THERMAL CONDUCTIVITY: LITERATURE DATA COMPILATION FOR FOODSTUFFS

Abstract

Published experimental data on thermal conductivity of food materials are scattered, and their utilization in food processing operations is difficult. Data of thermal conductivity for various foods in recent literature were classified and analyzed. The results of more than 100 food materials, classified in 11 food categories, are presented. The results concern the reported range of variation of moisture data together with the corresponding range of material moisture content and temperature. The relative literature sources are presented for each food material.

INTRODUCTION

Thermal conductivity data in the literature show a wide variation resulting from the effect of the following factors: a) diverse experimental methods, b) variation in composition of the material, and c) variation of the structure of the material. Thermal conductivity depends strongly on moisture content, temperature, and structure of the material. Despite the attempts in developing structural models (Rahman, 1995; Marinos and Maroulis, 1995) to predict the thermal conductivity of foods, a generic model does not exist at the moment (Chen et al., 1998). Thus, the analysis of the data that exist in the current literature is of great importance.

The scope of this article is to update and analyze the data of the above review publications, revealing the range of variation for each food material versus the corresponding ranges of material moisture content and temperature.

DATA COMPILATION

An exhaustive literature search was made in the most popular food engineering and food science journals during recent years. Those journals are as follows:

•	Drying Technology, 1983–1999
•	Journal of Food Science, 1981–1999
•	International Journal of Food Science and Technology, 1988–1999
•	Journal of Food Engineering, 1983–1999
•	Transactions of the ASAE, 1975–1999
•	International Journal of Food Properties, 1998–2000

A total 146 articles were retrieved from the aforementioned journals. The search resulted in 1210 items of data concerning the thermal conductivity of food materials.

RESULTS

A total of 146 articles were retrieved from the aforementioned journals according to the distribution presented in Figure 1. The accumulation of the articles versus the publishing time is also presented in Figure 2. The search resulted in 1210 items of data concerning the thermal conductivity in food materials. The 1210 items of data retrieved from the aforementioned search, plus 25 items of data from Okos (1986) were organized into a database and analyzed.

Figure 1. Number of papers concerning thermal conductivity data in food materials published in food engineering and food science journals during recent years.

Figure 2. Accumulation of published papers concerning thermal conductivity data for food materials versus time.

A total of 1188 items of data were obtained. These data are plotted versus moisture and temperature in Figures 3 and 4, respectively. These figures show a good picture concerning the range of variation of conductivity, moisture, and temperature values. More than 95% of the data are in the range:

•	Thermal Conductivity 0.03–2.0 W/m K
•	Moisture 0.01–65 kg/kg (dry basis)
•	Temperature −43–160°C

Figure 3. Thermal conductivity data for all foods at various moistures.

Figure 4. Thermal conductivity data for all foods at various temperatures.

Moreover, the histogram in Figure 5 reveals the distribution of the thermal conductivity values retrieved from the literature. The results obtained are presented in detail in Tables 1 and 2. More than 100 food materials are incorporated in Tables 1 and 2. They are classified into 11 food categories. Table 1 shows the related publications for every food material. Table 2 presents the range of variation and the average values of thermal conductivity for each material along with the corresponding ranges of moisture and temperature.

Table 1. Literature for Thermal Conductivity Data in Food Materials

Baked Products

Bread: Zanoni et al., 1995, Zanoni et al., 1994, Goedeken et al., 1998

Dough: Bouvier et al., 1987, Zanoni et al., 1995, Griffith et al., 1985

Soy flour: Maroulis et al.,1990, Wallapapan et al., 1982

Cup batter: Baik et al., 1999

Yellow batter: Baik et al., 1999

Cake: Zanoni et al., 1995

Cereal Products

Barley: Alagusundaram et al., 1991

Corn: Beke et al., 1994, Chang et al., 1980, Okos et al., 1986

Rice: Okos et al.,1986, Ramesh, 2000

Wheat: Chang et al., 1980, Okos et al., 1986

Corn Meal: Lai et al., 1992, Kumar et al., 1989

Idli Batter: Murthy et al., 1997

Maize: Halliday et al., 1995, Tolaba et al., 1988

Oat: Okos et al., 1986

Dairy

Cheese: Luna et al., 1985, Tavman et al., 1999

Milk: Duane et al., 1992, Duane et al., 1993, Duane et al., 1994, Mc Proud et al., 1983,

Hori, 1983, Ziegler et al., 1985, Reddy et al., 1993, Tavman et al., 1999, Okos et al., 1986

Cream: Duane et al., 1998

Butter: Tavman et al., 1999, Okos et al., 1986

Yogurt: Kim et al., 1997, Tavman et al., 1999

Whey: Okos et al., 1986

Fish

Cod: Sanz et al., 1987

Mackerel: Sanz et al., 1987

Squid: Rahman et al., 1991, Rahman, 1991

Carp: Hung et al., 1983

Surimi: Wang et al., 1990, AbuDagga et al., 1997

Cake: Borquez et al., 1999

Shrimp: Karunakar et al., 1998

Calamari: Rahman, 1991

Salmon: Sanz et al., 1987

Fruits

Apple: Ramaswamy et al., 1981, Mattea et al., 1989, Telis-Romero et al., 1998, Rahman, 1991,

Constenla et al., 1989, Bhumbla et al., 1989, Ziegler et al., 1985, Mattea et al., 1986,

Madamba et al., 1995, Sheen et al., 1993, Buhri et al., 1993, Okos et al., 1986, Chen et al, 1998

Banana: Njie et al., 1998

Peach: Okos et al., 1986

Strawberry: Delgado et al., 1997, Bhumbla et al., 1989, Okos et al., 1986

Raspberry: Bhumbla et al., 1989, Okos et al., 1986

Grape: Bhumbla et al., 1989, Okos et al., 1986

Plantain: Njie et al., 1998

Raisin: Vagenas et al., 1990

Pear: Mattea et al., 1989, Rahman, 1991, Dincer, 1997, Mattea et al., 1986, Okos et al., 1986

Orange: Telis-Romero et al., 1998, Bhumbla et al., 1989, Ziegler et al., 1985, Okos et al., 1986

Bilberry: Bhumbla et al., 1989, Okos et al., 1986

Cherry: Bhumbla et al., 1989, Okos et al., 1986

Legumes

Lentils: Alagusundaram et al., 1991

Meat

Beef: Hung et al., 1983, Marinos-Kouris et al., 1990, Mc Proud et al., 1983, Perez et al., 1984, Rahman, 1991, Baghe-Khandan et al., 1982, Sanz et al., 1987, Califano et al., 1997

Chicken: Rahman, 1991, Sanz et al., 1987

Sausage: Sheen et al., 1990, Ziegler et al., 1987, Akterian, 1997

Turkey: Sanz et al., 1987

Mutton: Sanz et al., 1987

Pork: Sanz et al., 1987

Pork/soy: Muzilla et al., 1990

Model Foods

Amioca: Maroulis et al., 1990, Lai et al., 1992, Drouzas et al., 1991, Maroulis et al., 1991, Drouzas et al., 1988

Hylon-7: Maroulis et al., 1990, Lai et al., 1992, Maroulis et al., 1991, Drouzas et al., 1988

Potato starch: Okos et al., 1986

Starch: Renaud et al., 1991, Njie et al., 1998, Maroulis et al., 1991, Morley et al., 1997, Wang et al., 1993,: Lan et al, 2000

Sucrose: Renaud et al., 1991, Ziegler et al., 1985

Gelatin: Renaud et al., 1991, Okos et al., 1986

Ovalbumin: Renaud et al., 1991

Karlsruhe: Hung et al., 1983

Tylose: Pham et al., 1990

Agar-water: Delgado et al., 1997, Barringer et al., 1995

Water-ovalbumin: Cornillon et al., 1995

Gelatin-sucrose-water: Halliday et al., 1995

Glycerin-water: Ryniecki et al., 1993

Amylose: Voudouris et al., 1995: Tong et al., 1993

Cellulose gum: Okos et al., 1986

Pectin: Okos et al., 1986

Pectin-glucose: Okos et al., 1986

Nuts

Macadamia: Rahman, 1991

Others

Coconut: Duane et al., 1995, Chen et al, 1998

Coffee: Sagara et al., 1994

Soybean: Okos et al., 1986

Palm kernel: Duane et al., 1996

Lard: Duane et al., 1997

Agar-water: Wang et al., 1992

Bentonite-water: Niekamp et al., 1984

Water-NaCl: Lucas et al., 1999

Water-sucrose: Lucas et al., 1999

Rapeseed: Bilanski et al., 1976, Moysey et al., 1977, Okos et al., 1986

Tobacco: Casada et al., 1989

Sorghum: Chang et al., 1980, Okos et al., 1986

Sugar: Okos et al., 1986

Albumen: Okos et al., 1986

NaCl: Okos et al., 1986

Honey: Okos et al., 1986

Albumine: Okos et al., 1986

Vegetables

Carrot: Niesteruk, 1998, Njie et al., 1998, Rahman, 1991, Buhri et al., 1993

Cassava: Njie et al., 1998

Garlic: Madamba et al., 1995

Onion: Rapusas et al., 1994

Pea: Sastry et al., 1983, Alagusundaram et al., 1991

Potato: Niesteruk, 1996, Niesteruk, 1997, Niesteruk, 1998, Hung et al., 1983, Lu et al., 1999, Njie et al., 1998, Wang et al., 1992, Rahman, 1991, Mattea et al., 1986, Halliday et al., 1995, Madamba et al., 1995, Buhri et al., 1993, Gratzek et al., 1993

Sugar beet: Niesteruk, 1998, Okos et al., 1986

Turnip: Buhri et al., 1993

Yam: Njie et al., 1998

Beetroot: Niesteruk, 1998

Parsley: Niesteruk, 1998

Celery: Niesteruk, 1998

Tomato: Dincer, 1997, Choi et al., 1983, Filkova et al., 1987, Doruzas et al., 1985, Okos et al., 1986

Cucumber: Dincer, 1997

Spinach: Delgado et al., 1997

Mushrooms: Shrivastava et al., 1999

Rutabagas: Buhri et al., 1993

Radish: Buhri et al., 1993

Parsnip: Buhri et al., 1993

Kidney bean: Zuritz et al., 1989

Table 2. Thermal Conductivity of Foods versus Moisture and Temperature (Variation Range of Available Data

	Conductivity (W/mK)			Moisture (db)			Temperature (°C)
Material	Minimum	Average	Maximum	Minimum	Average	Maximum	Minimum	Average	Maximum
Baked products	0.04	0.34	3.559	0.0	0.57	1.50	15	46	15
Bread	0.05	0.23	0.53	0.0	0.39	0.82	15	44	12
—	0.0	0.27	0.53	0.0	0.35	0.79	25	47	10
Crust	0.05	0.06	0.066	0.0	0.00	0.00	15	68	12
Crumb	0.23	0.26	0.298	0.7	0.76	0.82	15	17	1
Dough	0.06	0.34	0.71	0.0	0.89	1.50	20	60	15
Tortilla	0.06	0.27	0.71	1.0	1.24	1.50	55	65	7
Wheat bread	0.32	0.41	0.5	0.7	0.78	0.82	20	23	2
Rye bread	0.39	0.47	0.6	0.8	1.06	1.17	20	20	2
Biscuit	0.3	0.40	0.405	0.0	0.07	0.09	20	20	2
Soy	0.2	0.35	0.448	0.1	0.33	0.60	−150	150	15
Soy flour	0.04	0.22	0.95	0.0	0.21	0.64	20	27	6
Defatted	0.1	0.44	0.95	0.1	0.36	0.64	25	25	2
Dry defatted	0.10	0.12	0.143	0.0	0.00	0.00	20	40	6
Defatted	0.04	0.06	0.061	0.0	0.23	0.40	20	20	2
Cupcake batter	0.12	0.17	0.223	0.5	0.63	0.71	15	15	1
—	0.12	0.17	0.223	0.5	0.63	0.71	15	15	1
Yellow cake batter	0.22	0.22	0.223	0.7	0.71	0.71	20	20	2
—	0.22	0.22	0.223	0.7	0.71	0.71	20	20	2
Cake	0.04	0.62	3.559	0.1	0.56	1.22	20	51	10
—	0.04	0.62	3.559	0.1	0.56	1.22	20	51	10
Cereal products	0.06	0.29	0.74	0.0	0.67	8.09	−28	40	16
Barley	0.16	0.20	0.225	0.1	0.18	0.26	−28	0	2
Seeds	0.16	0.20	0.225	0.1	0.18	0.26	−28	0	2
Corn	0.08	0.39	0.74	0.0	1.55	8.09	10	36	7
Dent	0.14	0.16	0.175	0.0	0.20	0.42	36	36	3
Shelled	0.37	0.55	0.74	0.4	0.73	1.00	10	30	5
Dust	0.08	0.09	0.101	0.1	0.15	0.20	22	22	2
Syrup	0.34	0.43	0.513	0.2	4.16	8.09	27	52	7
Rice	0.08	0.15	0.366	0.1	0.22	0.43	20	48	7
Paddy	0.08	0.15	0.366	0.1	0.22	0.43	20	48	7
Wheat	0.06	0.26	0.689	0.0	0.13	0.29	−3	26	6
Dust	0.06	0.07	0.073	0.1	0.15	0.20	22	22	2
Hard red spring	0.14	0.16	0.166	0.0	0.17	0.29	−3	−3	–
Soft white	0.11	0.13	0.14	0.0	0.13	0.25	15	16	1
Flour	0.4	0.59	0.689	0.1	0.10	0.10	43	56	6
Corn meal	0.2	0.36	0.464	0.1	0.27	0.43	20	88	16
—	0.2	0.36	0.464	0.1	0.27	0.43	20	88	16
Idli batter	0.39	0.45	0.4931	1.0	1.71	2.33	15	16	2
—	0.39	0.45	0.4931	1.0	1.71	2.33	15	16	2
Maize	0.06	0.27	0.525	0.1	0.32	0.59	35	62	9
Kernel	0.15	0.17	0.174	0.1	0.16	0.20	50	50	5
Grits	0.06	0.29	0.525	0.1	0.36	0.59	35	65	9
Oat	0.1	0.13	0.13	0.1	0.14	0.14	27	27	2
White	0.1	0.13	0.13	0.1	0.14	0.14	27	27	2
Dairy	0.03	0.45	0.686	0.0	3.78	44.00	1	38	9
Cheese	0.34	0.42	0.548	0.5	1.20	2.94	15	22	3
Cheddar	0.34	0.35	0.351	0.5	0.56	0.56	15	23	3
Mozzarella	0.3	0.38	0.383	0.8	0.80	0.80	15	23	3
Cuartirolo argentino	0.37	0.37	0.372	1.2	1.20	1.20	15	15	1
Hamburger	0.38	0.39	0.398	0.6	0.69	0.69	15	23	3
Old kashkaval	0.36	0.38	0.384	0.6	0.69	0.69	15	23	3
Tulum	0.37	0.38	0.379	0.6	0.69	0.69	15	23	3
Fresh kashkaval	0.40	0.40	0.403	0.7	0.78	0.78	15	23	3
Buffet kashkaval	0.40	0.41	0.409	0.9	0.99	0.99	15	23	3
Fresh cream	0.43	0.43	0.434	1.2	1.29	1.29	15	23	3
Spreadable cheese	0.47	0.49	0.494	1.5	1.54	1.54	15	23	3
Labne	0.46	0.47	0.486	2.2	2.24	2.24	15	23	3
Low-fat labne	0.54	0.55	0.548	2.9	2.94	2.94	15	23	3
Milk	0.11	0.46	0.686	0.0	4.02	30.00	5	46	9
—	0.32	0.46	0.576	1.0	4.00	9.00	20	20	2
Fresh	0.5	0.57	0.57	9.0	9.00	9.00	23	23	2
Powder	0.11	0.11	0.115	22.0	25.33	30.00	25	25	2
Whole	0.2	0.46	0.629	0.3	3.04	9.00	5	53	9
Skim	0.481	0.57	0.646	1.5	6.33	19.00	5	36	7
Concentrated	0.32	0.41	0.498	0.4	0.92	1.50	35	50	6
Condensed	0.32	0.49	0.634	1.0	4.01	9.00	23	54	7
Half and half	0.47	0.54	0.634	2.3	5.11	9.00	5	40	7
Baby food	0.40	0.55	0.686	0.0	0.03	0.04	35	50	6
Powdered	0.18	0.30	0.538	0.0	0.05	0.14	54	54	5
Butter	0.09	0.22	0.345	0.0	0.20	0.42	15	21	3
—	0.22	0.23	0.233	0.1	0.18	0.18	15	23	3
Fat	0.09	0.21	0.345	0.0	0.21	0.42	20	20	2
Yogurt	0.03	0.45	0.639	0.0	3.60	6.58	1	31	5
—	0.52	0.56	0.603	6.2	6.25	6.25	1	21	4
Plain	0.03	0.33	0.639	0.0	2.05	5.66	25	40	5
Strained	0.53	0.54	0.54	2.8	2.88	2.88	15	23	3
Pasterized	0.57	0.58	0.593	4.7	4.71	4.71	15	23	3
Light	0.57	0.58	0.583	4.5	4.54	4.54	15	23	3
Extra light	0.58	0.59	0.596	6.5	6.58	6.58	15	23	3
Whey	0.54	0.59	0.642	9.0	9.00	9.00	7	40	8
—	0.54	0.59	0.642	9.0	9.00	9.00	7	40	8
Cream	0.12	0.13	0.127	44.0	44.00	44.00	25	25	2
Powder	0.12	0.13	0.127	44.0	44.00	44.00	25	25	2
Fish	0.0	0.79	1.72	0.0	3.29	5.25	−40	8	8
Cod	0.54	1.23	1.543	4.8	4.88	4.88	−22	−10
Perpendicular	0.54	1.23	1.543	4.8	4.88	4.88	−22	−10
Mackerel	0.40	0.80	1.428	3.4	3.42	3.42	−20	0	2
Perpendicular	0.40	0.80	1.428	3.4	3.42	3.42	−20	0	2
Squid	0.0	0.35	0.507	0.1	2.36	5.20	15	26	3
Fresh	0.4	0.50	0.5	4.7	5.04	5.20	30	30	3
Mantle	0.48	0.50	0.507	3.8	3.83	3.83	15	15	1
Dried	0.0	0.24	0.44	0.1	0.87	2.86	30	30	3
Tentacle,arrow	0.47	0.48	0.475	3.5	3.56	3.56	15	15	1
Tentacle	0.50	0.50	0.501	3.5	3.56	3.56	15	15	1
Carp	0.	1.21	1.72	0.8	0.83	0.83	−15	0	1
—	0.	1.21	1.72	0.8	0.83	0.83	−15	0	1
Surimi	0.47	0.78	1.508	2.8	4.02	5.25	−40	14	8
—	0.48	0.85	1.473	4.0	4.08	4.08	−40	−2	3
6% cryoprotectant conc	0.47	0.87	1.508	4.0	4.08	4.08	−40	−2	3
12% cryoprotectant conc	0.48	0.86	1.465	4.0	4.08	4.08	−40	−2	3
Pacific whiting	0.52	0.59	0.708	2.8	3.88	5.25	30	53	8
Cake	0.	0.10	0.1	0.0	0.00	0.00	15	15	1
Pressed	0.	0.10	0.1	0.0	0.00	0.00	15	15	1
Shrimp	0.4	1.03	1.6	1.0	3.24	4.20	−30	−8	3
Peeled and head removed	0.4	1.03	1.6	1.0	3.24	4.20	−30	−8	3
Calamari	0.50	0.51	0.517	4.0	4.04	4.04	15	15	1
Mantle	0.50	0.51	0.517	4.0	4.04	4.04	15	15	1
Salmon	0.49	1.06	1.245	2.0	2.40	2.70	−24	−12
Perpendicular	0.49	1.06	1.245	2.0	2.40	2.70	−24	−12
Fruits	0.04	0.45	2.27	0.1	3.73	19.00	−40	30	9
Apple	0.0	0.45	2.27	0.1	3.44	1900	−40	30	9
—	0.0	0.32	1.51	0.2	2.44	5.99	−40	20	4
Red	0.51	0.51	0.513	5.6	5.60	5.60	15	15	1
Green	0.40	0.41	0.405	0.1	0.14	0.14	45	45	4
Golden delicious	0.40	0.41	0.412	4.8	4.89	4.89	15	18	2
Granny Smith	0.0	0.19	0.296	0.5	2.17	4.00	25	25	2
Juice	0.2	0.53	2.27	0.2	3.81	19.00	−7	37	9
Sauce	0.59	0.59	0.591	10.1	10.11	10.11
Banana	0.48	0.48	0.481	3.1	3.12	3.12	20	20	2
Dessert	0.48	0.48	0.481	3.1	3.12	3.12	20	20	2
Peach	0.04	0.04	0.043				35	35	3
Clingstone	0.04	0.04	0.043				35	35	3
Plantain	0.1	0.37	0.52038	0.1	0.98	2.00	30	30	3
Fruits	0.1	0.37	0.520381	0.1	0.98	2.00	30	30	3
Pear	0.3	0.49	0.629	0.5	3.22	7.41	15	34	8
—	0.3	0.47	0.5572	0.5	2.85	4.90	23	24	2
Green	0.51	0.52	0.533	7.4	7.41	7.41	15	15	1
Juice	0.40	0.51	0.629	0.6	2.60	5.67	20	50	8
Williams	0.35	0.45	0.505	0.5	2.17	4.00	25	25	2
Orange	0.289	0.41	0.56	0.6	4.28	19.00	1	27	6
Juice	0.289	0.41	0.56	0.6	4.28	19.00	1	27	6
Bilberry	0.55	0.55	0.554	8.5	8.52	8.52	16	18	2
Juice	0.55	0.55	0.554	8.5	8.52	8.52	16	18	2
Cherry	0.55	0.55	0.554	6.5	6.52	6.52	16	18	2
Juice	0.55	0.55	0.554	6.5	6.52	6.52	16	18	2
Grape	0.39	0.52	0.639	0.5	4.08	8.09	16	42	8
—	0.39	0.52	0.639	0.5	3.60	8.09	20	50	8
Juice	0.53	0.55	0.556	5.5	5.54	5.54	16	18	2
Raspberry	0.54	0.55	0.553	7.7	7.70	7.70	16	18	2
Juice	0.54	0.55	0.553	7.7	7.70	7.70	16	18	2
Strawberry	0.520	0.63	0.9347	6.7	8.44	11.05	−15	14	2
Juice	0.57	0.57	0.571	11.0	11.05	11.05	16	18	2
Tioga	0.520	0.67	0.9347	6.7	6.70	6.70	−15	11	2
Raisin	0.12	0.23	0.392	0.1	1.35	4.00	45	45	4
—	0.12	0.23	0.392	0.1	1.35	4.00	45	45	4
Legumes	0.18	0.22	0.253	0.1	0.18	0.26	−21	2	2
Lentils	0.18	0.22	0.253	0.1	0.18	0.26	−21	2	2
Seeds	0.18	0.22	0.253	0.1	0.18	0.26	−21	2	2
Meat	0.04	0.71	1.66	0.0	2.40	5.10	−40	16	9
Beef	0.09	0.63	1.65	0.0	2.22	3.69	−30	28	9
—	0.45	0.54	0.622	2.2	2.43	2.57	−18	1	2
Fat	0.26	0.28	0.311	0.1	0.14	0.16	−10	7	1
Lean	0.5	1.03	1.55	0.6	0.63	0.63	−15	0	1
Ground	0.	1.01	1.62	0.7	0.75	0.75	−15	0	1
Minced	0.3	0.56	0.844	1.1	1.96	3.44	−5	11	3
Muscle semitendinosus	0.09	0.31	0.49	0.0	0.99	2.84	20	20	2
Dry fiber	0.1	0.21	0.243	0.3	1.03	2.30	25	25	2
Boneless	0.42	1.03	1.65	2.9	3.31	3.69	−30	−4	3
Ground round	0.45	0.51	0.59	1.9	2.53	2.94	30	60	9
Whole round	0.47	0.49	0.504	1.5	2.32	2.94	30	60	9
Ground shank	0.44	0.51	0.598	1.5	2.45	2.92	30	60	9
Ground birsket	0.43	0.44	0.458	1.3	2.38	3.05	30	60	9
Whole rib steak	0.45	0.50	0.552	1.0	1.84	2.32	30	60	9
Ground sirloin tip	0.4	0.49	0.518	1.6	2.35	2.92	30	60	9
Whole sirloin tip	0.46	0.48	0.494	1.3	2.27	2.92	30	60	9
Ground rib	0.36	0.41	0.45	0.7	1.11	1.37	30	60	9
Ground swiss steak	0.46	0.51	0.575	2.1	2.90	3.44	30	60	9
Whole swiss steak	0.46	0.49	0.508	1.8	2.82	3.44	30	60	9
Loaf, uncooked	0.	0.40	0.4	2.5	2.58	2.58	15	15	1
Loaf, heated	0.4	0.47	0.47	1.9	1.96	1.96	60	60	6
Chicken	0.4	1.05	1.452	2.9	3.46	5.10	−25	−9	2
Boneless	0.4	0.97	1.452	2.9	3.00	3.22	−20	−4	2
White	1.26	1.33	1.387	5.1	5.10	5.10	−25	−25	−2
Sausage	0.27	0.42	1.38	0.3	1.02	1.86	−10	18	2
—	0.28	0.33	0.367	0.4	1.24	1.86	20	22	2
Italian	0.4	0.93	1.38	0.6	0.64	0.64	−10	0	1
Salami cooked	0.3	0.37	0.37	1.7	1.70	1.70	22	22	2
Lebanon bologna	0.35	0.36	0.355	1.6	1.63	1.63	22	22	2
Salami cotto	0.36	0.37	0.365	1.3	1.33	1.33	22	22	2
Thuringer	0.34	0.35	0.345	0.9	0.96	0.96	22	22	2
Salami genoa	0.29	0.30	0.295	0.5	0.56	0.56	22	22	2
Salami hard	0.31	0.32	0.315	0.5	0.52	0.52	22	22	2
Pepperoni	0.27	0.28	0.275	0.3	0.37	0.37	22	22	2
Turkey	0.4	1.18	1.66	2.8	2.85	2.85	−24	−12
Boneless	0.4	1.18	1.66	2.8	2.85	2.85	−24	−12
Mutton	0.39	0.86	1.51	2.4	2.66	2.80	−40	−3	2
Boneless	0.39	0.86	1.51	2.4	2.66	2.80	−40	−3	2
Pork	0.4	0.93	1.45	3.1	3.25	3.31	−30	−4	3
Boneless	0.4	0.93	1.45	3.1	3.25	3.31	−30	−4	3
Pork/soy	0.04	0.05	0.055	3.0	3.41	3.75	25	25	2
Unprocessed	0.04	0.05	0.051	3.0	3.17	3.25	25	25	2
Processed	0.05	0.05	0.055	3.5	3.64	3.75	25	25	2
Model foods	0.03	0.63	2.33	0.0	5.26	65.67	−43	30	15
Amioca	0.07	0.32	1.1	0.0	3.35	20.00	20	52	15
—	0.07	0.25	1.1	0.0	2.86	20.00	25	58	15
Gelatinized	0.43	0.51	0.661	0.0	1.23	3.00	20	52	13
Powder	0.0	0.13	0.195	0.0	10.37	20.00	25	48	7
Granular	0.22	0.34	0.454	0.0	0.12	0.23	20	40	6
Hylon +7	0.0	0.33	0.661	0.0	5.08	20.00	20	60	15
—	0.0	0.22	0.449	0.0	5.99	20.00	25	85	15
Gelatinizd	0.44	0.53	0.661	0.0	1.90	4.00	20	46	7
Powder	0.	0.13	0.16	11.1	15.55	20.00	25	48	7
Granular	0.22	0.34	0.454	0.0	0.12	0.23	20	40	6
Potato Starch	0.03	0.04	0.041	0.0	0.08	0.14	41	41	4
Gel	0.03	0.04	0.041	0.0	0.08	0.14	41	41	4
Starch	0.06	0.68	2.1	0.0	4.71	24.00	−42	−42	12
—	0.0	0.10	0.1	0.0	0.00	0.00	25	25	2
Gel	0.4	1.02	2.1	1.7	8.80	24.00	−42	4	5
Gelatinized	0.3	0.34	0.355	0.1	0.10	0.10	20	50	8
Hydrated	0.36	0.38	0.388	0.2	0.28	0.28	10	47	8
Granular	0.06	0.09	0.125	0.0	0.20	0.30	15	45	7
Gels	0.436	0.50	0.5667	0.6	1.65	3.00	80	100	12
Sucrose	0.3	0.85	1.77	0.6	3.57	9.00	−41	−1	3
—	0.40	0.48	0.566	0.6	3.72	9.00	20	20	2
Gel	0.3	0.89	1.77	1.0	3.56	9.00	−41	−4	3
Gelatin	0.03	0.96	2.07	0.0	7.92	19.00	−41	0	4
Gel	0.03	0.96	2.07	0.0	7.92	19.00	−41	0	4
Ovalbumin	0.4	0.99	2.33	2.3	7.59	19.00	−43	−5	2
—	0.4	0.88	1.75	2.3	4.23	6.40	−43	−7	2
Gel	0.4	1.05	2.33	3.2	9.28	19.00	−42	−4	2
Tylose	0.48	0.99	1.53	3.3	3.35	3.35	−30	5	5
Gel	0.48	0.99	1.53	3.3	3.35	3.35	−30	5	5
Agar-water	0.	0.61	0.622	24.9	36.95	49.00	20	25	3
Gel	0.	0.61	0.622	24.9	36.95	49.00	20	25	3
Gelatin-water	0.59	0.59	0.594	65.6	65.67	65.67	25	25	2
—	0.59	0.59	0.594	65.6	65.67	65.67	25	25	2
Amylose	0.51	0.53	0.551	3.0	3.50	4.00	30	30	3
Gel	0.51	0.53	0.551	3.0	3.50	4.00	30	30	3
Cellulose gum	0.05	0.06	0.063	0.0	0.08	0.14	41	41	4
Gel	0.05	0.06	0.063	0.0	0.08	0.14	41	41	4
Pectin	0.04	0.05	0.047	0.0	0.08	0.14	41	41	4
Gel	0.04	0.05	0.047	0.0	0.08	0.14	41	41	4
Pectin glucose	0.04	0.05	0.05	0.0	0.08	0.14	41	41	4
Gel	0.04	0.05	0.05	0.0	0.08	0.14	41	41	4
Glycerin	0.4	0.47	0.49	3.3	3.79	4.26	20	20	2
—	0.4	0.47	0.49	3.3	3.79	4.26	20	20	2
Karlsrulte	0.5	1.10	1.65	0.7	0.77	0.77	−10	3	1
(Blank)	0.5	1.10	1.65	0.7	0.77	0.77	−10	3	1
Gelatin-sucrose water	0.39	0.44	0.487	0.6	1.44	2.22	15	15	1
—	0.39	0.44	0.487	0.6	1.44	2.22	15	15	1
	0.22	0.22	0.224	0.0	0.02	0.02	15	15	1
Maeadamia	0.22	0.22	0.224	0.0	0.02	0.02	15	15	1
Integrifolia	0.22	0.22	0.224	0.0	0.02	0.02	15	15	1
	0.078	0.43	1.9	0.0	3.81	24.00	−29	39	15
Carrot	0.18	0.48	0.605	0.1	5.85	9.00	15	22	4
—	0.18	0.45	0.605	0.1	3.82	9.00	15	27	4
Large	0.50	0.52	0.532	8.9	8.91	8.91	15	15	1
Cassava	0.1	0.47	0.57	0.2	1.22	2.33	30	30	3
Roots	0.1	0.47	0.57	0.2	1.22	2.33	30	30	3
Garlic	0.2	0.36	0.448	0.0	0.80	1.65	15	15	1
—	0.2	0.36	0.448	0.0	0.80	1.65	15	15	1
Onion	0.2	0.42	0.52	0.3	2.05	4.15	31	32	3
—	0.2	0.42	0.52	0.3	2.05	4.15	31	32	3
Pea	0.078	0.18	0.256	0.1	1.26	4.50	−29	−3	2
—	0.078	0.09	0.1003	4.5	4.50	4.50	−29	−19	−1
Seeds	0.18	0.22	0.256	0.1	0.18	0.26	−21	2	2
Potato	0.1	0.45	1.9	0.1	2.35	7.33	−15	49	13
—	0.20	0.42	0.643	0.3	2.74	7.33	24	57	13
Mashed	0.5	1.22	1.9	0.7	0.72	0.72	−15	0	1
Flesh	0.53	0.54	0.536	4.5	4.54	4.54	20	20	2
Granule	0.1	0.35	0.579	0.1	0.64	1.44	30	62	9
White	0.51	0.53	0.536	4.5	4.55	4.55	15	18	2
Spunta	0.33	0.46	0.55	0.5	2.17	4.00	25	25	2
Sugar Beet	0.44	0.53	0.589	1.5	3.38	5.67	20	22	2
—	0.53	0.56	0.585	3.0	4.22	5.67	25	25	2
Roots	0.44	0.52	0.589	1.5	2.75	4.00	20	20	2
Turnip	0.4	0.48	0.48	0.0	0.08	0.08	45	45	4
—	0.4	0.48	0.48	0.0	0.08	0.08	45	45	4
Yam	0.1	0.47	0.6	0.1	1.45	3.76	30	30	3
Tubes	0.1	0.47	0.6	0.1	1.45	3.76	30	30	3
Beetrout	0.54	0.56	0.572	6.9	9.10	11.30	20	20	2
—	0.54	0.56	0.572	6.9	9.10	11.30	20	20	2
Parsley	0.1	0.17	0.17	2.3	2.30	2.30	20	20	2
—	0.1	0.17	0.17	2.3	2.30	2.30	20	20	2
Celery	0.14	0.15	0.147	2.3	2.30	2.30	20	20	2
—	0.14	0.15	0.147	2.3	2.30	2.30	20	20	2
Tomato	0.2	0.51	0.67	0.2	6.23	19.83	20	68	15
—	0.611	0.61	0.6114	15.6	15.60	15.60	21	21	2
Juice	0.2	0.48	0.67	0.2	7.71	19.83	20	83	15
Paste	0.4	0.55	0.66	1.1	1.73	2.40	30	40	5
Cucumber	0.621	0.62	0.6212	24.0	24.00	24.00	22	22	2
—	0.621	0.62	0.6212	24.0	24.00	24.00	22	22	2
Spinach	0.346	0.38	0.434	8.3	11.01	13.66	−20	−2	2
Fresh	0.346	0.37	0.4002	13.6	13.66	13.66	−20	−2	2
Blanched	0.355	0.39	0.434	8.3	8.35	8.35	−20	−2	1
Mushrooms	0.217	0.37	0.5196	0.1	3.27	8.69	40	55	7
Pleurotus florida	0.217	0.37	0.5196	0.1	3.27	8.69	40	55	7
Rutabagas	0.44	0.45	0.447	0.0	0.08	0.08	45	45	4
—	0.44	0.45	0.447	0.0	0.08	0.08	45	45	4
Radish	0.49	0.50	0.499	0.0	0.06	0.06	45	45	4
—	0.49	0.50	0.499	0.0	0.06	0.06	45	45	4
Parsnip	0.39	0.39	0.392	0.2	0.21	0.21	45	45	4
—	0.39	0.39	0.392	0.2	0.21	0.21	45	45	4
Kidney bean	0.102	0.15	0.2012	0.1	0.24	0.41	20	20	2
—	0.102	0.15	0.2012	0.1	0.24	0.41	20	20	2
	0.03	0.23	0.99	0.0	2.06	32.00	−26	25	9
Coconut	0.11	0.15	0.217	0.1	3.08	26.00	25	37	5
Milk powder	0.11	0.15	0.217	0.1	3.08	26.00	25	37	5
Coffee	0.15	0.21	0.277	1.2	1.62	2.51	−14	6	2
Solutions	0.15	0.21	0.277	1.2	1.62	2.51	−14	6	2
Soybean	0.0	0.09	0.133	0.0	0.14	0.40	10	34	6
Powder	0.06	0.08	0.104	0.1	0.10	0.10	10	36	6
Whole	0.09	0.11	0.133	0.1	0.13	0.13	10	36	6
Crushed	0.08	0.10	0.126	0.1	0.11	0.11	10	36	6
Flour	0.0	0.05	0.061	0.0	0.22	0.40	26	26	2
Palm Kernel	0.10	0.10	0.102	26.0	26.00	26.00	25	25	2
Milk powder	0.10	0.10	0.102	26.0	26.00	26.00	25	25	2
Lard	0.1	0.12	0.12	32.0	32.00	32.00	25	25	2
Milk powder	0.1	0.12	0.12	32.0	32.00	32.00	25	25	2
Water NaCI	0.4	0.46	0.46	4.0	4.00	4.00	10	10	1
Solution	0.4	0.46	0.46	4.0	4.00	4.00	10	10	1
Water-sucrose	0.3	0.32	0.32	0.6	0.67	0.67	10	10	1
Solution	0.3	0.32	0.32	0.6	0.67	0.67	10	10	1
Rapeseed	0.0	0.11	0.8	0.0	0.10	0.24	−26	14	3
Whole	0.10	0.13	0.155	0.0	0.11	0.15	4	17	3
Ground	0.06	0.07	0.088	0.0	0.11	0.15	4	16	3
Torch	0.086	0.10	0.1197	0.0	0.10	0.24	−26	−4	1
Midas	0.092	0.09	0.0922	0.0	0.01	0.01	19	19	1
Crushed	0.0	0.13	0.8	0.0	0.11	0.15	4	18	3
Agar-water	0.61	0.62	0.617	19.9	19.90	19.90	30	30	3
Gel	0.61	0.62	0.617	19.9	19.90	19.90	30	30	3
Tobacco	0.055	0.06	0.0704	0.2	0.26	0.32	15	15	1
—	0.055	0.06	0.0704	0.2	0.26	0.32	15	15	1
Sugar	0.38	0.52	0.637	0.6	4.32	9.00	0	42	8
Glucose	0.4	0.54	0.637	1.5	4.80	8.09	2	44	8
Cane suger	0.38	0.51	0.637	0.6	4.00	9.00	0	40	8
Albumen	0.03	0.04	0.042	0.0	0.08	0.14	41	41	4
Gel	0.03	0.04	0.042	0.0	0.08	0.14	41	41	4
Sorghum	0.08	0.24	0.99	0.0	0.17	0.30	5	21	3
Rs610	0.1	0.14	0.15	0.1	0.22	0.28	5	5
NC+RS66	0.13	0.56	0.99	0.0	0.16	0.30	36	36	3
Grain dust	0.08	0.09	0.094	0.1	0.15	0.20	22	22	2
NaCL	0.56	0.61	0.656	4.0	4.00	4.00	10	43	8
Solution	0.56	0.61	0.656	4.0	4.00	4.00	10	43	8
Honey	0.4	0.53	0.618	1.5	4.83	9.00	2	36	7
—	0.4	0.53	0.618	1.5	4.83	9.00	2	36	7
Albumin	0.38	0.41	0.425	0.6	0.67	0.67	27	60	9
Solution	0.38	0.41	0.425	0.6	0.67	0.67	27	60	9

Figure 5. Histogram of observed values of thermal conductivity in food materials.

CONCLUSION

Average values and variation ranges of thermal conductivity of foods are determined from data in the literature for various food materials. These values are useful in process calculations, because generic models to predict thermal conductivity of food do not exist at present.

Acknowledgments