Application of near-infrared spectroscopy to predict sweetpotato starch thermal properties and noodle quality

Sweetpotato starch thermal properties and its noodle quality were analyzed using a rapid predictive method based on near-infrared spectroscopy （NIRS）. This method was established based on a total of 93 sweetpotato genotypes with diverse genetic background. Starch samples were scanned by NIRS and analyzed for quality properties by reference methods. Results of statistical modelling indicated that NIRS was reasonably accurate in predicting gelatinization onset temperature （To） （standard error of prediction SEP=2.014 ℃, coefficient of determination RSQ=0.85）, gelatinization peak temperature （Tp） （SEP=-1.371 ℃, RSQ=0.89）, gelatinization temperature range （Tr） （SEP=2.234 ℃, RSQ=0.86）, and cooling resistance （CR） （SEP=0.528, RSQ=0.89）. Gelatinization completion temperature （To）, enthalpy of gelatinization （△H）, cooling loss （CL） and swelling degree （SWD）, were modelled less well with RSQ between 0.63 and 0.84. The present results suggested that the NIRS based method was sufficiently accurate and practical for routine analysis of sweetpotato starch and its noodle quality.

Effect of wheat bran insoluble dietary fiber with different particle size on the texture properties, protein secondary structure, and microstructure of noodles

This study was conducted to explore how the insoluble dietary fiber(IDF)of wheat bran with different particle size affects the texture properties,water distribution,protein secondary structure and microstructure of noodles.The results suggested that IDF addition increased the cooking loss and decreased the sensory evaluation because of the damage on dough structure,while as the IDF particle size decreased,the sensory score increased from 78.8 to 82.3 and cooking loss decreased from 8.65%to 7.65%,which could be attributed to that small particle-sized IDF limited the damage on protein network structure,decreased the T22 and t-structure,and increased the β1-structure.Moreover,IDF particle size had a significant correlation with protein secondary structures,texture properties and evaluation score of noodles.In conclusion,adding appropriate particle sizewould be an effectiveway of enhancing the nutritional and textural properties of noodles.

Swelling Index of Glutenin (SIG) Related to Protein Quality, DoughCharacters and Noodle Quality

The swelling index of glutenin (SIG) and the protein fraction of 25 Chinese wheat varieties were studied with new protein fractions extracting method. The protein fractions compose of monomeric protein, soluble glutenin and insoluble glutenin. The relations between other protein index, dough character, and fresh noodle quality were also discussed. The SIG results at different time is positively and highly significantly related to the insoluble glutenin content (r= 0.808 -0.867, P< 0.01). The SIG result can reflect the insoluble glutenin content. The protein content, gluten index, farinograph stability time, extensibility length and extensigram energy were positively and significantly correlated with SIG5 and SIG20 (r= 0.516 - 0.734, P<0.05, 0.01).SIG proved to be applicable in Chinese wheat dough evaluation. Fresh noodle making quality parameters were evaluated by fresh noodle length, thickness, maximum resistance to extension, extension area and extension distance, while cooked noodle texture was determined by cutting firmness, compression recovery, surface firmness and TPA by using a texture analyzer of TA.XT2i. The noodle cooking quality was significantly correlated with SIG value. The surface firmness and cutting firmness were more desirable for predicating the quality difference than TPA test and compression. Cooking loss and water absorption were negatively related to SIG value and insoluble content (r = -0.556 - - 0.787, P < 0.05, 0.01). The results showed that SIG test was also suitable in evaluating noodle making and cooking quality in very small sample size, which was very important in wheat breeding programs. Therefore, SIG test, as a small scale test, is suitable to evaluate dough rheological properties for Chinese wheat varieties, and will be helpful in cereal research and wheat breeding program, especially, in early generations.

Investigation on Pasting Characteristics of Spring-sown Chinese Bread Wheats

Forty-seven spring wheat Triticumaestivum cultivars and advanced lines from spring-sown spring wheat regions, at twelve locations in 1998 and 1999, were used to investigate pasting properties of Chinese spring wheats. Starch pasting properties were closely associated with noodle quality. Significant differences were observed for all pasting characteristics. Samples collected from Harbin, Shenyang, Beijing, Ba-meng, Yongning, and Urumqi had better pasting quality than those from other locations. Genotype, environment, and genotype by environment interaction had large effects on all pasting characteristics. Significant correlations among pasting characteristics were observed and peak viscosity was considered the most important pasting characteristics.

Investigation on Paste Property of Chinese Bread Wheat Varieties

Starch viscosity is closely associated with noodle quality. RVA(rapid viscosity analyzer) was used to investigate the paste property of leading Chinese wheat varieties arid 38 Australian wheat lines. Results showed that significant variability for RVA parameters was observed among Chinese wheat varieties, particularly among spring wheat varieties. In general, Australia wheat lines performed better paste characters than that of Chinese winter wheats. Genotype (G), environment (E) and genotype by environment (G×E) interaction affected all paste traits. Correlation analysis indicated that peak viscosity correlated highly and significantly with viscosity, breakdown, setback, final viscosity, peak time, and falling number(r = 0.56-0.93, P<0.01). However breakdown was not significantly associated with most paste properties. Paste characters increased from low to high latitude both in the north and south part of Yellow and Huai Valley.

Performance of industrial dough mixers and its effects on noodle quality

The effects of different types of industrialized dough mixing units on the characteristics of noodle dough and noodle quality were investigated.The study involved four mixing units,including two horizontal mixers with double shafts and two continuous high-speed mixers.Of the four mixing modes,mixing mode I,which used a horizontal pin-mixer with a constant mixing speed,provided the worst performance.This finding was indicated by worse mixing uniformity and noodle quality,larger-sized dough crumbs,lower hardness and chewiness of cooked noodles,and lower sensory scores of both color and elasticity.Mixing mode II,which used a horizontal mixer with angled,large surface-area blades and adjustable-speed mixing,gave the best performance.The flour hydration was observed to be even,and smaller even-sized dough crumbs were formed.During boiling of the dried noodles,there was lower water uptake,less cooking loss,and the cooked noodles showed better stickiness scores with higher hardness and chewiness of TPA compared to the other mixing modes.Mixing mode III involved a vertical continuous high-speed mixer with a speed of 970 r/min and had better mixing uniformity compared to mixing mode IV,which involved a horizontal high-speed mixer and a higher mixing speed of 1440 r/min.No single mixer performed best over all three flours.Therefore,the final choice of mixing modes should be based on the major flour type used by the noodle manufacturer.