How do I save icon when choosing an item in ion-select, ion-option?

Ionic Framework ionic-v3
1

How do I save the icon related to each selection?
For example, [category=food, icon=restaurant], [category=money icon=cash], etc…

Code example,

    <ion-label>Category</ion-label>

    <ion-select type="text" [(ngModel)]="activity.category" name="category" required>
      <ion-option *ngFor="let activity of activities">{{category}}</ion-option>  
    </ion-select>

It would be helpful if someone can provide link to related documentation. Thanks.