Pitahaya, known as "dragon fruit", is an exotic fruit with excellent nutritional properties; however, the species from the Peruvian coast have been little studied. The objective of the present study was to determine the physicochemical and nutritional composition of two species of pitahaya Hylocereus undatus (Haw.) Britt and Rose (red pitahaya) and Hylocereus megalanthus (yellow pitahaya), cultivated in the central coast of Peru. Proximal analysis, physicochemical and mineral contents were determined by standardized methods. From the results found, the fiber content of red pitahaya (4.30 ± 0.75 g.100 g-1) and vitamin C (14.74 ± 0.53 mg.100 g-1) stand out. The macroelement with the highest proportion corresponded to potassium (215.83 ± 11.72 and 98.41 ± 5.54 mg.100 g-1, for red and yellow pitahaya, respectively). This was followed by phosphorus (28.70 ± 0.28 and 17.99 ± 1.48 mg.100 g-1, for red and yellow pitahaya, respectively) and magnesium (29.88 ± 0.53 and 16.09 ± 2.80 mg.100 g-1, for red and yellow pitahaya, respectively). Regarding the content of microelements, the contents of manganese (5.48 ± 0.1 mg.kg-1) and zinc (5.39 ± 0.25 mg.kg-1) for red pitahaya stood out; and in the case of yellow pitahaya, the highest values corresponded to iron (21.07 ± 0.18 mg.kg-1) and manganese (7.49 ± 1.12 mg.kg-1). The study concluded that red and yellow pitahaya fruits represent an important source of fiber, minerals and vitamin C and they can be used for the benefit of human health and nutrition.

In this research, the effect of ultrasound treatment on the extraction of pectin from dragon fruit peels was evaluated. In this sense, 13 treatments were compared, evaluating the effect on the degree of esterification (DE) as a dependent variable. Likewise, the factors contained in the treatments evaluated were pause time (PT), liquid-solid ratio (LSR) and total application time (TAT), being their levels: one, three and five seconds for PT; 30, 50 and 70 mL/g for LSR; and 15, 37.5 and 60 minutes for TAT. In this way, significant differences were found (p < 0.05) with the DE values in the range of 41.1% to 58.1%. The correlation was also searched between the factors evaluated and DE using the Pearson method, with PT having the greatest influence on DE (0.70). Finally, these results could be used to obtain a low GE pectin (< 50 %) and be applied in the formulation of low fat meat products; for this purpose, the best treatment would be with the following extraction parameters: 1 second for TP, 30 mL/g for RLS, and 37.5 minutes for TTA.

Oxidation of bioactive components is detrimental to some technological properties because they cause browning (enzymatic and non-enzymatic); a phenomenon commonly observed in the drying of fruit products and their by-products. To reduce this effect, three temperature levels (40, 55, and 70 °C) were compared in the drying of yellow dragon fruit (Hylocereus megalanthus) peel. A tray dryer with an airflow rate of 0.5 m/s was used. Drying time (hours) and color parameters (CIE Lab) were evaluated using a one-way ANOVA analysis of variance and the low significant difference (LSD) post hoc test, working at a 5% significance level (α = 0.05). In this way, a lower drying temperature (40 °C) provided a darker coloration in dragon fruit peel flour compared to drying at 55 and 70 °C, the latter ones being statistically similar (p > 0.05) in color and drying time. In conclusion, with drying at 55 °C, a light-colored dragon fruit peel flour was obtained, which would reduce changes in the visual perception of new food formulations.

Oxidation of bioactive components is detrimental to some technological properties because they cause browning (enzymatic and non-enzymatic); a phenomenon commonly observed in the drying of fruit products and their by-products. To reduce this effect, three temperature levels (40, 55, and 70 °C) were compared in the drying of yellow dragon fruit (Hylocereus megalanthus) peel. A tray dryer with an airflow rate of 0.5 m/s was used. Drying time (hours) and color parameters (CIE Lab) were evaluated using a one-way ANOVA analysis of variance and the low significant difference (LSD) post hoc test, working at a 5% significance level (α = 0.05). In this way, a lower drying temperature (40 °C) provided a darker coloration in dragon fruit peel flour compared to drying at 55 and 70 °C, the latter ones being statistically similar (p > 0.05) in color and drying time. In conclusion, with drying at 55 °C, a light-colored dragon fruit peel flour was obtained, which would reduce changes in the visual perception of new food formulations.

The main objective of this study was to optimize the extraction of dietary fiber (insoluble dietary fiber and soluble dietary fiber) and degree of esterification from yellow dragon fruit peels using ultrasound-assisted extraction. Additionally, the study aimed to investigate the potential application of this fiber as a fat replacement in alpaca-based sausages. The optimization process for extracting dietary fiber and degree of esterification involved considering various factors, including the liquid-to-solid ratio, pause time, and total ultrasound application time. A Box–Behnken design consisting of 15 treatments was employed to determine the optimal levels for ultrasound-assisted extraction. The optimized conditions were found to be a liquid-to-solid ratio = 30 mL/g, pause time = 1 s, and total ultrasound application time = 60 min, which resulted in the highest values of insoluble dietary fiber (61.3%), soluble dietary fiber (10.8%), and the lowest value of degree of esterification (39.7%). The predicted values were validated against experimental data and showed no significant differences (p > 0.05). Furthermore, a completely randomized design was utilized to assess the effect of dietary fiber on replacing fat content during the production of alpaca-based sausages. The findings revealed that up to 78% of the fat content could be successfully replaced by soluble dietary fiber obtained from yellow dragon fruit peels when compared to high-fat sausages. Additionally, experimental sausages using soluble dietary fiber showed similar (p > 0.05) quality characteristics, such as hardness (24.2 N), chewiness (11.8 N), springiness (0.900), cohesiveness (0.543), redness (a* = 17.4), and chroma values (20.0), as low-fat commercial sausages.