Fruit and vegetable residues typically discarded in the manufacture of isotonic sports drinks could be a rich nutrient source for other foodstuffs like bars and biscuits, Brazilian researchers have found.
Orange, passion fruit, watermelon, lettuce, courgette, carrot, spinach, mint, taro, cucumber and rocket salad residues typically wasted in the drink’s production, were put to use in bars and biscuits with favourable nutrient retention results over a 90 day shelf life except for sweet biscuits which developed mould after 30 days.
100 participants said they “slightly liked” the products – an average response of 6 out of 10.
The fruit and vegetable residues were formed into a flour which was then used in the bars and biscuits.
“The designed products presented high fibre content, reasonable consumer acceptance and were microbiologically stable,” concluded the researchers from the Department of Food Technology, Nutrition School, Food and Nutrition Master Program at the Federal University of Rio de Janeiro.
“This research promotes the reducing food waste since whole plant tissues have been used leading to the maximum exploitation of food raw materials.”
Methods and results
The flour extracted from the fruit and vegetable waste (FVR) showed a higher water holding capacity – respectively 7.43 and 1.91 g g−1 of flour. The researchers speculated this was down to its high levels of carbohydrates (53 %) and fibres (21.5 %).
Biscuits enriched with 35 % of FVR flour contained 57% to 118% higher fibre. When only 20% was added they still showed a 25% to 37% improvement.
Cereal bars presented about 75 % of fibres and variable mineral contents between 14 % and 37 %.
The addition of FVR did not change the fat content.
The researchers concluded, “…that the high fibre, protein and mineral contents and also the water holding capacity (WHC) and oil holding capacity (OHC) of the FVR flour are potentially suitable for use in food applications as a new low-calorie and functional raw material.”
Journal of Food Science Technology
Published online June 20, 2013 DOI 10.1007/s13197-013-1061-4
‘Formulation and characterization of functional foods based on fruit and vegetable residue flour’
Authors : Mariana S. L. Ferreira et al