Custom Search Index Content Always Returns Lower Case Content

Hello, Don't know why this Custom Search Index Content Always Returning Lower Case Content On Search Result. Is there anyone who can help me solve the issue and let me know why this is happening

Below is the CustomIndex Class

public class KidsHealthArticlesIndex : ICustomSearchIndex
{
    public void Rebuild(SearchIndexInfo srchInfo)
    {
        if (srchInfo != null)
        {
            // Gets an index writer object for the current index
            IIndexWriter iw = srchInfo.Provider.GetWriter(true);

            if (iw != null)
            {
                try
                {
                   SearchIndexSettingsInfo sisi = srchInfo.IndexSettings.Items[SearchHelper.CUSTOM_INDEX_DATA];
                    srchInfo.IndexDisplayName = srchInfo.IndexDisplayName.ToUpper();

                    // Gets the search path from the Index data field
                    string language = Convert.ToString(sisi.GetValue("CustomData"));
                    DataSet dsArticles = new DataQuery("NCH.KidsHealthTransformations.GetCategoryArticles").Distinct(true).Columns("ArticleTitle As Title", "ArticleBodyPageHtml As PageHtml", "ArticleAliasName As AliasName", "SectionDisplayName", "SectionAliasName", "IsArticlePage", "Language").WhereEquals("IsArticlePage", true).And().WhereEquals("Language", language).Result;
                    DataSet dsCategories = new DataQuery("NCH.KidsHealthTransformations.GetCategoryArticles").Distinct(true).Columns("CategoryDisplayName As Title", "CategoryBodyPageHtml As PageHtml", "CategoryAliasName As AliasName", "SectionDisplayName", "SectionAliasName", "IsArticlePage", "Language").WhereEquals("IsArticlePage", false).And().WhereEquals("Language", language).Result;
                    DataTable categoryArticlePages = new DataTable();
                    if (!DataHelper.DataSourceIsEmpty(dsArticles))
                    {
                        categoryArticlePages = dsArticles.Tables[0];
                        if (!DataHelper.DataSourceIsEmpty(dsCategories))
                        {
                            var dt1 = dsArticles.Tables[0];
                            var dt2 = dsCategories.Tables[0];
                            categoryArticlePages = dt1.AsEnumerable().Union(dt2.AsEnumerable()).OrderBy(d => d.Field<string>("Title")).CopyToDataTable();
                        }
                    }
                    if (categoryArticlePages.Rows.Count > 0)
                    {
                        foreach (DataRow row in categoryArticlePages.Rows)
                        {

                            // Creates a new Lucene.Net search document for the current text file
                            SearchDocumentParameters documentParameters = new SearchDocumentParameters()
                            {
                                Index = srchInfo,
                                Type = SearchHelper.CUSTOM_SEARCH_INDEX,
                                Id = Guid.NewGuid().ToString(),
                                Created = DateTime.Now
                            };
                            ISearchDocument doc = SearchHelper.CreateDocument(documentParameters);

                            // Adds a content field. This field is processed when the search looks for matching results.

                            doc.AddGeneralField(SearchFieldsConstants.CONTENT, Convert.ToString(row["Title"]), false, false); // SearchHelper.StoreContentField, true);

                            // Adds a title field. The value of this field is used for the search result title.
                            doc.AddGeneralField(SearchFieldsConstants.CUSTOM_TITLE, Convert.ToString(row["Title"]), false, false);

                            // Adds a content field. The value of this field is used for the search result excerpt.
                            doc.AddGeneralField(SearchFieldsConstants.CUSTOM_CONTENT, HTMLHelper.StripTags(Convert.ToString(row["PageHtml"])), false, false);

                            // Adds a date field. The value of this field is used for the date in the search results.
                            doc.AddGeneralField(SearchFieldsConstants.CUSTOM_DATE, DateTime.Now, true, false);

                            // Adds a url field. The value of this field is used for link urls in the search results.
                            doc.AddGeneralField(SearchFieldsConstants.CUSTOM_URL, "/health-information-library/" + Convert.ToString(row["Language"]) + "/" + Convert.ToString(row["SectionAliasName"]) + "/" + (Convert.ToBoolean(row["IsArticlePage"]) == true ? "article" : "category") + "/" + Convert.ToString(row["AliasName"]), true, false);

                            // Adds a title field. The value of this field is used for the search result title.
                            doc.AddGeneralField("ClassName", "KidsHealth", true, false);

                            // Adds an image field. The value of this field is used for the images in the search results.
                            // Commented out, since the image file does not exist by default
                            // doc.AddGeneralField(SearchFieldsConstants.CUSTOM_IMAGEURL, "textfile.jpg", true, false);

                            // Adds the document to the index
                            iw.AddDocument(doc);
                        }

                        // Flushes the index buffer
                        iw.Flush();

                        // Optimizes the index
                        iw.Optimize();
                    }
                }
                // Logs any potential exceptions
                catch (Exception ex)
                {
                    EventLogProvider.LogException("KidsHealthArticlesIndex", "Rebuild", ex);

                }
                // Always close the index writer
                finally
                {
                    iw.Close();
                }
            }
        }
    }
}