Abstract:The goals of this study were to increase the added value of algae and overcome the technical bottleneck of algae processing of high-quality food，with the aims of promoting the development of kelp and apple freeze-dried snack foods and improving their taste.The influences of different kelp pulp∶apple pulp mass ratio，quantity of added oligo fructose，re-dry time and re-dry temperature on the brittleness value of the product were determined via single factor analysis.The formulation was optimized via response surface methodology.Finally，the physical，chemical and microbiological indicators of the finished product were determined.The four groups in the single factor experiments significantly affected the crispness value of the kelp apple freeze-dried snack food （P＜0.05）.The optimal process formulation obtained via the Box-Behnken response surface methodology was kelp pulp∶apple pulp mass ratio 2.1∶1，0.23% oligo fructose，re-dry temperature of 58.6 ℃ and re-dry time of 5.2 h.The crispness value of the freeze-dried kelp apple using the optimal process formulation was 182.98±5.10，which was close to the predicted value of 192.81.The moisture content of the product prepared under optimal processing conditions was（4.26±0.25）%，the under-sieve content was（0.40±0.03）%，the total polysaccharide content of kelp was（12.95±0.29）%，the brown algae polyphenol content was（0.91±0.02）%，and the fucoxanthin content was（0.093±0.015）%.The total colony count was（886.0±20.8）CFU.No pathogenic bacteria were detected.The product complied with the relevant national health standards.