Potential of vacuum impregnation and osmotic dehydration techniques in producing jaggery-fortified apple snacks

Abstract

Fruits are nutrient-rich, highly perishable goods which contribute to postharvest losses and waste. The food industry continues the search for processing methods that allow for the manufacturing of attractive and convenient fortified fruits while extending their shelf life. To meet the present consumer demands for more nutritious and sustainable food products, innovative or revisited food processing techniques need to be explored. In the present work, jaggery is proposed as a non-conventional osmotic agent to produce fortified apple snacks through the combination of vacuum impregnation (VI) and osmotic dehydration (OD) techniques and further stabilization via convective hot air-drying (HAD) or freeze drying (FD). Physicochemical and antioxidant attributes of intermediate and final products were analyzed to evaluate the potential of these techniques to introduce jaggery bioactive constituents in the apple matrix. The results confirmed that the antioxidant properties of jaggery may be incorporated into the tissue by both VI and OD, especially with progressive OD (pOD) in solutions from 30 to 50 Brix degrees. Stabilization through HAD at 60 °C significantly enhanced the antioxidant properties of jaggery-enriched snacks (total phenols: 11.0 ± 0.6 (pOD HAD) and 8.0 ± 0.6 (VI HAD) vs. 6.3 ± 0.12 (HAD) mg GAE per g dry product), whereas FD maintained natural and incorporated antioxidants (total phenols: 10.8 ± 0.4 (pOD FD) and 6.2 ± 0.9 (VI FD) vs. 6.5 ± 0.2 (FD) mg GAE per g dry product). Optical and textural properties were affected by the addition of jaggery and processing techniques. Replacing intercellular air with liquid reduced luminosity, which increased after dehydration, especially through FD. In conclusion, jaggery or non-centrifugal cane sugar is proposed as a healthier osmotic agent to produce more nutritious and sustainable apple snacks by applying matrix engineering techniques such as vacuum impregnation and osmotic dehydration, followed by hot air-drying or freeze-drying stabilization.