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Effects of semidry flour milling on the quality attributes of rice flour and rice noodles in China


Journal of Cereal Science 62 (2015) 45e49

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Journal of Cereal Science
journal homepage: www.elsevier.com/locate/jcs

Effects of semidry ?our milling on the quality attributes of rice ?our and rice noodles in China
Li-Tao Tong a, Xiaoxu Gao b, Lizhong Lin c, Yejia Liu c, Kui Zhong a, Liya Liu a, Xianrong Zhou a, Li Wang b, Sumei Zhou a, *
a

Institute of Agro-Products Processing Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-Products Processing, Ministry of Agriculture, Beijing 100193, China The State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, 1800 Lihu Road, Wuxi 214122, China c Hunan Jinjian Cereals Industry Co., Ltd., Changde City, Hunan Province 415001, China
b

a r t i c l e i n f o
Article history: Received 24 July 2014 Received in revised form 19 November 2014 Accepted 13 December 2014 Available online 3 January 2015 Keywords: Rice noodles Semidry-milling Characteristics of rice ?ours Rice noodles qualities

a b s t r a c t
To investigate the effects of semidry-milling on the quality attributes of rice ?our and rice noodles, the properties of rice ?ours and cooking properties of rice noodles prepared with wet-, dry- and semidrymilled rice ?ours were characterized. The level of starch damage of semidry-milled rice ?our at 30% moisture was signi?cantly decreased to the level of wet-milled rice ?our (P < 0.05); the whiteness of drymilled rice ?our was decreased compared with wet-milled rice ?our (P < 0.05), while that of semidrymilled rice ?our was not; the wet- and semidry-milled rice ?ours showed similar morphology and water hydration properties; the dry milling method reduced signi?cantly the hardness, chewiness, and resilience of rice noodles (P < 0.05) compared with wet-milling, but semidry-milling did not; the cooking qualities of rice noodles produced by semidry-milling were comparable to wet-milling. It indicated the semidry-milling at 30% moisture may provide the protective effects on the characteristics of rice ?ours, which could be used to produce similar qualities of rice noodles to the wet-milling. ? 2015 Elsevier Ltd. All rights reserved.

1. Introduction Rice noodles produced from Indica rice, which are very popular in South-east Asian countries, such as China, Thailand, Sri Lanka, etc., are classi?ed into fresh, dried, or frozen products in various thicknesses and shapes (Fu, 2008). Since traditional rice noodles with unique taste are coveted by consumers as a result of a long history of their consumption, most of the rice noodle processing is still traditional in China (Lu et al., 2003). In this traditional process, wet-milling of rice following an overnight soaking in water is commonly used as a material processing stage (Lu et al., 2005). However, the long soaking time results in bacterial growth in rice, leading to a serious degradation in product quality (Charles et al., 2007). Therefore, the dry-milling method is used to break rice granules which needs more energy and increases the content of damaged starch in comparison to wet-milled rice ?our (Kumar et al., 2008). In addition, the extra heat leads to a reduction in the whiteness of rice ?ours, thereby affecting the sensory appeal of rice

* Corresponding author. Tel./fax: ?86 10 6281 3477. E-mail address: sumeizhoucaas@gmail.com (S. Zhou). http://dx.doi.org/10.1016/j.jcs.2014.12.007 0733-5210/? 2015 Elsevier Ltd. All rights reserved.

noodles (Takahashi et al., 2005). Chiang and Yeh (2002) and Heo et al. (2013) have reported that dry-milled rice ?our has poor pasting and hydration properties in comparison to wet-milled rice ?our. Therefore, the quality of rice noodles produced from drymilled rice ?our is not acceptable to consumers, despite the fact that dry-milling presents fewer health risks and improves the stability of rice products. Rice proteins do not form a stable network structure, so that the viscoelastic quality of rice noodles depends primarily on the properties of the starch component (Sandhu and Mukesh, 2010; Kim et al., 2014). However, the dry-milled method has a bad effect on starch structure. So, dry-milled ?our is often unable to meet the requirements of the rice noodle processing. Numerous studies have con?rmed that the addition of strengthening agents and speci?c treatments, such as fermentation, hydrothermal and enzyme treatments, can improve the network structure for producing rice noodles (Gujral et al., 2003; Yang and Tao, 2008; Hormdok and Noomhorm, 2007). Obviously, the addition of strengthening agents is a convenient and inexpensive method, but this may results in the overuse of additives to enhance product quality. Similarly, many countries such as Thailand and other

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L.-T. Tong et al. / Journal of Cereal Science 62 (2015) 45e49

South-east Asian countries are faced with the similar processing problems of rice products (Cham and Suwannaporn, 2010). In order to reduce the adverse effects of dry-milling on characteristics of rice ?our and cooking qualities of rice noodles, the present study was initiated to focus on the semidry-milling method. The semi-dry milling method may singly get similar rice noodle qualities to wet milling without adding additives. In our study, rice ?ours were prepared from wet-, dry- and semidry-milling methods, and their physicochemical characteristics were measured. Furthermore, rice noodles prepared with these different milled rice ?ours were used to determine their relative texture pro?le and cooking qualities. 2. Materials and methods 2.1. Materials The rice used for this study was early polished Indica rice of the Hunan fragrant rice variety (harvested in 2013.07) which was provided by Hunan Jinjian Cereals Industry Co., Ltd. (Changde, China). This product contained 6.40% protein, 1.63% crude fat, 0.35% ash, 88.69% total starch and 24.03% amylose. The protein and crude fat of rice were determined using the analytical method of Association of Of?cial Agricultural Chemists (AOAC, 984.13 and 945.16). Total nitrogen content of rice was determined by the Kjeldahl method gana s, Sweden), and a using a Kieltec analyzer (Foss Tecator AB, Ho conversion factor of 5.95 was used to estimate the protein content. The total starch content was determined using a Total Starch Assay Kit (JKY/K-TSTA 07/11, Megazyme International Ltd., Wicklow, Ireland) by the American Association for Clinical Chemistry (AACC) approved method 76.13. The amylose content was determined using an Amylose/Amylopectin Assay Kit (JKY/K-AMYL 07/11, Megazyme International Ltd., Wicklow, Ireland). The chemical compositions of rice were determined in triplicate for each rice sample, and all results were reported on a dry weight basis. 2.2. Preparation of wet-, dry-, and semidry-milled rice ?our For wet-milled ?our, 1 kg polished rice (14% moisture content) was steeped in 2 L deionized water at 25  C for 24 h, and then milled by using a grinder (YU8022, Wet miller, Hebei, China) and a homogenizer (JMS-30A, Langfang Langtong Machinery Co., Ltd., China). In order to con?rm the right moisture content, we tested moisture content at 24 h. The soaked rice contained 32% moisture. For dry-milled ?our, rice was ground into ?our using a cyclone mill and passed through a 100 mesh sieve (CT410, FOSS Scino (Suzhou) Co., Ltd., Suzhou, China). In the case of semidry-milled ?ours, a 1 kg portion of rice was in?ltrated with deionized water to get the 18%, 22%, 26%, and 30% moisture, and each hydrated sample was incubated at 25  C for 24 h. Then, the rice samples were ground into ?our using the same cyclone mill as mentioned above. All rice ?ours were freeze-dried to obtain the rice ?ours with 5% moisture and stored at 4  C for further analysis. 2.3. Starch damage The degree of starch damage of different rice ?ours was measured using the enzymatic colorimetric method with a Starch Damage Assay Kit (K-SDAM, Megazyme International Ltd., Wicklow, Ireland). 2.4. Determination of colour of rice ?our The CIE L* (lightness), a* (redness), and b* (yellowness) of the various rice ?ours were measured using a Hunter Lab D25LT

colorimeter (Hunter Associates Laboratory, Inc., Virginia, USA) according to a reported method (Pongjaruvat et al., 2014). The rice ?our samples (100 g) were placed under a plate glass for measurement. The colorimeter was set to an illuminant condition D65 and a standard observer of 10 . The hunter whiteness was calculated using the following formula based on reports (Hsu et al., 2003; Torbica et al., 2012).

i1=2 h Hunter whiteness ? 100 ? ?100 ? L*?2 ? a*2 ? b*2
2.5. Scanning electron microscopy (SEM) The morphology of the rice ?our samples was examined using a Scanning Electron Microscope (SEM Hitachi S-570, Hitachi, Co., Ltd., Tokyo, Japan). The rice ?our samples were spread directly on the surface of an aluminum stub and dried in an oven at 40  C for 4 h. The samples were coated with gold and examined in the scanning electron microscope under an acceleration voltage of 15 kV and a magni?cation of 1500?. 2.6. Water hydration properties The water absorption index (WAI), water solubility index (WSI) and swelling power index (SPI) of the rice ?our samples were determined according to a reported method (Ohishi et al., 2007; Heo et al., 2013). Brie?y, 0.1 g rice ?our was dispersed in 20 mL deionized water and agitated at 25  C and 100  C for 30min, respectively. After centrifuging the dispersion at 15,000 g for 30 min, the supernatant was dried in a hot air oven at 105  C until a constant weight was obtained. WAI, WSI and SPI were calculated by the following formulae.

WAI ? wet sediment weight=dry sample weight WSI ?%? ? dry supernatant weight=dry sample weight ? 100 SPI ? wet sediment weight=?dry sample weight ? ?1 ? WSI??

2.7. Preparation of rice noodles The rice noodles were prepared using a GY-MF rice noodle machine (Guangzhou National Institute Machinery Equipment Manufacturing Co., Ltd., Guangzhou, China), which mainly consists of an extruder wrapped with a heating mantle whose temperature is greater than 95  C and an electric fan for the cooling process. Deionized water was added into rice ?ours to keep the total water content at 55%. Pouring rice milk into the extruded pipe and starting the machine and electric fan, the rice milk was extruded through a multiple opening (0.2 cm diameter) in a circular die, and air-cooled by an electric fan, then stored at 4  C for further analysis. 2.8. Texture pro?le analysis (TPA) of rice noodles The texture pro?le of the rice noodles was determined using a TA-XT 2i/5 Texture Analyser (Stable Micro System Ltd., Godalming, England) according to a reported method with some modi?cations (Charutigon et al., 2008). The rice noodles were cooked in boiling deionized water for 2 min, followed by cooling to room temperature with deionized water at room temperature, and drained for 5 min before the measurement. Five samples of rice noodles, 4 cm in length with similar diameter, were prepared. Speci?c measurement parameters were: P/50R probes at the test speed of 1.0 mm/s,

L.-T. Tong et al. / Journal of Cereal Science 62 (2015) 45e49

47

50% compression ratio, 0.04905 N triggering force, 3 s interval between the compressions, and 200 pp/s data acquisition rate. Ten specimens for each treatment were measured and the values were averaged. 2.9. Cooking qualities of rice noodles The cooking qualities of the rice noodles were determined according to a published method with some modi?cations (Lee et al., 2008). Brie?y, 10 g of rice noodles was boiled in 150 mL deionized water for 2 min and then weighed after draining for 5 min. The cooking water was collected to measure its turbidity at 675 nm and then dried in an oven at 105  C to a constant weight. Water absorption and cooking loss were calculated by the following formulae.

Water absorption ? ?Weight of cooked rice noodles ? Weight of uncooked rice noodles? ? =Weight of uncooked rice noodles: Cooking loss ?Dry weight of the cooking water= Weight of uncooked rice noodles:

2.10. Statistical analysis The accumulated data were expressed as the mean ± standard deviation (SD) and analyzed by SPSS (Version 12.0 for Windows, SPSS Inc., Chicago, IL, USA) using TukeyeKramer's multiple comparison post hoc test. Variations were considered signi?cant at P < 0.05. 3. Results and discussion 3.1. Effects of semidry ?our milling on characteristics of rice ?our It has been widely reported that dry-milled rice ?our exhibits a higher degree of starch damage than wet-milled rice ?our, because the dry-milling applies more mechanical and thermal energy, which results in increased starch granule damage of rice ?our (Kumar et al., 2008; Heo et al., 2013). In the present study, the degree of starch damage of different rice ?ours was measured and the results are shown in Fig. 1. The content of damaged starch in dry-milled rice ?our was signi?cantly higher than that in wetmilled rice ?our (P < 0.05). Interestingly, the content of damaged

starch in the semidry-milled rice ?ours at 26% or 30% moisture was signi?cantly lower than that in dry-milled rice ?our (P < 0.05), even down to the same content in wet-milled rice ?our. These ?ndings indicated that semidry-milling may play a protective role in the rice milling process by reducing the degree of starch damage which is an important quality index of rice products. It is well known that the contents of ash and polyphenolics are critical factors affecting the whiteness of rice ?ours as an important quality index of rice noodles (Lu et al., 2005; Saka c et al., 2011; Torbica et al., 2012). Moreover, changes in the size of starch granules and chemical ingredients during the milling process also affect the whiteness of rice ?ours. A recent report demonstrated that the color of milled rice ?ours changed (increased a* and b*) after a heat treatment in an autoclave at 120  C for 60 min and oven at 160  C for 60 min compared with the ?our without the heat treatment (Takahashi et al., 2005). In other words, the increased temperature of rice ?our will reduce its Hunter whiteness. In the present study, the whiteness of dry-milled rice ?our was signi?cantly lower than that of wet-milled rice ?our as shown in Fig. 2 (P < 0.05). However the whiteness of semidry-milled rice ?our at 26% or 30% moisture was not signi?cantly different from that of wet-milled rice ?our. This may be because more mechanical and thermal energy needed in the process of dry-milling than wet-milling and semidry-milling results in the oxidation of polyphenolic compounds (Saka c et al., 2011; Torbica et al., 2012), which causes the decreased whiteness of rice ?our. On the other hand, the variation of starch granule morphology may be another reason for the variation in whiteness of rice ?ours. In order to determine the differences in the starch granule morphology of rice ?our samples, the morphological analysis was performed by Scanning Electron Microscopy. As shown in Fig. 3A, C, D, the wet-milled rice ?our and semidry-milled rice ?our at 26% or 30% moisture showed similar morphology, and they had relatively intact starch granules. This result was consistent with the previous reports which indicated that the wet-milling method can maintain the crystal structure of starch granules (Lu et al., 2005). However, the crystal structure of starch granules in dry-milled rice ?our was destroyed and became amorphous (Fig. 3B). These results indicate that the semidry-milling method is close to the wet-milling method in protecting the integrity of starch granules. The water hydration properties, such as WAI, WSI and SPI, are important quality attributes of rice ?our associated with the integrity and crystallinity of starch granules as suggested by Chiang

Fig. 1. Starch damage of wet-, dry-, and semidry-milled rice ?our. Means values ± standard deviation, n ? 3. Different superscript letters indicate signi?cant differences at P < 0.05 (TukeyeKramer's multiple comparison post hoc test).

Fig. 2. Hunter whiteness of wet-, dry-, and semidry-milled rice ?our. Means values ± standard deviation, n ? 3. Different superscript letters indicate signi?cant differences at P < 0.05 (TukeyeKramer's multiple comparison post hoc test).

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L.-T. Tong et al. / Journal of Cereal Science 62 (2015) 45e49

Fig. 3. Morphology of wet-milled rice ?our (A), dry-milled rice ?our (B), and semidry-milled rice ?our at 26% (C) and 30% (D) moisture. The samples were examined in the scanning electron microscope under an acceleration voltage of 15 kV and a magni?cation of 1500?.

and Yeh (2002) and Heo et al. (2013). When the rice ?our samples were heated, wet-milled rice ?our showed higher values of water absorption and swelling power than dry-milled ?our, because intact starch granules exhibited better water swelling (Güler et al., 2002). In addition, when the rice ?our samples were kept at room temperature (25  C), the disruption of crystallinity of starch granules during dry-milling increased the content of damaged starch,

leading to an increase in the water solubility. In the present study, the water hydration properties of rice ?our at 25  C and 100  C were investigated respectively as shown in Table 1. Dry-milling led to a signi?cant increase in water hydration properties of rice four (P < 0.05) compared with wet-milling, while semidry-milling resulted in similar water hydration properties to wet-milling. The results of WAI, WSI and SPI demonstrated a close relationship

Table 1 Water absorption index (WAI), water solubility index (WSI), and swelling power index (SPI) of rice ?our samples. Milling method WAI (g/g) 25  C Wet-milling Dry-milling Semidry-milling 26% 30% 2.29 ± 0.07 2.91 ± 0.18a
bc

WSI (%) 100  C 14.76 ± 0.32 12.00 ± 0.13c
a

SPI 100  C
a

25  C 4.98 ± 0.40 3.23 ± 0.27b 3.85 ± 0.72ab 4.38 ± 0.51a

25  C 2.41 ± 0.07 3.00 ± 0.18a
b

100  C 16.99 ± 0.22a 13.76 ± 0.14c 15.52 ± 0.39b 15.15 ± 0.43b

13.12 ± 0.74 12.76 ± 0.45 12.99 ± 0.58 11.19 ± 1.47

2.76 ± 0.26ab 2.20 ± 0.10c

13.51 ± 0.21b 14.57 ± 0.18a

2.87 ± 0.25a 2.28 ± 0.10b

Means values ± standard deviation, n ? 3. Different superscript letters indicate signi?cant differences at P < 0.05 (TukeyeKramer's multiple comparison post hoc test).

Table 2 Texture pro?le analysis (TPA) of rice noodles. Milling method TPA parameters Hardness (N) Wet-milling Dry-milling Semidry-milling 26% 30% 16.21 ± 1.17a 9.93 ± 1.10b 10.35 ± 1.14b 18.99 ± 2.75a Adhesiveness (N/s) ?0.36 ± 0.06 ?0.36 ± 0.05 ?0.40 ± 0.06 ?0.41 ± 0.06 Springiness 0.91 ± 0.03 0.89 ± 0.02 0.91 ± 0.02 0.92 ± 0.04 Cohesiveness 0.64 ± 0.02 0.65 ± 0.03 0.63 ± 0.02 0.65 ± 0.03 Chewiness (N) 9.47 ± 0.55a 5.71 ± 0.48b 5.92 ± 0.59b 11.38 ± 1.65a Resilience 0.42 ± 0.03a 0.29 ± 0.04b 0.33 ± 0.02b 0.41 ± 0.02a

Means values ± standard deviation, n ? 3. Different superscript letters indicate signi?cant differences at P < 0.05 (TukeyeKramer's multiple comparison post hoc test).

L.-T. Tong et al. / Journal of Cereal Science 62 (2015) 45e49 Table 3 Cooking properties of fresh rice noodles. Milling method Wet-milling Dry-milling Water absorption rate (%) 87.6 ± 1.3a 76.2 ± 2.3b Cooking loss (%) 8.08 ± 1.32c 15.29 ± 2.28a 10.17 ± 0.46b 8.85 ± 1.70c Turbidity (at 675 nm) 0.55 ± 0.3b 0.76 ± 0.1a 0.53 ± 0.4b 0.54 ± 0.2b

49

Acknowledgments This work was supported by the Special Fund for Agro-scienti?c Research in the Public Interest (Grant No. 201303070) and Core Research Budget of the Non-pro?t Governmental Research Institution (ICS, CAAS) (2014JB02).

Semidry-milling 26% 82.6 ± 1.2ab 30% 84.4 ± 2.1a

References
Cham, S., Suwannaporn, P., 2010. Effect of hydrothermal treatment of rice ?our on various rice noodles quality. J. Cereal Sci. 51 (3), 284e291. Charles, A.L., Huang, T.C., Lai, P.Y., Chen, C.C., Lee, P.P., Chang, Y.H., 2007. Study of wheat ?ourecassava starch composite mix and the function of cassava mucilage in Chinese noodles. Food Hydrocoll. 21 (3), 368e378. Charutigon, C., Jipupakdree, J., Namsree, P., Rungsardthong, V., 2008. Effects of processing conditions and the use of modi?ed starch and monoglycerde on some properties of extruded rice vermicelli. LWT-Food Sci. Technol. 41 (4), 642e651. Chiang, P.Y., Yeh, A.I., 2002. Effect of soaking on wet-milling of rice. J. Cereal Sci. 35 (1), 85e94. Fu, B.X., 2008. Asian noodles: history, classi?cation, raw materials, and processing. Food Res. Int. 41 (9), 888e902. Gujral, H.S., Guardiola, I., Carbonell, J.V., Rosell, C.M., 2003. Effect of cyclodextrin glycoxyl transferase on dough rheology and bread quality from rice ?our. J. Agric. Food Chem. 51 (13), 3814e3818. Güler, S., Koksel, H., Ng, P.K.W., 2002. Effects of industrial pasta drying temperatures on starch properties and pasta quality. Food Res. Int. 35 (5), 421e427. Heo, S., Lee, S.M., Shim, J.H., Yoo, S.H., Lee, S., 2013. Effect of dry- and wet-milled rice ?ours on the quality attributes of gluten-free dough and noodles. J. Food Eng. 116 (1), 213e217. Hormdok, R., Noomhorm, A., 2007. Hydrothermal treatments of rice starch for improvement of rice noodle quality. LWTeFood Sci. Technol. 40 (10), 1723e1731. Hsu, C.L., Chen, W., Weng, Y.M., Tseng, C.Y., 2003. Chemical composition, physical properties, and antioxidant activities of yam ?ours as affected by different drying methods. Food Chem. 83 (1), 85e92. Kim, Y., Kee, J.I., Lee, S., Yoo, S.,H., 2014. Quality improvement of rice noodle restructured with rice protein isolate and transglutaminase. Food Chem. 145, 409e416. Kumar, C.S., Malleshi, N., Bhattacharya, S., 2008. A comparison of selected quality attributes of ?ours: effects of dry and wet grinding methods. Int. J. Food Prop. 11 (4), 845e857. Lee, S., Bae, I.Y., Jung, J.H., Jang, K.I., Kim, Y.O., Lee, H.G., 2008. Physicochemical, textural and noodle-making properties of wheat dough containing alginate. J. Texture Stud. 39 (4), 393e404. Lu, Z.H., Li, L.T., Cao, W., Li, Z.G., Tatsumi, E., 2003. In?uence of natural fermentation on physico-chemical characteristics of rice noodles. Int. J. Food Sci. Technol. 38 (5), 505e510. Lu, Z.H., Li, L.T., Min, W.H., Wang, F., Tatsumi, E., 2005. The effects of natural fermentation on the physical properties of rice ?our and the rheological characteristics of rice noodles. Int. J. Food Sci. Technol. 40 (9), 985e992. Ohishi, K., Kasai, M., Shimada, A., Hatae, K., 2007. Effects of acetic acid on the rice gelatinization and pasting properties of rice starch during cooking. Food Res. Int. 40 (2), 224e231. Pongjaruvat, W., Methacanon, P., Seetapan, N., Fuongfuchat, A., Gamonpilas, C., 2014. In?uence of pregelatinised tapioca starch and transglutaminase on dough rheology and quality of gluten-free jasmine rice breads. Food Hydrocoll. 36, 143e150. Saka c, M., Torbica, A., Sedej, I., HadnaCev, M., 2011. In?uence of breadmaking on antioxidant capacity of gluten free breads based on rice and buckwheat ?ours. Food Res. Int. 44 (9), 2806e2813. Sandhu, K.S., Mukesh, M.K., 2010. Studies on noodle quality of potato and ice starches and their blends in relation to their physicochemical, pasting and el textural properties. LWTeFood Sci. Technol. 43 (8), 289e1293. Takahashi, T., Miura, M., Ohisa, N., Mori, K., Kobayashi, S., 2005. Heat treatments of milled rice and properties of the ?ours. Cereal Chem. 82, 228e232. Torbica, A., HadnaCev, M., HadnaCev, T.D., 2012. Rice and buckwheat ?our characterisation and its relation to cookie quality. Food Res. Int. 48 (1), 277e283. Yalcin, S., Basman, A., 2008. Effects of gelatinisation level, gum and transglutaminase on the quality characteristics of rice noodle. Int. J. Food Sci. Technol. 43 (9), 1637e1644. Yang, Y., Tao, W.Y., 2008. Effects of lactic acid fermentation on FT-IR and pasting properties of rice ?our. Food Res. Int. 41 (9), 937e940.

Means values ± standard deviation, n ? 3. Different superscript letters indicate signi?cant differences at P < 0.05 (TukeyeKramer's multiple comparison post hoc test).

between the content of damaged starch and the crystallinity of starch granules, which were in agreement with the reports of Güler et al. (2002) and Heo et al. (2013). 3.2. Effects of semi-dry ?our milling on qualities of rice noodles In order to evaluate the effects of semi-dry milling on the taste of rice noodles, the texture pro?le of rice noodles as the mainly tasty index was measured. As shown in Table 2, dry-milling led to a signi?cant reduction in the hardness, chewiness, and resilience of rice noodles (P < 0.05) compared with wet-milling, while semidrymilling at 30% moisture had similar texture properties to wetmilling. It suggested that semidry-milling could protect the characteristics of rice ?ours. The water absorption rate, cooking loss and cooking water turbidity of rice noodles are also important quality attributes of rice noodles, because these parameters measure the solid loss of materials to the cooking water, which determine the ability of rice noodles to maintain structural integrity during the hot-water cooking process (Yalcin and Basman, 2008; Kim et al., 2014). In the present study, the dry-milling decreased the water absorption rate of rice noodles and increased the cooking loss and turbidity signi?cantly (P < 0.05) (Table 3). The severe cooking loss of drymilled rice noodles seemed to be correlated with the high content of damaged starch as shown in Fig. 1, which is consistent with the reports of Heo et al. (2013) and Fu (2008). Because of the protective effect of semidry-milling on integrity of the starch granules, cooking qualities of rice noodles produced by semidry-milled ?our at 30% moisture are comparable to that of wet-milled ?our. 4. Conclusions The ?ndings in the present study demonstrated the expected effects of the semidry-milling method on qualities of rice ?our and rice noodles. Compared with the dry-milling method, the method of semidry-milling at 30% moisture showed protective effects on characteristics of rice ?our by reducing the degree of starch damage, and protecting the integrity of the starch granules and the whiteness of rice ?our. The semi-dry milled rice ?our exhibited water hydration properties that were similar to those of wet-milled rice ?our. Moreover, the texture pro?le and cooking qualities of rice noodles produced by the semidry-milling at 30% moisture were much better than those of the dry-milled rice noodles, and comparable to those of the wet-milled rice noodles. Therefore, the study demonstrates a feasible milling method for standardized and large-scale industrial production.


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