KIWIFRUIT PROCESSING STUDIES

Abstract

The kiwifruit is unique because of its high nutritional content, different flavours, vitamins, minerals, antioxidants, phytochemicals and fibre content. In terms of nutrient content, the kiwifruit is amongst the richest fruits: it is also very valuable in terms of health. It is usually consumed fresh but in recent years along with increased production, industrial use is increasing. It is used in the canned food industry, for marmalades, fruit sauces and candies and for fruit juice concentrates, either separately or mixed with strawberries or apples. The fruit is also canned, dried, frozen, and used for the preparation of nectars. In addition, kiwifruit are used in the cosmetic industry for production of lip balm, aromas, soap, shampoo, shower gel, and other products. However, most kiwifruit are eaten fresh and only a small proportion of the crop is processed. There are several reasons why kiwifruit processing has not developed further. The main problem is the characteristics of the fresh fruit: the instability of these characteristics means that standard processing technologies cannot be used. New processing options that are now being tested by different researchers include low temperature extraction, hot air-vacuum drying, high-pressure processing, UV-treatment, pervaporation, and rapid sterilisation. In particular, different techniques are used to remove polyphenols from kiwifruit juices during processing and storage. The effects of these techniques on the preservation of the health attributes, especially those due to polyphenols, micronutrients, aroma and volatile compounds are being investigated. In this study, different processing studies conducted by different researchers in Turkey and the rest of the world are examined in detail as a guide to further work.