Introduction. Pitaya peel has been applied as a functional ingredient for food due to the presence of betacyanins. However its polysaccharides can also contribute as a texture agent for food. The aim of this work was to evaluate the chemical characteristics and rheological behavior of the pitaya peel. Materials and methods. The samples were analyzed with regard to moisture and mineral content, protein, lipids, sugar, fiber, vitamin C, titratable acidity, soluble solids content and pH. Rheological measurements were performed on rheometer through flow curve, stress sweep, frequency sweep and the variation of temperature. Results and discussion. The results showed that pitaya peel is rich in insoluble fibers and exhibits non-Newtonian behavior, characteristic of a strong gel with a predominance of solid character. Furthermore, samples showed thermal resistance at the conditions of frequency, tension and temperature analyzed. Conclusion. Considering our results, in addition to use as a natural colorant in food, pitaya peel can also contribute to the nutritional value and texture of the products.

Introduction. Because of the long transportation times and storage durationsthat are often experienced, it is important to understand how pomelo properties changeover time; that will be indicative of how long samples can be stored before they dropbelow acceptable quality limits. As no information is available regarding storage ofpomelo fruit in the literature, the goal of our work was to study the change in pomelophysicochemical and textural properties following storage over a period of approximately4 months. Materials and methods. The changes in physical, chemical andtextural properties of commercial pomelo fruit were extensively evaluated over the courseof a 4-month storage period. The correlation among physical, color, chemical and texturalproperties were also assessed. Results. Color properties(L*, a*, b*) changed significantly withstorage; however, they did not change much during the initial 45 days of storage. Thechange in soluble solids content (SSC), acidity (A) and the [(SSC) / (A)] ratio suggestedthat pomelo fruit should not be stored for more than 75 days. Crucially, our studydemonstrates that the a* parameter (greenness, R = –0.556) correlatesbest with the chemical property the [(SSC) / (A)] ratio, which is a recognized measurementof the consumer acceptability of citrus fruit. This means that measuringa* is a non-destructive way of monitoring the taste characteristics ofpomelos in storage. This property also correlated well with the average firmness of thefruit and with the flesh texture. Conclusion. This fundamental information onthe pomelo fruit could prove useful in the physical handling and processing of the fruitby breeders and postharvest technologists as well as distributors, market agents,importers and exporters.