Abstract
In this study, flaxseed was used as a functional ingredient in yogurt formulations. The goal of this study was to produce prebiotic yogurt supplemented with flaxseed and investigation of its texture and sensory properties. Yogurt samples containing 0%-4% flaxseed was produced and stored at refrigerator (4-5°C) for 28 days. Textural properties were determined by texture analysis, and sensory characteristics were assessed by 26 trained panelists. Addition of flaxseed to yogurt samples increased the hardness, gumminess, chewiness, cohesiveness, and springiness values in produced yogurt samples. However, adhesiveness level was reduced in a sample enriched with flaxseed. By increasing flaxseed concentration, the color of samples was significantly different than the control sample; L* value was diminished and a* and b* value increased. Sensory scores including taste and mouthfeel, appearance, and overall acceptance showed reduction trend in samples containing a high level of flaxseed. In general, results showed that the addition of 2.63% flaxseed into yogurt samples lead to produce functional food with satisfactory texture, sensory characteristics that sustained these properties until 17.17 days after cold storage.
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Key Points
Textural and sensory properties are two important factors for assessment of Yogurt quality. Adding flaxseed into Yogurt samples can affect color, texture, and sensory properties of the final product. Hardness, adhesiveness, cohesiveness, gumminess, chewiness, and springiness properties are the most important parameters for the textural assessment of yogurt and other fermented milk products. This study assessed optimum flaxseed concentration that could be added into the yogurt samples to manufacture a product with excellent texture, sensory, and color attributes that sustained these properties during certain storage time. Response surface method has been used for survey of the rheology, color indexes, and sensory properties of flaxseed‐enriched yogurt samples. Analysis of rheology characteristics is considered as a useful procedure for assessing the hardness, adhesiveness, cohesiveness, chewiness, gumminess, and springiness in kinds of yogurt. The results showed that the variables of the flaxseed concentration and storage time in flaxseed‐enriched yogurt samples resulted in the significant increment of all mentioned rheological parameters, except of adhesiveness. Whereas sensory properties were decreased in this product compared to control yogurt sample. In addition, L* value as color index diminished in samples containing flaxseed, although, a* and b* values in this product were greater than control yogurt sample. Generally, addition of 2.63% flaxseed into yogurt samples could produce functional food with satisfactory texture and sensory characteristics that sustained these properties until 17.17 days after cold storage. Flaxseed‐enriched yogurt samples with suitable quality in industrial scale can be achieved by use of optimization amounts obtained by RSM in this study.