Acai pulp suffers adulteration by the addition of less expensive materials with the objective to increase yield and consequently the profit margin. Near-infrared spectroscopy has been used in the present work to detect adulteration of freeze-dried acai pulp samples. Adulterants used included cornstarch, beet pulp, grape juice, cassava starch, and maltodextrin. Adulteration was carried out on individual pulp samples at levels of 1, 5, 10, 25 and 50% w/w (wet basis). Spectral data were compressed by principal component analysis and analyzed using K-nearest neighbor (K-NN), Soft independent method of class analogy (SIMCA) and Partial least squares discriminant analysis (PLS-DA). The PCA chart control of Q(residual) and the K-NN models confirmed that it is possible to distinguish authentic from adulterated samples and to predict the type of adulterant present in a sample with 100% of correct classification. This study demonstrates that near-infrared spectroscopy is a rapid screening technique for detection of adulterants in freeze-dried acai pulp. (C) 2018 Elsevier Ltd. All rights reserved.