# Search results that are considered mostly satisfying after screening are marked with *
## 3 Results
### Interface Design  
Among the 19 papers reviewed, 8 studies designed interfaces that attached electrodes directly to the tips of the tongue [22, 29, 30, 31, 32, 33, 34], with sizes ranging from \(1\times 2\) cm\({}^{2}\) to \(1.5\times 4\) cm\({}^{2}\). Other studies reported interfaces integrated into eating utensils, including containers and eating tools. Eating containers included bowls [35], cups, and bottles [28, 29, 36, 37, 38, 39, 40]. Eating tools included spoons [37, 38, 41], forks [28, 42], chop-sticks [27, 29, 35], and straws [28, 31, 42, 43].  
Figure 3: Flowchart for paper selection.  
These interfaces typically use a pair of silver electrodes to deliver a direct but weak current to the taste buds. The electrodes are connected to a computer, allowing for the precise control of the electric stimulation with the aim of inducing various taste sensations.  
Specifically, [PERSON] and [PERSON] developed a system using a pair of straws to create electrical taste sensations while drinking. Users complete an electric circuit by drinking electrolyte-based beverages through the straws, which are connected to a voltage control system [28; 29]. Adjusting the voltage allows users to perceive various tastes, with isotonic drinks providing the best results due to their electrolyte content. This system demonstrates how electric taste technology can be seamlessly integrated into drinking tools. [PERSON] et al. introduced Spoon+ and similar utensil designs, which use silver electrodes to stimulate the tongue with low-power electrical pulses [38]. Spoon+ is capable of simulating multiple taste sensations, such as sour, salty, and bitter, as well as novel minty and spicy sensations through thermal modulation. These eating tools use a digital control system to adjust taste stimuli in real time. Forks and spoons [28; 37; 38; 41; 42] share similar operational principles but are optimized for different types of meals, broadening their applicability in both culinary and experimental settings.  
As for containers, artificial taste interface was embedded into the edge of the container. [PERSON] et al. designed taste-stimulating bowls and cups that were capable of delivering sour and salty sensations [35; 37]. Using an Arduino-based constant current source, the system generates electrical pulses within preselected ranges to simulate specific tastes. While bowls and cups differ in form, they shared similar functionality, making them versatile tools for liquid and semi-liquid foods. Bottle+ was another utensil developed by [PERSON] et al., designed with a focus on mobility and user-friendliness [38]. Bottle+ integrated silver electrodes within the bottle's mouthpiece to stimulate taste sensations during drinking. Additionally, it employed a digital control system for the precise management of taste and temperature stimuli, making it ideal for enhancing flavored beverages. Additionally, a cocktail glass system (Vocktail) developed by [PERSON] et al. incorporates a 3D printed structure that houses the electronics and a mobile application for control [40]. The Vocktail augmented beverages with digitally generated flavors, showcasing how traditional glassware could be adapted to incorporate advanced taste stimulation technology. The versatility of these interfaces demonstrates the potential for integrating digital taste augmentation into routine eating and drinking activities.