A starchy food that is initially a single-phase body turns into a multiphase body during boiling because of starch gelatinization. Fick's law is applicable only to a homogeneous system and is not applicable to such a multiphase system. Relative Water Content (RWC) model has been proposed as an alternative model that is able to describe water migration in multiphase food systems. In the RWC model, water migration is driven by the gradient of water content divided by the water holding capacity (WHC), m/m*. In this study a WHC profile (WHC plotted against water content with which starchy food is heat-treated) was assumed based on information concerning starch gelatinization. Using this WHC profile, the correlation between WHC profile and transient water content profile in a wheat flour dough slab during boiling was examined. A modified WHC profile was found to be applicable for describing certain characteristic features of the transient water content profile in a slab of wheat flour dough during boiling.

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 urban food garden is an interesting natural solution to the need to develop sponge cities structured and designed to absorb and capture rain water for reducing flooding, worldwide. This study applied a storm water management model and field experiments to investigate properties of the garden substrates. Taipei City was taken as a case study as the Taiwan government has promoted urban food garden projects since 2015. The urban food garden in Taipei has established a cultivable area of 197,168 m², 64,026 m² (32.5%) of which is designated as green-roof gardens and the rest as domestic gardens. Four substrate mixtures were found to have infiltration rates positively related to their soil water content. Substrate 1 had the highest infiltration rate (6.47 × 10⁻⁵ m/s) and soil water content (281%) when vegetation grows in limited containers. In 2019, the total water retention capacity of the urban food garden in Taipei City was 50,550.7 m³. This means that 1 m² of the urban food garden in Taipei retained 256.4 kg of water. Considering climatic conditions, the water retention capacity of the green-roof gardens in Taipei ranges from 28.2% to 41.0%. During short-term high-density rainfall events, the green-roof gardens were found to be more efficient in reducing the runoff volume, whereas during long-term high-density rainfall events, they were found to be more efficient in reducing the runoff peak flow duration (~20 mins) compared with concrete surfaces. This study proved that establishing the urban food garden contributes to increasing the water retention capacity and reducing the volume of surface runoff and the duration of runoff peak flow in prevention of flood disasters.