Physicochemical analysis and detection of molds in cultivated ecotypes of purple corn (Zea mays L.)

Abstract

Purple corn native to the Andes of South America is a starchy variety that has sustained demand and consumption due to the bioactive principles it contains. The objective was to determine the physicochemical characteristics and molds in purple corn varieties. Samples M1 and M2 were collected in the Huánuco-Peru region. The morphological characteristics of the corn were evaluated; color (CIE L*, a* and b*); physicochemical analysis (water activity, humidity, ash, fat, fiber, protein and carbohydrates); and anthocyanins with the differential pH method (cyanidin-3-glucoside); molds were also counted by colony forming units (CFUs), isolation and identification. The evaluations determined that the humidity of M1 was greater than M2, therefore, the dry matter content was inversely proportional. The highest water activity (0.71) was from M1. Anthocyanins reached 17.92 (mg of cyanidin-3-glucoside g^-1 of sample) in the crown of M1. The presence of molds was evident, however, a greater number of colonies was reported in M1 (1.43 x 10⁷ UFC g^-1), the same number that is related to the isolated genus, such as Aspergillus, Cladosporium, Fusarium, Penicillium and Rhizopus. The samples evaluated are an important source of nutrients and the contribution of antioxidant substances such as anthocyanins stands out, with the content being higher at the crown level. The presence of molds is influenced by humidity and inadequate storage considering that among the isolated genera it could be associated with the formation of mycotoxins. Corn grains are susceptible to molds and their secondary metabolites, representing a problem for food safety.