Vacuum modification of wheat bread with encapsulated rosehip extract: Evaluation of physicochemical and microstructural properties

Abstract

In this study, effect of vacuum modification (VM) on wheat bread containing rosehip extract (RE) and encapsulated rosehip extract (EnRE) was investigated in terms of the color parameters, textural properties, total phenolic content and antioxidant activity of breads. Analyzing starch crystalline structure and microstructure of breads were performed by X-ray diffraction and scanning electron microscopy. Rosehip extract was encapsulated using sodium alginate by ionic gelation method. Baking was conducted by conventional baking (CB, 220°C-17 min) and VM (220°C-12 min at atmospheric pressure and modification until −90 kPa vacuum pressure by 60 s time intervals at −30, −50, −70, and −90 kPa). PCA results showed that textural properties were the main distinctive feature with even harder texture of EnRE breads. VM led to have lower hardness for EnRE breads with the average hardness value of 781.51 ± 119.62 g than that of 1232.2 ± 83.83 g for conventional counterparts. Total phenolic content and antioxidant activity of EnRE breads were the highest after CB and VM. EnRE breads had more crystalline structure and less gluten aggregation after CB and VM processes. Results showed that vacuum modification is prominent technique to obtain softer texture of capsule containing breads with a high bioactivity.