Nutritional and Health Value of Tropical Fruits During Vacuum Frying

Tropical fruit has been widely recognized for their sensorial quality and  their health benefits, being an important source of carbohydrates, vitamins, minerals, fibers and a large number of bioactive compounds. Indonesia is a large producer of tropical fruits such as pineapple, mango, avocado and papaya. Due to a limited shelf life, fresh fruit needs to be processed to prolong the shelf life and maintain its value. Vacuum frying is an emerging technology of innovative processing for fruit and vegetable products. Vacuum frying is a deep-fat frying process, which is carried out in a closed system, below the atmospheric pressure, substantially reducing the boiling point of water and, hence, the frying temperature. Vacuum frying may process fresh fruit into chips that have low moisture and fat content, while preserving certain health benefits.

During vacuum frying, important process variables are temperature, vacuum level, and time as well as specific pre-treatments of the fruit. The frying process causes structural changes to take place; pores produced during gas vapour expansion in frying has been observed in sweet potato, banana, potato, carrot and apple (1-4). Moreover, maturity of the fruit plays a role in structural, compositional and physiological properties, and as a consequence ripening affects physical and textural changes. Starch that is converted into sucrose and maltose during banana ripening affect the product expansion and diameter shrinkage. However, little is known about the effect of vacuum frying on bioactive compounds. Also, the effect of fresh fruit composition and structural properties in relation to the vacuum fried fruit chips has been limited studied.

Many Asian countries (e.g. Indonesia, Japan, Thailand) are using the vacuum frying technology to produce high nutritious snacks with a low fat content. And vacuum fried fruit can be added as ingredient in many different forms to the ready-to-eat breakfast cereals.

Aim
Investigate the effect of ripening stage and structural properties (matrix) of selected tropical fruits on the quality (sensorial, nutritional and health) of vacuum fried fruits products.

Approach
Systematic literature review of vacuum frying: emphasis on color, texture and nutritional / phytochemical properties and role of maturity stages and fruit matrix.
The role of ripening stage, and fruit matrix on the color, texture and nutritional / phytochemical properties and sensory properties of vacuum fried product.
Quality of vacuum fired fruits during accelerated storage and/or packaging (water activity and rancidity of the products).
Consumer research on the perception and preference of vacuum fried tropical fruits as chips or ingredients of cereals.
Consumer-based optimized product and process design for vacuum frying.

References
1.         Yamsaengsung R, Ariyapuchai T, Prasertsit K. Effects of vacuum frying on structural changes of bananas. J Food Eng.
2011;106(4):298-305.
2.         Esan TA, Sobukola OP, Sanni LO, Bakare HA, Munoz L. Process optimization by response surface methodology and quality
attributes of vacuum fried yellow fleshed sweetpotato (Ipomoea batatas L.) chips. Food Bioprod Process. 2015;95:27-37.
3.         Yagua CV, Moreira RG. Physical and thermal properties of potato chips during vacuum frying. J Food Eng. 2011;104(2):272-83.
4.         Dueik V, Moreno MC, Bouchon P. Microstructural approach to understand oil absorption during vacuum and atmospheric frying.
J Food Eng. 2012;111(3):528-36.
5.         Nunes, Y. and R. G. Moreira. Effect of Osmotic Dehydration and Vacuum-Frying Parameters to Produce High-Quality Mango
Chips. Journal of Food Science. 2009; 74(7): E355-E362.