Fruit and vegetable powders

Fruits and vegetables are rich in vitamins, carotenoids, ascorbic acid, minerals and dietary fiber; however, they are climacteric and their shelf-life is very short after harvest. Uncontrolled browning, wilting and loss of nutritional value are typical of fresh fruits and vegetables even at ambient temperature and relative humidity. When converted into powder form they are easy to preserve, transport, store and use as ingredients. The greatly reduced water content and water activity help prolong the shelf-life of fruit and vegetable powders. The loss of important nutrients can also be minimized during the powder production process by judiciously selecting the drying methods and encapsulating shell materials.

 In broad terms, a fruit is a structure of a plant that contains its seeds. ‘Fruit’ normally means the fl eshy part of the seed and closely-associated structure of certain plants that are edible in the raw state, such as apples, oranges, grapes,strawberries, juniper berries and bananas. The word ‘vegetable’ usually means an edible plant or part of a plant other than a fruit or seed. This typically means the leaf, stem, or root of a plant. Apart from providing fl avor and variety to human diet, they serve as important and indispensable sources of vitamins and minerals. Besides, they can be processed into various products. The export of fruits and vegetables plays an important role in the economy for many countries. 

The development of science-based formulation concepts in food manufacturing and the demand for diversity in food products have driven a Fruit and vegetable powders 533 © Woodhead Publishing Limited, 2013 substantial market increase for food ingredients. Most ingredients are supplied in powdered form and therefore the technologies involved in manufacturing these food ingredients have become very important. Two major aspects of fruit and vegetable powders are that they have a biological origin and that they are ultimately consumed by humans. The major reason for producing powders from fruits and vegetables is simply to prolong the shelf-life of the ingredients by reducing water content (and hence water activity) as fruits and vegetables have a very short shelf-life. 

Fruit/vegetable powders and related products

 To meet customers’ expectations of storage and easy-to-use products, also for the reason that the abundance of fruit or vegetable can offer health promoting and nutritional benefi ts as the ingredients, a certain amount of fruit and vegetable powder can be found in supermarket.

Functional powders from fruits and vegetables

 Fruits and vegetables are rich in pectin, polyphenols, lycopene, dietary fi ber, enzyme, fl avonoids, vitamins, oligosaccharide, etc. which can be extracted to produce enriched functional foods or medical supplements. In this section we endeavor to provide the extraction and powder production aspects of the above mentioned functional compounds obtained from fruits and vegetables. 

The low Tg of fruits and vegetable powders makes it diffi cult for their preservation. Hence, storage stability of fruits and vegetable powders is one of the most important research challenges. The following are research topics which are important for future research into fruit and vegetable powders:

• Research in new drying aids and encapsulating shell materials (such as smart materials) for minimizing stickiness during drying and caking during storage (for effi ciently increasing the Tg without affecting the sensory attributes).

• Research in better encapsulating shell materials for better encapsulating and controlled release of the small functional components of fruits and vegetables.

• Research in hybrid or alternative drying technologies that maintain the stability of components (e.g. low temperature drying) while enhancing drying effi ciency.

• Research in ways to enhance stability of the functional powder components.