Two-stage freezing of part baked breads: Application and optimization

Extending shelf life and optimizing effective parameters by using clove oil (Syzygium aromaticum oleum)/orange oil (Citrus aurantium var dulcis oleum) in bread: thermal, morphological and sensory approach

The aim of the present study was to extend the shelf life of bread by using organic additives and optimization techniques. Quadruple effects of temperature (-18, + 4, + 20 °C), clove oil (0, 1, 2%), orange oil (0, 1, 2%), residence time (7, 14, 21 days) were investigated to determine optimum bread as moisture response. Quadratic model was found to be suitable with an accuracy of 0.9854 for moisture response. Rheological properties remained intact for 7 days at 20 °C in bread with 1% clove oil and 1% orange oil added. The effect of 4 effective parameters from 3 levels was examined with Box-Behnken in Design Expert. Optimum and control samples at two different temperatures were determined with SEM, TG-DTA and polarized light microscope. Consumer survey was conducted as appearance, colour, smell for optimum, control samples for bread and cake. It was concluded that bread samples could be stored with clove and orange oil at + 20 °C with period of 7 days without losing their quality properties.

Graphical abstract

Glycemic index and phenolics of partially-baked frozen bread with sourdough

Different lactic acid bacteria starters were used to prepare sourdough to make partially-baked frozen wholemeal wheat bread. The sourdough was prepared with a pure culture of Lactobacillus plantarum or with commercial starters containing Lactobacillus brevis combined with Saccharomyces cerevisiae var. chevalieri (LV4), Lactobacillus fermentum (PL1), or Lactobacillus fermentum with phytase (PL3). We determined the acetic and lactic acid concentrations in sourdough, bread chemical composition, total phenolics content and glycemic index (GI) in vivo. Depending on the starter, the lactic to acetic acid ratio in the sourdough was significantly different. The GI of control bread without sourdough (70) was significantly higher than that of bread containing sourdough prepared with LV4 starter (50), PL1 starter (56) or PL3 starter (56), but not from bread with L. plantarum sourdough (60). The addition of 10% sourdough with a lower molar ratio of lactic to acetic acid ( ≤ 4) and higher total phenolics content is preferable for generating bread with medium and low GI.