Quality Characteristics Of Tofu Research Articles

표고버섯 분말을 첨가한 두부의 품질 특성

표고버섯 분말을 첨가한 두부의 품질 특성

Processing technology optimization for tofu curded by fermented yellow whey using response surface methodology.

The technological applications utilized for tofu processing are diverse and complex, resulting in different yields and quality characteristics of tofu. The current study investigated the gel‐forming principle of soybean protein coagulated using fermented yellow whey (FYW) to produce tofu. The effects of several processing parameters (soybean‐to‐water ratio, boiling temperature, boiling time, and FYW content) on the yield and protein content of tofu produced by the boiling‐to‐filtering method (BFM) were studied and optimized using response surface methodology. Results indicated significant differences in yield and protein content of tofu using different processing parameters, with FYW content being the most significant (p < .05). Optimum processing parameters of the BFM were found to be: soybean‐to‐water ratio of 1:5 (kg:kg), boiling time 6.1 min, boiling temperature 105°C, and FYW content of 26%. Under optimum conditions, tofu's yield and protein content were 235.17 g/100 g and 10.60%, respectively, and these were 47.93 g/100 g and 4.16% higher than those before optimization. This study provides practical technical support and a theoretical basis for the standardized industrial production of high‐yield and high‐protein tofu.

Physicochemical and Consumer Acceptance of Tofu Supplemented with Licorice Powder.

To develop functionally and nutritionally improved tofu, the effects of partial (0.2~0.8%) replacement with licorice powder (LP) on the quality characteristics of tofu were investigated. The pH and turbidity values decreased upon addition of increasing amounts of LP (P<0.05). The yield of LP-supplemented tofu was higher than that of the control tofu, and it increased as the concentration of LP increased (P<0.05). Substituting 0.6% and above of LP significantly hardened the texture of tofu (P<0.05) while control and 0.2~0.4% samples were not significantly different among them (P> 0.05). Lightness significantly decreased with higher LP content in the formulation (P<0.05), as indicated by visual observation that the color of tofu became darker. Redness and yellowness significantly increased (P<0.05). 2,2-Diphenyl-1-picrylhydrazyl and 2,2′-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid radical scavenging activities significantly increased (P<0.05) with higher substitution of LP, and they were well correlated. Tofu incorporated with LP (0.2~0.8%) had a better shelf life which was approximately 4.32~26.64 h longer than the control tofu at the elevated temperature of 15°C. Finally, consumer acceptance test revealed that supplementation of LP more than 0.4% had an adverse effect on general consumer acceptance. On the basis of the overall observations, tofu samples supplemented with 0.2% (w/w) LP were found to benefit from the functional properties of LP, without compromising consumer acceptance.

Changes in quality characteristics of tofu with freezing treatment of soybeans.

The aim of this study was to investigate the influence of length of freezing time (-18°C for 5 or 24 h) on the quality characteristics of tofu. The yield and moisture content of tofu obtained from frozen soybean were lower than control tofu. Tofu made from frozen soybeans showed higher hardness, gumminess and chewiness than the control. Freezing treatment also made the microstructure of the tofu more uniform than the control. However, after 24-h freezing, hardness decreased and the microstructure of tofu appeared to form pores. Sensory evaluation showed that mouth-feel decreased with an increase of freezing time. Among all of tofu frozen at -18°C, 5-h freezing treatment showed the highest overall acceptability. These results indicate that the length of time that soybeans are frozen before making tofu affects the quality of tofu.

초석잠 분말을 첨가한 두부의 항산화 활성 및 품질 특성

This study is conducted to investigate the effects of Chinese artichoke powder on the antioxidant activities and the quality characteristics of tofu. Tofus are being prepared with different amounts of Chinese artichoke powder in ratios of 0, 0.2, 0.4, 0.6 and 0.8% according to the soy milk quantity. According to the increasing contents of Chinese artichoke powder, the yield and turbidity of tofus are significantly increased (p<0.001) whereas the pH levels of tofus are significantly decreased (p<0.001). In terms of color, the L, a and b values are significantly decreased with increasing Chinese artichoke powder concentrations (p<0.001). From the texture profile analysis of the tofus, the chewiness, gumminess and cohesiveness of tofus are significantly decreased (p>0.01) according to the levels of added Chinese artichoke powder content. The contents of isoflavones such as daidzin and genistin are significantly increased with increasing concentrations of Chinese artichoke powder (p<0.001). The microstructure of tofus is being examined by SEM (Scanning Electron Microscope). In the sensory test, the sample which contains 0.4% of Chinese artichoke powder is ranked significantly higher (p>0.001) than the other groups according to several sensory parameters such as appearance, color, flavor, taste, texture and the overall preferences.

Effect of Sulfate- and Carbonyl- Polysaccharides on Quality Characteristics of Tofu

The effect of ι-carrageenan (ι-C) and soybean soluble polysaccharide (SSPS), on quality characteristics of tofu was evaluated. The addition of 0.05-0.2% (w/v) polysaccharide increased the yield of tofu. However, higher polysaccharide concentration could not sustain the observed increase. At temperature rise ramp, dG'/dt of tofu with SSPS was increased slightly than the samples with ι-C, due to difference in charge density and thermodynamic incompatibility between polysaccharide and soybean globulin. The addition of SSPS exhibited more increase in hardness and springiness of tofu as compared to ι-C. Microstructure of tofu with SSPS was more homogeneous. The addition of properly selected polysaccharide could improve the properties of tofu, which may be beneficial for food process

떫은감 분말의 첨가에 따른 두부의 제조와 품질 특성

떫은감(청도반시) 분말을 첨가한 두부 제조법을 개발하기 위하여, 감 분말의 첨가 시기(응고제 첨가 직전과 직후)와 양(0, 3, 6, 9%)을 달리하여 두부를 제조하여 품질 특성을 조사하였다. 감의 첨가 시기가 응고제 첨가 직전인 경우가 직후인 경우보다 높은 두부 수율과 좋은 관능적 품질특성(외관, 조직감, 전체적인 기호도)을 보였다. 두부의 수율은 감 첨가구가 무첨가구보다 높은 결과를 보였으나 첨가량에 따른 유의적인 차이는 보이지 않았다. 감의 첨가량이 증가함에 따라 L값은 감소하였으나 a값과 b값은 큰 변화 경향을 보이지 않았다. 두부의 hardness, chewiness, crispness는 감 분말 6% 이상 첨가구에서 유의적으로 높게 나타났다. DPPH 유리기 소거능은 감의 첨가량이 증가함에 따라 증가하는 경향을 보였지만 3%와 6% 사이에 유의적인 차이는 보이지 않았다. 관능적 품질특성 중 외관과 색은 첨가구가 보다 나쁘게 평가되었으나 냄새, 콩비린내, 떫은맛 및 조직감은 첨가량에 따른 유의적인 차이를 보이지 않았고 전체적인 기호도는 9% 첨가구가 유의적으로 낮은 점수를 보였다. 따라서 떫은감 분말을 첨가하여 두부를 제조할 경우, 적합한 첨가 시기와 양은 응고제 첨가직전과 3-6% 정도인 것으로 확인되었다. Quality characteristics of tofu as affected by addition time (before or after coagulant) and the amount (0, 3, 6, and 9%) of astringent persimmon fruit (Diospyros kaki T. cv. Cheongdobansi) powder added were investigated. Yield and sensory acceptability were higher in tofu prepared by adding persimmon before than after adding the coagulant. The yield of tofu with added persimmon was higher than that of the control. The L value of the tofu decreased as the amount of added persimmon increased. Hardness, chewiness, and crispness of tofu made with 6% persimmon were higher than those of the others. DPPH radical scavenging activity tended to increase as persimmon concentration increased but no significant difference was observed between the 3% and 6% added persimmon treatments. A sensory evaluation showed no significant differences in aroma, beany, astringency, and texture. However, the 9% sample had the significantly lowest score for overall acceptability. Thus, astringent persimmon powder (3-6%, before coagulant addition) can be utilized as an additive during tofu processing.

The Effect of Chitosan on the Rheological Properties of Soymilk and Quality Characteristics of Tofu

The effects of low viscosity chitosan on the rheological properties of soymilk using a model system and on tofu qualities were examined. The flow behavior of soymilk with chitosan closed the Newtonian flow and stabilized according to increasing chitosan concentration. The soymilk containing glucono-δ-lactone exhibited a more pseudoplastic flow behavior compared with that of the control soymilk. The addition of low viscosity chitosan to the tofu preparation did not significantly affect its physicochemical properties. However, the results of the TEM image and instrumental textural properties showed that low viscosity chitosan affected the construction of the tofu structure. Chitosan tofu had low scores across the whole field of appearance in the sensory evaluation, and its overall eating quality was scored significantly lower. These results suggest that the addition of low viscosity chitosan affects the quality of tofu, which changes according to the degree of polymerization and concentration of chitosan.

젖산칼슘을 응고제로 한 두부의 품질특성과 저장성

다슬기 분말과 그 회분으로 제조한 젖산칼슘인 CaL-P와 -A의 두부 응고제로의 이용성을 검토하기 위하여 염화칼슘(CC), 염화마그네슘(MC), 황산칼슘(CS) 및 표준품 젖산칼슘(CaL-S)과의 응고력, 수율, 색상, 텍스쳐, 칼슘함량, 미세구조 및 관능적 특성을 상호 비교하였으며 저장중의 총균수와 침지액의 탁도변화를 살펴보았다. 응고력은 CaL-A가 가장 우수하였으며 CaL-P의 경우도 CaL-S보다 높았다. CaLA 두부의 수율은 CC 두부의 110%로 CS와 대등하였으나 CaL-P 두부의 수율은 CC의 50% 수준으로 낮았다. 응고제에 따른 두부의 색상은 뚜렷한 차이를 보이지 않았으나 CaL-P 두부는 L^*값이 낮은 반면 a^*, b^*값이 높았다. 두부의 견고성은 CaL-S>CS>CC>CaL-P>MC>CaL-A 순, 응집성은 MC>CaL-S>CC>CS>CaL-P>CaL-A 순을 나타내었으며, 탄력성은 MC가 가장 높았다. 두부의 칼슘함량은 116.12~204.48㎎/100 g이었으나 MC 두부는 57.1 ㎎으로 낮았다. 두부의 미세구조는 견고도가 낮고 부드러울수록 입자가 작고 균일하였는데 CaL-A와 MC 두부가 대체적으로 작고 균일하였으며 CaL-P는 CC와 같이 불규칙하였다. CaL-P와 CaL-A 두부는 타 두부에 비하여 질감, 탄력성, 풍미가 좋고 종합적인 맛이 우수하였으며 CaL-A의 경우는 견고성이 낮아 부드러운 맛이 높았다. 총 균수로 평가한 10℃에서의 shelf-life는 타 응고제를 사용한 경우 4~6일을 나타내었으나 CaL-P는 8일로 연장되었다. 탁도도 CaL-P의 경우가 가장 낮았다. 이상의 결과 CaL-P와 -A는 두부의 품질을 높일 수 있음과 동시에 체내 흡수력이 높은 칼슘을 공급할 수 있어 산업적으로 많이 사용하고 있는 칼슘의 체내 이용율이 낮은 CS를 대체할 수 있는 두부 응고제로 바람직한 것으로 평가되었다.

Studies on the Yield and Quality Characteristics of Tofu

ABSTRACTTofu made from imported U.S. soybeans and local Ta‐Lien soybeans showed a similar yield. The yield of tofu from whole soybean was higher than that of defatted soybean flake. Significant different qualities of tofu products were prepared by using various coagulants. It was found that calcium sulfate (gypsum) and bittern (called nigari in Japanese) were suitable coagulants for making the Chinese‐style tofu, but not glucono‐δ‐lactone. Other coagulants were not desirable for manufacturing good quality Chinese‐style tofu. Commercial tofu products in Taiwan had various rheological properties.