The ng-model attribute sets the selected option and also allows you to pipe a filter like orderBy:orderModel.value
index.html
<select ng-model="orderModel" ng-options="option.name for option in orderOptions"></select>
controllers.js
$scope.orderOptions = [
{"name":"Newest","value":"age"},
{"name":"Alphabetical","value":"name"}
];
$scope.orderModel = $scope.orderOptions[0];