Physical Properties of Wheat Flour Treated by Supercritical Carbon Dioxide

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1 Available online at APCBEE Procedia 2 (2012 ) ICBFS 2012: April 7-8, 2012, Bangkok, Thailand Physical Properties of Wheat Flour Treated by Supercritical Carbon Dioxide Hee-Moon Kang a, Joo-Hee Lee a, Ryoung-Hee Kim a, Jun-Ho Yun a and Byung-Soo Chun a,* a Department of Food Science and Technology, Pukyong National University, Daeyeon Campus 45, Yongso-ro, Nam-Gu, Busan , Republic of Korea Abstract Wheat flour is very popular food materials in worldwide. In this study, the aim of this work was to investigate the effect of supercritical carbon dioxide (SCO2) treatment on physical properties of wheat flours. Wheat flour was treated using SCO2 under different treatment conditions. SCO2 treatment was carried out to treat the wheat flour at different pressures of 10 to 30 MPa, constant temperature of 40 and additives 70%-ethanol. Whiteness and bulk density of wheat flour was increased in the treatment of SCO2. These results indicated that the treatment effect was high at high pressure. In case of particle size and angle of repose, SCO2 treatment was more efficient than SCO2 treatment with additives 70%-ethanol Published by by Elsevier B.V. B.V. Selection and/or and/or peer peer review review under under responsibility of Asia-Pacific of Asia-Pacific Chemical, Biological & Environmental Engineering Society Society Open access under CC BY-NC-ND license. Keywords: Supercritical Carbon Dioxide; Wheat flour; Repose; Bulk density 1. Introduction Wheat (Triticum spp.) [1] is a cereal grain, originally from the Levant region of the Near East, but now cultivated worldwide. Wheat is grown on more land area than any other commercial crop and is the most important staple food for humans. World trade in wheat is greater than for all other crops combined. [2] Wheat grain is a staple food used to make flour for leavened, flat and steamed breads, biscuits, cookies, cakes, a,* Corresponding author. Tel.: +82-(0) ; fax: +82-(0) address: bschun@pknu.ac.kr Published by Elsevier B.V. Selection and/or peer review under responsibility of Asia-Pacific Chemical, Biological & Environmental Engineering Society Open access under CC BY-NC-ND license. doi: /j.apcbee

2 28 Hee-Moon Kang et al. / APCBEE Procedia 2 ( 2012 ) breakfast cereal, pasta, noodles, couscous [3] and for fermentation to make beer, [4] other alcoholic beverages, [5]. 100 g of hard red winter wheat contain about 12.6 g of protein, 1.5 g of total fat, 71 g of carbohydrate (by difference), 12.2 g of dietary fiber, and 3.2 mg of iron (17% of the daily requirement); the same weight of hard red spring wheat contains about 15.4 g of protein, 1.9 g of total fat, 68 g of carbohydrate (by difference), 12.2 g of dietary fiber, and 3.6 mg of iron (20% of the daily requirement). [6] Wheat flour is a powder made from the grinding of wheat used for human consumption. More wheat flour is produced than any other flour. Wheat varieties are called "clean," "white," or "brown" if they have high gluten content, and they are called "soft" or "weak" flour if gluten content is low. Hard flour, or bread flour, is high in gluten, with 12% to 14% gluten content, and has elastic toughness that holds its shape well once baked. Soft flour is comparatively low in gluten and so results in a finer or crumbly texture. [7] Soft flour is usually divided into cake flour, which is the lowest in gluten, and pastry flour, which has slightly more gluten than cake flour. The aim of this present work was to assess the effect of supercritical carbon dioxide (SCO 2 ) treatment in different experiment conditions on physical properties of wheat flours. The conditions of extraction were selected by considering their feasibility for industrial application. 2. Materials and Methods 2.1. Materials The sample imported from North Dakota, USA was milled and used. The pure carbon dioxide (99.99%) was supplied by KOSEM (Yangsan, Republic of Korea). 70%-ethanol was purchased as additives Supercritical carbon dioxide extraction Experimental conditions of supercritical carbon dioxide showed in Table 1. Batch reactor filled with 5 kg of flour, it was treated for 3 h by 60 L/h of CO 2 and 4.2 L/h of ethanol. Both were preheated at 40. After the treatment, flour was collected from the reactor and sieved (1,000 ) by mesh. Treated samples were compared with the control group. Table 1. Conditioning of Supercritical Carbon Dioxide Extraction Flour From condition Control untreated wheat flour SFC1 wheat flour in treated pressure at 10 MPa and temperature 40 C SFC2 wheat flour in treated pressure at 20 MPa and temperature 40 C SFC3 wheat flour in treated pressure at 30 MPa and temperature 40 C SFC2E wheat flour in treated pressure at 20 MPa and temperature 40 C + 70%-ethanol SFC3E wheat flour in treated pressure at 30 MPa and temperature 40 C + 70%-ethanol 2.3. Whiteness Whiteness was measured 5 times repeatedly using Whiteness Testers (Kett C-100, Kett engineering, Japan) and was indicated average value using following equation by Jung (1991) [8] W = 100 (100 L) + a + b (1)

3 Hee-Moon Kang et al. / APCBEE Procedia 2 ( 2012 ) Bulk density Bulk density was measured using the modified method of Shopper test (Kim, 1997) [9] Particle size Particle size distribution was determined by Particle size analyzer (Coulter LS 100, USA) using laser spectroscopy. 1g of sample was diffused to isopropyl alcohol. Then particle size, specific surface area and particle distribution were estimated Angle of repose Angle of repose was assessed according to the method described previously by R. Soltermann (2006) [10] with a slight modification. Cone angle and diameter of outlet was 45 and 30 mm respectively. 100 g sample was filled up. These were free fallen 50 mm height. Diameter and height of sample piled up on the ground was measured 3 times repeatedly. 3. Results and Discussion 3.1. Whiteness of wheat flour Whiteness of wheat flour shows in Fig. 1. From Fig. 1, whiteness of untreated wheat flour and average of wheat flour treated by SCO 2 was, respectively, 81.1 and Increasing the pressure of SCO 2 treatment, whiteness of wheat flour was more high, but additives of 70%-ethanol was not efficient to whiteness of wheat flour. Whiteness of SFC3E was lower than that of untreated wheat flour. Comtrol 1) SFC1 2) SFC2 3) SFC3 4) SFC2E 5) SFC3E 6) Fig. 1. Whiteness values of flour stored at room temperature for different resting time.

4 30 Hee-Moon Kang et al. / APCBEE Procedia 2 ( 2012 ) ),2),3),4),5) and 6) : Refer to footnote of Table Bulk density of wheat flour Table 2 shows bulk density of wheat flour. According to Table 2, bulk density of untreated wheat flour was 512 g/l, and the average bulk density of wheat flour treated by SCO 2 was g/l, and wheat flour treated by SCO 2 with additives 70%-ethanol showed lower than wheat flour treated by SCO 2. Table 2. Bulk density of wheat flours Flour From Control 1) SFC1 2) SFC2 3) SFC3 4) SFC2E 5) SFC3E 6) Bulk Density 512 g/l 549 g/l 615 g/l 617 g/l 533 g/l 573 g/l 3.3. Particle size of wheat flour Particle size distribution shows in Table 3. The average particle size of untreated wheat flour and wheat flour treated by SCO 2 was, respectively, m and m. Wheat flour treated by SCO 2 with additives 70%-ethanol (SFC2E) indicated high values ( m) than wheat flour treated by SCO 2. According to the variation of pressure, wheat flour treated by SCO 2 and additives 70%-ethanol bound together. Table 3. Particle size distribution of wheat flours Flour From Particle size ( ) Volume below (%) SSA 8) Median Mean <38 ~75 ~150 >150 Control 1) SFC1 2) SFC2 3) SFC3 4) TWF 5) SFC2E 6) SFC3E 7) ),2),3),4),6) and 7) : Refer to footnote of Table 1. 5) Mean of SCO 2 treated wheat flour. 8) Specific surface Area. (cm 2 /g) 3.4. Angle of repose Table 4 shows angle of repose of wheat flour. The angle of repose of untreated wheat flour and wheat flour treated by SCO 2 was 37.7 and 27.7 on an average. Wheat flour treated by SCO 2 with additives 70%-ethanol was averagely 38.8, it was higher than that of SCO 2 treatment. Table 4. The angle of repose of wheat flours Flour From Diameter(cm) Height(cm) spread ratio 8) angle of repose Control 1) SFC1 2)

5 Hee-Moon Kang et al. / APCBEE Procedia 2 ( 2012 ) SFC2 3) SFC3 4) TWF 5) SFC2E 6) SFC3E 7) ),2),3),4),6) and 7) : Refer to footnote of Table 1. 5) Mean of S-CO 2 treated wheat flour. 8) Diameter/ Height 4. Conclusion In this study, physical properties of wheat flour treated using SCO 2 at different experimental conditions. Whiteness and bulk density of wheat flour was higher treated by SCO 2 than untreated wheat flour. Particle size of wheat flour was more higher treated by SCO 2 with additives (70% ethanol) than treated by SCO 2 and untreated wheat flour. Angle of repose was also high in the treatment of SCO 2 with additives. SCO 2 extraction of wheat flour was efficient than untreated wheat flour in terms of physical parameters. Acknowledgements This research was financially supported by a grant from the Ministry of Knowledge and Economy, National Research Foundation of Korea (NRF) through the Human Resources Training Project for Regional Innovation. References [1] Belderok, Bob & Hans M, Dingena A, Donner. Bread-Making Quality of Wheat. Springer; 2000, p.3. ISBN [2] Curtis, Rajaraman, MacPherson. "Bread Wheat". Food and Agriculture Organization of the United Nations; [3] Cauvain, Stanley P, Cauvain P. Bread Making. CRC Press; 2003, p ISBN ; [4] Palmer, John J. How to Brew. Defenestrative Pub Co; 2001, p ISBN [5] Neill, Richard. Booze: The Drinks Bible for the 21st Century. Octopus Publishing Group Cassell Illustrated; 2002, p ISBN [6] USDA National Nutrient Database for Standard Reference, Release 19; [7] Chu, Michael. "Wheat Flour". Cooking for Engineers; 2004 [8] Seung-Hyeon Jung, Gun-Jin Shin and Chun-Un Choi. Comparison of Physicochemical Properties of Corn, Sweet Potato, Potato,Wheat and Mungbean Strarches. KOREAN J. FOOD SCI. TECHNOL. Vol. 23, No. 3. pp ; [9] Myung-Shin Kim and Bong-Kyung Koh. Discoloration of Korean Wheat Flour Noodles with Additives. KOREAN J. FOOD SCI. TECHNOL. Vol. 32, No. 4, pp 792~798; [10] A.R. Gennaro, Remington's Pharmaceutical Science, 17th edition; 1985.