Resumo

MAKI-DIAZ, Griselda et al. Physical and chemical characteristics of cactus stems (Opuntia ficus-indica) for exportation and domestic markets. Agrociencia [online]. 2015, vol.49, n.1, pp.31-51. ISSN 2521-9766.

Nopal (edible cactus stems, Opuntia spp.) is consumed and produced in México and the selection criteria for its export include only color, size and the absence of deformations seen by producers at the time of harvest. The objective of this study was to evaluate the physical and chemical characteristics of nopal for export and to contrast them with those of nopal for national consumption. The hypothesis was that the subjective selection of the two types of nopal by producers is related to physical characteristics and indirectly, to composition. The experimental design was completely random with factorial arrangement, with two factors and two levels (factor 1: destination, nopal for national consumption and for export; factor 2: groups of producers, Grupo PRONACUA and Grupo Agrícola Ixquitlán), and 50 repetitions (each one represented by one nopal). The study was performed in Otumba and San Martín de las Pirámides, Estado de México, México. The results were analyzed with ANOVA and Tukey's multiple means comparison. The characteristics of the nopal samples evaluated were: weight, length, width, thickness, firmness and number of leaves, and content of moisture, mucilage, malic acid, chlorophyll and carotenoids. The presence of pesticides was also determined. Export nopales had significantly lower (p≤0.05) weight (38 g), length (2.2 cm), width (1 cm), apical thickness (0.8 cm), basal thickness (0.8 cm), moisture (0.3 %) and titratable acidity expressed as the malic acid content (0.2 %), and content of chlorophyll (0.46 mg 100 g^-1) and carotenoids (0.1 mmol g^-1) higher than those selected for national consumption; and both groups were free from the 20 most common pesticides used in vegetables. The physical characteristics and chemical composition of nopales for export are different than those destined for national consumption, and they could be used to complement the quality norms to help producers secure and increase the international market.

Palavras-chave : Acidity; quality; cladode; chlorophyll; mucilage; chemical residues.