Effect of Coating and Impregnation on the Quality and Probiotic Viability of Freeze-Dried Apple Snacks

Fruits are promising carriers for probiotic delivery; however, maintaining probiotic viability and product quality during processing and storage remains a major challenge. Apple, owing to its nutritional value and consumer acceptability, offers potential for development as a functional snack. The present study aimed to develop freeze-dried probiotic apple snacks using impregnation and coating techniques and to evaluate their quality attributes and probiotic stability.

Apple slices were prepared as control, probiotic-impregnated and probiotic-coated samples using Bacillus coagulans, followed by freeze drying. The developed snacks were evaluated for physical characteristics, proximate composition, mineral content, physico-chemical properties, sensory attributes and probiotic viability during storage at room temperature for 180 days. All analyses were performed in triplicate.

Probiotic incorporation did not alter the physical characteristics of apple snacks. Impregnated and coated samples showed slight improvements in protein, fiber, ash and mineral content, with coated samples exhibiting higher calcium, potassium and iron levels. Physico-chemical parameters remained within acceptable limits, with good retention of ascorbic acid. Sensory evaluation indicated good overall acceptability, with coated samples receiving higher scores. Probiotic viability decreased gradually during storage however, coated samples retained higher counts, remaining above the recommended minimum level throughout 180 days.