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Low-temperature deposition manufacturing has attracted much attention as a novel printing method, bringing new opportunities and directions for the development of biological 3D printing and complex-shaped food printing. In this article, we investigated the rheological and printing properties of gelatin solution and conducted numerical simulation and experimental research on the low-temperature extrusion process of gelatin solution. The velocity, local shear rate, viscosity, and pressure distribution of the material in the extrusion process were calculated using Comsol software. The effects of the initial temperature, inlet velocity, and print head diameter of the material on the flow field distribution and printing quality were explored. The results show that: (1) the fluidity and mechanical properties of gelatin solution vary with its concentration; (2) the initial temperature of material, inlet velocity, and print head diameter all have varying degrees of influence on the distribution of the flow field; (3) the concentration change of the material mainly affects the pressure distribution in the flow channel; (4) the greater the inlet velocity, the greater the velocity and shear rate in the flow field and the higher the temperature of the material in the outlet section; and (5) the higher the initial temperature of the gel, the lower the viscosity in the flow field. This article is of great reference value for the low-temperature 3D printing of colloidal materials that are difficult to form at room temperature. [ABSTRACT FROM AUTHOR]

Purpose: To determine the best deodorization process by comparing the deodorization effects of different treatment methods on tilapia meat. Methods: The sensory evaluation method of sorting was adopted, combined with the electronic nose and gas chromatography ion mobility spectroscopy (GC-IMS) data to select the best tilapia deodorization method. Results: The sensory analysis of tilapia meat treated with cooking wine compound method had the best sensory effect. Electronic nose analysis masking method, cooking wine compound method, and embedding method had significant changes in methyl and inorganic sulfide compounds in fish meat after deodorizing treatment. GC-IMS analysis identified 42 kinds of volatile compounds. Fish meat processed by the tomato compound method, fermentation method, masking method, and cooking wine compound method all formed their characteristic flavor regions on the fingerprint. The fish meat of the embedding method and the blank group had similar fingerprints. In the samples treated by tomato compound method and fermentation method, the relative contents of aldehydes that cause fishy smell, ketones and alcohols that enhance fishy smell were relatively high. The content of low molecular carbon chain aldehydes in tilapia meat after deodorization by masking method and cooking and wine complex method was the least, and the deodorization effect was the best. The results showed that in the tilapia meat treated with cooking wine, white vinegar and ginger juice, the relative content of aldehydes in the sample was reduced due to the introduction of flavor substances by ginger juice and cooking wine and the absorption of white vinegar to reduce fishy substances, and the best deodorizing effect. [ABSTRACT FROM AUTHOR]

Summary: In order to explore the relationship between water absorption properties and microstructure changes of sea cucumber body wall with different heat treatments. The microstructure, rheological characteristics and hydrogen bond content changes of sea cucumber body wall at different heat‐treatment times (4, 6, 8, 10 and 12 h) were investigated, as well as the distribution and phase of water during the soaking. The results showed that the heat treatment for 4 and 6 h mainly caused fibre fracture which led to more water binding sites and free water content. With prolonged heat‐treatment times, the degree of denaturation increases. The micro‐pores formed at 10 h heat treatment could accommodate the highest free water content, and the network structure was more intensive at 12 h with decreased porosity. The apparent viscosity, storage and loss modulus gradually decreased with heat‐treatment time, and the liquidity increased. Extended heat‐treatment time led to the breakage of the microstructure, and the longer time required for its free water and immobile water content to reach the maximum. However, the trend of bound water was the opposite. [ABSTRACT FROM AUTHOR]

The enzymatic hydrolysate of mussel was used as the raw material for preparing the thermal reaction essence with a seafood flavor through the Maillard reaction. The effects of reducing sugar type and addition amount, reaction time and reaction temperature on the Maillard reaction were investigated through using sensory scores as the indicators. The conditions for preparing mussel thermal reaction essence were optimized by the orthogonal experiments: mussel enzymatic hydrolysate 10%, xylose 5%, reaction time 90 min, reaction temperature 100 °. The obtained mussel essence had a high intensity of natural seafood flavor. The comparison of the powder state and physico-chemical properties of the essence powder prepared by ultrasonic spray-freeze drying, vacuum freeze-drying and spray drying revealed that the essence powder prepared by ultrasonic spray-freeze drying was the best, having a light yellow color, fine size, evenly dispersed nature, and high solubility. The solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) analyses revealed a total of 28 volatile compounds in the essence prepared via the three drying processes, including aldehydes, alcohols, pyrazines, furans, esters and ketones. The volatile components of the essence powders prepared by the three drying processes differed significantly, with the volatile profile of the essence obtained by the ultrasonic spray-freeze drying being the closest to that prior to drying (i.e. best powder state and strongest flavor). This study provides a theoretical basis for the production and processing of high-fidelitymussel thermal reaction essence with seafood flavor. [ABSTRACT FROM AUTHOR]