Analysis of selected functional properties, resource demands, and energy consumption of freeze‐dried vegetable snacks

Abstract

The study aimed to investigate a possibility of using fruits (apple and blackcurrant) pomace as carrier agents in freeze‐dried snacks and analyze selected properties of obtained products in comparison to snacks with addition of pectin as traditional carrier in terms of physical and functional characteristics modification. The addition of fruits pomace powders caused significant porosity and hygroscopicity reduction. The type of carrier also affected color and structure of the freeze‐dried snacks. Moreover, applied additives influenced textural properties inducing products with fruits pomace powders brittle and more fragile in comparison to material with pectin. Reformulation did not affect energy consumption that was determined mostly by freeze drying (90%), but replacement of hydrocolloid with fruit pomace powders may reduce environmental impact of freeze‐dried products. Considering obtained findings and possibilities resulting from application of pomace in new food products, further research is needed, especially in terms of influencing nutritional value and storage properties by such additives. Novelty impact statement The manuscript is focused on the newest approach in food technology related to management of food waste and by‐products as additives modifying properties of freeze‐dried materials. Our study included examination of the impact of fruits pomace powders as carrier agents in freeze‐dried fruit and vegetable snacks in relation to traditional hydrocolloid carrier on selected properties that are important in terms of stability and attractiveness of food products. Second part of the study was assessment of resource demand of manufacturing such products aimed on the possibilities of environmental impact reduction.

Recent Progress and Application of Freeze Dryers for Agricultural Product Drying

“…Developments of freeze-dried snacks have newly been one of the popular topics in food research [45]. Infrared is one of the appropriate candidates for combining with FD for rapid dehydration and energy efficiency [1].…”

The effect of apple pomace powder and calcium ions on selected physicochemical properties of freeze‐dried carrot‐orange‐ginger snacks

“…The WC and a w results were similar to those previously reported for freeze-dried snacks with various pomace powders and hydrocolloids. 8,9,21,[28][29][30] The reduction of these parameters most likely resulted from the water-holding capacity of both fibers inherent in AP powder 49 and LMP. 16 It was established previously that fiber contained in AP can bind and hold over 5 g of water per 1 g of powder.…”

“…Lowering of porosity and compact structure after the addition of AP to freeze-dried snacks have already been established. 8,29,30 The authors also noticed unevenness in products' skeletons and irregular pores' shapes and sizes. They indicated that it had resulted from a low structuring potential of apple pomace or limited accessibility of fibers and pectin contained in powder particles.…”

“…The fact that the texturizing ability of AP is lower than this feature of biopolymers (pectin, sodium alginate) was observed previously. 29,30 On the other hand, Ciurzyńska et al 8 investigated freeze-dried gels obtained by combining sodium alginate with apple pomace powder and established that increasing the pomace content had a greater influence on texture than increasing the content of hydrocolloid. The hardening of the material was also affected by dehydration and phase transition occurred due to freeze drying.…”

“…26,27 There have been a few successful attempts, corresponding with the sustainable development policy, to substitute hydrocolloids with AP powders as structure-forming additives in freeze-dried snacks. [28][29][30] Apple pomace is the main by-product remaining after the industrial processing of apples. Poland is one of the world's leading producers of apples (4 Mtons in 2021) and over half of the harvest is destined for juice production.…”