Search Results (3)

Various protein-rich foods are traditionally immersed in virgin olive oil (VOO), a medium rich in phenols, which are health-promoting and sensorially important compounds. Immersing tofu in VOO may modify the sensory properties and nutritional value of both due to the oil’s hydrophilic phenol interactions with proteins and water. In this study, cubes of fresh tofu (T) (70% water) and freeze-dried tofu (FD-T) (5% water) were immersed in VOO for 7 days of cold storage. The changes in the phenolic compound content and standard quality parameters of the oil were noted after 1, 3, 5, and 7 days of contact with the tofu. The total phenols in the oil were determined using the Fast Blue BB assay, while single phenols were analyzed by HPLC-UV/VIS. During the 7 days, the total phenols in the oil decreased by up to 56% and 26% under the influence of fresh and freeze-dried tofu, respectively, including a significant decrease in hydroxytyrosol, oleacein, tyrosol, and oleocanthal. The water content and its release from fresh tofu significantly contributed to this decline. The degradation of the quality of the oil in contact with the fresh tofu was observed only in its sensory properties, with a marked reduction in the intensity of its fruitiness, bitterness and pungency. Full article

The aim of this study was to check the impact of the addition of selected flavoring herbs on the organoleptic and antioxidant properties of homemade tofu, as well as the possibility of its storage extension by freezing. The optimization of homemade tofu production based on organic soy and the enrichment (2% w/w) of obtained tofu with dried plant additives (wild garlic, basil, Herbes de Provence, black cumin seeds, and dried cranberries) was performed. The manufactured tofu was compared to commercial tofu (control) in terms of antioxidant activity, total polyphenol content, and polyphenol profile using thin-layer chromatography (HPTLC). Moreover, the texture profile and organoleptic assessment of the compared products were performed. The antioxidant and texture parameters were also controlled in tofu fixed by different methods: cold herbal infusion and prolonged freezing of vacuum-packed products. It was shown that homemade tofu was characterized by better sensory and texture properties than commercial product. Moreover, the introduction of plant additives to tofu increased the antioxidant activity and the content of polyphenols in the final product; the greater the activity of the herbs used, the higher the degree of tofu enrichment was achieved. In terms of all analyzed parameters, cranberries and Herbes de Provence additives to tofu were found to be the first choice. It was found that the addition of herbs to tofu allowed us to create new sensory features, enhanced the pro-healthy value, and extended the storage time. Due to no significant changes in texture and antioxidant properties of frozen tofu, as well as its acceptable microbial quality, freezing vacuum-packed tofu can be recommended as a beneficial way to extend the storage time at home condition. The addition of herbs allows for the design of new versions of tofu in accordance with consumer preferences, and the proposed packaging method can be applied on an industrial scale. Full article

The amount of processed by-products such as crab shells is increasing, but industrial utilization is insufficient. In our previous study, crab shell extract (CSE) acted as a coagulant for tofu manufacturing. This study aimed to reduce freeze-dried (FD) tofu breakdown by improving its physical properties through adding sodium alginate (SA). FD state in tofu helps increase storage and availability, but FD tofu frequently fractures during processing, which is a concern for manufacturers. Tofu samples were prepared with either crab shell extract (CSE) or MgCl₂, and SA, and freeze-dried. In the yields of FD tofu samples, there were no significant differences (p < 0.05). The brokenness of FD tofu samples was lower in CSE than in MgCl₂ and was significantly reduced by SA in both tofu samples, which was affected by hardness. The water-holding capacity decreased after freeze-drying, and CSE reduced this decrease, regardless of SA addition. The microstructures differed depending on the coagulant and were dense upon SA addition. The FD tofu was packed into a multilayer film and stored at 25 °C or 45 °C for 6 months to investigate storage stability. During the storage, brokenness was unchanged in all tofu samples, indicating that they maintained their original structure. There were no significant differences in the volatile base nitrogen and thiobarbituric acid values according to the coagulant type and SA addition (p < 0.05). In conclusion, SA reduced FD tofu breakdown by improving the network structure, which may help increase FD tofu quality and decrease economic loss. Full article