Output the word in a string with the largest amount of vowels

I mostly have the method done but I am confused when it comes to the If statement concerned with storing a variable with the word with the most amount of vowels, NOTE I am not allowed to use arrays. below is my code

//method for vowels and consonants

public static int Vowelcount(String sentence) {

    int maxvowelcount =0;
    int minvowelcount =0;
    String vowel="";
    int consonantcount = 0;
    int vowelcount = 0;
    int index = 0;
    String currentword;
    int spacePos;
    int noOfchars = 0;
    int largest = 0 ;
    int smallest = 0 ;

    //gets rid of leading and trailing spaces so as to get the last word
    sentence=sentence.trim() + " ";




    //assignments
    spacePos=sentence.indexOf(" ");
    currentword = sentence.substring(0, spacePos);

        while (spacePos >-1)// when no spaces are found
{
    noOfchars=0;
    currentword = sentence.substring(0, spacePos);

    // remove the first word
    sentence = sentence.substring(spacePos+1);

    spacePos=sentence.indexOf(" ");



// to count the number of vowels in the string 
for(index = 0; index<currentword.length(); index++)
{
if(currentword.charAt(index)=='a' || currentword.charAt(index)=='e' || currentword.charAt(index)=='i' || currentword.charAt(index)=='o' ||
 currentword.charAt(index)=='A' || currentword.charAt(index) == 'E' || currentword.charAt(index) == 'I' || currentword.charAt(index) == 'O' )
 {

            vowelcount++;
 }      

 else
 {
            consonantcount++;
 }






        //if statement to overwrite currentword with largest/smallest


        if (index == 0)
        {
            minvowelcount = currentword.length();
            maxvowelcount = currentword.length();
        }

        if (vowelcount < minvowelcount)
        {
            minvowelcount = vowelcount;
        }


        if (vowelcount > maxvowelcount)
        {
            maxvowelcount = vowelcount;
            vowel=currentword;
        }   
    }   
}   






        //output to show the word with largest amount of vowels
        System.out.println( "word with largest amount of vowels is " + maxvowelcount);
        return vowelcount;  

}