06-T08238-レトルト殺菌白.indd

Size: px

Start display at page:

Download "06-T08238-レトルト殺菌-167-180白.indd"

ときなさんきち
7 years ago
Views:

1 , Vol. 9, No. 3, pp , Sep ATS A Practical Verification of Ambient Temperature Slide Method (ATS Method) during Retort Sterilization Isamu MUKAI 1 and Noboru SAKAI 2 1 Hisaka Works, LTD., Vital Industry Division, Design & Development Dep t Higashi-Konoikecho, Higashi-Osaka, Osaka , Japan 2 Tokyo University of Marine Science and Technology, Department of Food Science and Technology Konan, Minato-ku, Tokyo , Japan In our previous report [1], we have proposed the Ambient Temperature Slide Method (ATS Method) as a rational way to estimate the central temperature of individually packed foods during retort sterilization. In this paper, we aimed to get new knowledge by specifically comparing ATS Method with simple One-Dimensional Finite-Difference Method(s-OFD Method) that was improved for the practical use of a conventional method using numerical calculation in order to solve the heat conduction equation(one-dimensional Finite-Difference Method(OFD Method)). From the results of the experiments, it was clear that the Outside Film Heat-Transfer Coefficient h showed a smaller value than the expected one in the OFD Method and so surface heat transfer resistance is so large that it cannot be ignored. Because of this reason, it was thought to have been the obstacle for accurate estimating of the central temperature of foods. When we did parameter-fitting, ATS Method proved to be more than twice as good as the s-ofd Method in convergent accuracy and it was also good in convective foods as well as conductive foods. And, the F-value errors in simulation by using parameters obtained by parameter-fitting in the case of 4 food samples showed only one fifth of the value calculated on the s-ofd Method, it means that the convergent accuracy of ATS Method is five times better than the s-ofd Method. ATS Method showed approximately 1in the ratio of thermal diffusivity for conductive foods. This result may indicate the possibility in simple theoretical caluculation of parameter of heat transfer. From these results, ATS Method was thought to be several times better than the s-ofd method that is a conventional method and an improving one of OFD Method in estimating for the central temperature of foods. Keywords: Ambient Temperature Slide Method (ATS Method), One-Dimensional Finite-Difference Method (OFD Method), simple One-Dimensional Finite-Difference Method (s-ofd Method), Outside Film Heat-Transfer Coefficient h, F-Value 1 F Fax: , i-mukai@hisaka.co.jp F [1] ATS

, Vital Industry Division, Design & Development Dep t 2-1-48 Higashi-Konoikecho, Higashi-Osaka, Osaka 578-0973, Japan 2 Tokyo University of Marine Science and Technology, Department of Food Science

2 168 Ball Hayakawa [2] [3,4] ATS 1 One-Dimensional Finite-Difference Method, OFD OFD OFD F F p ATS OFD OFD s-ofd 8 F ATS h c twtw i h h h h c 4 h tw tp cal tp EXCEL tw tp EXCEL F F tp p F p F 0.01 cal 2 / 5 5 L 2L ATS V/A s-ofd OFD OFD utwt/twtp 0/L 2 Xx/L u/ 2 u/ X 2 u i, j 1u i, j /X 2 u i1, j2u i, j u i-1, j, at i1n1j1m 6 X2/N / X 2 1/2 tp ntp n-1 tw i n-1tp n-1 1 u i, 01at i1n1 7 twts1 twtw i 2 h twtp i 00 h 3 k t/ xhtwt at xl k t/ xhtwt at xl utw rt/tw rtp 0u rtw rtw/tw rtp 0 tw r

OFD OFD utwt/twtp 0/L 2 Xx/L u/ 2 u/ X 2 u i, j 1u i, j /X 2 u i1, j2u i, j u i-1, j, at i1n1j1m 6 X2/N / X 2 1/2 tp ntp n-1 tw i

3 169 k/h t/ xk/hl t/ Xtwt k/hl u/ Xtwt/tw rtp 0tw rt/tw r tp 0tw rtw/tw rtp 0 uu r mk/hl k/hl u/ Xm u/ Xuu r k/hl u/ Xm u/ Xuu r u 1(u 2 (X/m)u r)/(1(x/m)), at i1j1m at X1 at X1 8 u N1(u N (X/mu r)/(1(x/m)), at in1j1m 9 tw tp cal LNkhtp 0 tw r 6 9 EXCEL tw tp h EXCEL F tp s-ofd OFD 2.2 F F tpp F F caln F n/ F n100 p tp caltp/tp n 2 100/n F F cal tp tp cal [5] F / tp32250/18 12 F cal / tp cal 32250/1813 Table 1 Judgment Mark Table 1 Standard for evaluation of accuracy. Deviation of Food Temperature (p) Deviation of F-Value (F) under 1.0% between 1% under 2.0% between 5% under 3.0% between 15% 3.0% and over beyond 15% p h p c 2 F h F c ATS F 00.1 p Fig. 1 RCS-40RTG RCS-60/10SPX

2 F F tpp F F caln F n/ F n100 p tp caltp/tp n 2 100/n 10 11 F F cal tp tp cal [5] F /60101.8tp32250/18 12 F cal /60101.

4 170 Fig. 1 A flow diagram of a hot water retort min 20 min L100 THB-113 FVAC-V 3.2 Table CPP 12 PET B 1000 mpas Choi and Okos [6] wawb2l 2 4 2L wawb ATS V/A V A

2 Table 2 6070 CPP 12 PET 9 100 2 1 7 1 9 25 B 1000

5 171 Table 2 Samples for this work. NO. Kind of Samples (wawb2l) mm 1 Silicon Rubber ( ) 2 Tuna Flakes ( ) 3 Demi Glace Sauce ( ) 4 Gratin Sauce ( ) 5 Clam Chowder ( ) 6 Meat Sauce ( ) 7 Curry Sauce ( ) 8 White Sauce ( ) 9 Transfuse Liquid ( ) Material of Containner 595g unpacked 3kg 3kg 1kg 1kg 1kg 1kg 1kg 1000ml PE Pouch Characteristic Length in Heat Transfer (2L/) 25 (mm) k 25 < k 70 > (W/m) (20.4 / 7.993) <0.388> 25 < 70 > (cm 2 /sec) < > (38.0 / 13.90) (34.0 / 13.04) (25.0 / 10.97) (24.0 / 10.58) (23.0 / 8.879) (23.0 / 8.893) (23.0 / 8.907) (43.5 / 15.27) OFD OFD h 1/h h OFD ATS 1 h h 2 s-ofd s-ofd h F F p s-ofd k cal Choi and Okos 25 F p s-ofd cal ATS cal 1 2 cal/ F OFD h 2L k Choi and Okos h h

Liquid (12127043.5) Material of Containner 595g unpacked 3kg 3kg 1kg 1kg 1kg 1kg 1kg 1000ml PE Pouch Characteristic Length in Heat Transfer (2L/) 25 (mm) k 25 < k 70 > (W/m) (20.4 / 7.993) 0.394 <0.

6 172 1/h OFD h W/m 2 4 tp cal Fig. 2 tp h3500 W/m 2 OFD h OFD h 25kL h Fig. 3h W/m 2 Fig. 2 The history of measured temperature of ambient (twsolid line) and at the center of food body (tp light solid line) when silicon rubber is used as food in a hot-water retort. The temperature tp cal at the center of food body that was calculated directly by the simulation used properties and thickness at 25 and as h on the OFD Method is shown as the broken line. Fig. 3 The history of measured temperature of ambient (twsolid line) and at the center of food body (tplight solid line) when silicon rubber is used as food in a hot-water retort. The temperature tp cal at the center of food body that was calculated by the h-fitting used properties and thickness at 25 and covergent calculation of p on the OFD Method is shown as the broken line.

The temperature tp cal at the center of food body that was calculated directly by the simulation used properties and thickness at 25 and as h on the OFD Method is shown as the broken line. Fig.

7 173 N 10 N20 h17500 W/m 2 tp cal tp h17500 W/m 2 ATS kl 4 OFD Fig. 4 h hcal OFD 25 Table OFD s-ofd ATS s-ofd h h h W/m 2 1/h 8 10 s-ofd k k L 25 1 cal F Fp 2 tp cal Fig. 5 cal 25 cal/ Table 4 ATS tw tp 2 10 Fig cal Fig. 4 The history of measured temperature of ambient (twsolid line) and at the center of food body (tp light solid line) when silicon rubber is used as food in a hot-water retort. The temperature tp cal at the center of food body that was calculated by the parameter-fitting used convergent calculation with both F and p on the ATS Method is shown as the broken line.

8 174 Table 3 The result of the preliminary experiment using silicon rubber. NO. Sterilizing Condition OFD Method s-ofd Method A T S Method Sample: Silicon Rubber 1 Hot Water Retort min 2 Saturated Steam Retort min 3 Hot Water Spray Retort min 4 Water Bath System min Reference NO. Sample: Transfuse Liquid 1 Hot Water Spray Retort min Simulation 25 standard h W/m cm 2 /sec k0.394 W/m L1.02 cm 25 standard h W/m 2 Properties of water h-fitting p 25 standard cm 2 /sec k0.394 W/m L1.02 cm h h129.1 W/m 2 h c111.2 h h154.6 h c62.1 h h142.4 h c132.3 h h156.9 h c standard Properties of water h h17500 h c Fitting (p) 25 standard h17500 W/m 2 k water0.522 W/m L1.02 cm h cm 2 /sec c h c h c h c standard h17500 W/m 2 k water0.522 W/m h c Parameter-Fitting (Fp) No input data required to calculate. ( cal 2 / 3V/A ) h h51 sec ( hcal cm 2 /sec) c c55.5 h h45 ( hcal cm 2 /sec) c c24 h h48 ( hcal cm 2 /sec) c c54 h h44 ( hcal cm 2 /sec) c c48 ( hcal/ 25) ave.0.976(1) No input data required to calculate. h h24 ( hcal cm 2 /sec) c c 6 tw tp tp Fig. 5 The history of measured temperature of ambient (twsolid line) and at the center of food body (tplight solid line) when meat sauce is used as food in a hot-water retort. The temperature tp cal at the center of food body that was calculated by the -fitting used thermal conductivity and thickness at 25 and covergent calculation of F on the s-ofd Method is shown as the broken line.

System 10019 min Reference NO. Sample: Transfuse Liquid 1 Hot Water Spray Retort 11815 min Simulation 25 standard h W/m 2 0.0025 cm 2 /sec k0.394 W/m L1.

9 175 Table 4 The result of parameter-fitting of the central temperature of eight different commercial products. NO. Kind of Samples Details 9 Conductive Foods 1 Convective Medicine s-ofd Method (Input data k 25L 25 and h=17500 W/m 2 ) Result of the fitting used F and ( cal/ 25) Result of the fitting used p and ( cal/ 25) ATS Method Result of parameter fitting and ( cal / 25) 1 Tuna Flakes (0.79) (0.78) (0.997) (spray) min 2 Demi Glace Sauce (0.85) (0.75) (0.963) (hot-water) min 3 Gratin Sauce (0.64) (0.59) (0.976) (steam) min 4 Gratin Sauce (0.59) (0.60) (1.029) (hot-water) min 5 Clam Chowder (0.61) (0.59) (1.080) (spray) min 6 Clam Chowder (0.59) (0.57) (1.051) (spray-rolling)12338 min 7 Meat Sauce (0.78) (0.74) (0.988) (hot-water) min 8 Curry Sauce (0.73) (0.77) (1.006) (hot-water) min 9 White Sauce (0.76) (0.74) (0.991) (hot-water) min Average (0.71) (0.70) (1.01)1 Deviation 18% 18.7% 18% 15.5% 4.9% 6.7% 10 Transfuse Liquid (spray) min (9.36) (7.83) (8.02) Fig. 6 The history of measured temperature of ambient (twsolid line) and at the center of food body (tplight solid line) when meat sauce is used as food in a hot-water retort. The temperature tp cal at the center of food body that was calculated by the parameter-fitting used covergent calculation with both F and p on the ATS Method is shown as the broken line. ATS s-ofd 5 4 Fig. 78

cal/ 25) ATS Method Result of parameter fitting and ( cal / 25) 1 Tuna Flakes (0.79) (0.78) (0.997) (spray) 12285 min 2 Demi Glace Sauce (0.85) (0.75) (0.963) (hot-water) 12167 min 3 Gratin Sauce (0.

10 176 tw tp tp Fig. 7 The history of measured temperature of ambient (twsolid line) and at the center of food body (tplight solid line) when curry sauce is used as food in a hot-water retort. The temperature tp cal at the center of food body that was calculated by the simulation used the parameters which is obtained at slightly different sterilizing conditions on the s-ofd Method is shown as the broken line. Fig. 8 The history of measured temperature of ambient (twsolid line) and at the center of food body (tplight solid line) when curry sauce is used as food in a hot-water retort. The temperature tp cal at the center of food body that was calculated by the simulation used the parameters which is obtained at slightly different sterilizing conditions on the ATS Method is shown as the broken line. F ATS 2 s-ofd 4 6 Table 52 tp cal F cal F ATS F -45s-OFD h h RE [7] h

as the broken line. Fig. 8 The history of measured temperature of ambient (twsolid line) and at the center of food body (tplight solid line) when curry sauce is used as food in a hot-water retort.

11 177 NO. Table 5 The result of simulation of the central temperature of four different commercial products. Kind of Samples Way of Simulation Sterilizing condition brought the parameters and each evaluation of accuracy on the parameter-fitting 1 Meat Sauce 11542min (s-ofd) (ATS) 2 Curry Sauce 3 White Sauce 4 Transfuse Liquid 11539min (s-ofd) (ATS) 11536min (s-ofd) (ATS) 11815min (s-ofd) (ATS) Sterilizing condition to be tried using the parameters and F-value in practice 11038min F min F min F min F0.640 s-ofd Method Calculated F-value of food and the ratio of F-value F cal1.200 F cal/f=1.13 F cal1.198 F cal/f=1.23 F cal0.357 F cal /F=1.10 F cal0.690 F cal/f=1.08 Result of Simulation ATS Method Calculated F-value of food and the ratio of F-value F cal1.088 F cal/f=1.02 F cal1.021 F cal/f=1.05 F cal0.312 F cal/f=0.96 F cal0.661 F cal/f=1.03 (F cal/f) ave.1.14 (F cal/f) ave.1.02 Error rate 8%23% 4%5% 4 h cal [7] h 200 W/m 2 kl 25 h 70 2 h h W/m 2 h s-ofd 5.2 ATS s-ofd s-ofd 2 h 1 F p ATS 2 F p F F p 5.3 cal/ 25 ATS s-ofd s-ofd cal

4 Transfuse Liquid 11539min (s-ofd) (ATS) 11536min (s-ofd) (ATS) 11815min (s-ofd) (ATS) Sterilizing condition to be tried using the parameters and F-value in practice 11038min F1.066 11036min F0.

12 178 h cal h h tw ts h h s-ofd cal ATS ATS tw tp 2 s-ofd V/A cal/ 25 ave.1 s-ofd ATS F ATS F s-ofd F s-ofd ATS 5 ATS s-ofd ATS 5.5 ATS ATS ATS F ATS ATS 1 ATS ATS 3 F ATS 1 ATS 1

13 179 NOMENCLATURE A effective heat transfer area, m 2 F sterilization valuef-value), min L a half of thickness of food, m N number of mesh partitions, V volume of food, m 3 X X h dimensionless distance, dimensionless cut width, outside film heat-transfer coefficient, Wm -2-1 k thermal conductivity of food, Wm -1-1 n calculated order, t temperature of food at arbitrary position, tp central temperature of food, tw ambient temperature, tw( h) ambient temperature at last time of heating process, tw i simulated ambient temperature, tw r the highest sterilization temperature, ts surfase temperature of package, u dimensionless temperature, wa width of packed food, m wb length of packed food, m x distance from central point, m thermal diffusivity, m 2 s -1 p F deviation ratio of central temperature from average temperature in food, sliding time of ambient temperature, s time, s small time increment, s Fourier number, dimensionless cut time, deviation between food temperature-curve, deviation of F-value, parameter of heat transfer, distance from surface to center of food, m 0 initial value c cooling process h heating process cal calculated value 25 properties of properties of 70 Subscripts [1] [2] K. HayakawaEstimating food temperatures durring various processing or handling treatment, J. Food sci., 36, (1971). [3] [4] 5 FOOMA [5] 1991, pp [6] Y.Choi, M.R. OkosEffect of temperature and composition on the thermal properties of food. In Food Engineering and Process Applications, ed. M. Lemaguer and P. Jelen), pp , Elsevier Applied Science Publishers, London (1986). [7] 1977 pp [1] ATS 1 OFD s-ofd ATS h ATS 2 4 F 1/5 ATS 5 ATS 1 ATS 1 1

temperature of food, tw ambient temperature, tw( h) ambient temperature at last time of heating process, tw i simulated ambient temperature, tw r the highest sterilization temperature, ts surfase

Fig. 1 A schematic diagram of temperature profile in a food body and in its ambient. Fig. 2 A schematic diagram of temperature history at the center o

Fig. 1 A schematic diagram of temperature profile in a food body and in its ambient. Fig. 2 A schematic diagram of temperature history at the center o A Practical Method for Estimating Temperature History in Individual-Packed Foods During Retort Sterilization Isamu MUKAI Hisaka Works, LTD. Vital Industry Division, Engineering Section, 21-48 Higashi Konoikecho,

06-T08238-レトルト殺菌 白.indd

06-T08238-レトルト殺菌白.indd