Papaya enzymes are often able to produce an enzyme called papain. In general, the enzyme itself is in the sap or fruit that is still young. The sap of papaya (papain) is quite a lot containing a variety of enzymes that are proteolotik (decomposition of proteins). The enzyme will catalyze a peptide bond or protein compounds such as amino acids simpler. At this time of chitin and chitosan are widely used in the manufacturing production process, namely as a purifier material on fruit juice products.

This study aims to: 1) study the influence of papain enzyme extracted from papaya latex on the deproteinization process, 2) the effect of enzyme papain from papaya latex in the extraction of chitin in the manufacture of chitin-chitosan and 3) the effect of addition of chitosan as a purifier material on soursop juice. This research was conducted at the Laboratory of Agricultural Technology Faculty of Agriculture University of Malang in April 2009 to complete.

The method used in this study was completely randomized design (CRD) consisting of 2 stages. Phase I, the addition of enzyme papain treatment with 4 levels (Po: (no papain enzyme), P1: 1% enzyme papain, P2: enzyme papain 3% and P3: enzyme papain 5%) and stage II treatment of the addition of chitosan on soursop juice with 3 levels (K0: without chitosan, K1: K2 control and chitosan: chitosan papain 5%), each performed 3 replication. Phase I combination treatment produced the best of 5% chitosan treatment produces papain yield 9.22%, 10.48% moisture content, protein content 0.67%; ash content of 1.19% chitosan. For the use of chitosan as an ingredient in fruit juice soursop purification showed that the addition of chitosan can be used as a purifier material, characterized by a pH test, TPT, Lightness (color intensity), which showed significantly different results with fruit juices that are not experiencing the addition of chitosan.