Innovative fortified kale soup formulation designed for the elderly

Abstract

The nutritional needs of the elderly require immediate attention. Strategies to incorporate healthy, high-fibre, protein-rich ingredients into traditional diets have been identified to enhance health benefits. This study aimed to develop a new food product specifically for older adults, using kale (Brassica oleracea L. var. acephala DC), and to evaluate its nutritional, sensory, and antioxidant properties. Acceptance was assessed among institutionalised elderly individuals in Galicia (Spain) and Northern Portugal. Fresh kale, both blanched and non-blanched, was air-dried at 80 °C for 2 h. The dehydrated kale was then ground into small particles and/or powder. Blanching did not negatively affect the dehydrated samples’ protein, fibre, or carbohydrate content. The sensory analysis showed 0.5 %–0.8 % kale enrichment improved taste and texture, balancing appeal without bitterness or roughness from higher concentrations. Incorporating non-blanched dehydrated kale (at concentrations of 0.5 %, 0.8 %, and 1.0 %), pea protein isolate (0.58 %), and calcium lactate (0.25 %) into a traditional soup base resulted in a product with a higher protein content. A 240 g serving of this soup (dehydrated kale 0.8 %: sliced 0.5, and flour 0.3) provided approximately 10 % of the daily dietary fibre recommendation. The nutrient-dense soup was well received (66 %) by the Portuguese and was accepted (52 %) by Galician elders, offering a viable alternative to commercial nutritional supplements and common chewing hard foods rich in fibre and protein.