Response Surface Methodology (RSM) is a widely used mathematical tool for process optimization, setting their main factorial variables. The current research analyzes and summarizes the current knowledge about the RSM in the extraction of carotenoids from fruit and vegetable by-products, following a systematic review protocol (Prisma 2020 Statement). After an identification of manuscripts in Web of Science (September 2023) using inclusion search terms (“carotenoids”, “extraction”, “response-surface methodology”, “ultrasound”, “microwave” and “enzyme”), they were screened by titles and abstracts. Finally, 29 manuscripts were selected according to the PRISMA methodology (an evidence-based minimum set of items for reporting in systematic reviews), then, 16 questions related to the quality criteria developed by authors were applied. All studies were classified as having an acceptable level of quality criteria (≤50% “yes answers”), with four of them reaching a moderate level (>50 to ≤70% “yes answers”). No studies were cataloged as complete (>70% “yes answers”). Most studies are mainly focused on ultrasound-assisted extraction, which has been widely developed compared to microwave or enzymatic-assisted extractions. Most evidence shows that it is important to provide information when RSM is applied, such as the rationale for selecting a particular design, the specification of input variables and their potential levels, a discussion on the statistical model’s validity, and an explanation of the optimization procedure. In addition, the principles of open science, specifically data availability, should be included in future scientific manuscripts related to RSM and revalorization.

Tomato by-products are widely generated during processing, which deserve revalorization due to being rich in bioactive compounds that can be incorporated into novel formulas. This study explores the use of tomato by-products as a source of pigments and antioxidant compounds to develop a seasoned cucumber beverage enriched with encapsulated carotenoids. Extracts from industrial tomato pomace were obtained using ultrasound-assisted extraction (USAE) and accelerated solvent extraction (ASE), and then encapsulated by spray-drying with inulin (I), maltodextrin (M), or a maltodextrin–inulin blend (MI). The powders were added to a cucumber beverage treated with high hydrostatic pressure (HHP) and stored for 28 days at 4 °C. Physicochemical properties, microbial load, carotenoid content (U-HPLC), free phenolic content (FPC), and total antioxidant capacity (TAC) were monitored. Beverage samples with maltodextrin (ASE-M, USAE-M) and the maltodextrin–inulin blend (ASE-MI, USAE-MI) showed superior color stability and pH maintenance. USAE-MI achieved the highest TAC at the end of storage and ensured microbial safety by reducing mesophilic bacteria, molds, and yeast. During storage, FPC declined (to ~3.5–5 mg 100 mL⁻¹), TAC increased (to ~16–20 mg 100 mL⁻¹), and carotenoid was kept stable (~9–13 mg L⁻¹). These results highlight the potential of combining HHP with tomato by-product encapsulates to improve the shelf life, quality, pigment stability, and antioxidant properties of vegetable-based beverages.

Food industries generate tomato by-products rich in health-promoting compounds, which can be extracted and encapsulated for use in food products. This study aimed to fortify cucumber juice with encapsulated tomato by-products rich in carotenoids and assess its shelf life. The encapsulated tomato by-product, prepared by spray-drying with maltodextrin and inulin, was added to cucumber juice (5 g L⁻¹). The total antioxidant capacity (TAC) and microbial load were monitored for 3 weeks at 4 °C. High hydrostatic pressure (HHP) treatment improved the TAC by ~25% and reduced the microbial load by ~69%. No significant sensory or physical changes were observed, suggesting fortification enhances beverage health benefits during refrigeration.

[SPA] Esta tesis doctoral se presenta bajo la modalidad de compendio de publicaciones. El tomate (Solanum lycopersicum) es mundialmente reconocido como el segundo cultivo hortícola más importante y un componente fundamental de la dieta Mediterránea. Según el World Processing Tomato Council, cada año se procesan más de 130 millones de toneladas de tomate en el mundo, generando unos 8 millones de toneladas de subproductos. Sin embargo, estos subproductos, principalmente cáscaras y semillas, siguen siendo ricos en valiosos compuestos bioactivos como carotenoides, fenoles y vitaminas. Entre ellos, el licopeno es el antioxidante predominante, y representa el 80-90% del contenido total de pigmentos en los tomates maduros. Los estudios han demostrado una fuerte relación entre los carotenoides de la dieta, especialmente el licopeno, y la reducción del riesgo de carcinogénesis y enfermedades cardiovasculares. El objetivo de esta Tesis Doctoral es la revalorización sostenible de los subproductos del procesado del tomate extrayendo los nutracéuticos clave, principalmente carotenoides, y su incorporación en nuevos alimentos funcionales, como purés y bebidas vegetales para untar, mediante tecnologías verdes de extracción y procesado. La investigación comenzó con la caracterización de los subproductos del tomate para determinar sus perfiles fitoquímicos y de carotenoides, centrándose en compuestos como α-caroteno, β-caroteno, licopeno, luteína, zeaxantina y β-criptoxantina, utilizando técnicas analíticas avanzadas como U-HPLC y espectrofotometría. Posteriormente, se optimizó la extracción mediante ultrasonidos y acelerada por solventes para mejorar el rendimiento y preservar la integridad de los compuestos. Los resultados mostraron que los subproductos del tomate son ricos en polifenoles, β-caroteno y licopeno. La optimización mediante la metodología de superficie de respuesta reveló que los mayores rendimientos de carotenoides (licopeno: 2.586 mg/kg; Σβ- caroteno: 161 mg/kg) se produjeron a 45ºC, 82% de amplitud y 23-28 minutos. La microencapsulación con maltodextrina, inulina y su combinación mejoró la estabilidad, y los encapsulados por extracción asistida con ultrasonidos retuvieron hasta 775 mg/kg de licopeno en comparación con los 218 mg/kg de la extracción mediante solventes acelerados. Éstos se incorporaron a un puré de aguacate procesado mediante alta presión hidrostática, produciendo una pasta para untar microbiológicamente estable durante 3 semanas a 4ºC sin apenas cambios de color y con alto contenido en fenoles (>1,5 g GAE/kg) y carotenoides (>1,2 mg/kg). Asimismo, las bebidas a base de pepino enriquecidas con encapsulados de β-caroteno mostraron una capacidad antioxidante y un contenido en carotenoides estables (9-13 g/L), un pH reducido, un aumento de los sólidos solubles totales y seguridad microbiana durante 28 días bajo alta presión hidrostática. Los resultados de esta investigación doctoral confirman la viabilidad de la transformación de subproductos del tomate en ingredientes bioactivos de alto valor que pueden mejorar el perfil nutricional, la vida útil y el impacto en la salud de los productos alimentarios de nueva generación en consonancia con los objetivos de sostenibilidad.