The in vitro gas production technique was used to evaluate the fermentation kinetics of 125 whole citrus fruits samples (WCF). Six models were tested to describe the fermentation characteristics of this product characterized by high sugar and pectin and low protein content: 487, 195 and 64.7 g/kg dry matter, respectively. The models were: exponential with and without lag (EXP₀ and EXP_L, respectively); generalized Mitscherlich (GEXP_L); and one, dual and three pool logistic models (OLOG_L, DLOG_L and TLOG_L, respectively). EXP₀ had the highest residual standard deviation (RSD=9.0 ml), the lowest being for the TLOG_L (5.93 ml). TLOG_L model obtained the best values fitting individual curves with a mean prediction error of 0.25 ml. Significant correlations were observed between the three different fractions of the TLOG_L model and the chemical composition: quickly fermentable fraction with sugars (+0.43; P<0.001), high fermentable fraction with pectins (+0.23; P<0.05) and slow fermentable fraction with fibres (+0.38 and +0.34 for NDF and ADF, respectively; P<0.01), which could indicate the presence of three main fractions in WCF with different fermentation rates.