E#ect of Potato Starch Characteristics on the Textural Properties of Korean-style Cold Noodles Made from Wheat Flour and Potato Starch Blends

Transcription

1 Food Sci. Technol. Res., +, (.),,12,2-,,**0 E#ect of Potato Starch Characteristics on the Textural Properties of Korean-style Cold Noodles Made from Wheat Flour and Potato Starch Blends Takahiro NODA +, Shohei FUJIKAMI,, Hideho MIURA,, Michihiro FUKUSHIMA,, Shigenobu TAKIGAWA +, Chie MATSUURA-ENDO +, Sun-Ju KIM +, Naoto HASHIMOTO + and Hiroaki YAMAUCHI + + Department of Upland Agriculture, National Agricultural Research Center for Hokkaido Region (NARCH), Shinsei, Memuro, Kasai-gun, Hokkaido *2, **1+, Japan, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho, Obihiro, Hokkaido *2* 2///, Japan Received February -,,**0; Accepted September +0,,**0 The physicochemical properties of starches isolated from eight potato cultivars were analyzed. The phosphorus and amylose contents and median granule size, as well as the rapid visco-analyzer (RVA) pasting properties, di#erential scanning calorimetry (DSC) gelatinization properties, and gel firmness, were di#ered significantly among the starch samples tested. Korean-style cold noodles were prepared from wheat flour: potato starch (+ : +) blended flours with alkali and salt solution using a specific wheat flour and one of the 2 potato starches. Variations were observed in the textural properties of the cooked noodles were measured with a rheoner for each of the starch samples used. The phosphorus and amylose content, RVA pasting properties, DSC gelatinization properties, and gel firmness did not a#ect the elasticity of the noodles. In contrast, the granule size was seen as the most important factor for determining the elasticity of the cold noodles, and Konafubuki, Irish Cobbler, Kitamurasaki, and Toyoshiro starches with relatively small granule size appeared to be desirable for making cold noodles. The firmness of the noodles was not a#ected by any of the potato starch properties. Keywords : Potato starch, Wheat flour, Noodles, Textural properties, Starch granule size Introduction In Japan, potatoes are the primary source of the starches used by the food industry. In Hokkaido, the northernmost island of Japan, potato starch is manufactured in local factories. Potato starch possesses unique characteristics that are suitable for food application. For example, potato starch has a larger granule size than other commercially available starches (Jobling,,**.; Singh et al.,,**-). In addition, the degree of phosphorylation is higher in potato starch than in other starches (Hizukuri et al., +31*; Jobling,,**.; Singh et al.,,**-). The existence of phosphate in potato starch is of immense importance, as this confers high viscosity (Hopkins and Gormley,,***; Kimet al., +33/; Noda et al.,,**.a,,**.b,,**0a,,**0b; Singh et al.,,**-; Wiesenborn et al., +33.) and transparency of its gel (Craig, et al., +323; Singh et al.,,**,; Singh et al.,,**-). Potato starch plays a critical role in the production of several types of noodles. For example, starch noodles, which are free of wheat flour and are sometimes called glass noodles because of their clear and shiny appearance after cooking, are manufactured in part using potato starch. Some researchers have reported that potato starch noodles have a clearer appearance than other starch noodles (Kim and Wiesenborn, +330; Kim et al., To whom correspondence should be addressed. noda@a#rc.go.jp +330). In addition, noodles made from starches isolated from several specific potato varieties were harder and more cohesive than other starch noodles (Kim et al., +330; Singh et al.,,**,). Thus, the use of potato starch for making starch noodles results in favorable texture and appearance of cooked noodles. To produce instant noodles, a portion of the wheat flour could be replaced by potato starch. The use of potato starch with a high phosphorus content and peak viscosity resulted in favorable texture and hardness of the instant noodles made from wheat flour and potato starch blends (Noda et al.,,**0b). In addition to these noodles, production of Korean-style cold noodles (naengmyeon) is also a promising use for the e#ective use of potato starch. The traditional ingredients of cold noodles are wheat flour, buckwheat flour, starch, and alkali and a salt solution. Cold noodles were introduced from Korea to Japan about /* years ago. The noodles, called Morioka Reimen are popular in Japan. They contain /* 1* wheat flour and -* /* potato starch blends combined with alkali and salt solution, and are commonly served cold. Desirable characteristics of cold noodles are elasticity, firmness, and transparency. The textural properties of the cold noodles are assumed to be dependent on the source of starch used. Cold noodles made from wheat flour and potato starch blends had a more favorable texture than those made from specific wheat flour, sweet potato, corn and cassava starches (Toyama et al., +331). However, no reports are available

2 E#ect of Potato Starch Properties on Noodle Properties 279 concerning the relationship between the textural properties of the cold noodles and potato starch properties using starches isolated from several cultivars. In this investigation, the e#ects of starch properties isolated from eight Japanese potato cultivars on the textural properties of Korean-style cold noodles made from wheat flour and potato starch blends were evaluated. Materials and Methods Wheat flour and potato starch A commercial hardwheat flour, Camellia, was purchased from the Nisshin Flour Milling Co., Ltd., Tokyo, Japan. Five Japanese potato cultivars, Kitamurasaki, Konafubuki, Irish Cobbler, Toyoshiro, and Astarte, were grown in,**- at the experimental farm of the National Agricultural Research Center for the Hokkaido Region in Memuro, Hokkaido, Japan. The planting and harvesting dates were -* April and, October, respectively. Starches were isolated from these potato samples by sieving with distilled water as previously reported (Noda et al.,,**.b). Starches from three Japanese potato cultivars, Hokkaikogane, Eniwa, and Benimaru, were purchased from the Jinno Starch Co., Sarabetsu, Hokkaido, Japan. Potato starch analysis Several starch characteristics, namely, the amylose and phosphorus content, granule size distribution, RVA paste viscosity, and DSC thermal properties, were determined as previously reported (Noda et al.,,**.). Starch gels were obtained from RVA as follows. The starch suspension (+*, w/w, dry weight basis,,/ ml) was kept at /* for + min, heated to 3/ at +,., /min, kept at 3/ for,./ min, then cooled to 1* at 0.0 /min, and finally kept at 1* for, min. Six grams of the resulting paste was poured into a /* ml plastic tube with a flat bottom. The tube was centrifuged at -*** rpm for / min to remove bubbles from the paste and obtain gel discs measuring,./ cm in diameter and + cm in height. Afterwards, the tubes were kept at,* for, h to change the paste into a gel. The gels were then stored in a refrigerator at. for,. h. The compression test of starch gels was conducted using a rheoner (model RE---**/, Yamaden Co., Ltd., Tokyo) using the following method: the gel sample was compressed with a plunger (+0 mm diameter) at a speed of + mm/sec. The compression distance was 2/ of the gel thickness. From the compression curve, the gel firmness value was calculated as the ratio of force at / mm of the strain to the plunger surface area. Noodle preparation Fifty grams of a specific wheat flour was then blended with /* g of each one of the eight potato starches. Each of the blended flour samples was then mixed with a solution containing *.+2 gk,co -, *.+, g Na,CO - and -1./ ml distilled water for +* min using a Tezukuri Meijin KN-0*W (MK Seiko, Co., Ltd, Chikuma, Japan). The crumbly mix was transferred to Namakouchi Meijin (Okhotsk Butsuryu Co., Ltd., Abashiri, Japan) and extruded through a die with a hole diameter of +.3 mm. Each noodle strand was dried and cut into a length of about -* cm. The resulting noodles were kept at room temperature for -* min and then packed in airtight containers and stored in a refrigerator prior to analysis. Texture profile analysis of noodles The noodle strands were cooked in boiling water for - min. The cooked noodles were drained and then placed in cold water for + min. Next, they were kept in water at,* for, min before cutting each noodle strand to a length of about / cm. The textural profiles of each noodle strand were measured using a rheoner (model RE---**/, YAMADEN Co., Ltd., Tokyo) as reported by Ishida et al. (,**-). A cutting test was performed with a cutting plunger at a speed of / mm/sec. From the force-deformation of the curves, the maximum cutting force (breaking force) (BF) and breaking deformation (BD) were determined, and the ratio of BF to BD (BF/BD) was calculated. Three individual noodle strands were tested. Results and Discussion Chemical composition of potato starch The chemical composition and median granule size of starches from di#erent potato cultivars di#ered significantly (Table +). The content of phosphorus and amylose of starches from di#erent potato cultivars ranged from /30 to +*/* ppm and from +3.* to,,.., respectively. Astarte and Benimaru starches showed lower phosphorus contents (0.3 /30 ppm). In contrast, Kitamurasaki starch showed the highest phosphorus content (+*/* ppm), followed by Hokkaikogane (3** ppm), Eniwa (2.- ppm), and Konafubuki Table +. Chemical composition and median granule size of eight potato starches.

3 280 T. NODA et al. (2.+ ppm). Kitamurasaki and Eniwa starches had lower amylose contents (+3.* +3.. ), while Irish Cobbler, Benimaru, and Astarte starches had higher values (,,.-,,.. ). The median granule size varied between -,., and.0., mm. Lower values of the median granule size were observed for Irish Cobbler (-,., mm) and Toyoshiro (-../ mm) starches. Astarte starch had the highest median granule size (.0., mm), followed by Eniwa (.-.2 mm) and Benimaru (.*.* mm). RVA and DSC properties of potato starch The results of the RVA pasting properties and DSC gelatinization properties of starches from di#erent potato cultivars are summarized in Table,. The RVA data revealed that peak viscosity and breakdown of starches from di#erent potato cultivars di#ered significantly. Among the di#erent cultivars, Benimaru starch showed the lowest peak viscosity (,+- RVU) and breakdown (+,0 RVU), whereas Kitamurasaki starch showed the highest peak viscosity (-/* RVU) and breakdown (,,. RVU). Starches with lower phosphorus contents tended to exhibit lower peak viscosity and breakdown than those with higher phosphorus contents. As for DSC gelatinization properties, significant but relatively small di#erences in the onset and peak temperatures and enthalpy were observed among starches from di#erent potato cultivars. The onset and peak temperatures ranged from /3./ in Benimaru to 0,., in Eniwa and from 0,.1 in Astarte to 0/./ in Hokkaikogane, respectively. The enthalpy varied between +2.0 and,*.0 J/g, with Astarte showing the lowest value and Hokkaikogane the highest. Gel firmness of potato starch The firmness of starch gels stored at. for,. h for eight potato cultivars is presented in Fig. +. Among the potato cultivars, Astarte starch was the least firm, whereas Kitamurasaki starch was the firmest, followed by Hokkaikogane and Konafubuki. The order of the firmness of starch gels was generally similar to those observed for the phosphorus content and peak viscosity. Correlation analysis for potato starch The correlation coe$cients between the chemical compositions or median granule size and rheological properties for eight potato starches are listed in Table -. Two RVA parameters, the Table,. RVA and DSC properties of eight potato starches. Fig. +. Gel Firmness of eight potato starches after storage at. for,. h. Values are the mean of three determinations. Bars labeled with di#erent letters are significant at P *.*/.

4 E#ect of Potato Starch Properties on Noodle Properties 281 peak viscosity and breakdown, were positively correlated with the phosphorus content. Previous data with the use of many potato starches, including ours, indicated that a higher phosphorus content was closely associated with a higher peak viscosity (Hopkins and Gormley,,***; Kim et al., +33/; Noda et al.,,**.a,,**.b,,**0a,,**0b; Wiesenborn et al., +33.) and breakdown (Noda et al.,,**. a,,**.b,,**0b). The peak viscosity and breakdown were negatively correlated with the amylose content, which closely agreed with our previous reports (Noda et al.,,**. a,,**.b). Contrary to this, Wiesenborn et al. (+33.) and Hopkins and Gormley (,***) presented no significant correlation between the peak viscosity and the amylose content. Of the three DSC parameters, the onset and peak temperatures were negatively correlated with the amylose content, while only the peak temperature showed a positively significant correlation with the phosphorus content. Previous studies reported either no e#ect or very slight e#ects of the contents of amylose and phosphorus on DSC parameters (Kim et al., +33/; Noda et al.,,**.b). A highly positive correlation was found between the gel firmness and phosphorus content, while gel firmness was not significantly correlated with amylose content. Similar e#ects of the contents of phosphorus and amylose on the compression force of potato starch gels were observed in previous research (Hopkins and Gormley,,***). Tokimura et al. (,**,) reported that sweet potato starch gels stored at / were firmer in starches with high contents of amylose and phosphorus than in those with low contents of amylose and phosphorus. No significant correlations were observed between the rheological properties and median granule size, thus corroborating our previous data indicating that there was no e#ect of the starch granule size on the RVA pasting properties (Noda et al.,,**.a,,**.b) and DSC gelatinization properties (Noda et al.,,**.b). Textural properties of cold noodles Figure, shows the deformation curve for the measurement of the textural properties of cold noodles made from a mixture of hard-wheat flour and one representative potato starch, namely, Astarte, and includes a definition of the BF and BD. The BF provides information regarding the hardness of the noodles. The BF/BD, which represents the viscoelasticity, was calculated. Two parameters of the textural properties of cooked noodles, BF and BF/BD, as measured using a rheoner, are summarized in Table.. The BF and BF/BD of the noodles made from the mixtures of wheat flour and each one of the eight potato starches ranged between *..*/ and *.//3 N and between *.*2* and *.+** N/mm, respectively. Lower values of BF were observed in Hokkaikogane (*..*/ N) and Eniwa (*..+2 N), while Irish Cobbler had the highest ones (*.//3 N). This implied that the Irish Cobbler noodles were firmer than those made from Hokkaikogane and Eniwa. Benimaru and Astarte had lower BF/BD values (*.*2* *.*2+ N/ mm). In contrast, Konafubuki had the highest BF/BD (*.+** N/mm), followed by Irish Cobbler (*.*33 N/mm), Kitamurasaki (*.*3/ N/mm), and Toyoshiro (*.*3. N/mm). A higher BF/BD is generally associated with a higher elasticity in texture, suggesting good quality in Koreanstyle cold noodles. Thus, Konafubuki, Irish Cobbler, Kitamurasaki, and Toyoshiro starches, which have relatively small values for granule size, appear to be desirable for making Korean-style cold noodles. Obviously, the cold noodles made from wheat flour and potato starch blends exhibited di#erent textural properties among the Table -. Correlation coe$cients between chemical composition or median granule size and rheological properties for eight potato starches. Fig.,. Force-deformation curve of the cold noodles made from the mixture of wheat flour and Astarte starch.

5 282 T. NODA et al. Table.. Textural properties of Korean cold noodles made from wheat flour and potato starch blends. Table /. Correlation coe$cients between potato starch properties and textural properties of Korean cold noodles made from wheat flour and potato starch blends. potato starches examined. To learn how such variations occurred in terms of the characteristics of incorporated potato starch, the correlation coe$cients between the potato starch properties and textural properties of cold noodles were calculated (Table /). The quality parameters of potato starch were not significantly correlated with BF. The median granule size was significantly and negatively correlated with the BF/BD, while the correlation coe$cients of other quality parameters with the BF/ BD were insignificant. Characteristics of noodles made from potato starch Potato starch has unique characteristics, such as a high phosphorus content and viscosity as well as large granule size, and it has been used in the production of several types of noodles. Of these noodles, wheat flour-free starch noodles, which are also called glass noodles, transparent noodles, bihon, or harusame, are popular. Previous reports concluded that starch noodles made from potato starch are more suitable than those made from corn (Singh et al.,,**,) and edible bean (Kim et al., +330) starches with regard to their textural characteristics. In addition, more transparency has been observed in potato starch noodles than in other starch noodles (Kim and Wiesenborn, +330; Kim et al., +330). Singh et al. (,**,) compared the quality characteristics of starch noodles made from five potato starches and suggested that the higher the swelling power and gel firmness of the starch, the higher the noodle firmness. Chen et al. (,**-) reported, with the use of di#erent granule size fractions from potato and sweet potato starches, that the starch noodle quality is lower in large granule fractions than in small ones. In addition to starch noodles, instant noodles are generally manufactured from wheat flour and potato starch blends. Noda et al. (,**0b) demonstrated, using several potato starches, that instant noodles made from wheat flour with incorporated potato starch containing higher phosphorus contents and peak viscosities were harder, indicating a favorable texture. Quality index of cold noodles Korean-style cold noodles are also value-added products made from wheat flour and potato starch blends. There have been some reports on the texture attributes of cold noodles (Toyama et al., +331; Toyama and Taneya, +332, +333). In the study by Toyama et al. (+331), sweet potato, corn, and cassava starches were examined as a possible replacement of potato starch in the production of Korean-style cold noodles. They found that noodles supplemented with potato starch were firmer and more flexible than those supplemented with other starches. The present study provides new information indicating that potato starch with relatively small granules is well suited to the production of cold noodles with an elastic texture. Consequently, previous (Chen et al.,,**-) and present results concur that the starch granule size is an important factor in determining noodle quality. In contrast to the results of Singh et al. (,**,), starch gel firmness did not have any

6 E#ect of Potato Starch Properties on Noodle Properties 283 definite e#ects on firmness of the cold noodles in this study. Contrary to our previous data on instant noodles (Noda et al.,,**0b), the phosphorus content and peak viscosity, which are assumed to be important quality parameters of potato starch, did not have a significant correlation with the textural parameters of cold noodles. Conclusions In the present investigation, we separated starches from eight potato cultivars, each of which showed significant di#erences in physicochemical properties. Koreanstyle cold noodles made from mixtures of wheat flour and each one of the eight starches also showed significant differences in their rheological characteristics. Konafubuki, Irish Cobbler, Kitamurasaki, and Toyoshiro starches had relatively smaller granule size and seemed to be favorable for Korean-style cold noodle making. Data from this work suggested that the texture of cold noodles was improved by using potato starch with a small size. Acknowledgements This work was supported in part by a Grant in-aid for Research and Development Program for New-industry Initiative from Bio-oriented Technology Research Institution (BRAIN), Japan. We thank Mr. Zenta Nishio of the National Agricultural Research Center for the Hokkaido Region for permission to use the Sympatec HELOS Particle Size Analyzer. References Chen, Z., Schols, H.A. and Voragen, A.G. J. (,**-). Starch granule size strongly determines starch noodle processing and noodle quality. J. Food Sci., 02, +/2. +/23. Craig, S.A.S, Maningat, C.C., Seib, P.A. and Hoseney, R.C. (+323). Starch paste clarity. Cereal Chem., 00, ,. Hizukuri, S., Tabata, S. and Nikuni, Z. (+31*). Studies on starch phosphate: Part +. Estimation of glucose 0-phosphate residues in starch and the presence of tuber bound phosphate(s). Starch/Stärke,,,, Hopkins, S. and Gormley R. (,***). Rheological properties of pastes and gels made from starch separated from di#erent potato cultivars. Lebensm. Wiss. Technol., --, Ishida, N., Miura, H., Noda, T. and Yamauchi, H. (,**-). Mechanical properties of white salted noodles from near-isogenic wheat lines with di#erent wx protein-deficiency. Starch/Stärke, //, -3* -30. Jobling, S. (,**.). Improving starch for food and industrial applications. Current Opinion in Plant Biology, 1,,+*,+2. Kim, Y.S., Wiesenborn, D.P., Orr, P.H. and Grant, L.A. (+33/). Screening potato starch for novel properties using di#erential calorimetry. J. Food Sci., 0*, +*0* +*0/. Kim, Y.S. and Wiesenborn, D.P. (+330). Starch noodle quality as related to potato genotypes. J. Food Sci., 0+,,.2,/,. Kim, Y.S., Wiesenborn, D.P., Lorenzen, J.H. and Berglund, P. (+330). Suitability of edible bean and potato starches for starch noodles. Cereal Chem., 1-, -*, -*2. Hashimoto, N. and Yamauchi, H. (,**.a). Properties of starches from several potato varieties grown in Hokkaido. J. Appl. Glycosci., /+,,.+,.0. Saito, K., Mangalika, W.H.A., Hanaoka, A., Suzuki, Y. and Yamauchi, H. (,**.b). The e#ect of harvest dates on the starch properties in various potato cultivars. Food Chem., 20, ++3 +,/. Kim, S.-J., Hashimoto, N. and Yamauchi, H. (,**0a). Determination of the phosphorus content in potato starch using an energy-dispersive X-ray fluorescence method. Food Chem., 3/, 0-, 0-1. Kim, S.-J., Hashimoto, N. and Yamauchi, H. (,**0b). E#ect of potato starch properties on instant noodle quality in wheat flour and potato starch blends. Starch/Stärke, /2, +2,.. Singh, N., Singh, J. and Sodhi, N.S. (,**,). Morphological, thermal, rheological and noodle-making properties of potato and cornstarch. J. Sci. Food Agric., 2,, Singh, N., Singh, J., Kaur, L., Sodhi, N. S. and Gill, B.S. (,**-). Morphological, thermal, rheological properties of starches from di#erent botanical sources. Food Chem., 2+,,+3,-+. Tokimura, K., Shimozono, H., Ikeda, K. and Tanoue, H. (,**,). The retrogradation of starch gels and starch properties from various kinds of sweet potato starches. Oyo Toshitsu Kagaku,.3, -*/ -+, (in Japanese). Toyama, R., Miura, M.. and Taneya, S. (+331). E#ects of starch origin and contents on sensory properties of Reimen (Korean noodles). Nippon Chori Kagaku Kaishi, -*,,+-,,/ (in Japanese). Toyama, R. and Taneya, S. (+332). Influence of heating process after packing on physical properties of Reimen (Korean noodle). Nippon Shokuhin Kagaku Kogaku Kaishi,./,,,-,-+ (in Japanese). Toyama, R. and Taneya, S. (+332). Relationship between sensory evaluation and tensipresser analysis of Reimen (Korean noodle). Nippon Shokuhin Kagaku Kogaku Kaishi,.0, +// +0. (in Japanese). Wiesenborn, D.P., Orr, P.H., Casper, H.H. and Tacke, B.K. (+33.). Potato starch paste behavior as related to some physical/ chemical properties. J. Food Sci., /2,