Enhancing labneh with freeze-dried fruits or fruit flavours: Effects on physicochemical, microbiological, and sensory properties

The present study aimed to formulate novel labneh variants containing freeze-dried fruit pieces or fruit flavour and to evaluate their influence on physicochemical properties, microbiological quality, and sensory acceptance during storage. For this purpose, fruit-piece labneh was prepared by incorporating 6% freeze-dried strawberry, blackberry, or kiwi pieces, while fruit-flavoured labneh was formulated by adding 0.01% colouring and 0.1% fruit flavour derived from strawberry, blackberry, or kiwi juice. The labneh variants developed in this study were subjected to additional post-fermentation pasteurisation followed by hot filling. Samples were analysed on days 1, 7, 15, and 30 of storage for selected physicochemical, microbiological and sensory parameters. Compared with plain labneh, fruit-piece samples showed increased dry matter content, except for those containing kiwi. Conversely, water activity and fat content decreased, and variations in titratable acidity and pH were influenced by the type of fruit added. Microbiological analyses based on classical indicator microorganisms revealed low levels of total aerobic mesophilic bacteria ranging from 1.5 10¹ to 8.1 10¹ CFU·g–¹. The Enterobacteriaceae, Escherichia coli, yeasts and moulds were not detected, indicating good product safety. Notably, structural defects such as syneresis and increased bitterness were determined in kiwi-piece samples during storage. Sensory evaluation indicated that strawberry-flavoured, blackberry-flavoured, and strawberry-piece labneh were the most preferred by panellists. Overall, fruit- or flavour-enriched labneh produced with an additional post-fermentation heat treatment represents an attractive option for product diversification in the dairy industry. Based on their satisfactory safety, good microbiological stability and high sensory acceptance, these variants offer a strong potential for industrial application.