The fruit sauces importance is increasing as a result of the impact of these ingredients that enhance the functional properties of foods. Thus, the study aimed to produce a sweet-and-sour sauce with assai and unconventional food plants (UFP), as a healthy alternative in promoting the consumption of fruits and vegetables. Thus, 14 sauce prototypes were produced. A first-order orthogonal central composite design was used, and for the data analysis, the response surface methodology and the ridge analysis were used. The physical, physical-chemical, microbiological and sensory analyzes were performed. The characteristics of identity and quality of selected prototypes M2 and M5, were respectively: 24 and 28 oBrix; 0.72 and 0.86 (%) titratable acidity; 33.11 and 32.34 of ratio; 3.97 and 3.91 of pH; 1.00 and 1.10 μM Trolox mL⁻¹ of antioxidant activity; 141.0 and 158.16 mg GAE/100 g of phenolic compounds; 12.7 and 14.5 cm/30s of Bostwick consistency; 39.03 and 45.15 (%) of syneresis. There was no microbial growth. The sauces’ prototypes obtained good sensory acceptance and this was not influenced by the consumers' profile. Thus, ensuring the safety and quality of the sauces. Therefore, it was possible to obtain two prototypes for the sauce, with characteristics of identity and quality similar to those of ketchup and with functional potential.