Improvements in the Preparation of Sultanas for Marketing

Sultana raisins are an important product of Australia. This industry suffers from two major problems that hinder marketing. One problem is contaminants that are packed with the sultanas. Ways to improve contaminant removal were investigated. The two methods, screening out most of the stones and screening out the long stalks have already been applied in several packing sheds and improvements in contaminant removal are expected for the 1992 season. The second problem is sultana stickiness that creates handling problems, mainly in the food industry. The first step was to define and quantify the stickiness. A Friability Index was developed for that purpose, measuring disintegration with a standard sieve shaker. Its use to evaluate the factors influencing stickiness of transport, box filling method and duration of storage is described.