I used cellcolor to change the color of a cell in the table. But, for some strange reason, it doesnot color it completely. Why would that happen? Below is MWE:
\documentclass[twoside,b5paper,9.5pt,openright]{book}
\usepackage[total={13cm,19.5cm}]{geometry}
\usepackage[english]{babel}
\usepackage{amsmath}
\usepackage{tocloft}
\usepackage{fixltx2e}
\usepackage{graphicx} % include graphs/ figures in the file
\usepackage{setspace} % to set the line spacing in the document
\usepackage{ragged2e}
\usepackage{lscape} % to write pages in landscape environment
\usepackage{array,threeparttable} % to add footnotes to the tables
\usepackage{booktabs}
\usepackage{caption} % to create some space between table caption and table, otherwise there was no space
\captionsetup[figure]{font=small,skip=0pt}
\captionsetup[table]{font=small,skip=0pt}
\usepackage[normalem]{ulem} % to underline the text
\setcounter{secnumdepth}{3}
\usepackage{multirow}
\usepackage[labelfont=bf]{caption}
\let\newfloat\relax
\usepackage{floatrow}
\usepackage{array,threeparttable,siunitx}
\floatsetup[table]{capposition=top}
\floatsetup[figure]{capposition=bottom}
\usepackage{etoolbox}
\usepackage{subfig}
\usepackage[table]{xcolor}
\usepackage{grffile} % to avoid printing the figure name (or otherwise, give figure names without spaces)
\usepackage{float} % figures as 6 (a), 6 (b) etc.
\usepackage{tabu}
\usepackage{tikz}
\usepackage{arydshln}
\raggedbottom
%\allsectionsfont{\sf
\begin{document}
\begin{table}[h!]
\scriptsize
\centering
\caption{Free (mg/100g ter) and aride compos (gy maer) in pokuls}
\begin{tabular}{p{3cm}p{1.75cm}p{1.75cm}p{1.75cm}p{1.75cm}}
\toprule
\textbf{\cellcolor{blue!25}Frtion (matter)} & \multicolumn{1}{c}{\cellcolor{blue!25}\textbf{M\textsubscript{0}}} & \multicolumn{1}{c}{\cellcolor{blue!25}\textbf{M\textsubscript{15}}} & \multicolumn{1}{c}{\cellcolor{blue!25}\textbf{M\textsubscript{60}}} & \multicolumn{1}{c}{\cellcolor{blue!25}\textbf{M\textsubscript{120}}}\tabularnewline
\midrule
\textit{Esseo acids} & & & & \tabularnewline \addlinespace
Valine & \multicolumn{1}{c}{75} & \multicolumn{1}{c}{40} & \multicolumn{1}{c}{26} & \multicolumn{1}{c}{10} \tabularnewline \addlinespace
\textit{\textbf{Total }} & \multicolumn{1}{c}{\textbf{11.84}} & \multicolumn{1}{c}{\textbf{10.24}} & \multicolumn{1}{c}{\textbf{9.2}} & \multicolumn{1}{c}{\textbf{10.18}} \tabularnewline
\bottomrule
\end{tabular}%
\end{table}%
\end{document}