Solid food products are typically in an amorphous state, and their physical properties change dramatically at the glass to rubber transition temperature (Tsub(g)). Tsub(g) decreases with increasing water content because of water plasticizing effects. When Tsub(g) becomes lower than the ambient temperature, a glass to rubber transition occurs at the ambient temperature. The water content at Tsub(g) = 25℃ is usually described as the critical water content (w sub(c)). In this review, the effect of glass to rubber transition on the texture of cookies, the caking of mango powder and the compressibility of soup powder is explained. Tsub(g) of the food samples was evaluated by differential scanning calorimetry or thermal rheological analysis. Wsub(c) was determined from the relationship between Tsub(g) and water content. Fracture properties of the cookie samples changed from brittle to ductile at Wsub(c). Caking of mango powder occurred at water contents above Wsub(c). Hardness of soup powder compressed at temperatures above Tsub(g) was much higher than when compressed at temperatures below Tsub(g).

The structured food systems (i.e. cellular tissues) are dissipative structures whose functionality mainly concerns their properties (physico-chemical properties, chemical and biochemical reactions), external interactions with surroundings (interactions with micro-organisms, heat and mass transport pathway) and especially, their interactions with consumers (nutritional value, quality, taste and flavour, texture, appearance: size, shape, colour). Dehydration or rehydration processes concern heat and mass transport phenomena (water, solutes) coupled with micro and macrostructure changes both producing important effects on food functionality. Control of these changes is the major concern in food product development. This control must be applied not only to the changes in physico-chemical properties but also to those related with consumers' issues. Food matrixengineering is a branch of food engineering which aims to apply the knowledge of the food matrixcomposition, structure and properties to promote and control adequate changes which can improve some sensorial and/or functional properties in the food. These changes, which are caused by some basic operations, are related to the phenomena of heat and mass transfer, vaporization-condensation, internal gas or liquid release, structure deformation-relaxation and phase transitions in matrixcomponents, and are usually coupled throughout the operation's progress. The final product may be a new product with improved composition and sensorial properties and/or more stability. All these concepts are discussed in this paper using several examples related to the application of combined food dehydration techniques.

This comprehensive work explores the multifaceted field of electrolyzed water (EW) and its crucial role in altering the textural characteristics of various food categories. The analysis begins by providing a clear explanation of EW and its different types, including slightly acidic (AC) EW, plasma-activated EW, neutralized EW, alkaline EW, and weakly ACEW. The review highlights the novelty of EW in preserving food quality, making it a significant alternative to various cleaning and disinfecting methods. The focus then shifts to the applications of EW, examining the impact of different EW types on the textural compositions of various food categories. The examination of the textural profile of foods, which is a crucial determinant of consumer preference, is comprehensively conducted across various categories, encompassing baked goods, meat and poultry, marine foods, fruits and vegetables, as well as ready-to-cook items like noodles. Furthermore, the review investigates the combined effects of EW, when utilized in conjunction with other technologies. The integration of EW with ultrasound, high-pressure processing, plasma activation, slurry ice, and other technologies, assessing their collective impact on textural attributes, was explored. As a consequence, this paper examines the present uses and impacts of electrolyzed water on the texture of food and also investigates its potential synergies with other technologies. The thorough analysis presented here establishes a basis for future research directions in this rapidly developing area, facilitating the exploration of inventive methods for food processing and preservation.

Differences in recognition of physical properties of food in food science and engineering and the influence of water on them were discussed. The physical properties, 'Bussei' in Japanese, can be usually defined in food engineering and physics as 'the physical quantities that characterize a substance and do not depend on the shape and size of the material'. There seem, however, to be other interpretations of the physical properties among food researchers and technologists. For example, some researchers such as food chemists and cooking scientists refer to the dynamic properties and the texture of foods as the 'Bussei', whereas others such as technologists in food companies refer to it as the physical characteristics of foods reflecting some physical phenomena in food manufacturing and preservation processes. Most of the latter two types of 'Bussei' are influenced by the size and shape of materials and are not, therefore, the true physical properties. The type of 'Bussei' useful for food researchers and engineers would, however, vary depending on the situation or problem to be solved. Physical properties of foods are used for several purposes: first, they are indispensable parameters in the engineering models for predicting the optimal conditions for food manufacturing; second, the inner structure or state of food materials can be estimated from the behaviors of some of their physical properties. For example, water interacts with many food components; and thus the amount and/or state of water considerably influences the physical properties of foods, for example, by causing a change in the dynamic properties during sol-gel transition and the glass-rubber transition by the plasticizing effect of water.

In food packaging systems, moisture content influences chemical and physical film properties, also determining processes such as food spoilage, and properties of food texture and crispiness level. The study of water permeation and sorption processes of new materials intended to be used as packaging is very important to determine the best application conditions and to predict the film behavior under different moisture conditions inside and/or outside the packaging. In order to determine the suitable temperature and water activity (aw) application conditions for whey protein isolate (WPI)/polyvinyl alcohol (PVOH) blends as food flexible packaging, water permeation and water sorption thermodynamic behavior of these materials were evaluated. WPI/PVOH films and blends had solubility preponderant over the diffusion on the water permeation process. Water sorption experimental data were well described by the GAB model, and curves showed a more expressive increase of water sorption at aw > 0.75, with lower equilibrium moistures (Ye) at room than at chilled temperatures. Differential enthalpy decreased and differential entropy increased by the Ye gain, and the occurrence of enthalpy-entropy compensation was confirmed with enthalpy driving the sorption process. The addition of PVOH to the WPI matrix made the water sorption process more spontaneous. Water sorption thermodynamic analysis indicates that the application of WPI/PVOH blends as packaging is best suitable for foods and external environments with aw below 0.75 and at room temperature.

Natural biopolymers have become key players in the preparation of biodegradable food packaging. However, biopolymers are typically highly hydrophilic, which imposes limitations in terms of barrier properties that are associated with water interactions. Here, we enhance the barrier properties of biobased packaging using multilayer designs, in which each layer displays a complementary barrier function. Oxygen, water vapor, and UV barriers were achieved using a stepwise assembly of cellulose nanofibers, biobased wax, and lignin particles supported by chitin nanofibers. We first engineered several designs containing CNFs and carnauba wax. Among them, we obtained low water vapor permeabilities in an assembly containing three layers, i.e., CNF/wax/CNF, in which wax was present as a continuous layer. We then incorporated a layer of lignin nanoparticles nucleated on chitin nanofibrils (LPChNF) to introduce a complete barrier against UV light, while maintaining film translucency. Our multilayer design which comprised CNF/wax/LPChNF enabled high oxygen (OTR of 3 ± 1 cm³/m²·day) and water vapor (WVTR of 6 ± 1 g/m²·day) barriers at 50% relative humidity. It was also effective against oil penetration. Oxygen permeability was controlled by the presence of tight networks of cellulose and chitin nanofibers, while water vapor diffusion through the assembly was regulated by the continuous wax layer. Lastly, we showcased our fully renewable packaging material for preservation of the texture of a commercial cracker (dry food). Our material showed functionality similar to that of the original packaging, which was composed of synthetic polymers.

Gels are viscoelastic systems built up with a liquid phase entrapped in a three-dimensional network, which can behave as carriers for bioactive food ingredients. Many attempts have been made to design gel structures in the water phase (hydrogels, emulsion gels, bigels) or oil phase (organogels, bigels) in order to improve their delivery performances. Hydrogels are originated from proteins or polysaccharides, which are suitable for the delivery of hydrophilic ingredients. Organogels are mainly built up with the self-assembling of gelator molecules in the oil phase, and they offer good carriers for lipophilic ingredients. Emulsion gels and bigels, containing both aqueous and oil domains, can provide accommodations for lipophilic and hydrophilic ingredients simultaneously. Gel structures (e.g. rheology, texture, water holding capacity, swelling ratio) can be modulated by choosing different gelators, modifying gelation techniques, and the involvement of other ingredients (e.g. oils, emulsifiers, minerals, acids), which then alter the diffusion and release of the bioactive ingredients incorporated. Various studies have proved that gel-based delivery systems are able to improve the stability and bioavailability of many bioactive food ingredients. This review provides a state-to-art overview of different gel-based delivery systems, highlighting the significance of structure–functionality relationship, to provide advanced knowledge for the design of novel functional foods.

The kinetics of light-induced riboflavin loss were examined in several liquid samples, such as skim milk and buffered riboflavin solution, and solid samples, such as elbow macaroni, particulate macaroni, and non-fat dried milk. First and second order kinetics were determined for the liquid and dry system, respectively. Light intensity, using 25, 50, or 100 foot-candles, did not affect riboflavin loss kinetics in elbow macaroni, but the use of a dim light only produced first order loss kinetics. Riboflavin loss in elbow macaroni increased relative to humidity. A quantitative high-performance liquid chromatographic method was used for riboflavin assay. Degradation rate constants are reported. (wz)

Vegetable proteins proved to be good emulsifiers for food emulsions with dietetic advantages. The use of these emulsions as carriers for healthy ingredients, such as colourings, with antioxidant and other beneficial properties, is an interesting subject. In this work, the capacity of the biomass of the microalga Chlorella vulgaris (which has been widely used as a food supplement) as a fat mimetic, and its emulsifier ability, was evaluated. Pea protein emulsions with C. vulgaris addition (both green and orange - carotenogenic) were prepared at different protein and oil contents. The rheological properties of the respective food emulsions were measured in terms of the viscoelastic properties and steady state flow behaviour and texture properties. It was observed that the two microalgal forms evidenced a fat mimetic capacity in these emulsions, the performance of the green stage of this C. vulgaris organism was significantly (p < 0.05) better than the orange stage.