Abstract: To address the problem that bule honeysuckle (Lonicera caerulea L.) has poor flavor despite its high nutritional value, this study selected three cold-hardy berries in urgent need of high-value processing: bog bilberry (Vaccinium uliginosum L.), raspberry (Rubus idaeus L.), and blackcurrant (Ribes nigrum L.) to prepare vacuum freeze-dried pulp blends (LD, LS and LH) with bule honeysuckle (L. caerulea L.) at a 1:1 ratio. Liquid chromatography and ion chromatography were used to determine the key taste components of the freeze-dried products, gas chromatography-mass spectrometry (GC-MS) was used to analyze the difference in aroma substances among the different products, and the color and texture characteristics were analyzed. Sensory evaluation was used to screen for the product with the best flavor. Correlation analysis was used to clarify the effects of combination with other berries on the taste, odor and their interaction in freeze-dried bule honeysuckle pulp. The results showed that in terms of taste substances, the three combinations decreased the contents of sorbitol and glucose in freeze-dried honeysuckle blueberry pulp, but enriched the types of organic acids. In terms of aroma substances, the addition of bog bilberry, raspberry or blackcurrant enhanced the refreshing, bitter apricot kernel-like, roasted and fatty aromas of freeze-dried honeysuckle blueberry pulp and weakened the rose-like aroma caused by phenylacetaldehyde. In terms of quality characteristics, the L*, a* and b* values of freeze-dried honeysuckle blueberry pulp were significantly increased after blending with the other berries, and the hardness was also significantly enhanced. The sensory scores for odor preference of the freeze-dried pulp blends decreased in order of LS > LD > LH, while he sensory scores for taste preference decreased in order of LS > LH > LD. The correlation analysis results showed that there was an interaction between the odor and taste, and the color and texture had potential effects on the flavor quality of freeze-dried berries. This study provides a theoretical basis for the development of vacuum freeze-dried products of cold-hardy berries represented by blue honeysuckle.

Key words: berries; blending; volatile flavor; vacuum freeze drying; sensory evaluation