be routinely obtained within 2 to 4 minutes the invention can also be applica ble to continuous determinations of density with the appropriate electrical signals being sent to the AVC 80 volatility analyzer continuously or at the moment de sired for fat content determinations Also although particular formulas for fat determination for various materials will be given in this description which formu las are incorporated in the software in an AVC 80 chip or a plurality of such chips it is understood that other such formulas may also be derived and used for fat content determinations and for analyses for other com 0 25 45 50 65 8 ponents of materials and such are also within the pres ent invention To start the operation of the density meter after measuring the density of water or other base liquid with the apparatus the sample or samples of materials to be tested in liquid state are tempered or heated in the described water bath to a suitable temperature some times the same as or slightly hig
15. Sample Solids Fat Fat Fat Content No AVC 80 Invention Mojonnier Difference 76 1 41 05 12 53 12 35 18 2 41 20 12 56 12 46 10 3 41 75 12 45 12 41 04 4 40 50 12 28 12 37 09 5 41 64 12 72 12 78 06 6 41 40 12 60 12 67 07 7 41 39 12 58 12 68 10 8 43 16 13 47 13 44 4 03 9 43 16 13 44 13 48 04 10 42 95 13 09 12 95 14 1 41 84 12 64 12 60 04 12 42 95 13 04 12 99 05 13 37 94 11 57 11 66 09 14 40 59 12 15 12 22 07 15 36 46 11 21 11 24 03 When the products to be tested are not in flowable liquid state at room temperature they can be liquefied by melting dissolving or emulsifying and immiscible 4 651 285 15 liquids and or solids may be homogenized so that they can be added as a liquid to the oscillation cell Such technique is often useful for analyzing cheeses spreads peanut butter and butter In addition to the dairy prod ucts illustrated the invention is applicable to other foods such as meats salad dressings and food emul sions and may also be used to determine contents of components of non food materials such as oil in water and water in oil emulsions and creams e g cosmetic lotions and face creams It will be evident that in all the experiments in the specification and in the claims the analyses of fats include oils too and the word fat includes various lipophilic materials including oils which may be considered to be normally liquid fats The advantages o
16. United States Patent Collins et al 54 ANALYTICAL APPARATUS AND PROCESS 75 Inventors Michael J Collins Matthews Ronald J Goetchius Charlotte both of N C 73 Assignee CEM Corporation Matthews N C Notice The portion of the term of this patent subsequent to Jan 28 2003 has been disclaimed 21 Appl No 811 538 22 Filed Dec 19 1985 Related US Application Data 63 Continuation of Ser No 606 352 May 2 1984 Pat No 4 566 312 51 Int C4 es GO6F 15 46 GOIN 9 00 2 U S Cl 364 496 73 76 73 32 R 364 558 364 567 364 400 374 14 422 68 58 Field of Search 73 32 A 76 432 R 73 61 R 32 R 364 496 497 558 567 568 374 14 422 68 74 56 References Cited U S PATENT DOCUMENTS 3 839 909 10 1974 Sanden 364 558 X 3 909 598 9 1975 Collins et al 364 497 X 4 354 244 10 1982 Miller et al 364 497 X 4 359 638 11 1982 Allport 73 61 R 4 438 500 3 1984 Collins et al 364 567 4 554 132 11 1985 Collins ss 422 68 4 566 804 1 1986 Collins et al 374 14 Primary Examiner Errol A Krass Assistant Examiner Kevin J Teska 11 Patent Number 4 Date of Patent 4 651 285 Mar 17 1987 Attorney Agent or Firm Raymond F Kramer 57 ABSTRACT Apparatuses and processes are described for the auto matic determinations of fat contents of food
17. VC 80 unit em ployed the evaluations of samples of dairy products or comparable other materials for fat content or other component for which the analytical technique is suit able may begin The following description of the apparatus and the process of this invention will be with respect to deter mining the fat content of raw milk but it must be under stood that various other dairy products as well as other materials of properties such that they may be analyzed by the present system may also be the subject of the present invention For example among the dairy prod ucts one may also analyze pasteurized milk homoge nized milk cream half and half evaporated milk condensed milk ice cream and ice cream mixes and cottage cheese and other cheeses Materials that are normally in solid state are appropriately converted to liquids either by heating or by employment of a suitable solvent in known proportion In some instances materi als that are in the solid state may be finely divided and employed as suspensions The present invention while primarily directed to fat analyses of milk and other dairy products is also applicable to analyses of other foodstuffs such as meats meat products mayonnaises salad dressings margarines diet margarines and other fatty materials In some instances the invented method may be adaptable for protein determinations or determi nations of other materials present sometimes by differ ence
18. d in 1982 and reprinted in August 1983 the CEM Corporation bulletin entitled Moisture Solids Analyzer AV C 80 copyrighted in 1981 and an instruction manual and a bulletin both from Anton Paar K G and both entitled Digital Density Meter DMA 40 according to O Kratky H Leopold and H Stabinger no copyright or publication dates indicated Although the various patents and publications indi cate that efforts have been made to accurately and quickly measure the fat contents and contents of other components of various materials especially foods such as dairy products and meats and that various mechani cal physical electrical and electronic means have been employed in such attempts and although apparatuses are known that are capable of automatic moisture deter mination by microwave heating with automatic weigh ings and computer reporting of the moisture and or solids content on a display and for density determina tion by means of measurement of the resonant fre quency or period of an oscillator formation including the sample being tested with computer calculation of density from such data and reporting of the density on a display before the present invention the fat content of a dairy product had not been determined by means of a combination of means for automatically producing an electronic signal corresponding to the density of a dairy product with means for automatically producing an electronic signal corresponding to the
19. dures of Examples 1 and 2 are repeated with the materials tested being differently flavored liq uid ice cream mixes chocolate and vanilla For a choco late mix the percentage of solids is 41 77 and the per centage of fat is 9 51 compared to a Mojonnier analysis fat content of 9 49 T Ty is 0 128793 The experi ment is repeated 14 more times with other samples of chocolate ice cream and for the 15 samples the percent ages of solids are found to range from 37 36 to 43 21 whereas the percentages of fat range from 9 51 to 12 56 The Mojonnier fat contents range from 9 49 to 12 44 The deviation averages 0 06 and the standard error of fit is 0 1591 Table 3 gives the data from such experiments TABLE 3 Sample Solids Fat Fat Fat Contents No AVC 80 Invention Mojonnier Difference 46 i 41 77 9 51 9 49 02 2 42 46 12 56 12 44 12 3 37 36 9 86 9 87 01 4 41 79 9 81 9 82 01 5 43 17 12 12 11 96 16 6 41 72 11 94 11 84 10 7 41 36 11 79 11 72 07 8 43 21 11 83 11 85 02 9 41 86 11 98 12 06 08 10 41 14 11 36 11 45 09 11 42 17 11 26 11 33 07 12 41 82 9 88 9 91 03 13 42 03 11 67 11 68 01 14 42 27 11 99 11 90 4 09 10 15 25 30 35 35 65 14 TABLE 3 continued Sample Solids 96 Fat Fat Fat Contents No AVC 80 Invention Mojonnier Difference 96 15 42 72 12 00 12 06 06 TABLE 4 Sample Solids Fat Fat Fat Contents No AVC 80 Invention Mojonnier
20. e set to print some or all of the operation of the apparatuses such as the materials appearing at display 15 which materials can be printed on continuous paper sheet 33 In FIG 2 in which the automatic volatility computer parts and functions are illustrated schematically opera tor keyboard 35 which incorporates numeric and func tion input keys or equivalent synthetic plastic film cov 4 651 285 5 ered activator sections 37 and 39 FIG 1 allows the operator to input the microcomputer of the automatic volatility computer 11 The various inputs are numerals 1 through 9 and 0 and recall and water solids functions in area 37 with the remaining functions set power set time stop test mode change clear ready tare and run being in function area 39 but other arrangements are also practicable After inputting the microcomputer 41 by means of input output section 43 thereof the input signals are fed to microprocessor 45 and to peripheral interface 47 which is normally optional in such an auto matic volatility computer but is present in the present apparatus because of the need to interface with the density measuring apparatus 13 In addition peripheral interface 47 may allow interfacing with communication lines other computers and storage Input output area 43 also communicates with magnetron control 49 safety interlock 51 magnetron 53 and microwave power control 55 in the manner illustrated in FIG 2 Activation of the ma
21. ent Mar 17 1987 44 62 19 69 u Old Sn vHVddv SNIMNSVAW ALISN3Q 16 YI TIONLNOOD JINOYLOATA SYNLVYSAdWSL 6 M3lfhdWOO AALUTLLV TOA OIL VWOLnV U S Patent 17 1987 Sheet20f2 4 651 285 FIG 2 OPERATOR DATA 65 KEYBOARD 35 DISPLAY 63 ANALOG DIGITAL CONVERTER FILTER 49 MAGNETRON CONTROL 51 SAFETY INTERLOCKS 53 MAGNETRON 55 MICROCOMPUTER ELECTRONIC BALANCE MICROWAVE MICROWAVE DRYING POWER SYSTEM 57 SYSTEM ELECTRONIC DENSITY MEASURING APPARATUS 4 651 285 1 ANALYTICAL APPARATUS AND PROCESS This is a continuation of Ser No 606 352 filed May 2 1984 now U S Pat No 4 566 312 issued Jan 28 1986 This invention relates to apparatuses and processes for automatically determining fat contents of foods More particularly it relates to such apparatuses and related processes which are especially useful for deter mining the fat contents of dairy products such as milk which apparatuses and processes automatically measure product density and total solids content and from such measurements which are automatically electronically transmitted to a computer such as a microprocesser compute and report or record the fat content of the sample It is often desirable to be able to determine quickly the percentage of a particular chemical component in a sample of material It is important t
22. ess element 81 mounted on a front wall 83 When a sample is to be inserted into the U tube which is a part of the mechanical oscillator formation of the density apparatus such formation includes the oscil lating means the U tube and the sample contents of the U tube a tempered sample at desired temperature is transferred from vial 23 to a syringe not shown and is then inserted by means of the syringe into U tube 67 through line 69 During such insertion about five milli liters of the normal ten milliliters content of the vial are taken into the syringe and about four milliliters of this are discharged into inlet tube 69 with about 0 7 ml remaining in and filling the U tube and with the rest exiting from it through the outlet line corresponding to inlet 69 and through a drain outlet not shown into a waste pan not illustrated Due to the operation of the density measuring apparatus which is more fully de scribed in U S Pat No 3 523 446 issued to O Kratky et al which is hereby incorporated by reference the resonant period of the test sample compared to a base material such as water is related to and is indicative of the mass of the sample in the U tube and therefore relates to the density of the sample because the U tube volume is constant The resonant period or the period of oscillation is measured and from it the density is computed a control having been run first so that the difference between the resonant periods o
23. f the sample and the control can be measured and is displayed in display area 85 Other parts of the density apparatus 13 are an on off switch 85 a blower or air pump not shown and connections between the internal digital computer not shown and other parts of the apparatus including interfacing with the volatility computer The density measuring apparatus illustrated is like that shown and described in the Anton Paar K G instruc tion manual for their DMA 40 Digital Density Meter previously mentioned Because the volatility computer includes a microcomputer the computer of the density measuring apparatus may be dispensed with or omitted with the connections from the mechanical oscillator formation being made directly to the automatic volatil ity computer microprocessor through peripheral inter face 47 FIG 2 Other components of the automatic volatility com puter 11 include a door 87 handle 89 on off switch 91 and louvers 93 Not specifically illustrated are a weigh ing stem supporting a weigh pan on which the sample rests usually between two pieces of filter paper the magnetron and known circuitry for operation of the magnetron and for recording the weights on the weigh pan including tare weight weight with sample before microwave drying and weight with sample after micro wave drying The automatic volatility computer em ployed may be that described in the CEM Corporation bulletin entitled Moisture Solids Analyzer AV
24. f this invention have been referred to elsewhere in the specification and will be obvious to one of skill in the art from it and the reported working examples The apparatus is simple to use and is trouble free The procedures followed allow rapid determina tions of fat contents of dairy products and such determi nations are of acceptable accuracy in practical applica tions of the invention The equipment can be employed without the need for extensive training of the operator Thus the invention allows determinations of fat and oil contents of materials such as raw milk upon the fat content basis of which the farmer is paid and dairy products which are produced to certain fat content standards Thus the apparatus which can readily be made mobile and can be employed in the field as well as in the factory or dairy provides a rapid means of deter mining fat and oil contents of products without the need to employ less accurate more time consuming and less convenient test methods such as the Babcock Ger ber and Mojonnier or Roese Gottlieb methods and without using the solvents and reagents normally em ployed in such tests Also the equipment is considered to be more accurate faster and easier to operate than other electronic apparatuses such as the infrared absorption analyzer the near infrared reflectance analy zer and the Milko turbidometric tester The infrared and turbidity devices can operate satisfactorily in analy
25. gital read out on the density meter is stable the ready button on the AVC 80 computer is pressed The computer will then display the results aa S F indicating percent solids and percent fat in the sample Also indicated will be the percent of power capacity used and the time of magnetron actuation For this run the percentage of solids indicated is 12 45 87 55 volatiles principally moisture and the percentage of fat is 3 73 T T4 0 028394 and the actual percentage of fat as determined by a standard fat analysis technique Mojonnier is 3 62 The experiment is repeated with 14 other samples and for the fifteen tests the actual fat percentages range from 2 57 to 3 84 The percentages obtained by the present method range from 2 55 to 3 85 and the solids contents range from 11 35 to 12 58 The deviations from the actual percentages of fat range from 0 01 to 0 11 averaging 0 05 Especially in view of the speed of the determinations such an average variation is considered highly acceptable The standard error of fit is 0 3161 The formula shown which is programmed into the computer is intended for use with raw milk for which the fat content is within the range of 2 00 to 4 50 usu ally being from 3 40 to 4 10 The same formula can be used in measuring the fat contents of finished milks such as 0 5 1 2 3 5 and 4 fat milks but preferably for increased accuracies other equations will be derived f
26. gnetron causes electromagnetic radiation to enter the microwave cavity portion 57 Electronic balance 59 the pan of which is in the micro wave cavity of the apparatus transmits electronic sig nals indicative of weights of a sample before and after volatililzation of water and other volatiles therefrom through preamplifier and filter 61 and analog digital converter 63 to input output 43 Microprocessor 45 which receives electronic signals through input output unit 43 from analog digital converter 63 and peripheral interface 47 calculates the volatiles or solids content by weight loss Peripheral interface 47 is usually either a serial transmission device commonly referred to in the trade as an RS 232 type data transmission system or a parallel data transmission device commonly referred to as a BCD data binary coded decimal transmission system The serial RS 232 system is preferred The microcomputer may also contain other chips incorpo rating other formulas for fat content and other chips for different modes of operation e g moisture content protein content etc of other materials may also be included In response to a signal from operator key board 35 display 65 may report the final answer per centage fat present or may include operational instruc tions Instead of a visual display an audio report and audio instructions may be given or the printer may be utilized In FIG 3 which resembles FIG 3 of U S Pat No 3 523
27. her e g 1 to 10 C or 1 to 5 C higher than the temperature at which the sample is to be maintained in the density meter How ever usually the sample is heated to the same tempera ture as that which is maintained in the mechanical oscil lation formation Normally such temperature in the density meter will be from 20 to 55 or 60 C prefera bly 30 to 50 C and more preferably 35 to 45 C e g about 40 C for most dairy products Higher than about 40 C one will take care to avoid product separa tion which can occur after about 8 to 20 minutes heat ing The reason for tempering to a higher temperature when such is practiced is to thin the sample so that any entrapped air may escape The analytical technique is independent of viscosity and does not require measur ing out a particular volume or weight of sample but it can be sensitive to the presence of air bubbles in the product because they occupy volume and thereby de crease the mass of the sample in the tube or other con tainer of the mechanical oscillator formation While tempering to a temperature higher than the density testing temperature may be theoretically desirable as a practical matter it has been found that such is not re quired to obtain accurate fat analyses If the tempering temperature is higher than the temperature at which the oscillator formation is to be maintained the sample is soon cooled to such temperature after insertion into the
28. ine 29 to density measuring apparatus 13 wherein it controls the temperature of the sample in liquid state of material to be tested in which apparatus such material s density or a characteristic thereof will be measured The temperature controlled water deliv ered by tube 29 will be returned to temperature control ler 19 section 27 thereof via line 31 Temperature controller 19 is very desirably one which accurately controls the temperature of the circulating water and that in the well 21 Usually such control will be to within 0 5 C of the desired temperature preferably to within 0 2 C and more preferably to within 0 1 C or 0 05 C Normally the same water will circulate in both sections of the controller but at other times it may be preferable to utilize separated volumes of water or other heat transfer medium Within the temperature controller but not shown may be a mixer or circulator a pump a thermostat or a plurality of thermostats and means for adjusting the rate of flow of heat transfer medium from the temperature controller to the density measuring apparatus pinch clamps can be used for such purpose Printer 17 may be of any suitable type It is electroni cally connected to the computer of the apparatus which will preferably be incorporated in the automatic volatility computer unit 11 but can be separate or in the density measurer The printer will usually print in re sponse to a print instruction or may b
29. ions A search in the U S Patent and Trademark Office has resulted in the finding of the following patents which relate to various techniques for the analyses of materi als such as foods for particular components such as fats and oils U S Pat Nos 2 166 842 3 433 057 3 455 168 3 523 446 3 537 820 3 557 625 3 813 918 3 909 598 3 910 101 4 144 804 4 145 450 4 170 128 4 266 425 4 287 760 4 291 775 and 4 359 638 Of the mentioned U S Pat Nos 3 909 598 and 4 291 775 both of which are owned by the assignee of the present appli cation relate to computerized microwave analytical dryers or automatic volatility computers U S Pat Nos 3 523 446 3 910 101 4 170 128 relate to appara tuses for measuring densities of liquids by determining the resonant frequency of a container of the liquid being tested U S Pat Nos 4 144 804 4 145 450 4 266 425 and 4 359 638 describe apparatuses and processes for determining the fat contents of dairy products by physi cal or electrophysical methods In addition to the men tioned patents also relevant are various booklets manu als and bulletins issued by CEM Corporation manufac turer of the automatic volatility computer and Anton Paar K G of Graz Austria manufacturer of the den sity determining equipment Among such the most rele vant are considered to be the CEM Corporation opera tion and service manual entitled Automatic Volatility Computer Model AVC TM 80 copyrighte
30. mpletion of a run water or other suitable cleaning liquid is injected into the density meter so as to clean out any material present in it Repeated injections may be employed Normally it is preferred to follow the water injection s with one of a cleaning material which may include a volatile constituent to promote drying of the U tube by air or other gas which is subs 4 651 285 9 quently passed through such tube and the lines to and from it to promote rapid drying thereof Such cleaning and drying operations facilitate rapid density determi nations by the density meter without the need for re moving the sample tube from it and it has been found by repeated experiments that such cleaning operation is entirely satisfactory and the fat content readings ob tained are accurate The operation of the AVC 80 or other automatic volatility computer is essentially the same as has been described except for the fact that data from the density meter are also processed in the computer and are dis played After taring of the weight pan support stem and filter papers or other materials on which the sample is placed or between which it is placed the sample of the same composition as that the density of which is being determined in the density meter preferably at a temperature of about 1 to 10 C up to room tempera ture may also be employed is placed on one piece of filter paper and sandwiched between such paper and another and i
31. o be able to make such a rapid determination of the content of a compo nent in a product being continuously manufactured especially when such a product has specification set for it on the maximum and or minimum permitted content of such a component Thus for example by knowing the fat content of milk being processed in a dairy one is able to be assured that the product meets specifications for fat and if it doesn t steps can be taken to blend the product with another milk of different characteristics to make on specification material With rapid analysis being possible as by the method of this invention utiliz ing the apparatus thereof over specification products which might otherwise be manufactured to avoid non compliance with requirements for minimum contents of components may be avoided and economies in manu facturing operations may be achieved Because chemical tests and conventional extraction procedures for determining the contents of fats in dairy products and in other products and for determining the contents of other components in various materials have often been time consuming efforts have been made to accelerate the testing procedures For example the solvent extraction of fats and oils from materials such as butter margarine salad dressings and meats has been mechanized utilizing high speed mechanical agitation to effect rapid solvent extraction and the solvent has been automatically redistilled so that it
32. or such specific cases The following is a tabulation of data for fifteen differ ent samples of raw milk which proves the accuracy of the present apparatus and process in analyzing for fat contents Sample No 1 is that previously described herein TABLE 1 Sample Solids Fat Fat Fat Contents No AVC 80 Invention Mojonnier Difference 1 12 45 3 73 3 62 TI 2 12 44 3 73 3 62 11 3 12 24 3 51 3 49 02 4 12 15 3 39 3 40 01 5 12 23 3 65 3 66 01 6 12 18 3 65 3 62 4 03 7 12 39 3 63 3 61 02 8 12 33 3 70 3 65 05 9 12 58 3 85 3 84 01 10 12 05 3 48 342 06 11 12 05 3 49 3 44 05 12 12 28 3 44 3 54 10 13 12 28 3 45 3 54 09 14 11 35 2 55 2 57 02 15 11 31 2 58 2 59 01 Between determinations the syringe is removed from density measuring apparatus and the cell thereof is flushed with distilled water and a solvent containing cleaning solution Then the air pump which is included with the density meter apparatus is actuated to start the drying of the cell the container of the mechanical oscil lator formation The density meter read out for the apparatus employed will normally be within the range of 3 2200 to 3 2299 before drying is discontinued After drying the system is ready for the testing of another sample of the same type or it may be changed to test a different product To test such a different product the category heading is changed as was previously de scribed For instance in the nex
33. rein a plurality of selectable programs for determining the fat content of any of a plurality of foods from electronic signals corresponding to densities and solids contents thereof so that the com puter means is selectively capable of automatically de termining the fat content of any of a plurality of foods from such electronic signals 3 An apparatus for use in determining the content of a component of a material which component is of a different density from other components of the mate rial which comprises means for automatically measur ing a density characteristic of the material and produc ing an electronic signal corresponding to the density of the material means for automatically measuring a solids content characteristic of the material and producing an electronic signal corresponding to the solids content thereof computer means to determine the content of the component of the material from the electronic sig nals and means for transmitting the electronic signals to the computer means 4 A process for use in determining the content of a component of a material which component is of a dif ferent density from other components of the material which comprises automatically measuring a density characteristic of the material and producing an elec tronic signal corresponding to the density of the mate rial automatically measuring a solids content character istic of the material and producing an electronic signal corresponding
34. s such as dairy products e g milk wherein automatic density and solids content determining apparatuses are em ployed together with a computer to determine the fat contents of food samples being tested The density de termining apparatus is preferably one which is electro magnetically excited to vibrate at its natural resonant frequency so that from the change in such frequency compared to a control the mass of the sample may be determined The means for measuring the solids content is preferably an automatic volatility computer in which electromagnetic radiation microwave energy is em ployed to drive off the volatile material usually mostly water in the sample which is automatically weighed before and after such volatilization Preferably a mi crocomputer in the automatic volatility computer is employed to compute fat content from electronic feeds to it from the density and the solids content determining apparatuses By use of the described apparatuses and processes rapid determinations of fat contents of materials may be made facilitating modifications of production proce dures to provide products of desired fat content thereby preventing the production of off specification materials and avoiding producing over specification products which might otherwise be manufactured to avoid non compliance with requirements for minimum fat contents of products 5 Claims 3 Drawing Figures 4 651 285 Sheet 1 of 2 U S Pat
35. s a microprocessor see FIG 2 which measures weights of a test sample before and after evaporation of volatiles from it caused by microwave radiation and computes and reports the solids or volatiles or moisture in many cases content of the sample Electronic density measur ing apparatus 13 is electronically connected to the mi crocomputer and microprocessor of the automatic volatility computer Electronic signals characteristic of the density periods from such density measuring appa ratus are transmitted to the microcomputer and from such signals and signals characteristic of the volatiles or moisture content or of the solids content from the automatic volatility computer the fat content or a content of comparable material of the dairy product or other product is determined and is displayed by the automatic volatility computer in display 15 and or printed by printer 17 Temperature controller 19 acts to control the temper ature of water or other heat transfer liquid not shown in well 21 thereof in which containers or vials 23 are held supported by cage like holder 25 Containers 23 hold sample liquids which are being tempered prior to being inserted into the electronic density measuring apparatus 13 The temperature controller also includes a second portion or section 27 in which the temperature of the water bath is controlled so that water at a con trolled temperature may be delivered from section 27 through delivery l
36. s allowed for the temperature thereof to equilibrate to exactly 40 C The change button is pressed to record the numerical value indicated on the density meter display when it is constant Such value will normally be within the range of 4 3345 to 4 3342 In the present case it is 4 3344 The preliminary setting up of the apparatus having been completed the lab technician now proceeds to analyze one of the samples Approximately 10 ml of the sample which have been heated in a sealed vial in the 40 C water bath for a minimum of about 5 to 7 minutes note that several samples may be tempered at the same times are ready for injection Meanwhile because the moisture determination takes longer than the density determination two filter papers or support pads are placed on the balance of the volatility computer the door is closed and the tare button is pressed The sample is then applied to the pads preferably on one pad and covered by the other to minimize any spattering during heating and the Run button is pressed immediately The computer will display the peak weight reading The fat analysis is then started on the density meter First a small syringe holding about 5 ml is filled from the vial of tempered sample It is inserted slowly into the density meter cell and is not removed during the test On completion of the solids test the volatility 25 30 35 45 50 55 60 65 12 computer will signal audibly When the di
37. s positioned on the weigh pan The low temperature is to aid in preventing evaporation of vola tiles before the first weighing The weight is read and displayed by the computer and the difference is stored in the computer memory The power input and time of operation are then set and the unit is started with the microwave radiation heating the sample and evaporat ing moisture and any volatile materials from it and with most of the material removed being moisture By re gression analysis techniques which will be referred to subsequently relations between solids content or mois ture or volatile material content and density repre sented by the resonant period or frequency have been accurately related to fat contents for various dairy products Thus when the drying operation of the AVC 80 is complete the computer on command will display both the percent solids or moisture or volatiles and the fat content of the sample and will print these if desired Normally the time employed to dry the sample in the AVC 80 will be from 2 to 6 minutes preferably 2 to 4 or _ 5 minutes e g 34 minutes and the power input will preferably be from 80 to 95 more preferably 88 to 92 e g 90 With such drying times and power inputs it is found that the drying operation can be quickly and completely effected without burning the sample or causing decomposition of components thereof The formulas in the computer for fat contents of four materials
38. t example the program is changed to that for cream by pressing the change 4 651 285 13 button until Cream Fat shows after which the ready button is pressed EXAMPLE 2 The procedure of Example 1 is followed with the material tested being cream In such case the percent solids found is 45 96 the percentage of fat is 40 85 and T Ty 0 0192377 The actual fat content de termined by solvent extraction and evaporation is 40 89 Such determination is repeated for twelve ad ditional samples and for the thirteen samples the ac tual fat contents range from 31 07 to 44 96 whereas the calculated fat contents by the present method range from 31 12 to 44 82 The deviations from the actual percentages of fat range from 0 00 to 0 14 and the standard error of fit is 0 1187 The percentages of solids in the described materials ranged from 35 93 to 49 65 Table 2 sets forth the data obtained in this example using thirteen different cream samples TABLE 2 Sample Solids Fat Fat Fat Contents No AVC 80 Invention Mojonnier Difference 1 45 96 40 85 40 89 04 2 45 08 40 05 40 01 04 3 43 29 38 38 38 43 05 4 42 55 37 46 37 54 08 5 40 09 35 35 35 34 4 01 6 44 47 39 32 39 32 0 7 45 05 39 85 39 88 03 8 38 29 33 28 33 18 7 10 9 38 20 33 17 33 26 09 10 35 93 31 12 31 07 4 05 u 48 29 43 51 43 49 4 02 12 41 59 36 58 36 72 4 13 49 65 44 82 44 96 14 EXAMPLE 3 The proce
39. zing milk but they are inaccurate for fat analyses of cream and ice cream mixes and are susceptible to error when strong colorants or cell coating components are present Also changes in fat globule sizes can affect the analyti cal results and often a minor change in a component of a product can cause significant inaccuracies in an analy sis Furthermore the turbidometric technique is limited to fat analyses whereas the present invention has a wider use potential The invention has been described with respect to various illustrative embodiments and working examples but it is not to be limited to these because it is evident that one of skill in the art with the present specification 55 65 16 before him or her will be able to utilize substitutes and equivalents without departing from the invention What is claimed is 1 An apparatus for use in determining the fat content of a food which comprises means for automatically measuring a density characteristic of a food and produc ing an electronic signal corresponding to the density of the food means for automatically measuring a solids content characteristic of a food and producing an elec tronic signal corresponding to the solids content of the food computer means to determine the fat content of the food from the electronic signals and means for trans mitting the electronic signals to the computer means 2 An apparatus according to claim 1 wherein the computer has included the
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