Características físico-químicas de farinhas armazenadas com e sem infestações do Tribolium castaneum.

Abstract

Aiming at the quality of stored flours that are susceptible to the attack of the Tribolium castaneum, this work aimed to identify three of six flours more attractive to the red willow, to be stored with and without infestation of T. castaneum for five months, and their physical characteristics - chemistry evaluated by traditional method, besides determining the population growth rate of the insects. Initially, the food preference of T. castaneum was evaluated using the type X olfactometer test, when 20 male and female adults (10 ± 2 days old) were exposed in the center of the arena exposed to rice, peanut, corn, soybean, sesame, whole wheat and, as a control, artificial diet. Readings five were performed at 5, 10, 30, 60 and 90 minutes with four replicates and the data submitted to the non-parametric Qui Square test (X2) (P ≤ 0.05%) and the average attraction ratio of the flours to the insects were calculated from the equation adapted from Obeng-Ofori. The flours that obtained the highest percentage attractive in the test olfactometer to the carunchos, were stored for five months and submitted or not to infestation of the weevil. Every 30 days, the instantaneous rate of insect population growth (ri) was evaluated by counting the number of living individuals at each time. To determine the ri, the Walthall & Stark (1997) equation was used and the Qui Square (X2) hypothesis test was performed at P ≤ 0.05%. The flours were exposed, with and without infestation and stored for 0, 30, 60, 90, 120 and 150 days, when the granulometry, colorimetric characterization, water activity, water content, ashes, pH, total protein, total lipids, titratable total acidity, total fiber, total carbohydrates and triplicate caloric value. The statistical design employed was the completely randomized with factorial arrangement 4 x 2 x 6, represented by four flours, two procedures and six times. The data were submitted to analysis of variance and the means were compared by the Tukey test (P ≤ 0.05). For particle size analysis, the percentage retained in each mesh was determined and found the uniformity index (UI). The results allowed to conclude that: rice, corn and peanut flours provided greater attractiveness to T. castaneum in olfatometric sand environment; the insects present in the stored peanut flour tended to extinction, from 120 days of storage, however the artificial diet followed by corn flour provided the best instantaneous rate of insect population growth over the five months; the presence of insect infestation as well as the storage time affected the centesimal composition of the flours; heterogeneity occurred in the distribution of the flour particles in the two procedures.