This study aimed to establish the optimal conditions for producing gluten-free noodles by varying the amount of pregelatinized rice flour added to the regular rice flour and investigating their quality characteristics. With an increase in the amount of added pregelatinized rice flour, the brightness of the noodles decreased, and the color became more yellow both before and after cooking. Adding pregelatinized rice flour to the noodles also increased hardness, elasticity, chewiness, stickiness, and adhesiveness. The textures of the two groups of samples (PR-10 and PR-15) were similar to that of the control, indicating comparable structural characteristics. Furthermore, the absence of gluten made it inherently challenging to form gluten-free noodles. Still, adding pregelatinized rice flour improved the processability of the dough, leading to better noodle formation. An optimal addition of 15% pregelatinized rice flour was deemed suitable for optimal noodle formation in gluten-free noodles. This study established blending conditions using pregelatinized rice flour to improve the poor processability of gluten-free noodles. The findings are expected to be valuable for the industry’s future development of gluten-free processed food.

A rapid analytical method was developed and optimized to determine gluten content in bread. Existing gluten quantification methods were inappropriate for bread with high gluten content because they were optimized to analyze shallow gluten content. To overcome this problem, the first method of quantifying the gluten content in bread was developed by modifying the gluten analysis method in cereal grains. Heat-stable gliadin was selectively quantified for gluten quantification using high-performance liquid chromatography (HPLC), and gliadin peaks were separated using an Agilent SB-C8 column. The specificity, linearity, accuracy, precision, limit of detection (LOD), and limit of quantification (LOQ) were measured for validation. The calibration curve of gliadin had high linearity (R2 = 0.9996), and LOD and LOQ were 0.03 and 0.10 g/100 g, respectively. The relative standard deviation (RSD) values of intra- and inter-day precision were less than 2.49% and 1.54%, respectively. Recovery ranged from 90.73% to 93.87%, with RSD values less than 2.06%. These results indicate that the HPLC method for quantifying gluten in bakery products is efficient, reliable, and reproducible.

빵의 소비가 증가함에 따라 제빵 성능을 향상시킬 수 있는 기술은 제빵 산업에서 중요한 주제가 되고 있다. 활성글루텐(vital gluten)은 밀가루에 물을 첨가하여 전분을 제거한 후 글루텐만을 건조시킨 단백질이다. 품질이 낮은 밀가루에 활성글루텐을 첨가하면 반죽에 탄성과 신장성을 부여하여 제빵성능을 향상할 수 있다. 현재 제빵 산업에서 활성글루텐이 많이 활용되고 있지만 이들의 화학적, 물리화학적 특성 및 품질 평가에 필요한 품질 파라미터들에 대해 이해가 부족한 실정이다. 본 총설에서는, 활성글루텐의 품질을 예측하기 위한 파라미터의 이해를 돕기 위하여 밀 글루텐 단백질의 종류와 역할, 밀 반죽에서 형성되는 글루텐 네트워크, 밀가루 품질에 영향을 미치는 요인, 활성글루텐의 제조공정, 활성글루텐의 품질에 영향을 미치는 요인, 마지막으로 활성글루텐의 물리적 특성을 효과적으로 평가할 수 있는 글루토피크(Glutopeak)에 대해 설명하고자 한다. 본 총설을 통해 반죽 리올로지 특성과 제빵 성능에 영향을 미치는 활성글루텐의 품질 파라미터를 이해하고, 제빵 산업에서 활용할 수 있도록 도움이 되길 기대한다.

The demands of rice products have been steadily increasing because of their non-allergenic-functionalities. However, the use of rice flour in the gluten-free food industry has been still limited due to undesirable quality characteristics derived from the weak structural network by the lack of gluten. Therefore, there is a need to search for new approaches to enhance the structural network of gluten-free foods. In this study, zein, protein derived from corn, was applied to rice noodles as a structural network provider for sheeting and the rheological and structural properties of the rice noodles were investigated depending on the particle size of rice flour. The starch damage of the rice flours increased with decreasing particle size. The zein-rice flours with smaller particle size exhibited greater water hydration properties and pasting parameters that contributed to the increased elastic characteristics. The use of zein positively contributed to the formation of sheeted rice dough that could be successfully slit into noodle strips. The zein-rice noodles with medium particle size (100–150 mesh) had the highest breaking stress and hardness values that were correlated to the lowest cooking loss. This study thus provides a new opportunity for food industry to improve the qualities of gluten-free rice noodles by controlling particle size.

Baking characteristics of gluten-free rice bread were investigated, when 20, 30, 40, 50 and 60℃ water was added during mixing. The temperature of the dough before fermentation was affected by the temperature of the water and the mixing time. When 60℃ water was added, the specific gravity of the dough was the highest before fermentation (p<0.01). The specific gravity of the dough after fermentation was 32~39% of the specific gravity of the dough before fermentation. When 50℃ water was added, the volume and the specific volume of rice bread were higher than those in addition of water at other temperatures (p<0.001). In case of adding water of 50℃, the shape of the rice bread showed the largest volume, high appearance and a round shape. After storage for 2 and 24 hours, the addition of water of 50℃ resulted in the lowest hardness and chewiness values of rice bread. The sensory descriptive analysis revealed that when 50℃ water was added, the air cell size, springiness and hardness values of gluten-free rice bread were lower than those in addition of water at other temperatures. There was a difference in the appearance and texture of gluten-free rice bread, when 20, 30, 40, 50 and 60℃ water was added during mixing.

Gluten-free industry has experienced consistent growth with increasing the number of individuals with celiac disease. Among gluten-free products, the popularity of rice noodles has been worldwide increasing over the recent years. However, rice noodles have several processing limitations such as high cooking turbidity and long cooking time. Therefore, various ingredients have been incorporated into the formulation of rice noodles in order to improve their quality attributes. In this study, turanose which is known to be a new sugar alternative with low sweetness was applied to rice noodles and their effects were characterized in terms of thermal, rheological, and textural properties. Gluten-free rice noodles were prepared with different levels of turanose (0.5, 1.0, 1.5%, w/w) by using a twin-screw extruder. Rice flour with turanose had higher gelatinization temperature and also showed higher enthalpy values after storage at 4°C. The use of turanose also increased the pasting and mixing parameters of rice flour. In addition, the application of turanose to rice noodles affected their qualities such as texture and cooking loss. Thus, this study demonstrated that turanose could positively contribute to enhancing the qualities of gluten-free rice noodles as a new additive.

As the consumption of wheat has increased recently, the number of people who have digestive problems resulting from gluten in wheat has also increased. Teff has an attractive nutritional profile, as it not only gluten-free but also high in dietary fiber, protein, iron, and calcium. Seven samples were prepared for this study. The quality characteristics of gluten-free noodles were evaluated based on pH, salinity, water absorption, turbidity, color, texture properties, tensile strength, and SEM. The pH value was the highest in TF100 with a pH of 6.66 and the lowest in the control with a pH of 6.42. Salinity showed no significant difference among all samples, and it ranged from 0.02~0.04% (p<0.05). Water absorption was the highest in TFX with a value of 66.11%, and the lowest in the control with a value of 44.81%. Turbidity showed no significant difference among all samples, and it ranged from 0.14~0.21 O.D. (p<0.05). While the lightness and yellowness values decreased with an increase in teff flour content, the redness value tended to decrease. The color difference value was the highest in the sample group without gluten. Based on the texture profile analysis, the hardness was highest in the control with a value of 46.74 N and lowest in TF100 with a value of 18.34 N. The springiness showed no significant difference among all samples. The cohesiveness was highest in the control with a value of 0.92 N. The chewiness decreased with an increase in teff flour content. Although the control with gluten had the highest tensile strength at 3.42 kg/cm2, TFX had considerable tensile strength at 2.30 kg/cm2. This study demonstrated the processability of gluten-free noodles using teff flour.

This study investigated the quality characteristics and antioxidant activities of gluten-free cookies containing teff flour. By substituting 0% (control), 25% (TF25), 50% (TF50), 75% (TF75), and 100% (TF100) of wheat flour with teff flour, five samples were produced. Baking loss rate was the highest in TF25 at 13.76% and the lowest in TF75 at 4.03%. Spread factor was significantly higher in cookies made with teff flour (83.00~85.00) than in the control (81.33) (p<0.05). There was no significant difference in density among the samples at 1.17~1.25 g/mL (p<0.05); however, pH significantly decreased at 6.42~6.04 (p<0.05). While the L-value and b-value significantly decreased with the amount of teff flour, the a-value significantly increased (p<0.05). The ΔE value was the highest in the control at 31.31 and the lowest in TF100 at 58.69. Hardness was the highest in the control at 42.04 N than in cookies containing teff flour. The content of polyphenols was the highest in TF100 at 3.37 μg GAE/mg and the lowest in the control at 1.32 μg GAE/mg. The content of flavonoids was the highest in TF100 at 3.66 μg QE/mg and the lowest in controls at 0.45 μg QE/mg. The value of DPPH IC50 was the highest in the control at 3,723.00 μg/mL and the lowest in TF 100 at 405.27 μg/mL. The value of ABTS IC50 was the highest in the control at 1,822.32 μg/mL and the lowest in TF100 at 529.30 μg/mL. In sensory evaluation, while control, TF75, and TF100 had a higher score in appearance at 5.52~5.60, all samples had no significant differences in flavor, sweetness, savory taste, chewiness, and overall acceptability (p<0.05). These results showed that the gluten-free cookies containing teff flour can improve the quality characteristics and antioxidant activities of a cookie. We concluded that gluten-free cookies containing 100% teff flour are desirable.

The physical characteristics of gluten-free rice bread, commercial rice as well as wheat bread marketed in Korea were delineated, a sensory descriptive analysis performed, and a consumer acceptability study conducted. Both the specific gravity and color of gluten-free rice bread were higher than those of commercial rice and wheat bread. The sensory descriptive analysis revealed that the adhesiveness, fracturability, fermentation odor, and the powdery mouthfeel of gluten-free rice bread were higher than those of commercial rice and wheat bread. In contrast, the sweet odor, sweetness, egg taste, butter taste, and milk taste of gluten-free rice bread were lower than those of commercial rice and wheat bread. The consumer acceptability results revealed differences regarding odor, appearance, taste, texture, and overall acceptance between a blind test and an informed test of gluten-free rice bread, commercial rice, and wheat bread. The consumer acceptability findings were associated with those of the sensory descriptive analysis. In overall, the results indicated that the quality of gluten-free rice bread can be improved by controlling the decrease of adhesiveness, fracturability, and powdery mouthfeel.

This study investigated the effects of the mixing ratio of tofu paste and normal corn starch on the characteristics of gluten-free (GF) muffins. Soft wheat flour for wheat flour-based muffins (control) was replaced with the mixture of tofu paste and normal corn starch (NCS). The mixing ratios of tofu paste and NCS were 1:6.4 (S100), 1:5.1 (S80), 1:3.8 (S60), 1:2.6 (S40), 1:1.3 (S20), and 1:0 (S00), based on their total solid contents. GF muffins of S40- S100 developed the porous, sponge-like structure without crumb collapse. The weight and baking loss did not significantly differ in the control and GF muffins. By decreasing NCS in GF muffin batters, the moisture content, firmness, and crumb redness/yellowness of GF muffins increased, while their volume, specific volume, and crumb lightness decreased. Nevertheless, these characteristics (except for firmness) of S100 were much closer to those of the control. In the preference test, however, S60 (possessing lower attributes than S100 and S80) was most favored among GF muffins, and was very similar in all evaluations (except for appearance) to the control. Overall, the mixture of tofu paste and NCS would be a potential material to replace soft wheat flour in muffins.