Gelling properties of acid-induced tofu (soybean curd): Effects of acid type and nano-fish bone.

Area of Science:

• Food Science and Technology
• Materials Science
• Biochemistry

Background:

• Tofu production relies on acid coagulation, influencing its texture and properties.
• Nano fish bone (NFB) is explored as a novel additive to improve food characteristics.
• Understanding the interplay between coagulants and additives is crucial for optimizing tofu quality.

Purpose of the Study:

• To investigate the impact of different acid coagulants (glucono-d-lactone, citric acid, lactic acid, acetic acid) and NFB on tofu characteristics.
• To analyze the effects of these treatments on tofu's texture, syneresis, color, gel network, and secondary structure.
• To determine the optimal combination of acid coagulant and NFB for superior tofu quality.

Main Methods:

• Tofu samples were prepared using four acid coagulants and NFB.
• Texture analysis (breaking force, penetration distance) was performed.
• Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FT-IR), and syneresis measurements were employed.
• Analysis of soluble calcium content and secondary protein structure was conducted.

Main Results:

• Tofu coagulated with glucono-d-lactone (GDL) exhibited the highest breaking force and penetration distance, and lowest syneresis.
• NFB addition significantly increased soluble calcium content, enhancing tofu's breaking force and reducing syneresis, irrespective of the acid type.
• GDL-coagulated tofu demonstrated a denser, more uniform gel network with stronger intermolecular forces, particularly hydrophobic interactions.
• Secondary structure analysis revealed GDL tofu had the lowest α-helix and highest β-sheet content.

Conclusions:

• The combination of GDL and NFB offers synergistic benefits for improving tofu texture and stability.
• NFB enhances tofu characteristics by increasing soluble calcium and modifying the gel network structure.
• GDL is the most effective acid coagulant for producing high-quality tofu, especially when combined with NFB.