Application guide for the preparation of juices based on traditional fruits in Peru

Abstract

Given the absence of practical laboratory guides for fruit juice processing, this study aimed to implement a didactic guide for the production of juices derived from traditional Peruvian fruits as a strategy to bridge the gap between theoretical knowledge and practical application in food engineering education. A quantitative approach with an interactive instructional design was employed, enabling students to perform the complete nectar production process while applying both thermal pasteurization and ultrasound-assisted preservation techniques. Subsequently, the effects of these preservation methods on product quality were evaluated. The results demonstrated that ultrasound treatment (45°C for 15 min) provided significantly greater preservation of total polyphenols (33.59 mg GAE/100 g) compared with conventional pasteurization (23.35 mg GAE/100 g). Vitamin C content remained high under both treatments, with pasteurization at 80°C for 20 min showing the highest value (44.25 mg/100 mL). Physicochemical parameters, including pH, soluble solids (°Brix), titratable acidity, and viscosity, remained stable throughout the study, although ultrasound treatment exhibited superior viscosity retention. From a microbiological perspective, both preservation methods ensured product safety throughout 42 days of storage, complying with the requirements established by the Peruvian Technical Standard. The findings indicate that the proposed guide constitutes an effective educational tool for strengthening students’ competencies in critical analysis, decision-making, and innovation. By exposing learners to real experimental results, the guide facilitates a deeper understanding of the advantages offered by emerging food preservation technologies compared with conventional processing methods.