CONICET | Buscador de Institutos y Recursos Humanos

Orange contains large amounts of vitamin C and polyphenols that exert anantioxidant, anti-inflammatory, and anticancer effect. Freeze-dried orangepowder may be a good alternative to retain its nutritional and sensoryproperties. In order to reduce stickiness, inhibit caking, and guarantee the safehandling and storage of food powders, the key factors to be managed are themoisture content and the storage at low temperatures. Moreover, to improve thequality and stability of the freeze-dried fruit, the addition of high-molecularweight additives to the product before drying as encapsulating and anticakingagents is widely used. The aim of this work was to evaluate the chemicalstability of encapsulated orange pulp obtained by freeze-drying. Twobiopolymers systems were tested as encapsulating agents: gum arabic incombination with bamboo fiber (GA/GB) or cactus cladode mucilage (GA/GC).Hence, three powders were analyzed: orange pulp encapsulated with GA/GB(O-GB), orange pulp encapsulated with GA/GC (O-GC) and the blank: orangepulp powder without encapsulating agents (OP). They were stored undervacuum and in a dark condition for 10 months at 25 ºC. The results showed thatOP exhibited the lowest value of total phenol content, while both solutecontaining samples presented similar values. At the initial storage time, nodifference in this variable was found among the three powders. Therefore, a greater decrease in phenolic content was suffered by OP sample, evidencingthe protecting role during storage of the wall materials towards polyphenols.Regarding vitamin C content, OP sample was the only one that presented asignificant diminution in its content as a consequence of storage. O-GB samplepresented the highest value, concluding that GA in combination with BF forencapsulating orange pulp exerts a higher protective action than the systemGA/CM in the conditions studied. Analyzing the antiradical (ARA) andantioxidant (AOA) activity, all three samples evidenced a significant diminutionin both properties with time, although presenting differential reductions. OPsample was the one presenting the lowest values, indicating the selectedencapsulating agents added preserved to some extent the AOA and ARA of theorange pulp, result that can be correlated to the protection of phenoliccompounds in the encapsulated samples. Comparing the two encapsulatedsamples, O-GB showed an enhanced ARA and AOA. This difference could beattributed to a higher level of vitamin C in O-GB sample, which demonstratesthe higher stabilizing capacity of BF towards this compound over CM.