PENGARUH PERLAKUAN AWAL (PRE-TREATMENT) TERHADAP KARAKTERISTIK KIMIA DAN FUNGSIONAL TEPUNG UBI JALAR UNGU (The Effect of Pre-treatment on Chemical and Functional Characteristics of Purple Fleshed Sweet Potato Flour) - Daniah, Wiwin; Program Studi Ilmu dan Teknologi Pangan Fakultas Pertanian USU Medan Indonesia (Universitas Sumatera Utara, 2018)