Properties Of Tofu Research Articles

Effects of Organic Acid Coagulants on the Textural and Physical–Chemical Properties of Tofu

Tofu is obtained by heating soymilk, to which a coagulant, such as calcium sulfate or magnesium chloride, is added to make it curdle. This study aimed to parameterize the effects of the following three alternative organic coagulant types: apple, rice, and white vinegars, used in different proportions. Six treatments were established with three concentrations (1%, 3%, and 5%), evaluating the coagulation time and curd yield. The treatments with the lowest coagulation time were analyzed for texture by TPA, color through the CIEL*a*b scale, protein content, and moisture. The results showed that the rice vinegar + 3% white vinegar (T6C3) treatment showed the lowest coagulation time (0.78 min). The 5% apple vinegar (T1C5) treatment provided the highest curd yield, averaging 23.73%. This treatment’s protein and moisture contents were 3.93% protein and 69.73% moisture, confirming that better texture characteristics are recorded in tofu at lower pH values. The TPA results showed that using apple and rice vinegars as coagulants provided a challenging, less cohesive, more adhesive, and less elastic tofu. White vinegar provided a soft, more cohesive, less adhesive, and more elastic tofu. In the color analysis, it was observed that tofu coagulated with apple vinegar showed a tendency toward a yellow color, and tofu coagulated with rice and white vinegars showed a tendency toward a white color. These findings parameterize the effects of using each type of vinegar as a coagulant. These organic coagulants provide faster coagulation times and desirable texture characteristics, thus offering a practical alternative to traditional coagulants in tofu manufacturing.

Characterization and in vitro digestibility of soybean tofu: Influence of the different kinds of coagulant

This study explored the effect of diverse coagulants (glucono-δ-lactone (GDL), gypsum (GYP), microbial transglutaminase (MTGase), and white vinegar (WVG)) on microstructure, quality, and digestion properties of tofu. The four kinds of tofu were significantly different in their structure, composition, and digestibility. Tofu coagulated with MTGase had the highest springiness and cohesiveness while GDL tofu had the highest enthalpy (6.54 J/g). However, the WVG and GYP groups outperformed others in terms of thermodynamic, and digestion properties. The WVG group exhibited the highest nitrogen release (84.3%), water content, denaturation temperature, and the highest free-SH content but the lowest S-S content. Compared to WVG, the GYP group had the highest ash content, hardness, and chewiness. Results demonstrated that the tofu prepared by WVG and GYP show high digestibility. Meanwhile, the former has better thermal properties and the latter has better texture properties.

Improving Gelling Properties of Tofu: Study on ApnA Aspartic Protease Enzyme Impact on the Resulting Chemical and Microstructure Properties

Improving Gelling Properties of Tofu: Study on ApnA Aspartic Protease Enzyme Impact on the Resulting Chemical and Microstructure Properties

Influence of mealworms (Tenebrio molitor larvae) and their protein derivatives on the structural and rheological properties of tofu

This study investigates the effects of incorporating mealworms into tofu, regarding its structural and rheological properties. Tofu samples were prepared using only soybean flour (S), or by replacing soybean flour with mealworms (M), mealworm protein isolate (MPI), or mealworm protein hydrolysate (MPH) at a 1:1 ratio (SM, SMPI, and SMPH, respectively). Results revealed that S partial substitution with M, MPI, and MPH affected the particle size, polydispersity index, and zeta potential of soymilk. Intrinsic fluorescence and surface hydrophobicity showed the early formation of large aggregates in SMPI. As for tofu, gelation of SM mainly occurred due to soybean protein-protein interactions, suggesting that M can prevent gelation, as evidenced by the SDS-PAGE and ATR-FTIR patterns. SMPI had the highest ionic bonds, hydrogen bonds, and hydrophobic interaction content, whereas S had the highest SS bond content. Furthermore, SMPH, enriched with small molecules, exhibited the highest proportion of random coil and disrupted amide bands, leading to limited protein-protein interactions. Finally, apparent viscosity of soymilk, temperature sweep during tofu preparation, frequency sweep, and microstructure analyses of tofu indicated that MPI contributed to hardness (927.9 g/cm2) and gel-like properties, while M and MPH led to softer (135.0 g/cm2 and 32.0 g/cm2, respectively) and more liquid-like tofu compared to S (504.3 g/cm2). In conclusion, this study provides insights into selecting mealworm derivatives with varying structural and rheological properties, enhancing their applicability in gel-type food systems.

The Effects of Okara Ratio and Particle Size on the Physical Properties and Consumer Acceptance of Tofu.

Okara, the solid byproduct of soymilk production, poses a sustainability concern, despite being rich in fiber and other healthful compounds. In this study, the physical properties of tofu made from soymilk fortified with differing levels of okara-either whole or fine (<180 µm)-and made with the traditional coagulant nigari were examined. The yield increased linearly with the okara concentration with values of 18.2-29.5% compared to 14.5% for the control. The initial moisture in the fortified samples was higher than the control (79.69-82.78% versus 76.78%), and both the expressible moisture and total moisture after compression were also greater in the fortified samples. With a few exceptions, the texture parameters did not differ between samples. Dynamic rheology showed that all samples had G' > G″. The storage moduli increased at different rates during each gelling step, with G' before and after gelling increasing with the fortification level, and was greater for the samples with fine particles than with whole particles. Consumer sensory panels using the hedonic scale showed traditional tofu had a slightly higher acceptability, but the panelists indicated they would be more willing to purchase okara-fortified tofu because of the health and sustainability benefits it might have. Thus, tofu could be produced with added okara with predictable but not profound changes in its physical properties.

Conjugation of soymilk protein and arabinoxylan induced by peroxidase to improve the gel properties of tofu

Arabinoxylan (AX) can form stable covalent bonds with protein to improve gel properties. We aimed to prepare a conjugate between soymilk protein (SMP) and AX by peroxidase, followed by the addition of transglutaminase (TG) to prepare tofu gels. The conjugate’s properties and their effects on the mechanical properties, rheological properties, and microstructure of tofu gels were evaluated. Results revealed that the α-helix content decreased, the β-sheet content increased, and the surface hydrophobicity reduced from 1.60 × 105 to 1.27 × 105. The optimal amount of AX required to improve the properties of tofu gel was 1.0%. The tofu gel showed better hardness (118.44 g), water holding capacity (WHC) (86.17%), and higher storage modulus (G′) and loss modulus (G″). Low-Field NMR (LF-NMR) showed that the water was evenly distributed. Scanning electron microscopy (SEM) revealed a denser and more regular three-dimensional gel network.

Experimental investigation of the characteristic of vacuum spray cooling for tofu

The present study proposes a rapid cooling method based on vacuum spray cooling, and establishes an experimental system to study the cooling performance of this method by taking tofu as an example. In this study, the effects of vacuum spray cooling, vacuum cooling and immersion vacuum cooling on the cooling rate, water holding rate, PH, TPA and other properties of tofu were compared. The total cooling time of vacuum spray cooling (13.86 min) was shorter than that of immersion vacuum cooling (33.39 min) but longer than that of vacuum cooling (10.64 min) for a temperature decrease from 70°C to 4°C. For weight loss from 70°C to 4°C, vacuum spray cooling (2.96%) was significantly less than that of vacuum cooling (10.21%). The PH value after cooling has no significant difference, but the color difference and water holding capacity of the sample after vacuum spray cooling are obviously better. However, the textural properties of the sample cooled by vacuum spray cooling were close to (for elasticity and viscosity) and better (for hardness and chewiness) than those of immersion vacuum cooling. In addition, compared with the two cooling methods in terms of storage, vacuum spray cooling can effectively maintain the moisture content, water holding rate, PH, chromatism and TPA of tofu, thus extending the fresh-keeping period of tofu. The conclusions of this paper provide theoretical support for prolonging the preservation period of food and optimizing the cooling process.

The Impact of Processing Methods and Conditions on Nutritional Properties of Soybean-Based Tofu: A Review

The soybean seed is used for the preparation of protein rich tofu. Along with protein, it is also rich in many other nutrients including carbohydrate, crude fibre, carbohydrate, fat, minerals, and isoflavones. Antinutrients are also present in tofu, although the concentration is less that the raw grains. The nutrient content is affected by the tofu preparation method used starting from selection of suitable soybean seed, seed soaking, sprouting, soymilk production and coagulation using different types of natural and artificial coagulants. These procedures also affect the textural properties of the tofu and their shelf life.

Effect of Coagulant and Treatment Conditions on the Gelation and Textural Properties of Acidic Whey Tofu.

This study aimed to investigate the properties of acidic whey tofu gelatin generated from two acidic whey coagulants by pure fermentation of Lactiplantibacillus paracasei and L. plantarum, as well as the characteristics of acidic whey tofu. The optimal holding temperature and the amount of coagulants added were determined based on the pH, water-holding capacity, texture, microstructure, and rheological properties of tofu gelation. Then, the differences in quality between tofu produced by pure bacterial fermentation and by natural fermentation were investigated under optimal tofu gelatin preparation conditions. The tofu gelatin presented the best texture at 37 °C with a 10% addition of coagulants fermented by both L. paracasei and L. plantarum. Under these conditions, the coagulant produced by the fermentation of L. plantarum resulted in a shorter formation time and stronger tofu gelatin compared with that produced from L. paracasei. Tofu produced by the fermentation of L. paracasei had higher pH, less hardness, and a rougher network structure, whereas tofu produced by the fermentation of L. plantarum was closer to tofu produced by natural fermentation in terms of pH, texture, rheology, and microstructure.

Gelation properties of tofu induced by different coagulants: Effects of molecular interactions between nano-sized okara dietary fiber and soybean proteins

Gelation of soybean proteins with different coagulates as affected by okara nano-sized dietary fiber (NDF) were investigated. As compared with the MgCl2 tofu, the tofu induced by glocono-δ-lactone was softer with higher moisture and denser microstructure. As the volumetric ratio of NDF increased, pH, viscosity, particle size, and zeta potential of the NDF soymilk steadily increased. Regardless of coagulate type, tofu proteins’ prevalence of α-helix + β-turn increased with the NDF ratio up to 40 % while β-sheet + random coil decreased. At the same time, intermolecular interactions (predominate hydrophobic interaction) significantly decreased, leading to form more porous structures in the two types of tofu. Accordingly, yield and moisture of tofu increased gradually with the NDF ratio, water holding capacity increased and then decreased, hardness decreased continuously. Results suggested that NDF affected the secondary structure and intermolecular interactions of soymilk proteins, which was independent of coagulate.

Effect of Transglutaminase Pre-Crosslinking Treatment Incorporated with Glucono-δ-lactone on the Physicochemical and Digestive Properties of Tofu.

This study evaluated the effect of transglutaminase (TGase) pre-crosslinking treatment on the physicochemical and digestive characteristics of tofu coagulated by glucono-δ-lactone (GDL). Results showed that certain TGase pre-crosslinking times (0.5, 1, 2 and 3 h) could promote the colloidal stability of soymilk with increased particle average sizes and absolute values of zeta potential. Particularly, the water holding capacity and gel strength of tofu pre-crosslinked by TGase for 2 h were 6.8% and 47.7% enhancement, respectively, compared to the control, and exhibited the highest score of overall acceptability. However, extensive pre-crosslinking by TGase for 3 h had an adverse impact on the sensory of tofu with poor firmness, rough structure and whey separation. Hence, the tofu gel pre-crosslinked by TGase for 2 h and then coagulated by GDL was recommended which showed a “slow release” mode of soluble proteins during the in vitro digestion phase, and had more chances to release bioactive peptides than soymilk.

Evaluation of optical properties of tofu samples produced with different coagulation temperatures and times using near-infrared transmission spectroscopy

To investigate the feasibility of using near-infrared (NIR) spectroscopy to evaluate the coagulation extent of tofu, the optical properties of tofu samples obtained with different coagulation temperatures and times were measured in the wavelength range 1300–1800 nm. The apparent absorbance was measured using the NIR transmission spectrum, and then divided into absorption and scattering components by curve fitting. The apparent absorbance increased over the entire wavelength range as the coagulation temperature increased, in which the scattering increase was dominant over that of the absorption. The viscosity was measured as an index of the physical properties of tofu, which increased with the coagulation temperature and had a high correlation (R2 = 0.803) with one of the fitting parameters of the scattering. The microstructure of the tofu became finer as the coagulation temperature increased, which suggests that the increase in scattering might be due to changes in the microstructure. Furthermore, the light scattering increased with the coagulation time as well as with the coagulation temperature. The increase in scattering with the coagulation time followed the first-order reaction kinetics. Both scattering intensity and increase speed were larger at shorter wavelengths. This can be explained by the theory of Mie scattering and multiple scattering, indicating that scattering measurements at shorter wavelengths are useful for monitoring of coagulation. Thus, light scattering measurements using NIR spectroscopy are promising for investigating the physical properties of tofu.

Properties of tofu coagulated with Cardoon flower (Cynara Cardunculus L.)

Tofu was elaborated using water-soluble extract of soybean grains from the cultivar BRS 267 with cardoon flower (C. Cardunculus L.), as coagulant as an alternative to the traditional coagulant magnesium chloride. The tofu were evaluated in relation to physical, chemical, microbiological and sensory properties during 14 days. Was obsersed for the tofu coagulated with cardoon flower that the moisture, pH, total mineral, protein, and syneresis decreased with the storage, while Kunitz Trypsin Inhibitor, ureatic activity and phytic acid did not change. It was also obtained a positive effect for color (L*, a*) parameters, phytic acid, yield, syneresis, and acceptance. The textural properties, showed a tendency to increase of hardness and stickiness, while springiness and cohesiveness decreased during storage. Structurally, presented irregular-shaped, small pores or cavities. The sensory analysis, showed has great acceptance and purchase intent. Then, the cardoon flower can be used as vegetal coagulant improving the quality properties of tofu, in relation to magnesium chloride.

Effect of Partial Replacement of Soybean with Chickpea to the Nutritional and Textural Properties of Tofu

&#x0D; Abstract— Tofu is an oriental food that originated from China and later became a traditional cuisine in many South East Asia Countries, e.g. Indonesia, Singapore, and Thailand. The tofu was made by coagulating soy milk with salt to form curds, which further compress to form a solid block. Tofu usually uses soybeans as the main ingredients; however, in this experiment, the soybeans were partially replaced with chickpeas to increase the amount of dietary fibre and reduce fat levels in the final products. The tofu was made of soybean and chickpea at a ratio of 100:0 (control), 90:10, 80:20 and, 70:30. The products were evaluated based on their nutritional contents (crude protein, crude fat, and crude fibre), and textural properties using Texture Profile Analysis. Some analytical parameters, such as pH, moisture content, and colour were also studied. Partial replacement of soybean with chickpea decreased overall crude protein and fat content, whereas increased crude fibre. The presence of chickpea in the blends, up to 30% (w/w), had affected the tofu curd's protein stability, lowered their pH, and moisture content. A denser tofu curd was obtained by adding more chickpea to the product. The 70:30 blend has the highest hardness value compared to the other formulations. This low soy content mixture, however, can not produce a cohesive and springy tofu gel. The CIELAB colour space of the soybean/chickpea tofu cubes records a trend of increase in redness and yellowness values for tofu with chickpea.

Effects and characterization of different soybean varieties in yield and organoleptic properties of tofu

Tofu is a soft food made from soybean processing. Soybeans are made up of two types of Genetically Modified Organism (GMO) and non-Genetically Modified Organism (non-GMO). Transgenic soybeans are soybeans that undergo genetic changes for a specific purpose. Non-transgenic soybeans that do not undergo genetic changes. The purpose of this study was to analysis of the effect of raw material soybeans on yield, protein content, and water content, amino acid type, and organoleptic properties of tofu. This study uses two types of soybeans to make tofu, namely transgenic soybeans (Lotus USA) and non-GMO (Anjasmoro). Its methods include soybean soaking, soy milk peeling, filtration, heating, coagulation, and squeezing. The results showed the yield and tofu protein of non-transgenic soybeans were higher than transgenic. The non-transgenic soybean water content is lower than transgenic. The taste and aroma of non-transgenic soybeans are superior to that of transgenic soybeans because they are more savory and smell typical of soybeans, for the texture and color of tofu transgenic soybeans are superior to non-transgenic soybeans. Tofu of non-transgenic soybeans has lower levels of the essential amino acids arginine, phenylalanine, and leucine than transgenic. But tofu of non-transgenic soybeans has higher levels of the non-essential amino acid glutamic than transgenic.

Synergistic effects of processing parameters on the biochemical and physical properties of tofu made from yellow field pea (Pisum sativum), as determined by response surface methodology.

Peas are an underutilized crop that do not require allergen labeling and are rarely genetically modified. Peas contain less protein than soy and vary in protein composition. Because peas contain more starch than soy and less lipids, an alternative procedure for pea tofu production needs to be developed to prevent excessive starch gelatinization while promoting curd development. To accomplish this, a response surface model design was utilized to determine optimal oil addition, cook time, and salt concentration. Treatment ranges were from 0.0% to 4.2% for oil addition, 60–134 min for cook time, and 5.0%–9.2% for MgCl2 addition. Treatments had varying effects on tofu texture. Cook time was directly proportional to the hardness and could be used to match the soft, firm, and extra firm texture targets of conventional soy tofu. Protein secondary structure was not related to gel strength, indicating a system with synergies between multiple components other than protein. This research will help satisfy the growing demand for alternatives to soy‐based foods.

The effect of extraction method and types of coagulants on the results and physicochemical properties of tofu

Abstract Extraction and coagulation techniques are essential stages in tofu production. This research studies the effect of extraction and coagulation techniques on physicochemical properties of soybean extract, soy pulp, and tofu. This study applies three extraction techniques, namely manual heat extraction, manual cold extraction, and cold extraction using mechanical devices. They used nigari coagulant. As a control, the process of making tofu follows the procedure process as in the small industry of tofu with whey coagulant. The measurement of material mass balance is done at each stage of the process, while the evaluation of the product includes water content, ash, protein, fat, magnesium, and texture. The experimental results show that an increase in the ratio of water to soybeans and the increase of extraction temperature can increase the amount of extracted protein. The coagulation using nigari produced 22.18 kg tofu in hot extraction treatment, 19.61 kg in cold extraction and 17.60 kg in machine extraction. The control treatment produced 36.8 kg of tofu. The water content in the control treatment was higher than the other three treatments. Protein levels, magnesium levels, hardness and chewing power for treatment with nigari coagulant were significantly higher than those with whey.

Improvement of the phenolic content, antioxidant activity, and nutritional quality of tofu fermented with Actinomucor elegans

The present work aimed to investigate the effects of fermentation with Actinomucor elegans on the phenolic components, antioxidant activities, and nutritional compounds of tofu. A significant increase in the total and soluble phenolic content and a decrease in insoluble phenolic content in tofu were observed after fermentation. The soluble phenolic content in tofu exhibited a high correlation with α-amylase, β-glucosidase, endoglucanase, exoglucanase, esterase, and protease activities released by A. elegans during fermentation. Meanwhile, isoflavone glycosides were hydrolyzed into their corresponding aglycones during fermentation. The fermented tofu also showed higher antioxidant activities than the unfermented tofu. Metabolomic analysis revealed that the nutritional composition including carbohydrates, alcohols, fatty acids, organic acids, inorganic acids, amino acids, and a miscellaneous of tofu was significantly increased during fermentation, and the metabolites in tofu were traced back to their corresponding biosynthesis pathways to clarify the substance transformation process. These findings demonstrated that A. elegans fermentation could significantly enhance the nutritional and functional properties of tofu.

The utilization of bilimbi (Averrhoa bilimbi) and lime (Citrus aurantifolia) juices as natural acid coagulants for tofu production.

The influences of coagulation conditions on the characteristics of tofu have been investigated by many studies, with limited perspectives on the utilization of organic acid coagulants. Hence, this research aimed to study the psychochemical and functional properties of tofu coagulated by bilimbi (Averrhoa bilimbi) and lime (Citrus aurantifolia) juices. The highest tofu protein content was quantified for tofu prepared with 20% bilimbi and 5% lime juices, as much as 52.11 and 52.03% (DW), respectively. The corresponding yield was 73.46 and 69.17%. The hardness (155.98g), gumminess (116.45g), and chewiness (112.69g) of treated tofu were found significantly higher than commercial tofu (p < 0.05). Total phenolic content of commercial tofu was about 370.09μg GAE/g sample (DW). This value was significantly higher than that of treated tofu (p < 0.05). However, the antioxidant activity of the commercial tofu was lower than tofu coagulated with fruit juices. Based on SDS-PAGE analysis, protein band for 11S fraction of tofu coagulated by bilimbi and lime juices were thicker than that of commercial tofu. These small molecular weight peptides might contribute for higher antioxidant activities of tofu coagulated by bilimbi and lime juices. Conclusively, bilimbi and lime juices are potent natural acid coagulants for enhancing the physicochemical and functional properties of tofu.

Tailoring Physical and Sensory Properties of Tofu by the Addition of Jet-Milled, Superfine, Defatted Soybean Flour.

The use of defatted soybean flour (DSF) in food as a source of dietary fiber has been limited due to its rough texture and bitter taste. Our previous work indicates that superfine DSF prepared by jet milling could overcome these problems, as it positively affected physical and sensory properties. Therefore, differently sized DSFs were incorporated in tofu, and their impacts on physical and sensory properties were investigated in this study. Coarse DSF (Dv50 = 341.0 µm), fine DSF (Dv50 = 105.3 µm), and superfine DSF (Dv50 = 5.1 µm) were prepared by conventional sifting and jet milling. Tofu was made with a 5% addition of differently sized DSFs and without DSF (control tofu). The quality of tofu was evaluated by scanning electron microscopy, color measurement, texture profile analysis, and quantitative descriptive analysis. The tofu made with coarse and fine DSF showed negative changes in its physical and organoleptic qualities, such as reduced yields, a less pure color, a harder texture, and a rougher mouthfeel. However, the tofu made with superfine DSF showed only minimal changes in its qualities compared to the control. Therefore, superfine DSF is a promising fiber supplement that does not change the physical and sensory properties in the making of high-quality tofu.